Merge github.com:grpc/grpc into bye-bye-completion-queue-pie

45 files changed, 676 insertions, 532 deletions

diff --git a/src/compiler/cpp_generator.cc b/src/compiler/cpp_generator.cc
index 735e7e58a8..a0c9d3d468 100644
--- a/src/compiler/cpp_generator.cc
+++ b/src/compiler/cpp_generator.cc
@@ -156,50 +156,16 @@ grpc::string GetHeaderIncludes(const grpc::protobuf::FileDescriptor *file,
       "#include <grpc++/impl/internal_stub.h>\n"
       "#include <grpc++/impl/rpc_method.h>\n"
       "#include <grpc++/impl/service_type.h>\n"
+      "#include <grpc++/async_unary_call.h>\n"
       "#include <grpc++/status.h>\n"
+      "#include <grpc++/stream.h>\n"
       "\n"
       "namespace grpc {\n"
       "class CompletionQueue;\n"
       "class ChannelInterface;\n"
       "class RpcService;\n"
-      "class ServerContext;\n";
-  if (HasUnaryCalls(file)) {
-    temp.append(
-        "template <class OutMessage> class ClientAsyncResponseReader;\n");
-    temp.append(
-        "template <class OutMessage> class ServerAsyncResponseWriter;\n");
-  }
-  if (HasClientOnlyStreaming(file)) {
-    temp.append("template <class OutMessage> class ClientWriter;\n");
-    temp.append("template <class InMessage> class ServerReader;\n");
-    temp.append("template <class OutMessage> class ClientAsyncWriter;\n");
-    temp.append(
-        "template <class OutMessage, class InMessage> class "
-        "ServerAsyncReader;\n");
-  }
-  if (HasServerOnlyStreaming(file)) {
-    temp.append("template <class InMessage> class ClientReader;\n");
-    temp.append("template <class OutMessage> class ServerWriter;\n");
-    temp.append("template <class OutMessage> class ClientAsyncReader;\n");
-    temp.append("template <class InMessage> class ServerAsyncWriter;\n");
-  }
-  if (HasBidiStreaming(file)) {
-    temp.append(
-        "template <class OutMessage, class InMessage>\n"
-        "class ClientReaderWriter;\n");
-    temp.append(
-        "template <class OutMessage, class InMessage>\n"
-        "class ServerReaderWriter;\n");
-    temp.append(
-        "template <class OutMessage, class InMessage>\n"
-        "class ClientAsyncReaderWriter;\n");
-    temp.append(
-        "template <class OutMessage, class InMessage>\n"
-        "class ServerAsyncReaderWriter;\n");
-  }
-  temp.append("}  // namespace grpc\n");
-
-  temp.append("\n");
+      "class ServerContext;\n"
+      "}  // namespace grpc\n\n";
 
   if (!file->package().empty()) {
     std::vector<grpc::string> parts =
@@ -216,54 +182,314 @@ grpc::string GetHeaderIncludes(const grpc::protobuf::FileDescriptor *file,
   return temp;
 }
 
+void PrintHeaderClientMethodInterfaces(grpc::protobuf::io::Printer *printer,
+                             const grpc::protobuf::MethodDescriptor *method,
+                             std::map<grpc::string, grpc::string> *vars,
+                             bool is_public) {
+  (*vars)["Method"] = method->name();
+  (*vars)["Request"] =
+      grpc_cpp_generator::ClassName(method->input_type(), true);
+  (*vars)["Response"] =
+      grpc_cpp_generator::ClassName(method->output_type(), true);
+
+  if (is_public) {
+    if (NoStreaming(method)) {
+      printer->Print(
+          *vars,
+          "virtual ::grpc::Status $Method$(::grpc::ClientContext* context, "
+          "const $Request$& request, $Response$* response) = 0;\n");
+      printer->Print(
+          *vars,
+          "std::unique_ptr< "
+          "::grpc::ClientAsyncResponseReaderInterface< $Response$>> "
+          "Async$Method$(::grpc::ClientContext* context, "
+          "const $Request$& request, "
+          "::grpc::CompletionQueue* cq, void* tag) {\n");
+      printer->Indent();
+      printer->Print(
+          *vars,
+          "return std::unique_ptr< "
+          "::grpc::ClientAsyncResponseReaderInterface< $Response$>>("
+          "Async$Method$Raw(context, request, cq, tag));\n");
+      printer->Outdent();
+      printer->Print("}\n");
+    } else if (ClientOnlyStreaming(method)) {
+      printer->Print(
+          *vars,
+          "std::unique_ptr< ::grpc::ClientWriterInterface< $Request$>>"
+          " $Method$("
+          "::grpc::ClientContext* context, $Response$* response) {\n");
+      printer->Indent();
+      printer->Print(
+          *vars,
+          "return std::unique_ptr< ::grpc::ClientWriterInterface< $Request$>>"
+          "($Method$Raw(context, response));\n");
+      printer->Outdent();
+      printer->Print("}\n");
+      printer->Print(
+          *vars,
+          "std::unique_ptr< ::grpc::ClientAsyncWriterInterface< $Request$>>"
+          " Async$Method$(::grpc::ClientContext* context, $Response$* response, "
+          "::grpc::CompletionQueue* cq, void* tag) {\n");
+      printer->Indent();
+      printer->Print(
+          *vars,
+          "return std::unique_ptr< "
+          "::grpc::ClientAsyncWriterInterface< $Request$>>("
+          "Async$Method$Raw(context, response, cq, tag));\n");
+      printer->Outdent();
+      printer->Print("}\n");
+    } else if (ServerOnlyStreaming(method)) {
+      printer->Print(
+          *vars,
+          "std::unique_ptr< ::grpc::ClientReaderInterface< $Response$>>"
+          " $Method$(::grpc::ClientContext* context, const $Request$& request)"
+          " {\n");
+      printer->Indent();
+      printer->Print(
+          *vars,
+          "return std::unique_ptr< ::grpc::ClientReaderInterface< $Response$>>"
+          "($Method$Raw(context, request));\n");
+      printer->Outdent();
+      printer->Print("}\n");
+      printer->Print(
+          *vars,
+          "std::unique_ptr< ::grpc::ClientAsyncReaderInterface< $Response$>> "
+          "Async$Method$("
+          "::grpc::ClientContext* context, const $Request$& request, "
+          "::grpc::CompletionQueue* cq, void* tag) {\n");
+      printer->Indent();
+      printer->Print(
+          *vars,
+          "return std::unique_ptr< "
+          "::grpc::ClientAsyncReaderInterface< $Response$>>("
+          "Async$Method$Raw(context, request, cq, tag));\n");
+      printer->Outdent();
+      printer->Print("}\n");
+    } else if (BidiStreaming(method)) {
+      printer->Print(
+          *vars,
+          "std::unique_ptr< ::grpc::ClientReaderWriterInterface< $Request$, $Response$>> "
+          "$Method$(::grpc::ClientContext* context) {\n");
+      printer->Indent();
+      printer->Print(
+          *vars,
+          "return std::unique_ptr< "
+          "::grpc::ClientReaderWriterInterface< $Request$, $Response$>>("
+          "$Method$Raw(context));\n");
+      printer->Outdent();
+      printer->Print("}\n");
+      printer->Print(
+          *vars,
+          "std::unique_ptr< "
+          "::grpc::ClientAsyncReaderWriterInterface< $Request$, $Response$>> "
+          "Async$Method$(::grpc::ClientContext* context, "
+          "::grpc::CompletionQueue* cq, void* tag) {\n");
+      printer->Indent();
+      printer->Print(
+          *vars,
+          "return std::unique_ptr< "
+          "::grpc::ClientAsyncReaderWriterInterface< $Request$, $Response$>>("
+          "Async$Method$Raw(context, cq, tag));\n");
+      printer->Outdent();
+      printer->Print("}\n");
+    }
+  } else {
+    if (NoStreaming(method)) {
+      printer->Print(
+          *vars,
+          "virtual ::grpc::ClientAsyncResponseReaderInterface< $Response$>* "
+          "Async$Method$Raw(::grpc::ClientContext* context, "
+          "const $Request$& request, "
+          "::grpc::CompletionQueue* cq, void* tag) = 0;\n");
+    } else if (ClientOnlyStreaming(method)) {
+      printer->Print(
+          *vars,
+          "virtual ::grpc::ClientWriterInterface< $Request$>*"
+          " $Method$Raw("
+          "::grpc::ClientContext* context, $Response$* response) = 0;\n");
+      printer->Print(
+          *vars,
+          "virtual ::grpc::ClientAsyncWriterInterface< $Request$>*"
+          " Async$Method$Raw(::grpc::ClientContext* context, "
+          "$Response$* response, "
+          "::grpc::CompletionQueue* cq, void* tag) = 0;\n");
+    } else if (ServerOnlyStreaming(method)) {
+      printer->Print(
+          *vars,
+          "virtual ::grpc::ClientReaderInterface< $Response$>* $Method$Raw("
+          "::grpc::ClientContext* context, const $Request$& request) = 0;\n");
+      printer->Print(
+          *vars,
+          "virtual ::grpc::ClientAsyncReaderInterface< $Response$>* "
+          "Async$Method$Raw("
+          "::grpc::ClientContext* context, const $Request$& request, "
+          "::grpc::CompletionQueue* cq, void* tag) = 0;\n");
+    } else if (BidiStreaming(method)) {
+      printer->Print(
+          *vars,
+          "virtual ::grpc::ClientReaderWriterInterface< $Request$, $Response$>* "
+          "$Method$Raw(::grpc::ClientContext* context) = 0;\n");
+      printer->Print(
+          *vars,
+          "virtual ::grpc::ClientAsyncReaderWriterInterface< "
+          "$Request$, $Response$>* "
+          "Async$Method$Raw(::grpc::ClientContext* context, "
+          "::grpc::CompletionQueue* cq, void* tag) = 0;\n");
+    }
+  }
+}
+
 void PrintHeaderClientMethod(grpc::protobuf::io::Printer *printer,
                              const grpc::protobuf::MethodDescriptor *method,
-                             std::map<grpc::string, grpc::string> *vars) {
+                             std::map<grpc::string, grpc::string> *vars,
+                             bool is_public) {
   (*vars)["Method"] = method->name();
   (*vars)["Request"] =
       grpc_cpp_generator::ClassName(method->input_type(), true);
   (*vars)["Response"] =
       grpc_cpp_generator::ClassName(method->output_type(), true);
-  if (NoStreaming(method)) {
-    printer->Print(*vars,
-                   "::grpc::Status $Method$(::grpc::ClientContext* context, "
-                   "const $Request$& request, $Response$* response);\n");
-    printer->Print(
-        *vars,
-        "std::unique_ptr< ::grpc::ClientAsyncResponseReader< $Response$>> "
-        "Async$Method$(::grpc::ClientContext* context, "
-        "const $Request$& request, "
-        "::grpc::CompletionQueue* cq, void* tag);\n");
-  } else if (ClientOnlyStreaming(method)) {
-    printer->Print(
-        *vars,
-        "std::unique_ptr< ::grpc::ClientWriter< $Request$>> $Method$("
-        "::grpc::ClientContext* context, $Response$* response);\n");
-    printer->Print(
-        *vars,
-        "std::unique_ptr< ::grpc::ClientAsyncWriter< $Request$>> Async$Method$("
-        "::grpc::ClientContext* context, $Response$* response, "
-        "::grpc::CompletionQueue* cq, void* tag);\n");
-  } else if (ServerOnlyStreaming(method)) {
-    printer->Print(
-        *vars,
-        "std::unique_ptr< ::grpc::ClientReader< $Response$>> $Method$("
-        "::grpc::ClientContext* context, const $Request$& request);\n");
-    printer->Print(*vars,
-                   "std::unique_ptr< ::grpc::ClientAsyncReader< $Response$>> "
-                   "Async$Method$("
-                   "::grpc::ClientContext* context, const $Request$& request, "
-                   "::grpc::CompletionQueue* cq, void* tag);\n");
-  } else if (BidiStreaming(method)) {
-    printer->Print(
-        *vars,
-        "std::unique_ptr< ::grpc::ClientReaderWriter< $Request$, $Response$>> "
-        "$Method$(::grpc::ClientContext* context);\n");
-    printer->Print(*vars,
-                   "std::unique_ptr<  ::grpc::ClientAsyncReaderWriter< "
-                   "$Request$, $Response$>> "
-                   "Async$Method$(::grpc::ClientContext* context, "
-                   "::grpc::CompletionQueue* cq, void* tag);\n");
+
+  if (is_public) {
+    if (NoStreaming(method)) {
+      printer->Print(
+          *vars,
+          "::grpc::Status $Method$(::grpc::ClientContext* context, "
+          "const $Request$& request, $Response$* response) GRPC_OVERRIDE;\n");
+      printer->Print(
+          *vars,
+          "std::unique_ptr< ::grpc::ClientAsyncResponseReader< $Response$>> "
+          "Async$Method$(::grpc::ClientContext* context, "
+          "const $Request$& request, "
+          "::grpc::CompletionQueue* cq, void* tag) {\n");
+      printer->Indent();
+      printer->Print(
+          *vars,
+          "return std::unique_ptr< "
+          "::grpc::ClientAsyncResponseReader< $Response$>>("
+          "Async$Method$Raw(context, request, cq, tag));\n");
+      printer->Outdent();
+      printer->Print("}\n");
+    } else if (ClientOnlyStreaming(method)) {
+      printer->Print(
+          *vars,
+          "std::unique_ptr< ::grpc::ClientWriter< $Request$>>"
+          " $Method$("
+          "::grpc::ClientContext* context, $Response$* response) {\n");
+      printer->Indent();
+      printer->Print(
+          *vars,
+          "return std::unique_ptr< ::grpc::ClientWriter< $Request$>>"
+          "($Method$Raw(context, response));\n");
+      printer->Outdent();
+      printer->Print("}\n");
+      printer->Print(
+          *vars,
+          "std::unique_ptr< ::grpc::ClientAsyncWriter< $Request$>>"
+          " Async$Method$(::grpc::ClientContext* context, $Response$* response, "
+          "::grpc::CompletionQueue* cq, void* tag) {\n");
+      printer->Indent();
+      printer->Print(
+          *vars,
+          "return std::unique_ptr< ::grpc::ClientAsyncWriter< $Request$>>("
+          "Async$Method$Raw(context, response, cq, tag));\n");
+      printer->Outdent();
+      printer->Print("}\n");
+    } else if (ServerOnlyStreaming(method)) {
+      printer->Print(
+          *vars,
+          "std::unique_ptr< ::grpc::ClientReader< $Response$>>"
+          " $Method$(::grpc::ClientContext* context, const $Request$& request)"
+          " {\n");
+      printer->Indent();
+      printer->Print(
+          *vars,
+          "return std::unique_ptr< ::grpc::ClientReader< $Response$>>"
+          "($Method$Raw(context, request));\n");
+      printer->Outdent();
+      printer->Print("}\n");
+      printer->Print(
+          *vars,
+          "std::unique_ptr< ::grpc::ClientAsyncReader< $Response$>> "
+          "Async$Method$("
+          "::grpc::ClientContext* context, const $Request$& request, "
+          "::grpc::CompletionQueue* cq, void* tag) {\n");
+      printer->Indent();
+      printer->Print(
+          *vars,
+          "return std::unique_ptr< ::grpc::ClientAsyncReader< $Response$>>("
+          "Async$Method$Raw(context, request, cq, tag));\n");
+      printer->Outdent();
+      printer->Print("}\n");
+    } else if (BidiStreaming(method)) {
+      printer->Print(
+          *vars,
+          "std::unique_ptr< ::grpc::ClientReaderWriter< $Request$, $Response$>>"
+          " $Method$(::grpc::ClientContext* context) {\n");
+      printer->Indent();
+      printer->Print(
+          *vars,
+          "return std::unique_ptr< "
+          "::grpc::ClientReaderWriter< $Request$, $Response$>>("
+          "$Method$Raw(context));\n");
+      printer->Outdent();
+      printer->Print("}\n");
+      printer->Print(
+          *vars,
+          "std::unique_ptr<  ::grpc::ClientAsyncReaderWriter< "
+          "$Request$, $Response$>> "
+          "Async$Method$(::grpc::ClientContext* context, "
+          "::grpc::CompletionQueue* cq, void* tag) {\n");
+      printer->Indent();
+      printer->Print(
+          *vars,
+          "return std::unique_ptr< "
+          "::grpc::ClientAsyncReaderWriter< $Request$, $Response$>>("
+          "Async$Method$Raw(context, cq, tag));\n");
+      printer->Outdent();
+      printer->Print("}\n");
+    }
+  } else {
+    if (NoStreaming(method)) {
+      printer->Print(
+          *vars,
+          "::grpc::ClientAsyncResponseReader< $Response$>* "
+          "Async$Method$Raw(::grpc::ClientContext* context, "
+          "const $Request$& request, "
+          "::grpc::CompletionQueue* cq, void* tag) GRPC_OVERRIDE;\n");
+    } else if (ClientOnlyStreaming(method)) {
+      printer->Print(
+          *vars,
+          "::grpc::ClientWriter< $Request$>* $Method$Raw("
+          "::grpc::ClientContext* context, $Response$* response) "
+          "GRPC_OVERRIDE;\n");
+      printer->Print(
+          *vars,
+          "::grpc::ClientAsyncWriter< $Request$>* Async$Method$Raw("
+          "::grpc::ClientContext* context, $Response$* response, "
+          "::grpc::CompletionQueue* cq, void* tag) GRPC_OVERRIDE;\n");
+    } else if (ServerOnlyStreaming(method)) {
+      printer->Print(
+          *vars,
+          "::grpc::ClientReader< $Response$>* $Method$Raw("
+          "::grpc::ClientContext* context, const $Request$& request)"
+          " GRPC_OVERRIDE;\n");
+      printer->Print(
+          *vars,
+          "::grpc::ClientAsyncReader< $Response$>* Async$Method$Raw("
+          "::grpc::ClientContext* context, const $Request$& request, "
+          "::grpc::CompletionQueue* cq, void* tag) GRPC_OVERRIDE;\n");
+    } else if (BidiStreaming(method)) {
+      printer->Print(
+          *vars,
+          "::grpc::ClientReaderWriter< $Request$, $Response$>* "
+          "$Method$Raw(::grpc::ClientContext* context) GRPC_OVERRIDE;\n");
+      printer->Print(
+          *vars,
+          "::grpc::ClientAsyncReaderWriter< $Request$, $Response$>* "
+          "Async$Method$Raw(::grpc::ClientContext* context, "
+          "::grpc::CompletionQueue* cq, void* tag) GRPC_OVERRIDE;\n");
+    }
   }
 }
 
