requests.c

#include <stdlib.h>     /* exit, atoi, malloc, free */
#include <stdio.h>
#include <unistd.h>     /* read, write, close */
#include <string.h>     /* memcpy, memset */
#include <sys/socket.h> /* socket, connect */
#include <netinet/in.h> /* struct sockaddr_in, struct sockaddr */
#include <netdb.h>      /* struct hostent, gethostbyname */
#include <arpa/inet.h>
#include "requests.h"
#include "client.h"

void compute_message(char *message, const char *line)
{
    strcat(message, line);
    strcat(message, "\r\n");
}

char *compute_get_request(char *host, char *url, char *query_params,
                          char** extra_headers, int extra_headers_count,
                          char **cookies, int cookies_count)
{
    char *message = calloc(BUFLEN, sizeof(char));
    char *line = calloc(LINELEN, sizeof(char));

    // Step 1: write the method name, URL, request params (if any) and protocol type
    if (query_params != NULL) {
        sprintf(line, "GET %s?%s HTTP/1.1", url, query_params);
    } else {
        sprintf(line, "GET %s HTTP/1.1", url);
    }
    compute_message(message, line);

    // Step 2: add the host
    sprintf(line, "Host: %s", host);
    compute_message(message, line);

    if (extra_headers != NULL && extra_headers_count > 0) {
        for (int i = 0; i < extra_headers_count; i++) {
            sprintf(line, "%s", extra_headers[i]);
            compute_message(message, line);
        }
    }

    // Step 3 (optional): add headers and/or cookies, according to the protocol format
    if (cookies != NULL) {
        sprintf(line, "Cookie: ");
        int offset = strlen("Cookie: ");
        for (int i = 0; i < cookies_count; i++) {
            sprintf(line + offset, "%s; ", cookies[i]);
            offset += strlen(cookies[i]) + strlen("; ");
        }
        compute_message(message, line);
    }
    // Step 4: add final new line
    compute_message(message, "");

    free(line);
    return message;
}

char *compute_post_request( char *host, char *url, char* content_type, char *payload_data, int payload_size,
                            char** extra_headers, int extra_headers_count,
                            char **cookies, int cookies_count)
{
    char *message = calloc(BUFLEN, sizeof(char));
    char *line = calloc(LINELEN, sizeof(char));

    // Step 1: write the method name, URL and protocol type
    sprintf(line, "POST %s HTTP/1.1", url);
    compute_message(message, line);

    // Step 2: add the host
    sprintf(line, "Host: %s", host);
    compute_message(message, line);

    // Step mata: add extra fields
    if (extra_headers != NULL && extra_headers_count > 0) {
        for (int i = 0; i < extra_headers_count; i++) {
            sprintf(line, "%s", extra_headers[i]);
            compute_message(message, line);
        }
    }

    /* Step 3: add necessary headers (Content-Type and Content-Length are mandatory)
            in order to write Content-Length you must first compute the message size
    */
    sprintf(line, "Content-Type: %s", content_type);
    compute_message(message, line);

    sprintf(line, "Content-Length: %d", payload_size);
    compute_message(message, line);

    // Step 4 (optional): add cookies
    if (cookies != NULL) {
        sprintf(line, "Cookie: ");
        int offset = strlen("Cookie: ");
        for (int i = 0; i < cookies_count; i++) {
            sprintf(line + offset, "%s; ", cookies[i]);
            offset += strlen(cookies[i]) + strlen("; ");
        }
        compute_message(message, line);
    }

    // Step 5: add new line at end of header
    compute_message(message, "");

    // Step 6: add the actual payload data
    memset(line, 0, LINELEN);
    strcat(message, payload_data);

    free(line);
    return message;
}

char *compute_put_request( char *host, char *url, char* content_type, char *payload_data, int payload_size,
                            char** extra_headers, int extra_headers_count,
                            char **cookies, int cookies_count)
{
    char *message = calloc(BUFLEN, sizeof(char));
    char *line = calloc(LINELEN, sizeof(char));

