How use CURLOPT_WRITEFUNCTION when download a file by CURL

Question

My Class for download file direct from a link:

MyClass{

          function download($link){
                ......
                $ch = curl_init($link);
          


        

Answer 1

I know this is an old question, but maybe my answer will be of some help for you or someone else. Try this:

function get_write_function(){
    return function($curl, $data){
        return strlen($data);
    }
}

I don't know exactly what you want to do, but with PHP 5.3, you can do a lot with the callback. What's really great about generating a function in this way is that the values passed through the 'use' keyword remain with the function afterward, kind of like constants.

function get_write_function($var){
    $obj = $this;//access variables or functions within your class with the object variable
    return function($curl, $data) use ($var, $obj) {
        $len = strlen($data);
        //just an example - you can come up with something better than this:
        if ($len > $var){
            return -1;//abort the download
        } else {
            $obj->do_something();//call a class function
            return $len;
        }
    }
}

You can retrieve the function as a variable as follows:

function download($link){
    ......
    $var = 5000;
    $write_function = $this->get_write_function($var);
    $ch = curl_init($link);
    curl_setopt($ch, CURLOPT_FILE, $File->handle);
    curl_setopt($ch, CURLOPT_WRITEFUNCTION , $write_function);
    curl_exec($ch);
    curl_close($ch);
    $File->close();
    ......

}

That was just an example. You can see how I used it here: Parallel cURL Request with WRITEFUNCTION Callback. I didn't actually test all of this code, so there may be minor errors. Let me know if you have problems, and I'll fix it.