@@ -357,18 +583,37 @@ void PrintHeaderService(grpc::protobuf::io::Printer *printer,
 
   // Client side
   printer->Print(
-      "class Stub GRPC_FINAL : public ::grpc::InternalStub {\n"
+      "class StubInterface {\n"
       " public:\n");
   printer->Indent();
+  printer->Print("virtual ~StubInterface() {}\n");
+  for (int i = 0; i < service->method_count(); ++i) {
+    PrintHeaderClientMethodInterfaces(printer, service->method(i), vars, true);
+  }
+  printer->Outdent();
+  printer->Print("private:\n");
+  printer->Indent();
+  for (int i = 0; i < service->method_count(); ++i) {
+    PrintHeaderClientMethodInterfaces(printer, service->method(i), vars, false);
+  }
+  printer->Outdent();
+  printer->Print("};\n");
+  printer->Print(
+      "class Stub GRPC_FINAL : public StubInterface,"
+      " public ::grpc::InternalStub {\n public:\n");
+  printer->Indent();
   printer->Print(
       "Stub(const std::shared_ptr< ::grpc::ChannelInterface>& channel);\n");
   for (int i = 0; i < service->method_count(); ++i) {
-    PrintHeaderClientMethod(printer, service->method(i), vars);
+    PrintHeaderClientMethod(printer, service->method(i), vars, true);
   }
   printer->Outdent();
-  printer->Print(" private:\n");
+  printer->Print("\n private:\n");
   printer->Indent();
   for (int i = 0; i < service->method_count(); ++i) {
+    PrintHeaderClientMethod(printer, service->method(i), vars, false);
+  }
+  for (int i = 0; i < service->method_count(); ++i) {
     PrintHeaderClientMethodData(printer, service->method(i), vars);
   }
   printer->Outdent();
@@ -535,93 +780,85 @@ void PrintSourceClientMethod(grpc::protobuf::io::Printer *printer,
                    "}\n\n");
     printer->Print(
         *vars,
-        "std::unique_ptr< ::grpc::ClientAsyncResponseReader< $Response$>> "
-        "$ns$$Service$::Stub::Async$Method$(::grpc::ClientContext* context, "
+        "::grpc::ClientAsyncResponseReader< $Response$>* "
+        "$ns$$Service$::Stub::Async$Method$Raw(::grpc::ClientContext* context, "
         "const $Request$& request, "
         "::grpc::CompletionQueue* cq, void* tag) {\n");
     printer->Print(*vars,
-                   "  return std::unique_ptr< "
-                   "::grpc::ClientAsyncResponseReader< $Response$>>(new "
+                   "  return new "
                    "::grpc::ClientAsyncResponseReader< $Response$>("
                    "channel(), cq, "
                    "rpcmethod_$Method$_, "
-                   "context, request, tag));\n"
+                   "context, request, tag);\n"
                    "}\n\n");
   } else if (ClientOnlyStreaming(method)) {
     printer->Print(*vars,
-                   "std::unique_ptr< ::grpc::ClientWriter< $Request$>> "
-                   "$ns$$Service$::Stub::$Method$("
+                   "::grpc::ClientWriter< $Request$>* "
+                   "$ns$$Service$::Stub::$Method$Raw("
                    "::grpc::ClientContext* context, $Response$* response) {\n");
     printer->Print(*vars,
-                   "  return std::unique_ptr< ::grpc::ClientWriter< "
-                   "$Request$>>(new ::grpc::ClientWriter< $Request$>("
-                   "channel(),"
+                   "  return new ::grpc::ClientWriter< $Request$>("
+                   "channel(), "
                    "rpcmethod_$Method$_, "
-                   "context, response));\n"
+                   "context, response);\n"
                    "}\n\n");
     printer->Print(*vars,
-                   "std::unique_ptr< ::grpc::ClientAsyncWriter< $Request$>> "
-                   "$ns$$Service$::Stub::Async$Method$("
+                   "::grpc::ClientAsyncWriter< $Request$>* "
+                   "$ns$$Service$::Stub::Async$Method$Raw("
                    "::grpc::ClientContext* context, $Response$* response, "
                    "::grpc::CompletionQueue* cq, void* tag) {\n");
     printer->Print(*vars,
-                   "  return std::unique_ptr< ::grpc::ClientAsyncWriter< "
-                   "$Request$>>(new ::grpc::ClientAsyncWriter< $Request$>("
+                   "  return new ::grpc::ClientAsyncWriter< $Request$>("
                    "channel(), cq, "
                    "rpcmethod_$Method$_, "
-                   "context, response, tag));\n"
+                   "context, response, tag);\n"
                    "}\n\n");
   } else if (ServerOnlyStreaming(method)) {
     printer->Print(
         *vars,
-        "std::unique_ptr< ::grpc::ClientReader< $Response$>> "
-        "$ns$$Service$::Stub::$Method$("
+        "::grpc::ClientReader< $Response$>* "
+        "$ns$$Service$::Stub::$Method$Raw("
         "::grpc::ClientContext* context, const $Request$& request) {\n");
     printer->Print(*vars,
-                   "  return std::unique_ptr< ::grpc::ClientReader< "
-                   "$Response$>>(new ::grpc::ClientReader< $Response$>("
-                   "channel(),"
+                   "  return new ::grpc::ClientReader< $Response$>("
+                   "channel(), "
                    "rpcmethod_$Method$_, "
-                   "context, request));\n"
+                   "context, request);\n"
                    "}\n\n");
     printer->Print(*vars,
-                   "std::unique_ptr< ::grpc::ClientAsyncReader< $Response$>> "
-                   "$ns$$Service$::Stub::Async$Method$("
+                   "::grpc::ClientAsyncReader< $Response$>* "
+                   "$ns$$Service$::Stub::Async$Method$Raw("
                    "::grpc::ClientContext* context, const $Request$& request, "
                    "::grpc::CompletionQueue* cq, void* tag) {\n");
     printer->Print(*vars,
-                   "  return std::unique_ptr< ::grpc::ClientAsyncReader< "
-                   "$Response$>>(new ::grpc::ClientAsyncReader< $Response$>("
+                   "  return new ::grpc::ClientAsyncReader< $Response$>("
                    "channel(), cq, "
                    "rpcmethod_$Method$_, "
-                   "context, request, tag));\n"
+                   "context, request, tag);\n"
                    "}\n\n");
   } else if (BidiStreaming(method)) {
     printer->Print(
         *vars,
-        "std::unique_ptr< ::grpc::ClientReaderWriter< $Request$, $Response$>> "
-        "$ns$$Service$::Stub::$Method$(::grpc::ClientContext* context) {\n");
+        "::grpc::ClientReaderWriter< $Request$, $Response$>* "
+        "$ns$$Service$::Stub::$Method$Raw(::grpc::ClientContext* context) {\n");
     printer->Print(*vars,
-                   "  return std::unique_ptr< ::grpc::ClientReaderWriter< "
-                   "$Request$, $Response$>>(new ::grpc::ClientReaderWriter< "
+                   "  return new ::grpc::ClientReaderWriter< "
                    "$Request$, $Response$>("
-                   "channel(),"
+                   "channel(), "
                    "rpcmethod_$Method$_, "
-                   "context));\n"
+                   "context);\n"
                    "}\n\n");
     printer->Print(
         *vars,
-        "std::unique_ptr< ::grpc::ClientAsyncReaderWriter< "
-        "$Request$, $Response$>> "
-        "$ns$$Service$::Stub::Async$Method$(::grpc::ClientContext* context, "
+        "::grpc::ClientAsyncReaderWriter< $Request$, $Response$>* "
+        "$ns$$Service$::Stub::Async$Method$Raw(::grpc::ClientContext* context, "
         "::grpc::CompletionQueue* cq, void* tag) {\n");
     printer->Print(*vars,
-                   "  return std::unique_ptr< ::grpc::ClientAsyncReaderWriter< "
-                   "$Request$, $Response$>>(new "
+                   "  return new "
                    "::grpc::ClientAsyncReaderWriter< $Request$, $Response$>("
                    "channel(), cq, "
                    "rpcmethod_$Method$_, "
-                   "context, tag));\n"
+                   "context, tag);\n"
                    "}\n\n");
   }
 }
diff --git a/src/core/iomgr/socket_utils_common_posix.c b/src/core/iomgr/socket_utils_common_posix.c
index 3c8cafa315..a9af594700 100644
--- a/src/core/iomgr/socket_utils_common_posix.c
+++ b/src/core/iomgr/socket_utils_common_posix.c
@@ -76,6 +76,19 @@ int grpc_set_socket_nonblocking(int fd, int non_blocking) {
   return 1;
 }
 