    // Step 1: write the method name, URL and protocol type
    sprintf(line, "PUT %s HTTP/1.1", url);
    compute_message(message, line);

    // Step 2: add the host
    sprintf(line, "Host: %s", host);
    compute_message(message, line);

    // Add extra fields
    if (extra_headers != NULL && extra_headers_count > 0) {
        for (int i = 0; i < extra_headers_count; i++) {
            sprintf(line, "%s", extra_headers[i]);
            compute_message(message, line);
        }
    }

    /* Step 3: add necessary headers (Content-Type and Content-Length are mandatory)
            in order to write Content-Length you must first compute the message size
    */
    sprintf(line, "Content-Type: %s", content_type);
    compute_message(message, line);

    sprintf(line, "Content-Length: %d", payload_size);
    compute_message(message, line);

    // Step 4 (optional): add cookies
    if (cookies != NULL) {
        sprintf(line, "Cookie: ");
        int offset = strlen("Cookie: ");
        for (int i = 0; i < cookies_count; i++) {
            sprintf(line + offset, "%s; ", cookies[i]);
            offset += strlen(cookies[i]) + strlen("; ");
        }
        compute_message(message, line);
    }

    // Step 5: add new line at end of header
    compute_message(message, "");

    // Step 6: add the actual payload data
    memset(line, 0, LINELEN);
    strcat(message, payload_data);

    free(line);
    return message;
}

char *compute_delete_request(char *host, char *url,
                             char** extra_headers, int extra_headers_count,
                             char **cookies, int cookies_count)
{
    char *message = calloc(BUFLEN, sizeof(char));
    char *line = calloc(LINELEN, sizeof(char));

    // Step 1: write the method name, URL, request params (if any) and protocol type
    sprintf(line, "DELETE %s HTTP/1.1", url);
    compute_message(message, line);

    // Step 2: add the host
    sprintf(line, "Host: %s", host);
    compute_message(message, line);

    // Add extra fields
    if (extra_headers != NULL && extra_headers_count > 0) {
        for (int i = 0; i < extra_headers_count; i++) {
            sprintf(line, "%s", extra_headers[i]);
            compute_message(message, line);
        }
    }

    // Step 3 (optional): add headers and/or cookies, according to the protocol format
    if (cookies != NULL) {
        sprintf(line, "Cookie: ");
        int offset = strlen("Cookie: ");
        for (int i = 0; i < cookies_count; i++) {
            sprintf(line + offset, "%s; ", cookies[i]);
            offset += strlen(cookies[i]) + strlen("; ");
        }
        compute_message(message, line);
    }
    // Step 4: add final new line
    compute_message(message, "");

    free(line);
    return message;
}

int make_session_cookie(char** cookie) {
    if (session_token == NULL) {
        *cookie = NULL;
        return 0;
    }
    *cookie = calloc(1, 1024);
    strcat(*cookie, "session=");
    strcat(*cookie, session_token);
    return 1;
}

int make_auth_header(char** header) {
    if (library_access_jwt == NULL) {
        *header = NULL;
        return 0;
    }
    *header = calloc(1, 256);
    strcat(*header, "Authorization: Bearer ");
    strcat(*header, library_access_jwt);
    return 1;
}

char* get_session_token_cookie(char* http_response, int* token_length) {
    char* cookie = strstr(http_response, "Set-Cookie:");
    if (cookie == NULL) {
        return NULL;
    }
    char* session = strstr(cookie,"session=");
    if (session == NULL) {
        perror("bogus session in cookie");
        exit(-1);
    }
    char* session_endpos = strchr(session, ';');

    char* ret = session + strlen("session=");
    *token_length = session_endpos - session - strlen("session=");

    return ret;
}

char* get_json_payload(char* http_response) {
    char* json = strchr(http_response, '{');
    if (json[0] != '{'){
        puts("get_json_payload error: no json detected");
        return NULL;
    }
    return json;
}