Objectives

Upon completion of this short, you will be able to:

  • connect a client to a server through a socket
  • send the contents of a file from the client to the server

Overview

Simple Client/Server

Send File to Server

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>

#define PORT 2023

int main(int argc, char *argv[]) {
    int sock;
    struct sockaddr_in server;
    char message[1000], server_reply[2000], file_contents[10000];
    FILE *fp;

    if (argc != 2) {
        printf("Usage: %s <file name>\n", argv[0]);
        return 1;
    }

    // Open the file
    fp = fopen(argv[1], "r");
    if (fp == NULL) {
        perror("Error opening file");
        return 1;
    }

    // Read file contents
    fread(file_contents, sizeof(char), sizeof(file_contents), fp);
    fclose(fp);

    // Create socket
    sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock == -1) {
        printf("Could not create socket");
    }

    // Prepare the sockaddr_in structure
    server.sin_addr.s_addr = inet_addr("127.0.0.1");
    server.sin_family = AF_INET;
    server.sin_port = htons(PORT);

    // Connect to remote server
    if (connect(sock, (struct sockaddr *)&server, sizeof(server)) < 0) {
        perror("connect failed. Error");
        return 1;
    }

    printf("Connected\n");

    // Send file contents to the server
    if (send(sock, file_contents, strlen(file_contents), 0) < 0) {
        printf("send failed");
        return 1;
    }

    // Receive message from the server
    if (recv(sock, server_reply, 2000, 0) < 0) {
        printf("recv failed");
        return 1;
    }

    printf("Server reply: %s\n", server_reply);

    close(sock);
    return 0;
}

Errata

None collected yet. Let us know.