+int grpc_set_socket_no_sigpipe_if_possible(int fd) {
+#ifdef GPR_HAVE_SO_NOSIGPIPE
+  int val = 1;
+  int newval;
+  socklen_t intlen = sizeof(newval);
+  return 0 == setsockopt(fd, SOL_SOCKET, SO_NOSIGPIPE, &val, sizeof(val)) &&
+         0 == getsockopt(fd, SOL_SOCKET, SO_NOSIGPIPE, &newval, &intlen) &&
+         (newval != 0) == val;
+#else
+  return 1;
+#endif
+}
+
 /* set a socket to close on exec */
 int grpc_set_socket_cloexec(int fd, int close_on_exec) {
   int oldflags = fcntl(fd, F_GETFD, 0);
diff --git a/src/core/iomgr/socket_utils_posix.h b/src/core/iomgr/socket_utils_posix.h
index c161082afc..d2a315b462 100644
--- a/src/core/iomgr/socket_utils_posix.h
+++ b/src/core/iomgr/socket_utils_posix.h
@@ -63,6 +63,11 @@ int grpc_set_socket_low_latency(int fd, int low_latency);
    state to library users, we turn off IPv6 sockets. */
 int grpc_ipv6_loopback_available(void);
 
+/* Tries to set SO_NOSIGPIPE if available on this platform.
+   Returns 1 on success, 0 on failure.
+   If SO_NO_SIGPIPE is not available, returns 1. */
+int grpc_set_socket_no_sigpipe_if_possible(int fd);
+
 /* An enum to keep track of IPv4/IPv6 socket modes.
 
    Currently, this information is only used when a socket is first created, but
diff --git a/src/core/iomgr/tcp_client_posix.c b/src/core/iomgr/tcp_client_posix.c
index e20cc3d1b2..2401fe00e4 100644
--- a/src/core/iomgr/tcp_client_posix.c
+++ b/src/core/iomgr/tcp_client_posix.c
@@ -69,7 +69,8 @@ static int prepare_socket(const struct sockaddr *addr, int fd) {
   }
 
   if (!grpc_set_socket_nonblocking(fd, 1) || !grpc_set_socket_cloexec(fd, 1) ||
-      (addr->sa_family != AF_UNIX && !grpc_set_socket_low_latency(fd, 1))) {
+      (addr->sa_family != AF_UNIX && !grpc_set_socket_low_latency(fd, 1)) ||
+      !grpc_set_socket_no_sigpipe_if_possible(fd)) {
     gpr_log(GPR_ERROR, "Unable to configure socket %d: %s", fd,
             strerror(errno));
     goto error;
diff --git a/src/core/iomgr/tcp_posix.c b/src/core/iomgr/tcp_posix.c
index 06725fbc89..f7dae5f86c 100644
--- a/src/core/iomgr/tcp_posix.c
+++ b/src/core/iomgr/tcp_posix.c
@@ -53,6 +53,12 @@
 #include <grpc/support/sync.h>
 #include <grpc/support/time.h>
 
+#ifdef GPR_HAVE_MSG_NOSIGNAL
+#define SENDMSG_FLAGS MSG_NOSIGNAL
+#else
+#define SENDMSG_FLAGS 0
+#endif
+
 /* Holds a slice array and associated state. */
 typedef struct grpc_tcp_slice_state {
   gpr_slice *slices;       /* Array of slices */
@@ -461,7 +467,7 @@ static grpc_endpoint_write_status grpc_tcp_flush(grpc_tcp *tcp) {
     GRPC_TIMER_BEGIN(GRPC_PTAG_SENDMSG, 0);
     do {
       /* TODO(klempner): Cork if this is a partial write */
-      sent_length = sendmsg(tcp->fd, &msg, 0);
+      sent_length = sendmsg(tcp->fd, &msg, SENDMSG_FLAGS);
     } while (sent_length < 0 && errno == EINTR);
     GRPC_TIMER_END(GRPC_PTAG_SENDMSG, 0);
 
diff --git a/src/core/iomgr/tcp_server_posix.c b/src/core/iomgr/tcp_server_posix.c
index 7e31f2d7a5..d1cd8a769c 100644
--- a/src/core/iomgr/tcp_server_posix.c
+++ b/src/core/iomgr/tcp_server_posix.c
@@ -235,7 +235,8 @@ static int prepare_socket(int fd, const struct sockaddr *addr, int addr_len) {
 
   if (!grpc_set_socket_nonblocking(fd, 1) || !grpc_set_socket_cloexec(fd, 1) ||
       (addr->sa_family != AF_UNIX && (!grpc_set_socket_low_latency(fd, 1) ||
-                                      !grpc_set_socket_reuse_addr(fd, 1)))) {
+                                      !grpc_set_socket_reuse_addr(fd, 1))) ||
+      !grpc_set_socket_no_sigpipe_if_possible(fd)) {
     gpr_log(GPR_ERROR, "Unable to configure socket %d: %s", fd,
             strerror(errno));
     goto error;
@@ -296,6 +297,8 @@ static void on_read(void *arg, int success) {
       }
     }
 
+    grpc_set_socket_no_sigpipe_if_possible(fd);
+
     sp->server->cb(
         sp->server->cb_arg,
         grpc_tcp_create(grpc_fd_create(fd), GRPC_TCP_DEFAULT_READ_SLICE_SIZE));
diff --git a/src/core/surface/call.c b/src/core/surface/call.c
index bb2c20af32..647c0ab63c 100644
--- a/src/core/surface/call.c
+++ b/src/core/surface/call.c
@@ -708,6 +708,10 @@ static void call_on_done_recv(void *pc, int success) {
           break;
       }
     }
+    if (!success) {
+      grpc_stream_ops_unref_owned_objects(&call->recv_ops.ops[i],
+                                          call->recv_ops.nops - i);
+    }
     if (call->recv_state == GRPC_STREAM_RECV_CLOSED) {
       GPR_ASSERT(call->read_state <= READ_STATE_READ_CLOSED);
       call->read_state = READ_STATE_READ_CLOSED;
@@ -736,14 +740,9 @@ static void call_on_done_recv(void *pc, int success) {
   GRPC_TIMER_BEGIN(GRPC_PTAG_CALL_ON_DONE_RECV, 0);
 }
 
