aboutsummaryrefslogtreecommitdiffhomepage
path: root/include/grpc++/impl/codegen/server_context.h
blob: a2d6967bf8421a54adeb98cdf8902895ddde8b4e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
/*
 *
 * Copyright 2015 gRPC authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#ifndef GRPCXX_IMPL_CODEGEN_SERVER_CONTEXT_H
#define GRPCXX_IMPL_CODEGEN_SERVER_CONTEXT_H

#include <map>
#include <memory>
#include <vector>

#include <grpc/impl/codegen/compression_types.h>

#include <grpc++/impl/codegen/call.h>
#include <grpc++/impl/codegen/completion_queue_tag.h>
#include <grpc++/impl/codegen/config.h>
#include <grpc++/impl/codegen/create_auth_context.h>
#include <grpc++/impl/codegen/metadata_map.h>
#include <grpc++/impl/codegen/security/auth_context.h>
#include <grpc++/impl/codegen/string_ref.h>
#include <grpc++/impl/codegen/time.h>

struct grpc_metadata;
struct grpc_call;
struct census_context;

namespace grpc {
class ClientContext;
template <class W, class R>
class ServerAsyncReader;
template <class W>
class ServerAsyncWriter;
template <class W>
class ServerAsyncResponseWriter;
template <class W, class R>
class ServerAsyncReaderWriter;
template <class R>
class ServerReader;
template <class W>
class ServerWriter;
namespace internal {
template <class W, class R>
class ServerReaderWriterBody;
template <class ServiceType, class RequestType, class ResponseType>
class RpcMethodHandler;
template <class ServiceType, class RequestType, class ResponseType>
class ClientStreamingHandler;
template <class ServiceType, class RequestType, class ResponseType>
class ServerStreamingHandler;
template <class ServiceType, class RequestType, class ResponseType>
class BidiStreamingHandler;
class UnknownMethodHandler;
template <class Streamer, bool WriteNeeded>
class TemplatedBidiStreamingHandler;
class Call;
}  // namespace internal

class CompletionQueue;
class Server;
class ServerInterface;

namespace testing {
class InteropServerContextInspector;
class ServerContextTestSpouse;
}  // namespace testing

/// A ServerContext allows the person implementing a service handler to:
///
/// - Add custom initial and trailing metadata key-value pairs that will
///   propagated to the client side.
/// - Control call settings such as compression and authentication.
/// - Access metadata coming from the client.
/// - Get performance metrics (ie, census).
///
/// Context settings are only relevant to the call handler they are supplied to,
/// that is to say, they aren't sticky across multiple calls. Some of these
/// settings, such as the compression options, can be made persistant at server
/// construction time by specifying the approriate \a ChannelArguments
/// to a \a grpc::ServerBuilder, via \a ServerBuilder::AddChannelArgument.
///
/// \warning ServerContext instances should \em not be reused across rpcs.
class ServerContext {
 public:
  ServerContext();  // for async calls
  ~ServerContext();

  /// Return the deadline for the server call.
  std::chrono::system_clock::time_point deadline() const {
    return Timespec2Timepoint(deadline_);
  }

  /// Return a \a gpr_timespec representation of the server call's deadline.
  gpr_timespec raw_deadline() const { return deadline_; }

  /// Add the (\a meta_key, \a meta_value) pair to the initial metadata
  /// associated with a server call. These are made available at the client side
  /// by the \a grpc::ClientContext::GetServerInitialMetadata() method.
  ///
  /// \warning This method should only be called before sending initial metadata
  /// to the client (which can happen explicitly, or implicitly when sending a
  /// a response message or status to the client).
  ///
  /// \param meta_key The metadata key. If \a meta_value is binary data, it must
  /// end in "-bin".
  /// \param meta_value The metadata value. If its value is binary, the key name
  /// must end in "-bin".
  void AddInitialMetadata(const grpc::string& key, const grpc::string& value);

  /// Add the (\a meta_key, \a meta_value) pair to the initial metadata
  /// associated with a server call. These are made available at the client
  /// side by the \a grpc::ClientContext::GetServerTrailingMetadata() method.
  ///
  /// \warning This method should only be called before sending trailing
  /// metadata to the client (which happens when the call is finished and a
  /// status is sent to the client).
  ///
  /// \param meta_key The metadata key. If \a meta_value is binary data,
  /// it must end in "-bin".
  /// \param meta_value The metadata value. If its value is binary, the key name
  /// must end in "-bin".
  void AddTrailingMetadata(const grpc::string& key, const grpc::string& value);

  /// IsCancelled is always safe to call when using sync API.
  /// When using async API, it is only safe to call IsCancelled after
  /// the AsyncNotifyWhenDone tag has been delivered.
  bool IsCancelled() const;

  /// Cancel the Call from the server. This is a best-effort API and
  /// depending on when it is called, the RPC may still appear successful to
  /// the client.
  /// For example, if TryCancel() is called on a separate thread, it might race
  /// with the server handler which might return success to the client before
  /// TryCancel() was even started by the thread.
  ///
  /// It is the caller's responsibility to prevent such races and ensure that if
  /// TryCancel() is called, the serverhandler must return Status::CANCELLED.
  /// The only exception is that if the serverhandler is already returning an
  /// error status code, it is ok to not return Status::CANCELLED even if
  /// TryCancel() was called.
  void TryCancel() const;

