Parallel cURL Request with WRITEFUNCTION Callback

Question

I\'m trying to limit my cURL responses as suggested in these posts:Retrieve partial web page and PHP CURLOPT_WRITEFUNCTION doesn't appear to be working. The idea is to l

Answer 1

I finally got it figured out. The biggest problem was the fact that cURL was ignoring the WRITEFUNCTION until I placed it as the very last option specified, as I posted here: cURL WRITEFUNCTION not Being Called. I actually didn't need the return transfer, since I wrote the output to a class variable. That was necessary because when the callback returns -1, nothing gets returned. The following code works great:

var $full_length = array();
var $result = array();

function get_headers($urls){
    $curly = array();
    $mh = curl_multi_init();
    foreach ($urls as $key => $url) {
        $callback = $this->get_write_function($key);
        $curly[$key] = curl_init
        curl_setopt($curly[$key], CURLOPT_URL,            $url);
        curl_setopt($curly[$key], CURLOPT_HEADER,         0);
        curl_setopt($curly[$key], CURLOPT_WRITEFUNCTION, $callback);
        curl_multi_add_handle($mh, $curly[$key]);
    }
    $running = null;
    do {
        curl_multi_exec($mh, $running);
    } while($running > 0);
    foreach($curly as $key => $cnt) {
        curl_multi_remove_handle($mh, $cnt);
    }
    curl_multi_close($mh);
    return $this->result;
}

function get_write_function($key){
    $this->full_length[$key] = 0;
    $this->result[$key] = '';
    $obj = $this;
    $funky = function ($ch, $str) use ($obj, $key){
        $obj->result[$key] .= $str;
        $length = strlen($str);
        $obj->full_length[$key] += $length;
        if($obj->full_length[$key] >= 4000){
            return -1;
        }
        return $length;
    };
    return $funky;
}