-static grpc_mdelem_list chain_metadata_from_app(grpc_call *call, size_t count,
-                                                grpc_metadata *metadata) {
+static int prepare_application_metadata(grpc_call *call, size_t count,
+                                        grpc_metadata *metadata) {
   size_t i;
-  grpc_mdelem_list out;
-  if (count == 0) {
-    out.head = out.tail = NULL;
-    return out;
-  }
   for (i = 0; i < count; i++) {
     grpc_metadata *md = &metadata[i];
     grpc_metadata *next_md = (i == count - 1) ? NULL : &metadata[i + 1];
@@ -753,9 +752,27 @@ static grpc_mdelem_list chain_metadata_from_app(grpc_call *call, size_t count,
     l->md = grpc_mdelem_from_string_and_buffer(call->metadata_context, md->key,
                                                (const gpr_uint8 *)md->value,
                                                md->value_length);
+    if (!grpc_mdstr_is_legal_header(l->md->key)) {
+      gpr_log(GPR_ERROR, "attempt to send invalid metadata key");
+      return 0;
+    } else if (!grpc_mdstr_is_bin_suffixed(l->md->key) &&
+               !grpc_mdstr_is_legal_header(l->md->value)) {
+      gpr_log(GPR_ERROR, "attempt to send invalid metadata value");
+      return 0;
+    }
     l->next = next_md ? (grpc_linked_mdelem *)&next_md->internal_data : NULL;
     l->prev = prev_md ? (grpc_linked_mdelem *)&prev_md->internal_data : NULL;
   }
+  return 1;
+}
+
+static grpc_mdelem_list chain_metadata_from_app(grpc_call *call, size_t count,
+                                                grpc_metadata *metadata) {
+  grpc_mdelem_list out;
+  if (count == 0) {
+    out.head = out.tail = NULL;
+    return out;
+  }
   out.head = (grpc_linked_mdelem *)&(metadata[0].internal_data);
   out.tail = (grpc_linked_mdelem *)&(metadata[count - 1].internal_data);
   return out;
@@ -951,8 +968,16 @@ static grpc_call_error start_ioreq(grpc_call *call, const grpc_ioreq *reqs,
     } else if (call->request_set[op] == REQSET_DONE) {
       return start_ioreq_error(call, have_ops, GRPC_CALL_ERROR_ALREADY_INVOKED);
     }
-    have_ops |= 1u << op;
     data = reqs[i].data;
+    if (op == GRPC_IOREQ_SEND_INITIAL_METADATA ||
+        op == GRPC_IOREQ_SEND_TRAILING_METADATA) {
+      if (!prepare_application_metadata(call, data.send_metadata.count,
+                                        data.send_metadata.metadata)) {
+        return start_ioreq_error(call, have_ops,
+                                 GRPC_CALL_ERROR_INVALID_METADATA);
+      }
+    }
+    have_ops |= 1u << op;
 
     call->request_data[op] = data;
     call->request_set[op] = set;
diff --git a/src/core/transport/chttp2_transport.c b/src/core/transport/chttp2_transport.c
index dae1b1e1b7..a6f9f782a1 100644
--- a/src/core/transport/chttp2_transport.c
+++ b/src/core/transport/chttp2_transport.c
@@ -823,24 +823,23 @@ static void unlock(transport *t) {
   finish_reads(t);
 
   /* gather any callbacks that need to be made */
-  if (!t->calling_back && cb) {
-    perform_callbacks = prepare_callbacks(t);
-    if (perform_callbacks) {
-      t->calling_back = 1;
-    }
-    if (t->error_state == ERROR_STATE_SEEN && !t->writing) {
-      call_closed = 1;
-      t->calling_back = 1;
-      t->cb = NULL; /* no more callbacks */
-      t->error_state = ERROR_STATE_NOTIFIED;
-    }
-    if (t->num_pending_goaways) {
-      goaways = t->pending_goaways;
-      num_goaways = t->num_pending_goaways;
-      t->pending_goaways = NULL;
-      t->num_pending_goaways = 0;
-      t->cap_pending_goaways = 0;
-      t->calling_back = 1;
+  if (!t->calling_back) {
+    t->calling_back = perform_callbacks = prepare_callbacks(t);
+    if (cb) {
+      if (t->error_state == ERROR_STATE_SEEN && !t->writing) {
+        call_closed = 1;
+        t->calling_back = 1;
+        t->cb = NULL; /* no more callbacks */
+        t->error_state = ERROR_STATE_NOTIFIED;
+      }
+      if (t->num_pending_goaways) {
+        goaways = t->pending_goaways;
+        num_goaways = t->num_pending_goaways;
+        t->pending_goaways = NULL;
+        t->num_pending_goaways = 0;
+        t->cap_pending_goaways = 0;
+        t->calling_back = 1;
+      }
     }
   }
 
@@ -1928,8 +1927,10 @@ static void recv_data(void *tp, gpr_slice *slices, size_t nslices,
       break;
     case GRPC_ENDPOINT_CB_OK:
       lock(t);
-      for (i = 0; i < nslices && process_read(t, slices[i]); i++)
-        ;
+      if (t->cb) {
+        for (i = 0; i < nslices && process_read(t, slices[i]); i++)
+          ;
+      }
       unlock(t);
       keep_reading = 1;
       break;
diff --git a/src/core/transport/metadata.c b/src/core/transport/metadata.c
index 74e94b2c24..c80d67823f 100644
--- a/src/core/transport/metadata.c
+++ b/src/core/transport/metadata.c
@@ -569,3 +569,19 @@ void grpc_mdctx_locked_mdelem_unref(grpc_mdctx *ctx, grpc_mdelem *gmd) {
 }
 
 void grpc_mdctx_unlock(grpc_mdctx *ctx) { unlock(ctx); }
+
+int grpc_mdstr_is_legal_header(grpc_mdstr *s) {
+  /* TODO(ctiller): consider caching this, or computing it on construction */
+  const gpr_uint8 *p = GPR_SLICE_START_PTR(s->slice);
+  const gpr_uint8 *e = GPR_SLICE_END_PTR(s->slice);
+  for (; p != e; p++) {
+    if (*p < 32 || *p > 126) return 0;
+  }
+  return 1;
+}
+
+int grpc_mdstr_is_bin_suffixed(grpc_mdstr *s) {
+  /* TODO(ctiller): consider caching this */
+  return grpc_is_binary_header((const char *)GPR_SLICE_START_PTR(s->slice),
+                               GPR_SLICE_LENGTH(s->slice));
+}
diff --git a/src/core/transport/metadata.h b/src/core/transport/metadata.h
index 21b8ae2b78..e7508718f5 100644
--- a/src/core/transport/metadata.h
+++ b/src/core/transport/metadata.h
@@ -135,6 +135,9 @@ void grpc_mdelem_unref(grpc_mdelem *md);
    Does not promise that the returned string has no embedded nulls however. */
 const char *grpc_mdstr_as_c_string(grpc_mdstr *s);
 
+int grpc_mdstr_is_legal_header(grpc_mdstr *s);
+int grpc_mdstr_is_bin_suffixed(grpc_mdstr *s);
+
 /* Batch mode metadata functions.
    These API's have equivalents above, but allow taking the mdctx just once,
    performing a bunch of work, and then leaving the mdctx. */
diff --git a/src/cpp/server/server.cc b/src/cpp/server/server.cc
index 08c956601c..1ff9ff4b32 100644
--- a/src/cpp/server/server.cc
+++ b/src/cpp/server/server.cc
@@ -446,8 +446,12 @@ void Server::RunRpc() {
     ScheduleCallback();
     if (ok) {
       SyncRequest::CallData cd(this, mrd);
-      mrd->Request(server_);
-
+      {
+        grpc::unique_lock<grpc::mutex> lock(mu_);
+        if (!shutdown_) {
+          mrd->Request(server_);
+        }
+      }
       cd.Run();
     }
   }
diff --git a/src/csharp/Grpc.Core.Tests/ClientServerTest.cs b/src/csharp/Grpc.Core.Tests/ClientServerTest.cs
index caa6220f2c..b69b933aba 100644
--- a/src/csharp/Grpc.Core.Tests/ClientServerTest.cs
+++ b/src/csharp/Grpc.Core.Tests/ClientServerTest.cs
@@ -84,7 +84,7 @@ namespace Grpc.Core.Tests
         {
             server = new Server();
             server.AddServiceDefinition(ServiceDefinition);
-            int port = server.AddListeningPort(Host + ":0");
+            int port = server.AddListeningPort(Host, Server.PickUnusedPort);
             server.Start();
             channel = new Channel(Host + ":" + port);
         }
@@ -220,7 +220,7 @@ namespace Grpc.Core.Tests
             }
         }
 
-        private static async Task<string> EchoHandler(string request)
+        private static async Task<string> EchoHandler(ServerCallContext context, string request)
         {
             if (request == "THROW")
             {
@@ -229,7 +229,7 @@ namespace Grpc.Core.Tests
             return request;
         }
 
-        private static async Task<string> ConcatAndEchoHandler(IAsyncStreamReader<string> requestStream)
+        private static async Task<string> ConcatAndEchoHandler(ServerCallContext context, IAsyncStreamReader<string> requestStream)
         {
             string result = "";
             await requestStream.ForEach(async (request) =>
diff --git a/src/csharp/Grpc.Core.Tests/ServerTest.cs b/src/csharp/Grpc.Core.Tests/ServerTest.cs
index 2a1855da67..02c773c9cc 100644
--- a/src/csharp/Grpc.Core.Tests/ServerTest.cs
+++ b/src/csharp/Grpc.Core.Tests/ServerTest.cs
@@ -47,7 +47,7 @@ namespace Grpc.Core.Tests
             GrpcEnvironment.Initialize();
 
             Server server = new Server();
-            server.AddListeningPort("localhost:0");
+            server.AddListeningPort("localhost", Server.PickUnusedPort);
             server.Start();
             server.ShutdownAsync().Wait();
 
diff --git a/src/csharp/Grpc.Core/AsyncClientStreamingCall.cs b/src/csharp/Grpc.Core/AsyncClientStreamingCall.cs
index e81ce01ebb..b95776f66d 100644
--- a/src/csharp/Grpc.Core/AsyncClientStreamingCall.cs
+++ b/src/csharp/Grpc.Core/AsyncClientStreamingCall.cs
@@ -40,7 +40,9 @@ namespace Grpc.Core
     /// <summary>
     /// Return type for client streaming calls.
     /// </summary>
-    public struct AsyncClientStreamingCall<TRequest, TResponse>
+    public sealed class AsyncClientStreamingCall<TRequest, TResponse>
+        where TRequest : class
+        where TResponse : class
     {
         readonly IClientStreamWriter<TRequest> requestStream;
         readonly Task<TResponse> result;
diff --git a/src/csharp/Grpc.Core/AsyncDuplexStreamingCall.cs b/src/csharp/Grpc.Core/AsyncDuplexStreamingCall.cs
index 1cb30f4779..ee05437416 100644
--- a/src/csharp/Grpc.Core/AsyncDuplexStreamingCall.cs
+++ b/src/csharp/Grpc.Core/AsyncDuplexStreamingCall.cs
@@ -40,7 +40,9 @@ namespace Grpc.Core
     /// <summary>
     /// Return type for bidirectional streaming calls.
     /// </summary>
-    public struct AsyncDuplexStreamingCall<TRequest, TResponse>
+    public sealed class AsyncDuplexStreamingCall<TRequest, TResponse>
+        where TRequest : class
+        where TResponse : class
     {
         readonly IClientStreamWriter<TRequest> requestStream;
         readonly IAsyncStreamReader<TResponse> responseStream;
diff --git a/src/csharp/Grpc.Core/AsyncServerStreamingCall.cs b/src/csharp/Grpc.Core/AsyncServerStreamingCall.cs
index d614916fb7..73b9614985 100644
--- a/src/csharp/Grpc.Core/AsyncServerStreamingCall.cs
+++ b/src/csharp/Grpc.Core/AsyncServerStreamingCall.cs
@@ -40,7 +40,8 @@ namespace Grpc.Core
     /// <summary>
     /// Return type for server streaming calls.
     /// </summary>
-    public struct AsyncServerStreamingCall<TResponse>
+    public sealed class AsyncServerStreamingCall<TResponse>
+        where TResponse : class
     {
         readonly IAsyncStreamReader<TResponse> responseStream;
 
