4x7y / xrpc

A simple C rpc generator

XRPC

In this project, I implemented a simple rpc generator, which allows user to define messages and rpc function in a json style format and generate server-stub.h and client-stub.h to include. The objective platform is Linux and OS X and do not depend on other libraries.

The xrpc generator consists of a simple parser which is used to read rpc definition files , a C socket program skeleton and some data strutures for saving message and rpc function data. The following is a sample of my rpc definition file:

message FiveNumbers
{
	int num1
	int num2
	int num3
	int num4
	int num5
}

message MinMaxAverage
{
	int max
	int min
	double average
}

rpc Statistics
{
	param  FiveNumbers
	reply  MinMaxAverage
}

message , rpc, param and reply are keywords. param and reply indicate the input and output of a rpc function.

Compile

Use the following command

gcc rpc_gen.c -o rpc-gen

and you will have the generator program.

Usage

Write your rpc definition file and pass the filename to the rpc-gen as a parameter.

./rpc-gen ./stat.proto

and it will automatically generate two stub files client_stub.h and server_stub.h.

Include these header files in your client and server program respectively will allow you to use rpc service.

/*
    C socket server example
*/

#include "server_stub.h"

MinMaxAverage event_callback(FiveNumbers nums)
{
	MinMaxAverage reply;

	int max = nums.num1;
	int min = nums.num1;

	double sum = 0;
	int *pnum = &(nums.num1);
	for (int i = 0; i < 5; i++)
	{
		if (*pnum > max) max = *pnum;
		if (*pnum < min) min = *pnum;
		sum += *pnum;
		pnum++;
	}

printf("average = %f\n", sum / 5.0);
	reply.min = min;
	reply.max = max;
	reply.average = 3;

	return reply;
}

int main(int argc , char *argv[])
{
    rpc_server_handler_t server = create_rpc_server(8888);
    start_rpc_server(server, event_callback);

    return 0;
}

/*
    C ECHO client example using sockets
*/
#include "client_stub.h"

int main(int argc , char *argv[])
{
	rpc_client_handler_t client
		= create_rpc_client("127.0.0.1", 8888);
	if (!client) return FAILURE;

    FiveNumbers message;
    message.num1 = 5;
    message.num2 = 3;
    message.num3 = 1;
    message.num4 = 4;
    message.num5 = 2;
    MinMaxAverage response;
    Statistics(client, message, &response);
    printf("Min: %d\tMax: %d\tAverage: %f\n", response.min, response.max, response.average);

    close_rpc_client(client);
    return SUCCESS;
}