  /// Return a collection of initial metadata key-value pairs sent from the
  /// client. Note that keys may happen more than
  /// once (ie, a \a std::multimap is returned).
  ///
  /// It is safe to use this method after initial metadata has been received,
  /// Calls always begin with the client sending initial metadata, so this is
  /// safe to access as soon as the call has begun on the server side.
  ///
  /// \return A multimap of initial metadata key-value pairs from the server.
  const std::multimap<grpc::string_ref, grpc::string_ref>& client_metadata()
      const {
    return *client_metadata_.map();
  }

  /// Return the compression algorithm to be used by the server call.
  grpc_compression_level compression_level() const {
    return compression_level_;
  }

  /// Set \a algorithm to be the compression algorithm used for the server call.
  ///
  /// \param algorithm The compression algorithm used for the server call.
  void set_compression_level(grpc_compression_level level) {
    compression_level_set_ = true;
    compression_level_ = level;
  }

  /// Return a bool indicating whether the compression level for this call
  /// has been set (either implicitly or through a previous call to
  /// \a set_compression_level.
  bool compression_level_set() const { return compression_level_set_; }

  /// Return the compression algorithm to be used by the server call.
  grpc_compression_algorithm compression_algorithm() const {
    return compression_algorithm_;
  }
  /// Set \a algorithm to be the compression algorithm used for the server call.
  ///
  /// \param algorithm The compression algorithm used for the server call.
  void set_compression_algorithm(grpc_compression_algorithm algorithm);

  /// Set the load reporting costs in \a cost_data for the call.
  void SetLoadReportingCosts(const std::vector<grpc::string>& cost_data);

  /// Return the authentication context for this server call.
  ///
  /// \see grpc::AuthContext.
  std::shared_ptr<const AuthContext> auth_context() const {
    if (auth_context_.get() == nullptr) {
      auth_context_ = CreateAuthContext(call_);
    }
    return auth_context_;
  }

  /// Return the peer uri in a string.
  /// WARNING: this value is never authenticated or subject to any security
  /// related code. It must not be used for any authentication related
  /// functionality. Instead, use auth_context.
  grpc::string peer() const;

  /// Get the census context associated with this server call.
  const struct census_context* census_context() const;

  /// Async only. Has to be called before the rpc starts.
  /// Returns the tag in completion queue when the rpc finishes.
  /// IsCancelled() can then be called to check whether the rpc was cancelled.
  void AsyncNotifyWhenDone(void* tag) {
    has_notify_when_done_tag_ = true;
    async_notify_when_done_tag_ = tag;
  }

  /// Should be used for framework-level extensions only.
  /// Applications never need to call this method.
  grpc_call* c_call() { return call_; }

 private:
  friend class ::grpc::testing::InteropServerContextInspector;
  friend class ::grpc::testing::ServerContextTestSpouse;
  friend class ::grpc::ServerInterface;
  friend class ::grpc::Server;
  template <class W, class R>
  friend class ::grpc::ServerAsyncReader;
  template <class W>
  friend class ::grpc::ServerAsyncWriter;
  template <class W>
  friend class ::grpc::ServerAsyncResponseWriter;
  template <class W, class R>
  friend class ::grpc::ServerAsyncReaderWriter;
  template <class R>
  friend class ::grpc::ServerReader;
  template <class W>
  friend class ::grpc::ServerWriter;
  template <class W, class R>
  friend class ::grpc::internal::ServerReaderWriterBody;
  template <class ServiceType, class RequestType, class ResponseType>
  friend class ::grpc::internal::RpcMethodHandler;
  template <class ServiceType, class RequestType, class ResponseType>
  friend class ::grpc::internal::ClientStreamingHandler;
  template <class ServiceType, class RequestType, class ResponseType>
  friend class ::grpc::internal::ServerStreamingHandler;
  template <class Streamer, bool WriteNeeded>
  friend class ::grpc::internal::TemplatedBidiStreamingHandler;
  friend class ::grpc::internal::UnknownMethodHandler;
  friend class ::grpc::ClientContext;

  /// Prevent copying.
  ServerContext(const ServerContext&);
  ServerContext& operator=(const ServerContext&);

  class CompletionOp;

  void BeginCompletionOp(internal::Call* call);
  /// Return the tag queued by BeginCompletionOp()
  internal::CompletionQueueTag* GetCompletionOpTag();

  ServerContext(gpr_timespec deadline, grpc_metadata_array* arr);

  void set_call(grpc_call* call) { call_ = call; }

  uint32_t initial_metadata_flags() const { return 0; }

  CompletionOp* completion_op_;
  bool has_notify_when_done_tag_;
  void* async_notify_when_done_tag_;

  gpr_timespec deadline_;
  grpc_call* call_;
  CompletionQueue* cq_;
  bool sent_initial_metadata_;
  mutable std::shared_ptr<const AuthContext> auth_context_;
  internal::MetadataMap client_metadata_;
  std::multimap<grpc::string, grpc::string> initial_metadata_;
  std::multimap<grpc::string, grpc::string> trailing_metadata_;

  bool compression_level_set_;
  grpc_compression_level compression_level_;
  grpc_compression_algorithm compression_algorithm_;

  internal::CallOpSet<internal::CallOpSendInitialMetadata,
                      internal::CallOpSendMessage>
      pending_ops_;
  bool has_pending_ops_;
};

}  // namespace grpc

#endif  // GRPCXX_IMPL_CODEGEN_SERVER_CONTEXT_H