diff --git a/src/csharp/Grpc.Core/Call.cs b/src/csharp/Grpc.Core/Call.cs
index 070dfb569d..771cc083da 100644
--- a/src/csharp/Grpc.Core/Call.cs
+++ b/src/csharp/Grpc.Core/Call.cs
@@ -41,6 +41,8 @@ namespace Grpc.Core
     /// Abstraction of a call to be invoked on a client.
     /// </summary>
     public class Call<TRequest, TResponse>
+        where TRequest : class
+        where TResponse : class
     {
         readonly string name;
         readonly Marshaller<TRequest> requestMarshaller;
diff --git a/src/csharp/Grpc.Core/Calls.cs b/src/csharp/Grpc.Core/Calls.cs
index a8d2b9498e..ba42a2d4f8 100644
--- a/src/csharp/Grpc.Core/Calls.cs
+++ b/src/csharp/Grpc.Core/Calls.cs
@@ -44,6 +44,8 @@ namespace Grpc.Core
     public static class Calls
     {
         public static TResponse BlockingUnaryCall<TRequest, TResponse>(Call<TRequest, TResponse> call, TRequest req, CancellationToken token)
+            where TRequest : class
+            where TResponse : class
         {
             var asyncCall = new AsyncCall<TRequest, TResponse>(call.RequestMarshaller.Serializer, call.ResponseMarshaller.Deserializer);
             // TODO(jtattermusch): this gives a race that cancellation can be requested before the call even starts.
@@ -52,6 +54,8 @@ namespace Grpc.Core
         }
 
         public static async Task<TResponse> AsyncUnaryCall<TRequest, TResponse>(Call<TRequest, TResponse> call, TRequest req, CancellationToken token)
+            where TRequest : class
+            where TResponse : class
         {
             var asyncCall = new AsyncCall<TRequest, TResponse>(call.RequestMarshaller.Serializer, call.ResponseMarshaller.Deserializer);
             asyncCall.Initialize(call.Channel, GetCompletionQueue(), call.Name);
@@ -61,6 +65,8 @@ namespace Grpc.Core
         }
 
         public static AsyncServerStreamingCall<TResponse> AsyncServerStreamingCall<TRequest, TResponse>(Call<TRequest, TResponse> call, TRequest req, CancellationToken token)
+            where TRequest : class
+            where TResponse : class
         {
             var asyncCall = new AsyncCall<TRequest, TResponse>(call.RequestMarshaller.Serializer, call.ResponseMarshaller.Deserializer);
             asyncCall.Initialize(call.Channel, GetCompletionQueue(), call.Name);
@@ -71,6 +77,8 @@ namespace Grpc.Core
         }
 
         public static AsyncClientStreamingCall<TRequest, TResponse> AsyncClientStreamingCall<TRequest, TResponse>(Call<TRequest, TResponse> call, CancellationToken token)
+            where TRequest : class
+            where TResponse : class
         {
             var asyncCall = new AsyncCall<TRequest, TResponse>(call.RequestMarshaller.Serializer, call.ResponseMarshaller.Deserializer);
             asyncCall.Initialize(call.Channel, GetCompletionQueue(), call.Name);
@@ -81,6 +89,8 @@ namespace Grpc.Core
         }
 
         public static AsyncDuplexStreamingCall<TRequest, TResponse> AsyncDuplexStreamingCall<TRequest, TResponse>(Call<TRequest, TResponse> call, CancellationToken token)
+            where TRequest : class
+            where TResponse : class
         {
             var asyncCall = new AsyncCall<TRequest, TResponse>(call.RequestMarshaller.Serializer, call.ResponseMarshaller.Deserializer);
             asyncCall.Initialize(call.Channel, GetCompletionQueue(), call.Name);
diff --git a/src/csharp/Grpc.Core/Grpc.Core.csproj b/src/csharp/Grpc.Core/Grpc.Core.csproj
index 9c91541d90..f5f2cf5f22 100644
--- a/src/csharp/Grpc.Core/Grpc.Core.csproj
+++ b/src/csharp/Grpc.Core/Grpc.Core.csproj
@@ -96,6 +96,7 @@
     <Compile Include="Internal\ServerResponseStream.cs" />
     <Compile Include="Internal\AtomicCounter.cs" />
     <Compile Include="Internal\DebugStats.cs" />
+    <Compile Include="ServerCallContext.cs" />
   </ItemGroup>
   <ItemGroup>
     <None Include="packages.config" />
diff --git a/src/csharp/Grpc.Core/IAsyncStreamReader.cs b/src/csharp/Grpc.Core/IAsyncStreamReader.cs
index 61cf57f7e0..699741cd05 100644
--- a/src/csharp/Grpc.Core/IAsyncStreamReader.cs
+++ b/src/csharp/Grpc.Core/IAsyncStreamReader.cs
@@ -44,9 +44,10 @@ namespace Grpc.Core
     /// </summary>
     /// <typeparam name="T"></typeparam>
     public interface IAsyncStreamReader<T>
+        where T : class
     {
         /// <summary>
-        /// Reads a single message. Returns default(T) if the last message was already read.
+        /// Reads a single message. Returns null if the last message was already read.
         /// A following read can only be started when the previous one finishes.
         /// </summary>
         Task<T> ReadNext();
diff --git a/src/csharp/Grpc.Core/IAsyncStreamWriter.cs b/src/csharp/Grpc.Core/IAsyncStreamWriter.cs
index 724bae8f31..4bd8bfb8df 100644
--- a/src/csharp/Grpc.Core/IAsyncStreamWriter.cs
+++ b/src/csharp/Grpc.Core/IAsyncStreamWriter.cs
@@ -44,6 +44,7 @@ namespace Grpc.Core
     /// </summary>
     /// <typeparam name="T"></typeparam>
     public interface IAsyncStreamWriter<T>
+        where T : class
     {
         /// <summary>
         /// Writes a single message. Only one write can be pending at a time.
diff --git a/src/csharp/Grpc.Core/IClientStreamWriter.cs b/src/csharp/Grpc.Core/IClientStreamWriter.cs
index 6da42e9ccc..0847a928e6 100644
--- a/src/csharp/Grpc.Core/IClientStreamWriter.cs
+++ b/src/csharp/Grpc.Core/IClientStreamWriter.cs
@@ -44,6 +44,7 @@ namespace Grpc.Core
     /// </summary>
     /// <typeparam name="T"></typeparam>
     public interface IClientStreamWriter<T> : IAsyncStreamWriter<T>
+        where T : class
     {
         /// <summary>
         /// Closes the stream. Can only be called once there is no pending write. No writes should follow calling this.
diff --git a/src/csharp/Grpc.Core/IServerStreamWriter.cs b/src/csharp/Grpc.Core/IServerStreamWriter.cs
index e76397d8a0..199a585a3f 100644
--- a/src/csharp/Grpc.Core/IServerStreamWriter.cs
+++ b/src/csharp/Grpc.Core/IServerStreamWriter.cs
@@ -43,6 +43,7 @@ namespace Grpc.Core
     /// A writable stream of messages that is used in server-side handlers.
     /// </summary>
     public interface IServerStreamWriter<T> : IAsyncStreamWriter<T>
+        where T : class
     {
     }
 }
diff --git a/src/csharp/Grpc.Core/Internal/AsyncCallServer.cs b/src/csharp/Grpc.Core/Internal/AsyncCallServer.cs
index 91106cd407..1f0335e4e6 100644
--- a/src/csharp/Grpc.Core/Internal/AsyncCallServer.cs
+++ b/src/csharp/Grpc.Core/Internal/AsyncCallServer.cs
@@ -138,9 +138,7 @@ namespace Grpc.Core.Internal
 
                 ReleaseResourcesIfPossible();
             }
-            // TODO(jtattermusch): check if call was cancelled.
-
-            // TODO: handle error ...
+            // TODO(jtattermusch): handle error
 
             finishedServersideTcs.SetResult(null);
         }
diff --git a/src/csharp/Grpc.Core/Internal/ClientRequestStream.cs b/src/csharp/Grpc.Core/Internal/ClientRequestStream.cs
index 6854922a6f..1697058732 100644
--- a/src/csharp/Grpc.Core/Internal/ClientRequestStream.cs
+++ b/src/csharp/Grpc.Core/Internal/ClientRequestStream.cs
@@ -38,6 +38,8 @@ namespace Grpc.Core.Internal
     /// Writes requests asynchronously to an underlying AsyncCall object.
     /// </summary>
     internal class ClientRequestStream<TRequest, TResponse> : IClientStreamWriter<TRequest>
+        where TRequest : class
+        where TResponse : class
     {
         readonly AsyncCall<TRequest, TResponse> call;
 
diff --git a/src/csharp/Grpc.Core/Internal/ClientResponseStream.cs b/src/csharp/Grpc.Core/Internal/ClientResponseStream.cs
index 7fa511faa8..b2378cade6 100644
--- a/src/csharp/Grpc.Core/Internal/ClientResponseStream.cs
+++ b/src/csharp/Grpc.Core/Internal/ClientResponseStream.cs
@@ -38,6 +38,8 @@ using System.Threading.Tasks;
 namespace Grpc.Core.Internal
 {
     internal class ClientResponseStream<TRequest, TResponse> : IAsyncStreamReader<TResponse>
+        where TRequest : class
+        where TResponse : class
     {
         readonly AsyncCall<TRequest, TResponse> call;
 
diff --git a/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs b/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs
index 01b2a11369..95d8e97869 100644
--- a/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs
+++ b/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs
@@ -45,6 +45,8 @@ namespace Grpc.Core.Internal
     }
 
     internal class UnaryServerCallHandler<TRequest, TResponse> : IServerCallHandler
+        where TRequest : class
+        where TResponse : class
     {
         readonly Method<TRequest, TResponse> method;
         readonly UnaryServerMethod<TRequest, TResponse> handler;
@@ -72,7 +74,8 @@ namespace Grpc.Core.Internal
                 var request = await requestStream.ReadNext();
                 // TODO(jtattermusch): we need to read the full stream so that native callhandle gets deallocated.
                 Preconditions.CheckArgument(await requestStream.ReadNext() == null);
-                var result = await handler(request);
+                var context = new ServerCallContext();  // TODO(jtattermusch): initialize the context
+                var result = await handler(context, request);
                 await responseStream.Write(result);
             } 
             catch (Exception e)
@@ -93,6 +96,8 @@ namespace Grpc.Core.Internal
     }
 
     internal class ServerStreamingServerCallHandler<TRequest, TResponse> : IServerCallHandler
+        where TRequest : class
+        where TResponse : class
     {
         readonly Method<TRequest, TResponse> method;
         readonly ServerStreamingServerMethod<TRequest, TResponse> handler;
@@ -121,7 +126,8 @@ namespace Grpc.Core.Internal
                 // TODO(jtattermusch): we need to read the full stream so that native callhandle gets deallocated.
                 Preconditions.CheckArgument(await requestStream.ReadNext() == null);
 
-                await handler(request, responseStream);
+                var context = new ServerCallContext();  // TODO(jtattermusch): initialize the context
+                await handler(context, request, responseStream);
             }
             catch (Exception e)
             {
@@ -142,6 +148,8 @@ namespace Grpc.Core.Internal
     }
 
     internal class ClientStreamingServerCallHandler<TRequest, TResponse> : IServerCallHandler
+        where TRequest : class
+        where TResponse : class
     {
         readonly Method<TRequest, TResponse> method;
         readonly ClientStreamingServerMethod<TRequest, TResponse> handler;
@@ -162,11 +170,12 @@ namespace Grpc.Core.Internal
             var finishedTask = asyncCall.ServerSideCallAsync();
             var requestStream = new ServerRequestStream<TRequest, TResponse>(asyncCall);
             var responseStream = new ServerResponseStream<TRequest, TResponse>(asyncCall);
+            var context = new ServerCallContext();  // TODO(jtattermusch): initialize the context
 
