[cURL]コールバック関数を利用してURLの内容をバッファに溜め込む

curl_writefunction.c

/* $ gcc -Wall -g [-DDEBUG] curl_writefunction.c -lcurl */
/* $ ./a.out [URL] */

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

#define BUFFER_MAX 0x10000
size_t write_length = 0;

size_t recvf(void *ptr, size_t size, size_t nmemb, void *userp)
{
	size_t written = size*nmemb;

#ifdef DEBUG
	fprintf(stderr, "recvf(ptr=%p, size=%zd, nmemb=%zd, userp=%p); length=%zd\n",
		ptr, size, nmemb, userp, write_length);
#endif
	if ((write_length + written) >= BUFFER_MAX) { return 0; }

//	fwrite(ptr, size, nmemb, (FILE *)userp);
	memcpy((userp + write_length), ptr, written);
//	strlcat(userp, ptr, BUFFER_MAX);
//	strncat(userp, ptr, written);
	write_length += written;

	return written;
}

int main(int argc, char **argv)
{
	CURL *curl = curl_easy_init();
	CURLcode res;
	char write_data[BUFFER_MAX+1] = {'\0'};
	char *url = "http://www.newlisp.org/";

	if (argv[1] != NULL) {
		url = argv[1];
	}

	curl_easy_setopt(curl, CURLOPT_URL, url);
	curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
	curl_easy_setopt(curl, CURLOPT_WRITEDATA, &write_data);
	curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, recvf);

	res = curl_easy_perform(curl);

	if (res != CURLE_OK) {
		printf("ERR: %s\n", curl_easy_strerror(res));
	} else {
		printf("WRITEDATA=[text]%s[/text]\n", write_data);
		printf("LENGTH=%zd / %d\n", write_length, BUFFER_MAX);
		// or strlen(write_data)
	}

	curl_easy_cleanup(curl);

	return 0;
}

Sample:

• http://curl.haxx.se/libcurl/c/getinmemory.html
• http://stackoverflow.com/questions/2329571/c-libcurl-get-output-into-a-string