cWikiBot/http.c

#include "http.h"

#include <string.h>
#include <curl/curl.h>
#include <stdlib.h>

static CURL* httpHandler = NULL;

char* request(char *url)
{
	// initialize curl on the first call of this function
	if(!httpHandler)
	{
		httpHandler = curl_easy_init();
		curl_easy_setopt(httpHandler,CURLOPT_USERAGENT, "cWikiBot/0.1 (https://git.zom.bi/cpp/cWikiBot; cpp@zom.bi) libcurl4/7.64.0");
		curl_easy_setopt(httpHandler,CURLOPT_WRITEFUNCTION, httpResponseCallback);
	}

	struct httpResponse_t httpResponse;
	httpResponse.response = malloc(1);
	httpResponse.size = 0;
	CURLcode return_code;
	if(httpHandler) {
		curl_easy_setopt(httpHandler,CURLOPT_URL, url);
		curl_easy_setopt(httpHandler,CURLOPT_WRITEDATA, (void *)&httpResponse);
		return_code = curl_easy_perform(httpHandler);
	}
	else
	{
		fprintf(stderr, "CURL Error\n");
		free(httpResponse.response);
		return NULL;
	}
	if(return_code != CURLE_OK)
	{
		fprintf(stderr, "HTTP Error: %s (%d)\n",curl_easy_strerror(return_code), return_code);
		free(httpResponse.response);
		return NULL;
	}
	return httpResponse.response;
}
size_t httpResponseCallback(char *data, size_t wordlength, size_t bytecount, void *out)
{
	// wordlength should be always 1, but this appears to be more secure.
	size_t size = wordlength * bytecount;
	struct httpResponse_t *mem = (struct httpResponse_t *) out;

	char *newData = realloc(mem->response, mem->size + size +1);
	if(newData == NULL)
		return 0;
	mem->response = newData;
	memcpy(&(mem->response[mem->size]), data, size);
	mem->size += size;
	// Null-terminate the byte chunk, to effectively have a C-String.
	mem->response[mem-> size] = 0;

	return size;
}