             Status status = Status.DefaultSuccess;
             try
             {
-                var result = await handler(requestStream);
+                var result = await handler(context, requestStream);
                 try
                 {
                     await responseStream.Write(result);
@@ -195,6 +204,8 @@ namespace Grpc.Core.Internal
     }
 
     internal class DuplexStreamingServerCallHandler<TRequest, TResponse> : IServerCallHandler
+        where TRequest : class
+        where TResponse : class
     {
         readonly Method<TRequest, TResponse> method;
         readonly DuplexStreamingServerMethod<TRequest, TResponse> handler;
@@ -215,11 +226,12 @@ namespace Grpc.Core.Internal
             var finishedTask = asyncCall.ServerSideCallAsync();
             var requestStream = new ServerRequestStream<TRequest, TResponse>(asyncCall);
             var responseStream = new ServerResponseStream<TRequest, TResponse>(asyncCall);
+            var context = new ServerCallContext();  // TODO(jtattermusch): initialize the context
 
             Status status = Status.DefaultSuccess;
             try
             {
-                await handler(requestStream, responseStream);
+                await handler(context, requestStream, responseStream);
             }
             catch (Exception e)
             {
diff --git a/src/csharp/Grpc.Core/Internal/ServerCalls.cs b/src/csharp/Grpc.Core/Internal/ServerCalls.cs
index 5c6b335c7f..81279678b9 100644
--- a/src/csharp/Grpc.Core/Internal/ServerCalls.cs
+++ b/src/csharp/Grpc.Core/Internal/ServerCalls.cs
@@ -41,21 +41,29 @@ namespace Grpc.Core.Internal
     internal static class ServerCalls
     {
         public static IServerCallHandler UnaryCall<TRequest, TResponse>(Method<TRequest, TResponse> method, UnaryServerMethod<TRequest, TResponse> handler)
+            where TRequest : class
+            where TResponse : class
         {
             return new UnaryServerCallHandler<TRequest, TResponse>(method, handler);
         }
 
         public static IServerCallHandler ClientStreamingCall<TRequest, TResponse>(Method<TRequest, TResponse> method, ClientStreamingServerMethod<TRequest, TResponse> handler)
+            where TRequest : class
+            where TResponse : class
         {
             return new ClientStreamingServerCallHandler<TRequest, TResponse>(method, handler);
         }
 
         public static IServerCallHandler ServerStreamingCall<TRequest, TResponse>(Method<TRequest, TResponse> method, ServerStreamingServerMethod<TRequest, TResponse> handler)
+            where TRequest : class
+            where TResponse : class
         {
             return new ServerStreamingServerCallHandler<TRequest, TResponse>(method, handler);
         }
 
         public static IServerCallHandler DuplexStreamingCall<TRequest, TResponse>(Method<TRequest, TResponse> method, DuplexStreamingServerMethod<TRequest, TResponse> handler)
+            where TRequest : class
+            where TResponse : class
         {
             return new DuplexStreamingServerCallHandler<TRequest, TResponse>(method, handler);
         }
diff --git a/src/csharp/Grpc.Core/Internal/ServerRequestStream.cs b/src/csharp/Grpc.Core/Internal/ServerRequestStream.cs
index aa311059c3..d9ee0c815b 100644
--- a/src/csharp/Grpc.Core/Internal/ServerRequestStream.cs
+++ b/src/csharp/Grpc.Core/Internal/ServerRequestStream.cs
@@ -38,6 +38,8 @@ using System.Threading.Tasks;
 namespace Grpc.Core.Internal
 {
     internal class ServerRequestStream<TRequest, TResponse> : IAsyncStreamReader<TRequest>
+        where TRequest : class
+        where TResponse : class
     {
         readonly AsyncCallServer<TRequest, TResponse> call;
 
diff --git a/src/csharp/Grpc.Core/Internal/ServerResponseStream.cs b/src/csharp/Grpc.Core/Internal/ServerResponseStream.cs
index 686017c048..da688d504f 100644
--- a/src/csharp/Grpc.Core/Internal/ServerResponseStream.cs
+++ b/src/csharp/Grpc.Core/Internal/ServerResponseStream.cs
@@ -39,6 +39,8 @@ namespace Grpc.Core.Internal
     /// Writes responses asynchronously to an underlying AsyncCallServer object.
     /// </summary>
     internal class ServerResponseStream<TRequest, TResponse> : IServerStreamWriter<TResponse>
+        where TRequest : class
+        where TResponse : class
     {
         readonly AsyncCallServer<TRequest, TResponse> call;
 
diff --git a/src/csharp/Grpc.Core/Server.cs b/src/csharp/Grpc.Core/Server.cs
index 1561aec07a..4a7abbb33f 100644
--- a/src/csharp/Grpc.Core/Server.cs
+++ b/src/csharp/Grpc.Core/Server.cs
@@ -47,6 +47,11 @@ namespace Grpc.Core
     /// </summary>
     public class Server
     {
+        /// <summary>
+        /// Pass this value as port to have the server choose an unused listening port for you.
+        /// </summary>
+        public const int PickUnusedPort = 0;
+
         // TODO(jtattermusch) : make sure the delegate doesn't get garbage collected while
         // native callbacks are in the completion queue.
         readonly CompletionCallbackDelegate serverShutdownHandler;
@@ -89,29 +94,25 @@ namespace Grpc.Core
         /// Add a non-secure port on which server should listen.
         /// Only call this before Start().
         /// </summary>
-        public int AddListeningPort(string addr)
+        /// <returns>The port on which server will be listening.</returns>
+        /// <param name="host">the host</param>
+        /// <param name="port">the port. If zero, an unused port is chosen automatically.</param>
+        public int AddListeningPort(string host, int port)
         {
-            lock (myLock)
-            {
-                Preconditions.CheckState(!startRequested);
-                return handle.AddListeningPort(addr);
-            }
+            return AddListeningPortInternal(host, port, null);
         }
 
         /// <summary>
-        /// Add a secure port on which server should listen.
+        /// Add a non-secure port on which server should listen.
         /// Only call this before Start().
         /// </summary>
-        public int AddListeningPort(string addr, ServerCredentials credentials)
+        /// <returns>The port on which server will be listening.</returns>
+        /// <param name="host">the host</param>
+        /// <param name="port">the port. If zero, , an unused port is chosen automatically.</param>
+        public int AddListeningPort(string host, int port, ServerCredentials credentials)
         {
-            lock (myLock)
-            {
-                Preconditions.CheckState(!startRequested);
-                using (var nativeCredentials = credentials.ToNativeCredentials())
-                {
-                    return handle.AddListeningPort(addr, nativeCredentials);
-                }
-            }
+            Preconditions.CheckNotNull(credentials);
+            return AddListeningPortInternal(host, port, credentials);
         }
 
         /// <summary>
@@ -164,6 +165,26 @@ namespace Grpc.Core
             handle.Dispose();
         }
 
+        private int AddListeningPortInternal(string host, int port, ServerCredentials credentials)
+        {
+            lock (myLock)
+            {
+                Preconditions.CheckState(!startRequested);    
+                var address = string.Format("{0}:{1}", host, port);
+                if (credentials != null)
+                {
+                    using (var nativeCredentials = credentials.ToNativeCredentials())
+                    {
+                        return handle.AddListeningPort(address, nativeCredentials);
+                    }
+                }
+                else
+                {
+                    return handle.AddListeningPort(address);    
+                }
+            }
+        }
+
         /// <summary>
         /// Allows one new RPC call to be received by server.
         /// </summary>
diff --git a/src/csharp/Grpc.Core/ServerCallContext.cs b/src/csharp/Grpc.Core/ServerCallContext.cs
new file mode 100644
index 0000000000..e873b3e88a
--- /dev/null
+++ b/src/csharp/Grpc.Core/ServerCallContext.cs
@@ -0,0 +1,56 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Runtime.CompilerServices;
+using System.Threading.Tasks;
+
+namespace Grpc.Core
+{
+    /// <summary>
+    /// Context for a server-side call.
+    /// </summary>
+    public sealed class ServerCallContext
+    {
+        
+        // TODO(jtattermusch): add cancellationToken
+
+        // TODO(jtattermusch): add deadline info
+
+        // TODO(jtattermusch): expose initial metadata sent by client for reading
+
+        // TODO(jtattermusch): expose method to send initial metadata back to client
+
+        // TODO(jtattermusch): allow setting status and trailing metadata to send after handler completes.
+    }
+}
diff --git a/src/csharp/Grpc.Core/ServerMethods.cs b/src/csharp/Grpc.Core/ServerMethods.cs
index 6646bb5a89..377b78eb30 100644
--- a/src/csharp/Grpc.Core/ServerMethods.cs
+++ b/src/csharp/Grpc.Core/ServerMethods.cs
@@ -42,20 +42,28 @@ namespace Grpc.Core
     /// <summary>
     /// Server-side handler for unary call.
     /// </summary>
-    public delegate Task<TResponse> UnaryServerMethod<TRequest, TResponse>(TRequest request);
+    public delegate Task<TResponse> UnaryServerMethod<TRequest, TResponse>(ServerCallContext context, TRequest request)
+        where TRequest : class
+        where TResponse : class;
 
     /// <summary>
     /// Server-side handler for client streaming call.
     /// </summary>
-    public delegate Task<TResponse> ClientStreamingServerMethod<TRequest, TResponse>(IAsyncStreamReader<TRequest> requestStream);
+    public delegate Task<TResponse> ClientStreamingServerMethod<TRequest, TResponse>(ServerCallContext context, IAsyncStreamReader<TRequest> requestStream)
+        where TRequest : class
+        where TResponse : class;
 
     /// <summary>
     /// Server-side handler for server streaming call.
     /// </summary>
-    public delegate Task ServerStreamingServerMethod<TRequest, TResponse>(TRequest request, IServerStreamWriter<TResponse> responseStream);
+    public delegate Task ServerStreamingServerMethod<TRequest, TResponse>(ServerCallContext context, TRequest request, IServerStreamWriter<TResponse> responseStream)
+        where TRequest : class
+        where TResponse : class;
 
     /// <summary>
     /// Server-side handler for bidi streaming call.
     /// </summary>
-    public delegate Task DuplexStreamingServerMethod<TRequest, TResponse>(IAsyncStreamReader<TRequest> requestStream, IServerStreamWriter<TResponse> responseStream);
+    public delegate Task DuplexStreamingServerMethod<TRequest, TResponse>(ServerCallContext context, IAsyncStreamReader<TRequest> requestStream, IServerStreamWriter<TResponse> responseStream)
+        where TRequest : class
+        where TResponse : class;
 }
diff --git a/src/csharp/Grpc.Core/ServerServiceDefinition.cs b/src/csharp/Grpc.Core/ServerServiceDefinition.cs
index 01b1dc8f7b..81846beb2f 100644
--- a/src/csharp/Grpc.Core/ServerServiceDefinition.cs
+++ b/src/csharp/Grpc.Core/ServerServiceDefinition.cs
@@ -76,6 +76,8 @@ namespace Grpc.Core
             public Builder AddMethod<TRequest, TResponse>(
                 Method<TRequest, TResponse> method,
                 UnaryServerMethod<TRequest, TResponse> handler)
+                    where TRequest : class
+                    where TResponse : class
             {
                 callHandlers.Add(GetFullMethodName(serviceName, method.Name), ServerCalls.UnaryCall(method, handler));
                 return this;
@@ -84,6 +86,8 @@ namespace Grpc.Core
             public Builder AddMethod<TRequest, TResponse>(
                 Method<TRequest, TResponse> method,
                 ClientStreamingServerMethod<TRequest, TResponse> handler)
+                    where TRequest : class
+                    where TResponse : class
             {
                 callHandlers.Add(GetFullMethodName(serviceName, method.Name), ServerCalls.ClientStreamingCall(method, handler));
                 return this;
@@ -92,6 +96,8 @@ namespace Grpc.Core
             public Builder AddMethod<TRequest, TResponse>(
                 Method<TRequest, TResponse> method,
                 ServerStreamingServerMethod<TRequest, TResponse> handler)
+                    where TRequest : class
+                    where TResponse : class
             {
                 callHandlers.Add(GetFullMethodName(serviceName, method.Name), ServerCalls.ServerStreamingCall(method, handler));
                 return this;
@@ -100,6 +106,8 @@ namespace Grpc.Core
             public Builder AddMethod<TRequest, TResponse>(
                 Method<TRequest, TResponse> method,
                 DuplexStreamingServerMethod<TRequest, TResponse> handler)
+                    where TRequest : class
+                    where TResponse : class
             {
                 callHandlers.Add(GetFullMethodName(serviceName, method.Name), ServerCalls.DuplexStreamingCall(method, handler));
                 return this;
diff --git a/src/csharp/Grpc.Core/Stub/AbstractStub.cs b/src/csharp/Grpc.Core/Stub/AbstractStub.cs
index cf5ab958c5..4a8b254357 100644
--- a/src/csharp/Grpc.Core/Stub/AbstractStub.cs
+++ b/src/csharp/Grpc.Core/Stub/AbstractStub.cs
@@ -64,6 +64,8 @@ namespace Grpc.Core
         /// Creates a new call to given method.
         /// </summary>
         protected Call<TRequest, TResponse> CreateCall<TRequest, TResponse>(string serviceName, Method<TRequest, TResponse> method)
+            where TRequest : class
+            where TResponse : class
         {
             var headerBuilder = Metadata.CreateBuilder();
             config.HeaderInterceptor(headerBuilder);
diff --git a/src/csharp/Grpc.Examples.MathServer/MathServer.cs b/src/csharp/Grpc.Examples.MathServer/MathServer.cs
index abc7ef05e4..cfde9b42c7 100644
--- a/src/csharp/Grpc.Examples.MathServer/MathServer.cs
+++ b/src/csharp/Grpc.Examples.MathServer/MathServer.cs
@@ -46,7 +46,7 @@ namespace math
 
