simple-web-request.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#if defined(WIN32) || defined(_WIN32)
#include <winsock2.h>
#include <ws2tcpip.h>
#include <windows.h>
#include <stdint.h>
#pragma comment(lib,"ws2_32.lib") // Winsock Library
#else
#include <netinet/tcp.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#define closesocket close
#endif

int socket_connect(const char *host, uint16_t port){
    struct hostent *hp;
    struct sockaddr_in addr = { 0 };
    int on = 1, sock;

    if ((hp = gethostbyname(host)) == NULL) {
        return -1;
    }
    memcpy(&addr.sin_addr, hp->h_addr, hp->h_length);
    addr.sin_port = htons(port);
    addr.sin_family = hp->h_addrtype;
    sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (sock < 0) {
        return -1;
    }
    setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, (const char *)&on, sizeof(int));

    if (connect(sock, (struct sockaddr *)&addr, sizeof(struct sockaddr_in)) < 0) {
        closesocket(sock);
        return -1;
    }
    return sock;
}

#define BUFFER_SIZE 1024

typedef void (*FN_recv_data)(uint8_t *data, size_t len, void *p);

void launch_web_request(const char *host, uint16_t port, const char *request_head, FN_recv_data cb, void *p) {
    int fd = -1;
    char buffer[BUFFER_SIZE] = { 0 };
    size_t count = 0;

#ifdef _WIN32
    static int WSAStartup_flag = 0;
    if (WSAStartup_flag == 0) {
        WSADATA wsa = { 0 };
        WSAStartup(MAKEWORD(2,2), &wsa);
        WSAStartup_flag = 1;
    }
#endif

    do {
        if (cb == NULL) {
            break;
        }
        if (request_head) {
            strcpy(buffer, request_head);
        } else {
            sprintf(buffer, "GET / HTTP/1.0\r\nHost: %s\r\n\r\n", host);
        }
        fd = socket_connect(host, port);
        if (fd < 0) {
            break;
        }
        if (send(fd, buffer, strlen(buffer), 0) < 0) {
            break;
        }

        memset(buffer, 0, BUFFER_SIZE);
        while ( (count = (size_t) recv(fd, buffer, BUFFER_SIZE - 1, 0)) > 0) {
            cb((uint8_t*)buffer, count, p);
            memset(buffer, 0, BUFFER_SIZE);
        }
    } while (0);

    if (fd > 0) {
#if !defined(SHUT_RDWR)
#define SHUT_RDWR 2
#endif
        shutdown(fd, SHUT_RDWR);
        closesocket(fd);
    }

#ifdef _WIN32
#if 0
    WSACleanup(); // do not call it here, maybe crash your App.
#endif
#endif
}

#if defined(__TEST_WEB__)

void test_recv_data(uint8_t *data, size_t len, void *p) {
    char *txt = (char *)p;
    memcpy(txt, data, len);
}

int main(int argc, char *argv[]){
    char txt[BUFFER_SIZE] = { 0 };
    if(argc < 3){
        fprintf(stderr, "Usage: %s <hostname> <port>\n", argv[0]);
        exit(1);
    }

    launch_web_request(argv[1], atoi(argv[2]), NULL, &test_recv_data, txt);

    printf("%s\n", txt);

    return 0;
}

#endif // __TEST_WEB__