Empty Accept-Encoding: Header doesn't override CURLOPT_ACCEPT_ENCODING on 2nd request with reused handle #785
Description
The test program below (modified from examples/httpcustomheader.c) attempts to send 2 requests to a host, and reuse the curl handle. On the second request, it attempts to disable CURLOPT_ACCEPT_ENCODING by explicitly setting the Accept-Encoding:-header without a value.
This works as expected (i.e. no Accept-Encoding header is sent in the request) only if a "fresh" handle is used or no previous request with that handle has ever actually sent a request with the Accept-Encoding header set via CURLOPT_ACCEPT_ENCODING.
#include <stdio.h>
#include <curl/curl.h>
CURL *curl;
void request(char * url, int compress)
{
CURLcode res;
if(curl) {
struct curl_slist *chunk = NULL;
curl_easy_setopt(curl, CURLOPT_URL, url);
res = curl_easy_setopt(curl, CURLOPT_ACCEPT_ENCODING, "");
if (compress == 0) {
chunk = curl_slist_append(chunk, "Accept-Encoding: ");
}
res = curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk);
//curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
res = curl_easy_perform(curl);
if(res != CURLE_OK) fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
curl_easy_reset(curl);
curl_slist_free_all(chunk);
}
}
int main(void)
{
curl_global_init(CURL_GLOBAL_ALL);
curl = curl_easy_init();
request("http://localhost:14080/headers.php", 1);
request("http://localhost:14080/headers.php", 0);
curl_easy_cleanup(curl);
return 0;
}