cURL download progress in PHP

Question

I\'m pretty new to cURL so I\'ve been struggling with this one for hours. I\'m trying to download the source of a website in an iframe using cURL and while it\'s loading to

Answer 1

What you need is

<?php
ob_start();

echo "<pre>";
echo "Loading ...";

ob_flush();
flush();

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "http://stackoverflow.com");
//curl_setopt($ch, CURLOPT_BUFFERSIZE,128);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_PROGRESSFUNCTION, 'progress');
curl_setopt($ch, CURLOPT_NOPROGRESS, false); // needed to make progress function work
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_USERAGENT, $_SERVER['HTTP_USER_AGENT']);
$html = curl_exec($ch);
curl_close($ch);


function progress($resource,$download_size, $downloaded, $upload_size, $uploaded)
{
    if($download_size > 0)
         echo $downloaded / $download_size  * 100;
    ob_flush();
    flush();
    sleep(1); // just to see effect
}

echo "Done";
ob_flush();
flush();

?>

Answer 2

This is how the callback looks in C:

typedef int (*curl_progress_callback)(void *clientp,
                                      double dltotal,
                                      double dlnow,
                                      double ultotal,
                                      double ulnow);

Probably in PHP it should look like

curl_progress_callback($clientp, $dltotal, $dlnow, $ultotal, $ulnow)

So, assuming you have page.html which loads a .php file in an iframe.

In your php script, you will require the following functions:

curl_setopt($curl, CURLOPT_PROGRESSFUNCTION, 'curl_progress_callback');    
curl_setopt($curl, CURLOPT_BUFFERSIZE,64000);    
curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true);

which should produce an output similar to the following:

0
0.1
0.2
0.2
0.3
0.4
...

then on the iframe page, you will have a progress bar

<div id="progress-bar">
    <div id="progress">0%</div>
</div>

CSS would be something like this

#progress-bar {
    width: 200px;
    padding: 2px;
    border: 2px solid #aaa;
    background: #fff;
}

#progress {
    background: #000;
    color: #fff;
    overflow: hidden;
    white-space: nowrap;
    padding: 5px 0;
    text-indent: 5px;
    width: 0%;
}

The javascript

var progressElement = document.getElementById('progress')

function updateProgress(percentage) {
    progressElement.style.width = percentage + '%';
    progressElement.innerHTML = percentage + '%';
}

You can have it output JavaScript and have it update the progress bar for you, for example:

<script>updateProgress(0);</script>
<script>updateProgress(0.1);</script>
<script>updateProgress(0.2);</script>

You might be interested in some more example code

Answer 3

To use the callback inside a class, you must do it like this:

curl_setopt($ch, CURLOPT_PROGRESSFUNCTION, array($this, 'progress'));

or if using static functions, like this:

curl_setopt($ch, CURLOPT_PROGRESSFUNCTION, array('self', 'progress'));

... to a callback function to do whatever you need:

private static function progress($resource, $downloadSize, $downloaded, $uploadSize, $uploaded)
{
    // emit the progress
    Cache::put('download_status', [
        'resource' => $resource,
        'download_size' => $downloadSize,
        'downloaded' => $downloaded,
        'upload_size' => $uploadSize,
        'uploaded' => $uploaded
    ], 10);
}