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/*
*
* 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.
*
*/
#include <iostream>
#include <memory>
#include <string>
#include <grpc++/grpc++.h>
#include <grpc/support/log.h>
#include <thread>
#include "helloworld.grpc.pb.h"
using grpc::Channel;
using grpc::ClientAsyncResponseReader;
using grpc::ClientContext;
using grpc::CompletionQueue;
using grpc::Status;
using helloworld::HelloRequest;
using helloworld::HelloReply;
using helloworld::Greeter;
class GreeterClient {
public:
explicit GreeterClient(std::shared_ptr<Channel> channel)
: stub_(Greeter::NewStub(channel)) {}
// Assembles the client's payload and sends it to the server.
void SayHello(const std::string& user) {
// Data we are sending to the server.
HelloRequest request;
request.set_name(user);
// Call object to store rpc data
AsyncClientCall* call = new AsyncClientCall;
// stub_->AsyncSayHello() performs the RPC call, returning an instance to
// store in "call". Because we are using the asynchronous API, we need to
// hold on to the "call" instance in order to get updates on the ongoing RPC.
call->response_reader = stub_->AsyncSayHello(&call->context, request, &cq_);
// Request that, upon completion of the RPC, "reply" be updated with the
// server's response; "status" with the indication of whether the operation
// was successful. Tag the request with the memory address of the call object.
call->response_reader->Finish(&call->reply, &call->status, (void*)call);
}
// Loop while listening for completed responses.
// Prints out the response from the server.
void AsyncCompleteRpc() {
void* got_tag;
bool ok = false;
// Block until the next result is available in the completion queue "cq".
while (cq_.Next(&got_tag, &ok)) {
// The tag in this example is the memory location of the call object
AsyncClientCall* call = static_cast<AsyncClientCall*>(got_tag);
// Verify that the request was completed successfully. Note that "ok"
// corresponds solely to the request for updates introduced by Finish().
GPR_ASSERT(ok);
if (call->status.ok())
std::cout << "Greeter received: " << call->reply.message() << std::endl;
else
std::cout << "RPC failed" << std::endl;
// Once we're complete, deallocate the call object.
delete call;
}
}
private:
// struct for keeping state and data information
struct AsyncClientCall {
// Container for the data we expect from the server.
HelloReply reply;
// Context for the client. It could be used to convey extra information to
// the server and/or tweak certain RPC behaviors.
ClientContext context;
// Storage for the status of the RPC upon completion.
Status status;
std::unique_ptr<ClientAsyncResponseReader<HelloReply>> response_reader;
};
// Out of the passed in Channel comes the stub, stored here, our view of the
// server's exposed services.
std::unique_ptr<Greeter::Stub> stub_;
// The producer-consumer queue we use to communicate asynchronously with the
// gRPC runtime.
CompletionQueue cq_;
};
int main(int argc, char** argv) {
// Instantiate the client. It requires a channel, out of which the actual RPCs
// are created. This channel models a connection to an endpoint (in this case,
// localhost at port 50051). We indicate that the channel isn't authenticated
// (use of InsecureChannelCredentials()).
GreeterClient greeter(grpc::CreateChannel(
"localhost:50051", grpc::InsecureChannelCredentials()));
// Spawn reader thread that loops indefinitely
std::thread thread_ = std::thread(&GreeterClient::AsyncCompleteRpc, &greeter);
for (int i = 0; i < 100; i++) {
std::string user("world " + std::to_string(i));
greeter.SayHello(user); // The actual RPC call!
}
std::cout << "Press control-c to quit" << std::endl << std::endl;
thread_.join(); //blocks forever
return 0;
}
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