client.c

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <netdb.h>
#include <dirent.h>

#define MSG_LEN 2000
#define CMND_LEN 4
#define LIST "List"
#define GET "Get "
#define PUT "Put "
#define QUIT "Quit"
//#define SRV_PORT	7777

/*
 * A Client Application for a http-like protocol
 * with simple Get, Put, and List Commands for server interaction
 */
int main(int argc, char *args[])
{

    int s_tcp; /* socket descriptor */
    char *port; // server port
    char *srv_adr; // server address
    struct addrinfo *result, *p;
    struct addrinfo hints;
    int n;

    char msg[MSG_LEN]; // message
    char buffer[MSG_LEN]; // buffer for send and receive

    srv_adr = args[1]; // first main parameter for destination address

    if (argc == 3)
    {
        port = args[2]; // second main parameter for destination port
    }
    else if (argc == 2)
    {
        port = NULL;
    }
    else
    {
        perror("incorrect parameters");
        return 1;
    }

    memset(&hints, 0, sizeof hints);
    hints.ai_family = AF_UNSPEC; // use of IPv4 or IPv6 possible
    hints.ai_socktype = SOCK_STREAM; // TCP Stream

    /* serveradress as dns name oder ip address will be parsed
     * and the information will be put into the struct addrinfo
     * with specified IP-Address families
     */
    if (getaddrinfo(srv_adr, port, &hints, &result) != 0)
    {
        perror("getaddrdinfo failed");
        return 1;
    }

    /*
     * result as p is a linked list
     * it will be iterated to establish a connection
     */
    for (p = result; p != NULL; p = p->ai_next)
    {
        if ((s_tcp = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) == -1)
        {
            perror("TCP Socket");
            continue;
        }

        if (connect(s_tcp, p->ai_addr, p->ai_addrlen) == -1)
        {
            perror("Connect");
            continue;
        }

        break;
    }

    /*
     * if a serverconnection with the infomation addrinfo is not possible
     * the client will terminate
     */
    if (p == NULL)
    {
        fprintf(stderr, "client: failed to connect\n");
        return 2;
    }

    freeaddrinfo(result);

    while (1)
    {

        printf("Enter command: \n");

        fgets(msg, MSG_LEN, stdin);

        if (strncmp(msg, QUIT, CMND_LEN) == 0)
        {
            printf("connection terminated\n");
            close(s_tcp);
            return 0;
        }
        else if ((strncmp(msg, PUT, CMND_LEN) == 0))
        {
            char *fname;
            FILE *fp;
            int fc;
            char str[10];
            char tmp[MSG_LEN];
            int c;

            fname = strtok(msg, " ");
            fname = strtok(NULL, "\n");



            fp = fopen(fname, "r");
            if (fp == NULL)
            {
                perror("error file");
            }
            else
            {
                while ((c = fgetc(fp)) != EOF)
                {
                    sprintf(str, "%c", c);
                    strncat(tmp, str, sizeof(tmp));
                }
                fclose(fp);
            }
            sprintf(msg, "%s", tmp);
        }

        /*
         * other commands than Quit or Put will be send direct to the server
         * the server decides if they are correct or not
         */
        if ((send(s_tcp, msg, strlen(msg), 0)) > 0)
        {
            printf("Message %s sent.\n", msg);
        }

        /*
         * received server messages will be print to console
         */
        if (n = (recv(s_tcp, buffer, sizeof(buffer), 0)) > 0)
        {
            printf("%s\n", buffer);
        }

        memset(buffer, 0, strlen(buffer));
        memset(msg, 0, strlen(msg));
    }
    close(s_tcp);
    return 0;
}