tcp-ip-sockets-in-c/ch3/TCPEchoClient.c

#include <string.h>
#include <unistd.h>

#include "TCPClientUtility.h"
#include "Practical.h"

int main(int argc, char **argv) {
    if (argc < 3 || argc > 4) {
        DieWithUserMessage(
            "Parameter(s)",
            "<Server Address/Name> <Echo Word> [<Server Port/Service>]"
        );
    }

    char *server = argv[1];
    char *echo_str = argv[2];
    char *service = (argc == 4) ? argv[3] : "echo";

    int sock = setup_tcp_client_socket(server, service);
    if (sock < 0) {
        DieWithUserMessage(
            "setup_tcp_client_socket() failed",
            "Unable to connect"
        );
    }

    const size_t echo_str_len = strlen(echo_str);

    ssize_t num_bytes = send(sock, echo_str, echo_str_len, 0);
    if (num_bytes < 0) {
        DieWithSystemMessage("send() failed");
    } else if ((size_t) num_bytes != echo_str_len) {
        DieWithUserMessage("send()", "Sent unexpected amount of bytes");
    }

    unsigned int total_bytes_rcvd = 0;
    fputs("Received: ", stdout);
    while (total_bytes_rcvd < echo_str_len) {
        char buf[BUFSIZE];
        num_bytes = recv(sock, buf, BUFSIZE - 1, 0);
        if (num_bytes < 0) {
            DieWithSystemMessage("recv() failed");
        } else if (num_bytes == 0) {
            DieWithUserMessage("recv()", "Connection closed prematurely");
        }
        total_bytes_rcvd += num_bytes;
        buf[num_bytes] = '\0';
        fputs(buf, stdout);
    }

    fputc('\n', stdout);

    close(sock);

    return 0;
}