/*********************************************************************************
 *      Copyright:  (C) 2018 LingYun IoT Studio
 *                  All rights reserved.
 *
 *       Filename:  socket_client.c
 *    Description:  This file is socket client sample source code, it will connect
 *                  socket server and send to/receive from it.
 *                 
 *        Version:  1.0.0(10/23/2018)
 *         Author:  Guo Wenxue <guowenxue@gmail.com>
 *      ChangeLog:  1, Release initial version on "2018-10-23 01:38:08 PM"
 *                 
 ********************************************************************************/
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define SERVER_IP          "127.0.0.1"
#define SERVER_PORT        8889
#define MSG_STR            "Hello, Unix Network Program World!"

int main(int argc, char **argv)
{
    int                     conn_fd = -1;
    int                     rv = -1;    
    char                    buf[1024]; 
    struct sockaddr_in      serv_addr;

    conn_fd = socket(AF_INET, SOCK_STREAM, 0);
    if(conn_fd < 0)
    {
        printf("create socket failure: %s\n", strerror(errno));
        return -1;
    }

    memset(&serv_addr, 0, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(SERVER_PORT);
    inet_aton( SERVER_IP, &serv_addr.sin_addr );

    if( connect(conn_fd, (struct sockaddr *)&serv_addr, sizeof(serv_addr))  < 0)
    {
        printf("connect to server [%s:%d] failure: %s\n", SERVER_IP, SERVER_PORT, strerror(errno));
        return 0;
    }
    
    if( write(conn_fd, MSG_STR, strlen(MSG_STR)) < 0 )
    {
        printf("Write data to server [%s:%d] failure: %s\n", SERVER_IP, SERVER_PORT, strerror(errno));
	goto cleanup;
    }
    
    memset(buf, 0, sizeof(buf));
    rv = read(conn_fd, buf, sizeof(buf));    
    if(rv < 0)
    {
	    printf("Read data from server failure: %s\n", strerror(errno));
	    goto cleanup;
    }
    else if( 0 == rv )
    {
	    printf("Client connect to server get disconnected\n");
	    goto cleanup;
    }

    printf("Read %d bytes data from server: '%s'\n", rv, buf);


cleanup:
    close(conn_fd);
}