block execution of php script in ajax request - php

Question

My little application works in this way: in a simple text input user are asked to insert an url. on change my script tries to extract and display the first 10 images found on this page.
<input type="text" name="url" id="url" value="">
$("form.link-form input#url").change(function() {
var request = $.ajax({
type: "GET",
url: "funzioni/ajax/loadImagestFromUrl.php",
data: "url=" + insertedUrl,
dataType: "html",
timeout: 5000,
success: function(res) {
loadUrlImages2div(msg99);
},
error: function() {
request.abort();
}
});
});
the PHP script loadImagestFromUrl.php run this code, using PHP Simple HTML DOM Parser library:
set_time_limit(5);
$html = file_get_html($url); // load into this variable the entire html of the page
$count=1;
foreach($html->find('img') as $key=>$element) { // only images
if ($count==11) break; //only first 10 images
echo "<img class=\"imgFromUrl\" src=\"".$element->src."\" />\n";
}
$count++;
}
This work great on most cases but there are some urls that are not available in few seconds, or protected under password and the server keep executing something even if I set a timeout of 5 seconds for the ajax request and 5 second for the execution of php code.
When this happens everything get blocked, even refreshing the page is impossible, because it load and load and only after a lot of time it returns "504 Gateway Time-out. The server didn't respond in time."
Can somene help me in understanding how to completely block this request and let the server keep working?

Answer 1

Got that the solution must be find in the php code timeout and not with ajax timeout. This is clear.
I found this interesting discussion
Great answer: Handling delays when retrieving files from remote server in PHP
that suggests to use context parameter in the file_get_contents function.
But actually it doesn’t work on my app.
So, as suggested by Wieger I have tried to use curl instead of file_get content. I defined this function
function file_get_contents_curl($url) {
$ch = curl_init();
$timeout=2;
curl_setopt($ch, CURLOPT_AUTOREFERER, TRUE);
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_TIMEOUT, $timeout);
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, TRUE);
$data = curl_exec($ch);
curl_close($ch);
return $data;
}
and used it instead of file_get_contents inside the parser library.
Again, it works for most of case, but some url make the server load for a lot of time until gateway timeout.