http-get.c

/**
 * @brief Give an url on format http://hostname/file or https://hostname/file
 *        retrieve such file with a get. File is not saved.
 * @author Daniel Hilst Selli <danielhilst@gmail.com>
 */

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

#define pexit(x)                                \
        do {                                    \
                perror(x);                      \
                exit(EXIT_FAILURE);             \
        } while (0)

static char buf[BUFSIZ];

int main(int argc, char **argv)
{
        int sock;
        int error;
        int n = 3;
        int bytes = 0;
        struct addrinfo *resaddr;
        char *service;
        char *hostname;
        char *file;
        char *ptr;

        if (argc != 2) {
                fprintf(stderr, "Usage: %s {http|https}://HOSTNAME[/FILE]\n", argv[0]);
                exit(EXIT_FAILURE);
        }

        ptr = strchr(argv[1], ':');
        if (!ptr) {
                fprintf(stderr, "ERROR: Bad Service\n");
                fprintf(stderr, "Usage: %s {http|https}://HOSTNAME[/FILE]\n", argv[0]);
                exit(EXIT_FAILURE);
        }

        *ptr++ = '\0';          /* replace `://' to `\0\0\0' */
        *ptr++ = '\0';          /* terminating service string */
        *ptr++ = '\0';
        service = argv[1];
        printf("Service => %s\n", service);

        hostname = ptr;
        ptr = strchr(ptr, '/');
        if (ptr)
                *ptr++ = '\0';          /* replace `/' to `\0' terminating hostname string */

        printf("Hostname => %s\n", hostname);

        file = ptr ? ptr : "";
        printf("File => %s\n", file);

        error = getaddrinfo(hostname, service, NULL, &resaddr);
        if (error) {
                fprintf(stderr, "ERROR: %s\n", gai_strerror(error));
                exit(EXIT_FAILURE);
        }

        printf("IP Address => %s\n", inet_ntoa(((struct sockaddr_in *)resaddr->ai_addr)->sin_addr));

        /* create socket */
        sock = socket(resaddr->ai_family, resaddr->ai_socktype, resaddr->ai_protocol);
        if (sock == -1)
                pexit("socket");

        error = setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &n, sizeof(int));

        error = connect(sock, resaddr->ai_addr, resaddr->ai_addrlen);
        if (error)
                pexit("connect");
        puts("Connected!");

        freeaddrinfo(resaddr);  /* free addrinfo linked list */

        snprintf(buf, BUFSIZ, "GET /%s\r\n", file);
        n = send(sock, buf, strlen(buf), MSG_WAITALL);
        if (n < 0)
                perror("send");
        printf("%s\n", buf);

        while ((n = recv(sock, buf, BUFSIZ, 0)) > 0) {
                bytes += n;
                printf("%d bytes transferred\n", bytes);
                /* printf("%.*s", n, buf); */
        }

        if (n == -1)
                pexit("recv");

        return 0;
}