ParallelCurl with CURLOPT_WRITEFUNCTION - php

Question

I am trying to use ParallelCurl with a callback when cURL receives data from the server it is connected to. Here is the code I currently have:
function request_finished($content, $url, $ch, $user_data) {
echo "Request Finished: ", $content, "\n";
}
$pc=new ParallelCurl();
$servers=Server::loadNewAllFromDB(); //Returns an array of 'Server' objects which store connection information
foreach ($servers as $server) {
$pc->setOptions(
array(
CURLOPT_USERAGENT=>'My UserAgent String',
CURLOPT_WRITEFUNCTION=>
function ($ch, $string) {
echo "WRITEFUNCTION Called! | ", $string;
return strlen($string);
}
)
);
//print_r($pc->options);
$pc->startRequest(
'http://' . $server->address . ':' . $server->portbase . '/someurl'),
'request_finished'
);
}
$pc->finishAllRequests();
Now, what I expect to happen is for my anonymous function to be called when cURL has data to output. Instead, it simply seems to ignore the fact that CURLOPT_WRITEFUNCTION is set at all.
Note that if I am not using ParallelCurl, I can set the very same anonymous function as CURLOPT_WRITEFUNCTION just fine. It as if my function is being overridden somewhere later. I have also verified that it is in fact being set. You can see the line that I have commented out, //print_r($pc->options). It outputs my closure object.
Any thoughts on this would be most appreciated. Thanks.

Answer 1

This turned out to be a bug with either ParallelCurl, or curl_set_opt_array(). Here is the function in ParallelCurl as-is:
// Start a fetch from the $url address, calling the $callback function passing the optional
// $user_data value. The callback should accept 3 arguments, the url, curl handle and user
// data, eg on_request_done($url, $ch, $user_data);
public function startRequest($url, $callback, $user_data = array(), $post_fields=null) {
if( $this->max_requests > 0 )
$this->waitForOutstandingRequestsToDropBelow($this->max_requests);
$ch = curl_init();
curl_setopt_array($ch, $this->options);
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
if (isset($post_fields)) {
curl_setopt($ch, CURLOPT_POST, TRUE);
curl_setopt($ch, CURLOPT_POSTFIELDS, $post_fields);
}
curl_multi_add_handle($this->multi_handle, $ch);
$this->outstanding_requests[$ch] = array(
'url' => $url,
'callback' => $callback,
'user_data' => $user_data,
);
$this->checkForCompletedRequests();
}
Now the problem lies in where curl_setopt_array($ch, $this->options) sits. If I move it below all of the other curl_setopt(), then it works fine. Funny thing is, is that my User-Agent parameter that I pass in the same array as CURLPOT_WRITEFUNCTION was working fine. So, it seems that curl_setpot_array() behaves differently when given objects as values in the array. Anyway, simply moving the call worked fine. My modified function:
// Start a fetch from the $url address, calling the $callback function passing the optional
// $user_data value. The callback should accept 3 arguments, the url, curl handle and user
// data, eg on_request_done($url, $ch, $user_data);
public function startRequest($url, $callback, $user_data = array(), $post_fields=null) {
if( $this->max_requests > 0 )
$this->waitForOutstandingRequestsToDropBelow($this->max_requests);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
if (isset($post_fields)) {
curl_setopt($ch, CURLOPT_POST, TRUE);
curl_setopt($ch, CURLOPT_POSTFIELDS, $post_fields);
}
curl_setopt_array($ch, $this->options);
curl_multi_add_handle($this->multi_handle, $ch);
$this->outstanding_requests[$ch] = array(
'url' => $url,
'callback' => $callback,
'user_data' => $user_data,
);
$this->checkForCompletedRequests();
}