Function which calls a service in gRPC - c++

Question

I have to write a function in c++ which calls shared library which is created from gRPC client which runs the gRPC client and returns the result.
Is there any samples?

Answer 1

Here are Some Examples I hope i would be helpful somehow.
#include <iostream>
#include <memory>
#include <string>
#include <grpcpp/grpcpp.h>
#ifdef BAZEL_BUILD
#include "examples/protos/helloworld.grpc.pb.h"
#else
#include "helloworld.grpc.pb.h"
#endif
using grpc::Channel;
using grpc::ClientContext;
using grpc::Status;
using helloworld::HelloRequest;
using helloworld::HelloReply;
using helloworld::Greeter;
class GreeterClient
{
public:
GreeterClient(std::shared_ptr<Channel> channel): stub_(Greeter::NewStub(channel)) {}
// Assembles the client's payload, sends it and presents the response back from the server.
std::string SayHello(const std::string &user)
{
// Data we are sending to the server.
HelloRequest request;
request.set_name(user);
// 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;
// The actual RPC.
Status status = stub_->SayHello(&context, request, &reply);
// Act upon its status.
if (status.ok())
{
return reply.message();
}
else
{
std::cout << status.error_code() << ": " << status.error_message() <<
std::endl;
return "RPC failed";
}
}
private:
std::unique_ptr<Greeter::Stub > stub_;
};
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()));
std::string user("world");
std::string reply = greeter.SayHello(user);
std::cout << "Greeter received: " << reply << std::endl;
return 0;
}
OR
#include <iostream>
#include <string>
#include <dlfcn.h > // for dlopen, dlsym, dlclose
using namespace std;
int main()
{
void *handle; // handle to the library
string(*func)(string); // function pointer
char *error; // error message
handle = dlopen("/home/user/Desktop/grpc_client/libgrpc_client.so", RTLD_NOW); // open the library
if (!handle)
{
fputs(dlerror(), stderr); // print error message
exit(1);
}
func = (string(*)(string)) dlsym(handle, "run_grpc_client"); // get the function pointer
if ((error = dlerror()) != NULL)
{
fputs(error, stderr); // print error message
exit(1);
}
string result = func("hello"); // call the function
cout << result << endl;
dlclose(handle); // close the library
return 0;
}