Curl will not post multiple data to server - c++

Question

I am writing an application for work that needs to perform HTTP requests to a server, and get a response, in JSON back.
At the moment, my code connects to the server, and gets a response back, which is great. However, I also need to send data to the server, which will process it, and send me the jSON.
My problem is that I am able to send, thanks to POSTFIELDS, only a single "field", and won't get any response if I insert more that one.
The code is the following:
// writefunc works, so there is no point adding its code in here
size_t Simulator::writefunc(void *ptr, size_t size, size_t nmemb, struct string *buffer_in);
void Simulator::move(Player *player)
{
std::ostringstream ss_url;
ss_url << API_URL << "functionCalled";
char const *url = ss_url.str().c_str();
std::ostringstream ss_postfields;
// This will not work - And all values do NOT contain any space
// The server do NOT receive any data (in POST and GET)
ss_postfields << "user_name=" << player->getName()
<< "&user_secret=" << player->secret()
<< "&app_id=" << player->getApp_id()
<< "&lat=" << player->getLocation()->getLat()
<<"&lon=" << player->getLocation()->getLon();
// This will not work either
// ss_postfields << "user_name=nicolas&app_id=2";
// This works and will send the data to the server, which will receive and process it.
// ss_postfields << "user_name=" << player->getName();
const char *postfields = ss_postfields.str().c_str();
CURL *curl_handle;
curl_global_init(CURL_GLOBAL_ALL);
curl_handle = curl_easy_init();
if(curl_handle){
struct string s;
init_string(&s);
curl_easy_setopt(curl_handle, CURLOPT_URL, url);
curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, writefunc);
curl_easy_setopt(curl_handle, CURLOPT_NOPROGRESS, 1L);
curl_easy_setopt(curl_handle, CURLOPT_WRITEDATA, &s);
curl_easy_setopt(curl_handle, CURLOPT_POSTFIELDS, postfields);
curl_easy_setopt(curl_handle, CURLOPT_POSTFIELDSIZE, strlen(postfields));
curl_easy_setopt(curl_handle, CURLOPT_POST, 1L);
CURLcode res = curl_easy_perform(curl_handle);
if(CURLE_OK != res)
{
printf("Error: %s\n", strerror(res));
exit(0);
}
printf("%s\n", s.ptr);
curl_easy_cleanup(curl_handle);
curl_global_cleanup();
}
}
I thought I would also give the output of CURLOPT_HEADER and CURLOPT_VERBOSE for when I send only 1 value, or multiple values:
When I Send One value only:
* About to connect() to localhost port 8888 (#0)
* Trying ::1...
* connected
* Connected to localhost (::1) port 8888 (#0)
> POST [api_url] HTTP/1.1
Host: localhost:8888
Accept: */*
Content-Length: 22
Content-Type: application/x-www-form-urlencoded
* upload completely sent off: 22 out of 22 bytes
< HTTP/1.1 200 OK
< Date: Sun, 24 Nov 2013 17:25:14 GMT
< Server: Apache
< X-Powered-By: PHP/5.3.20
< Cache-Control: no-cache
< X-Debug-Token: a41727
< Transfer-Encoding: chunked
< Content-Type: application/json
<
* Connection #0 to host localhost left intact
0
HTTP/1.1 200 OK
Date: Sun, 24 Nov 2013 17:25:14 GMT
Server: Apache
X-Powered-By: PHP/5.3.20
Cache-Control: no-cache
X-Debug-Token: a41727
Transfer-Encoding: chunked
Content-Type: application/json
[ OUTPUT FROM SERVER HERE ]
* Closing connection #0
And when I send multiple values:
* About to connect() to localhost port 8888 (#0)
* Trying ::1...
* connected
* Connected to localhost (::1) port 8888 (#0)
> POST [api_url] HTTP/1.1
Host: localhost:8888
Accept: */*
Content-Length: 1
Content-Type: application/x-www-form-urlencoded
* upload completely sent off: 1 out of 1 bytes
< HTTP/1.1 200 OK
< Date: Sun, 24 Nov 2013 17:30:13 GMT
< Server: Apache
< X-Powered-By: PHP/5.3.20
< Cache-Control: no-cache
< X-Debug-Token: d1947e
< Transfer-Encoding: chunked
< Content-Type: application/json
<
* Connection #0 to host localhost left intact
0
HTTP/1.1 200 OK
Date: Sun, 24 Nov 2013 17:30:13 GMT
Server: Apache
X-Powered-By: PHP/5.3.20
Cache-Control: no-cache
X-Debug-Token: d1947e
Transfer-Encoding: chunked
Content-Type: application/json
[ OUTPUT FROM SERVER HERE ]
* Closing connection #0

Answer 1

Well you seem to be missing an equals sign!
ss_postfields << "user_name=" << player->getName()
<< "&user_secret=" << player->secret()
<< "&app_id=" << player->getApp_id()
<< "&lat=" << player->getLocation()->getLat()
<<"&lon=" << player->getLocation()->getLon();
instead of
ss_postfields << "user_name=" << player->getName()
<< "&user_secret" << player->secret()
<< "&app_id=" << player->getApp_id()
<< "&lat=" << player->getLocation()->getLat()
<<"&lon=" << player->getLocation()->getLon();

Answer 2

Since I was in a rush, I rewrote everything using HTTP sockets. But I could not be done with this issue, so I went back to it, and finally found the problem. It seems like cUrl does not really like streams.
I thought I would update this post in the case anyone is having the same issue:
Therefore, something like the following will NOT work:
std::ostringstream ss_postfields;
// This will not work - And all values do NOT contain any space
// The server do NOT receive any data (in POST and GET)
ss_postfields << "user_name=" << player->getName()
<< "&user_secret=" << player->getSecret();
const char *postfields = ss_postfields.str().c_str();
// ...
curl_easy_setopt(curl_handle, CURLOPT_POSTFIELDS, postfields);
CURLcode res = curl_easy_perform(curl_handle);
However, and bizarrely, this will work:
std::string str_postfields;
std::string user_name = player->getName();
std::string user_secret = player->getSecret();
std::string str_postfields = "user_name=" +user_name +"&user_secret=" +user_secret;
const char *postfields = str_postfields.c_str();
// ...
curl_easy_setopt(curl_handle, CURLOPT_POSTFIELDS, postfields);
CURLcode res = curl_easy_perform(curl_handle);