ERROR reading response from socket

[rigid flax]

Hello, I have a problem reading the response of a web server from HTTP POST Request.

[plucky valve]

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[rigid flax]

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


#define HOST "mywebsite.com"
#define PORT 443
void error(const char *msg) {
    perror(msg);
    exit(EXIT_FAILURE);
}

int main(void) {
    struct hostent *server;
    struct sockaddr_in serv_addr;

    int sockfd, bytes, sent, received, total;
    char response[4096];
    char *message = "POST mywebsite.com HTTP/1.1\r\n"
            "Host: " HOST "\r\n"
            "Content-type: application/json; charset=utf-8\r\n"
            "Cookie: somecookie\r\n"
            "User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:98.0) Gecko/20100101 Firefox/98.0\r\n"
            "Accept: application/json\r\n"
            "Accept-Language: en-US,en;q=0.5\r\n"
            "Accept-Encoding: gzip, deflate\r\n"
            "Referer: mywebsite.com/\r\n"
            "Origin: mywebsite.com\r\n"
            "Sec-Fetch-Dest: empty\r\n"
            "Sec-Fetch-Mode: cors\r\n"
            "Sec-Fetch-Site: same-origin\r\n"
            "Te: trailers\r\n"
            "Connection: close\r\n"
            "\r\n"
            "{\r\n"
            "t0ken: \"sometoken\"\r\n"
            "username: \"helloworld\"\r\n"
            "}\r\n"
            "\r\n";

    printf("Request:\n%s\n", message);

    // Create the socket
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0) error("ERROR opening socket");

    // Lookup the ip address
    server = gethostbyname(HOST);
    if (server == NULL) error("No Such Host");

    // Fill in the structure
    memset(&serv_addr, 0, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(PORT);
    memcpy(&serv_addr.sin_addr.s_addr, server->h_addr, server->h_length);

// Connect the socket
    if (connect(sockfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0) error("ERROR Connecting");
    // Send The Request
    total = strlen(message);
    sent = 0;
    do {
        bytes = write(sockfd, message+sent, total-sent);
        if (bytes < 0) error("ERROR writing message to socket");
        if (bytes == 0) break;
        sent += bytes;
    } while (sent < total);

    // Receive the response
    memset(response, 0, sizeof(response));
    total = sizeof(response)-1;
    received = 0;
    do {
        bytes = read(sockfd, response+received, total-received);
        if (bytes < 0) error("ERROR reading response from socket");
        if (bytes == 0) break;
        received += bytes;
    } while (received < total);

    if (received == total) error("ERROR storing complete response from socket");
    // Close socket
    close(sockfd);

    // process response
    printf("Response: \n%s\n", response);
    
    return EXIT_SUCCESS;
}

ERROR reading response from socket: Connection reset by peer

[umbral sphinx]

This error occurs if you try to read from a connection which was closed by the server. I think the problem is that the server closes the connection after sending the response and you try to read from it, which results in an error since it's closed. So if you just break the loop instead of exitting you should be fine.

[rigid flax]

if I do this i get no response

I mean it does not work

[umbral sphinx]

ah, wait if you try to connect over https (port 443) this won't work. You first need to execute a TLS handshake etc.

[rigid flax]

Wow

maybe i do it the wrong way

maybe using socket is too hard

maybe i should do this ?

https://fm4dd.com/openssl/sslconnect.shtm

[umbral sphinx]

I'd say, yes