             Server server = new Server();
             server.AddServiceDefinition(MathGrpc.BindService(new MathServiceImpl()));
-            int port = server.AddListeningPort(host + ":23456");
+            int port = server.AddListeningPort(host, 23456);
             server.Start();
 
             Console.WriteLine("MathServer listening on port " + port);
diff --git a/src/csharp/Grpc.Examples.Tests/MathClientServerTests.cs b/src/csharp/Grpc.Examples.Tests/MathClientServerTests.cs
index 332795e0e5..4ada95edd6 100644
--- a/src/csharp/Grpc.Examples.Tests/MathClientServerTests.cs
+++ b/src/csharp/Grpc.Examples.Tests/MathClientServerTests.cs
@@ -59,7 +59,7 @@ namespace math.Tests
 
             server = new Server();
             server.AddServiceDefinition(MathGrpc.BindService(new MathServiceImpl()));
-            int port = server.AddListeningPort(host + ":0");
+            int port = server.AddListeningPort(host, Server.PickUnusedPort);
             server.Start();
             channel = new Channel(host + ":" + port);
 
diff --git a/src/csharp/Grpc.Examples/MathGrpc.cs b/src/csharp/Grpc.Examples/MathGrpc.cs
index 60408b9018..03f5c31cb7 100644
--- a/src/csharp/Grpc.Examples/MathGrpc.cs
+++ b/src/csharp/Grpc.Examples/MathGrpc.cs
@@ -133,13 +133,13 @@ namespace math
         // server-side interface
         public interface IMathService
         {
-            Task<DivReply> Div(DivArgs request);
+            Task<DivReply> Div(ServerCallContext context, DivArgs request);
 
-            Task Fib(FibArgs request, IServerStreamWriter<Num> responseStream);
+            Task Fib(ServerCallContext context, FibArgs request, IServerStreamWriter<Num> responseStream);
 
-            Task<Num> Sum(IAsyncStreamReader<Num> requestStream);
+            Task<Num> Sum(ServerCallContext context, IAsyncStreamReader<Num> requestStream);
 
-            Task DivMany(IAsyncStreamReader<DivArgs> requestStream, IServerStreamWriter<DivReply> responseStream);
+            Task DivMany(ServerCallContext context, IAsyncStreamReader<DivArgs> requestStream, IServerStreamWriter<DivReply> responseStream);
         }
 
         public static ServerServiceDefinition BindService(IMathService serviceImpl)
diff --git a/src/csharp/Grpc.Examples/MathServiceImpl.cs b/src/csharp/Grpc.Examples/MathServiceImpl.cs
index 83ec2a8c3d..800dee8735 100644
--- a/src/csharp/Grpc.Examples/MathServiceImpl.cs
+++ b/src/csharp/Grpc.Examples/MathServiceImpl.cs
@@ -46,12 +46,12 @@ namespace math
     /// </summary>
     public class MathServiceImpl : MathGrpc.IMathService
     {
-        public Task<DivReply> Div(DivArgs request)
+        public Task<DivReply> Div(ServerCallContext context, DivArgs request)
         {
             return Task.FromResult(DivInternal(request));
         }
 
-        public async Task Fib(FibArgs request, IServerStreamWriter<Num> responseStream)
+        public async Task Fib(ServerCallContext context, FibArgs request, IServerStreamWriter<Num> responseStream)
         {
             if (request.Limit <= 0)
             {
@@ -68,7 +68,7 @@ namespace math
             }
         }
 
-        public async Task<Num> Sum(IAsyncStreamReader<Num> requestStream)
+        public async Task<Num> Sum(ServerCallContext context, IAsyncStreamReader<Num> requestStream)
         {
             long sum = 0;
             await requestStream.ForEach(async num =>
@@ -78,7 +78,7 @@ namespace math
             return Num.CreateBuilder().SetNum_(sum).Build();
         }
 
-        public async Task DivMany(IAsyncStreamReader<DivArgs> requestStream, IServerStreamWriter<DivReply> responseStream)
+        public async Task DivMany(ServerCallContext context, IAsyncStreamReader<DivArgs> requestStream, IServerStreamWriter<DivReply> responseStream)
         {
             await requestStream.ForEach(async divArgs =>
             {
diff --git a/src/csharp/Grpc.IntegrationTesting/InteropClientServerTest.cs b/src/csharp/Grpc.IntegrationTesting/InteropClientServerTest.cs
index 45380227c2..9e49ce0d17 100644
--- a/src/csharp/Grpc.IntegrationTesting/InteropClientServerTest.cs
+++ b/src/csharp/Grpc.IntegrationTesting/InteropClientServerTest.cs
@@ -59,7 +59,7 @@ namespace Grpc.IntegrationTesting
 
             server = new Server();
             server.AddServiceDefinition(TestServiceGrpc.BindService(new TestServiceImpl()));
-            int port = server.AddListeningPort(host + ":0", TestCredentials.CreateTestServerCredentials());
+            int port = server.AddListeningPort(host, Server.PickUnusedPort, TestCredentials.CreateTestServerCredentials());
             server.Start();
 
             var channelArgs = ChannelArgs.CreateBuilder()
diff --git a/src/csharp/Grpc.IntegrationTesting/InteropServer.cs b/src/csharp/Grpc.IntegrationTesting/InteropServer.cs
index ad5200774f..ca54aed041 100644
--- a/src/csharp/Grpc.IntegrationTesting/InteropServer.cs
+++ b/src/csharp/Grpc.IntegrationTesting/InteropServer.cs
@@ -93,16 +93,17 @@ namespace Grpc.IntegrationTesting
             var server = new Server();
             server.AddServiceDefinition(TestServiceGrpc.BindService(new TestServiceImpl()));
 
-            string addr = "0.0.0.0:" + options.port;
+            string host = "0.0.0.0";
+            int port = options.port.Value;
             if (options.useTls)
             {
-                server.AddListeningPort(addr, TestCredentials.CreateTestServerCredentials());
+                server.AddListeningPort(host, port, TestCredentials.CreateTestServerCredentials());
             }
             else
             {
-                server.AddListeningPort(addr);
+                server.AddListeningPort(host, options.port.Value);
             }
-            Console.WriteLine("Running server on " + addr);
+            Console.WriteLine("Running server on " + string.Format("{0}:{1}", host, port));
             server.Start();
 
             server.ShutdownTask.Wait();
diff --git a/src/csharp/Grpc.IntegrationTesting/TestServiceGrpc.cs b/src/csharp/Grpc.IntegrationTesting/TestServiceGrpc.cs
index d1f8aa12c7..9f14dad6c0 100644
--- a/src/csharp/Grpc.IntegrationTesting/TestServiceGrpc.cs
+++ b/src/csharp/Grpc.IntegrationTesting/TestServiceGrpc.cs
@@ -171,17 +171,17 @@ namespace grpc.testing
         // server-side interface
         public interface ITestService
         {
-            Task<Empty> EmptyCall(Empty request);
+            Task<Empty> EmptyCall(ServerCallContext context, Empty request);
 
-            Task<SimpleResponse> UnaryCall(SimpleRequest request);
+            Task<SimpleResponse> UnaryCall(ServerCallContext context, SimpleRequest request);
 
-            Task StreamingOutputCall(StreamingOutputCallRequest request, IServerStreamWriter<StreamingOutputCallResponse> responseStream);
+            Task StreamingOutputCall(ServerCallContext context, StreamingOutputCallRequest request, IServerStreamWriter<StreamingOutputCallResponse> responseStream);
 
-            Task<StreamingInputCallResponse> StreamingInputCall(IAsyncStreamReader<StreamingInputCallRequest> requestStream);
+            Task<StreamingInputCallResponse> StreamingInputCall(ServerCallContext context, IAsyncStreamReader<StreamingInputCallRequest> requestStream);
 
-            Task FullDuplexCall(IAsyncStreamReader<StreamingOutputCallRequest> requestStream, IServerStreamWriter<StreamingOutputCallResponse> responseStream);
+            Task FullDuplexCall(ServerCallContext context, IAsyncStreamReader<StreamingOutputCallRequest> requestStream, IServerStreamWriter<StreamingOutputCallResponse> responseStream);
 
-            Task HalfDuplexCall(IAsyncStreamReader<StreamingOutputCallRequest> requestStream, IServerStreamWriter<StreamingOutputCallResponse> responseStream);
+            Task HalfDuplexCall(ServerCallContext context, IAsyncStreamReader<StreamingOutputCallRequest> requestStream, IServerStreamWriter<StreamingOutputCallResponse> responseStream);
         }
 
         public static ServerServiceDefinition BindService(ITestService serviceImpl)
diff --git a/src/csharp/Grpc.IntegrationTesting/TestServiceImpl.cs b/src/csharp/Grpc.IntegrationTesting/TestServiceImpl.cs
index 8b0cf3a2d0..40f32b5a88 100644
--- a/src/csharp/Grpc.IntegrationTesting/TestServiceImpl.cs
+++ b/src/csharp/Grpc.IntegrationTesting/TestServiceImpl.cs
@@ -46,19 +46,19 @@ namespace grpc.testing
     /// </summary>
     public class TestServiceImpl : TestServiceGrpc.ITestService
     {
-        public Task<Empty> EmptyCall(Empty request)
+        public Task<Empty> EmptyCall(ServerCallContext context, Empty request)
         {
             return Task.FromResult(Empty.DefaultInstance);
         }
 
-        public Task<SimpleResponse> UnaryCall(SimpleRequest request)
+        public Task<SimpleResponse> UnaryCall(ServerCallContext context, SimpleRequest request)
         {
             var response = SimpleResponse.CreateBuilder()
                 .SetPayload(CreateZerosPayload(request.ResponseSize)).Build();
             return Task.FromResult(response);
         }
 
