baidu-rpc

code

public/baidu-rpc/example/asynchronous_echo_c++/server.cpp

virtual void Echo(google::protobuf::RpcController* cntl_base,
                      const example::EchoRequest* request,
                      example::EchoResponse* response,
                      google::protobuf::Closure* done) {
        // This object helps you to call done->Run() in RAII style. If you need
        // to process the request asynchronously, pass done_guard.release().
        baidu::rpc::ClosureGuard done_guard(done);
        //done表示Echo执行完成后，框架需要执行的后续操作，如果实现异步调用的话，直接返回一个response给client，然后异步执行自定义代码，自定义代码函数执行完之后，再执行done->Run();告诉框架执行后续操作。

public/baidu-rpc/example/asynchronous_echo_c++/client.cpp

// Since we are sending asynchronous RPC (`done' is not NULL),
        // these objects MUST remain valid until `done' is called.
        // As a result, we allocate these objects on heap
        example::EchoResponse* response = new example::EchoResponse();
        baidu::rpc::Controller* cntl = new baidu::rpc::Controller();
        // Notice that you don't have to new request, which can be modified
        // or destroyed just after stub.Echo is called.
        example::EchoRequest request;
        request.set_message("hello world");
        cntl->set_log_id(log_id ++);  // set by user
        if (FLAGS_send_attachment) {
            // Set attachment which is wired to network directly instead of
            // being serialized into protobuf messages.
            cntl->request_attachment().append("foo");
        }
        // We use protobuf utility `NewCallback' to create a closure object
        // that will call our callback `HandleEchoResponse'. This closure
        // will automatically delete itself after being called once
        google::protobuf::Closure* done = baidu::rpc::NewCallback(
            &HandleEchoResponse, cntl, response);
        stub.Echo(cntl, &request, response, done);
        // This is an asynchronous RPC, so we can only fetch the result
        // inside the callback

done是回调闭包，必须创建在堆上，response是回调函数的返回参数，也必须创建在堆上，如果在栈上分配的话，在触发回调函数时，内存已经失效了。

public/baidu-rpc/example/http_c++/http_server.cpp

void Echo(google::protobuf::RpcController* cntl_base,
              const HttpRequest*,
              HttpResponse*,
              google::protobuf::Closure* done) {
        // This object helps you to call done->Run() in RAII style. If you need
        // to process the request asynchronously, pass done_guard.release().
        baidu::rpc::ClosureGuard done_guard(done);
        baidu::rpc::Controller* cntl =
            static_cast<baidu::rpc::Controller*>(cntl_base);
        // Fill response.
        cntl->http_response().set_content_type("text/plain");
        base::IOBufBuilder os;
        os << "queries:";
        for (baidu::rpc::URI::QueryIterator it = cntl->http_request().uri().QueryBegin();
                it != cntl->http_request().uri().QueryEnd(); ++it) {
            os << ' ' << it->first << '=' << it->second;
        }
        os << "\nbody: " << cntl->request_attachment() << '\n';
        os.move_to(cntl->response_attachment());
    }

注意在http服务端中Echo函数参数const HttpRequest*, HttpResponse*,，HttpRequest，Response是没有成员变量。