Question

I have a simple cURL script that works just fine.
But I’m curious about how to detect a bad Url. And by “bad” I mean a non-existant URL, or if the server I am calling is down for a period of time, or I made a mistake and entered the wrong URL. (just examples)

here’s what I have so far:

<?php

$url = 'http://someurl_or_ip.com/some_file.php';
$post_fields = "type=whatever";
$post_fields .= "&first=".$first;
$post_fields .= "&last=".$last;


$ch = curl_init($url); // create a new cURL resource 
curl_setopt($ch, CURLOPT_POST,1); 
curl_setopt($ch, CURLOPT_POSTFIELDS, $post_fields); 
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST,  2); 
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); 
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);   
curl_setopt($ch, CURLOPT_TIMEOUT, 1800);  

// Execute the request. 
$raw_response = curl_exec($ch); 
$succeeded  = curl_errno($ch) == 0 ? true : false; 

echo $raw_response;

?>

typically the $raw_response is something I can parse and use for other things, like how I want to display data to a user.

I simply replaced $url with a non-existent file (but to a valid domain), and I get “Not Found….The requested URL…..was not found on this server…”

Does this mean I need to parse this apache server message to know it’s not a good URL? Or does cURL have a way to detect it, via header information?

Answer 1

You can look at the HTTP response code in the header, which will be 404 for a file not found:

$http = curl_init($url);
$result = curl_exec($http);
$http_status = curl_getinfo($http, CURLINFO_HTTP_CODE);
curl_close($http);
echo $http_status;

If the server is not available, you obviously won’t get a response from the server at all, thus no HTTP response code. In this case curl_exec() would return with false, in which case you can handle the error:

if(curl_exec($ch) !== false) {
    // Success
} else {
    // Error
    $error_str = curl_error($ch);
    $error_num = curl_errno($ch);
}