-        public async Task StreamingOutputCall(StreamingOutputCallRequest request, IServerStreamWriter<StreamingOutputCallResponse> responseStream)
+        public async Task StreamingOutputCall(ServerCallContext context, StreamingOutputCallRequest request, IServerStreamWriter<StreamingOutputCallResponse> responseStream)
         {
             foreach (var responseParam in request.ResponseParametersList)
             {
@@ -68,7 +68,7 @@ namespace grpc.testing
             }
         }
 
-        public async Task<StreamingInputCallResponse> StreamingInputCall(IAsyncStreamReader<StreamingInputCallRequest> requestStream)
+        public async Task<StreamingInputCallResponse> StreamingInputCall(ServerCallContext context, IAsyncStreamReader<StreamingInputCallRequest> requestStream)
         {
             int sum = 0;
             await requestStream.ForEach(async request =>
@@ -78,7 +78,7 @@ namespace grpc.testing
             return StreamingInputCallResponse.CreateBuilder().SetAggregatedPayloadSize(sum).Build();
         }
 
-        public async Task FullDuplexCall(IAsyncStreamReader<StreamingOutputCallRequest> requestStream, IServerStreamWriter<StreamingOutputCallResponse> responseStream)
+        public async Task FullDuplexCall(ServerCallContext context, IAsyncStreamReader<StreamingOutputCallRequest> requestStream, IServerStreamWriter<StreamingOutputCallResponse> responseStream)
         {
             await requestStream.ForEach(async request =>
             {
@@ -91,7 +91,7 @@ namespace grpc.testing
             });
         }
 
-        public async Task HalfDuplexCall(IAsyncStreamReader<StreamingOutputCallRequest> requestStream, IServerStreamWriter<StreamingOutputCallResponse> responseStream)
+        public async Task HalfDuplexCall(ServerCallContext context, IAsyncStreamReader<StreamingOutputCallRequest> requestStream, IServerStreamWriter<StreamingOutputCallResponse> responseStream)
         {
             throw new NotImplementedException();
         }
diff --git a/src/php/.gitignore b/src/php/.gitignore
index 0bb5f8e956..ecde2ca4c6 100644
--- a/src/php/.gitignore
+++ b/src/php/.gitignore
@@ -18,4 +18,5 @@ missing
 mkinstalldirs
 
 ext/grpc/ltmain.sh
-
+composer.lock
+vendor/
diff --git a/src/php/composer.lock b/src/php/composer.lock
deleted file mode 100644
index c2d723def4..0000000000
--- a/src/php/composer.lock
+++ /dev/null
@@ -1,315 +0,0 @@
-{
-    "_readme": [
-        "This file locks the dependencies of your project to a known state",
-        "Read more about it at http://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
-        "This file is @generated automatically"
-    ],
-    "hash": "bb81ea5f72ddea2f594a172ff0f3b44d",
-    "packages": [
-        {
-            "name": "firebase/php-jwt",
-            "version": "2.0.0",
-            "target-dir": "Firebase/PHP-JWT",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/firebase/php-jwt.git",
-                "reference": "ffcfd888ce1e4f2d70cac2dc9b7301038332fe57"
-            },
-            "dist": {
-                "type": "zip",
-                "url": "https://api.github.com/repos/firebase/php-jwt/zipball/ffcfd888ce1e4f2d70cac2dc9b7301038332fe57",
-                "reference": "ffcfd888ce1e4f2d70cac2dc9b7301038332fe57",
-                "shasum": ""
-            },
-            "require": {
-                "php": ">=5.2.0"
-            },
-            "type": "library",
-            "autoload": {
-                "classmap": [
-                    "Authentication/",
-                    "Exceptions/"
-                ]
-            },
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "BSD-3-Clause"
-            ],
-            "authors": [
-                {
-                    "name": "Neuman Vong",
-                    "email": "neuman+pear@twilio.com",
-                    "role": "Developer"
-                },
-                {
-                    "name": "Anant Narayanan",
-                    "email": "anant@php.net",
-                    "role": "Developer"
-                }
-            ],
-            "description": "A simple library to encode and decode JSON Web Tokens (JWT) in PHP. Should conform to the current spec.",
-            "homepage": "https://github.com/firebase/php-jwt",
-            "time": "2015-04-01 18:46:38"
-        },
-        {
-            "name": "google/auth",
-            "version": "dev-master",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/google/google-auth-library-php.git",
-                "reference": "35f87159b327fa6416266948c1747c585a4ae3ad"
-            },
-            "dist": {
-                "type": "zip",
-                "url": "https://api.github.com/repos/google/google-auth-library-php/zipball/35f87159b327fa6416266948c1747c585a4ae3ad",
-                "reference": "35f87159b327fa6416266948c1747c585a4ae3ad",
-                "shasum": ""
-            },
-            "require": {
-                "firebase/php-jwt": "2.0.0",
-                "guzzlehttp/guzzle": "5.2.*",
-                "php": ">=5.4"
-            },
-            "require-dev": {
-                "phplint/phplint": "0.0.1",
-                "phpunit/phpunit": "3.7.*"
-            },
-            "type": "library",
-            "autoload": {
-                "classmap": [
-                    "src/"
-                ],
-                "psr-4": {
-                    "Google\\Auth\\": "src"
-                }
-            },
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "Apache-2.0"
-            ],
-            "description": "Google Auth Library for PHP",
-            "homepage": "http://github.com/google/google-auth-library-php",
-            "keywords": [
-                "Authentication",
-                "google",
-                "oauth2"
-            ],
-            "time": "2015-04-30 11:57:19"
-        },
-        {
-            "name": "guzzlehttp/guzzle",
-            "version": "5.2.0",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/guzzle/guzzle.git",
-                "reference": "475b29ccd411f2fa8a408e64576418728c032cfa"
-            },
-            "dist": {
-                "type": "zip",
-                "url": "https://api.github.com/repos/guzzle/guzzle/zipball/475b29ccd411f2fa8a408e64576418728c032cfa",
-                "reference": "475b29ccd411f2fa8a408e64576418728c032cfa",
-                "shasum": ""
-            },
-            "require": {
-                "guzzlehttp/ringphp": "~1.0",
-                "php": ">=5.4.0"
-            },
-            "require-dev": {
-                "ext-curl": "*",
-                "phpunit/phpunit": "~4.0",
-                "psr/log": "~1.0"
-            },
-            "type": "library",
-            "extra": {
-                "branch-alias": {
-                    "dev-master": "5.0-dev"
-                }
-            },
-            "autoload": {
-                "psr-4": {
-                    "GuzzleHttp\\": "src/"
-                }
-            },
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "MIT"
-            ],
-            "authors": [
-                {
-                    "name": "Michael Dowling",
-                    "email": "mtdowling@gmail.com",
-                    "homepage": "https://github.com/mtdowling"
-                }
-            ],
-            "description": "Guzzle is a PHP HTTP client library and framework for building RESTful web service clients",
-            "homepage": "http://guzzlephp.org/",
-            "keywords": [
-                "client",
-                "curl",
-                "framework",
-                "http",
-                "http client",
-                "rest",
-                "web service"
-            ],
-            "time": "2015-01-28 01:03:29"
-        },
-        {
-            "name": "guzzlehttp/ringphp",
-            "version": "1.0.7",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/guzzle/RingPHP.git",
-                "reference": "52d868f13570a9a56e5fce6614e0ec75d0f13ac2"
-            },
-            "dist": {
-                "type": "zip",
-                "url": "https://api.github.com/repos/guzzle/RingPHP/zipball/52d868f13570a9a56e5fce6614e0ec75d0f13ac2",
-                "reference": "52d868f13570a9a56e5fce6614e0ec75d0f13ac2",
-                "shasum": ""
-            },
-            "require": {
-                "guzzlehttp/streams": "~3.0",
-                "php": ">=5.4.0",
-                "react/promise": "~2.0"
-            },
-            "require-dev": {
-                "ext-curl": "*",
-                "phpunit/phpunit": "~4.0"
-            },
-            "suggest": {
-                "ext-curl": "Guzzle will use specific adapters if cURL is present"
-            },
-            "type": "library",
-            "extra": {
-                "branch-alias": {
-                    "dev-master": "1.0-dev"
-                }
-            },
-            "autoload": {
-                "psr-4": {
-                    "GuzzleHttp\\Ring\\": "src/"
-                }
-            },
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "MIT"
-            ],
-            "authors": [
-                {
-                    "name": "Michael Dowling",
-                    "email": "mtdowling@gmail.com",
-                    "homepage": "https://github.com/mtdowling"
-                }
-            ],
-            "description": "Provides a simple API and specification that abstracts away the details of HTTP into a single PHP function.",
-            "time": "2015-03-30 01:43:20"
-        },
-        {
-            "name": "guzzlehttp/streams",
-            "version": "3.0.0",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/guzzle/streams.git",
-                "reference": "47aaa48e27dae43d39fc1cea0ccf0d84ac1a2ba5"
-            },
-            "dist": {
-                "type": "zip",
-                "url": "https://api.github.com/repos/guzzle/streams/zipball/47aaa48e27dae43d39fc1cea0ccf0d84ac1a2ba5",
-                "reference": "47aaa48e27dae43d39fc1cea0ccf0d84ac1a2ba5",
-                "shasum": ""
-            },
-            "require": {
-                "php": ">=5.4.0"
-            },
-            "require-dev": {
-                "phpunit/phpunit": "~4.0"
-            },
-            "type": "library",
-            "extra": {
-                "branch-alias": {
-                    "dev-master": "3.0-dev"
-                }
-            },
-            "autoload": {
-                "psr-4": {
-                    "GuzzleHttp\\Stream\\": "src/"
-                }
-            },
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "MIT"
-            ],
-            "authors": [
-                {
-                    "name": "Michael Dowling",
-                    "email": "mtdowling@gmail.com",
-                    "homepage": "https://github.com/mtdowling"
-                }
-            ],
-            "description": "Provides a simple abstraction over streams of data",
-            "homepage": "http://guzzlephp.org/",
-            "keywords": [
-                "Guzzle",
-                "stream"
-            ],
-            "time": "2014-10-12 19:18:40"
-        },
-        {
-            "name": "react/promise",
-            "version": "v2.2.0",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/reactphp/promise.git",
-                "reference": "365fcee430dfa4ace1fbc75737ca60ceea7eeeef"
-            },
-            "dist": {
-                "type": "zip",
-                "url": "https://api.github.com/repos/reactphp/promise/zipball/365fcee430dfa4ace1fbc75737ca60ceea7eeeef",
-                "reference": "365fcee430dfa4ace1fbc75737ca60ceea7eeeef",
-                "shasum": ""
-            },
-            "require": {
-                "php": ">=5.4.0"
-            },
-            "type": "library",
-            "extra": {
-                "branch-alias": {
-                    "dev-master": "2.0-dev"
-                }
-            },
-            "autoload": {
-                "psr-4": {
-                    "React\\Promise\\": "src/"
-                },
-                "files": [
-                    "src/functions_include.php"
-                ]
-            },
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "MIT"
-            ],
-            "authors": [
-                {
-                    "name": "Jan Sorgalla",
-                    "email": "jsorgalla@googlemail.com"
-                }
-            ],
-            "description": "A lightweight implementation of CommonJS Promises/A for PHP",
-            "time": "2014-12-30 13:32:42"
-        }
-    ],
-    "packages-dev": [],
-    "aliases": [],
-    "minimum-stability": "stable",
-    "stability-flags": {
-        "google/auth": 20
-    },
-    "prefer-stable": false,
-    "prefer-lowest": false,
-    "platform": {
-        "php": ">=5.5.0"
-    },
-    "platform-dev": []
-}