Setting Curl's Timeout in PHP

Question

I'm running a curl request on an eXist database through php. The dataset is very large, and as a result, the database consistently takes a long amount of time to return an XML response. To fix that, we set up a curl request, with what is supposed to be a long timeout.

$ch = curl_init();
$headers["Content-Length"] = strlen($postString);
$headers["User-Agent"] = "Curl/1.0";

curl_setopt($ch, CURLOPT_URL, $requestUrl);
curl_setopt($ch, CURLOPT_HEADER, false);
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_USERPWD, 'admin:');
curl_setopt($ch,CURLOPT_TIMEOUT,1000);
$response = curl_exec($ch);
curl_close($ch);

However, the curl request consistently ends before the request is completed (<1000 when requested via a browser). Does anyone know if this is the proper way to set timeouts in curl?

Answer 1

Your code sets the timeout to 1000 seconds. For milliseconds, use CURLOPT_TIMEOUT_MS.

Answer 2

There is a quirk with this that might be relevant for some people... From the PHP docs comments.

If you want cURL to timeout in less than one second, you can use CURLOPT_TIMEOUT_MS, although there is a bug/"feature" on "Unix-like systems" that causes libcurl to timeout immediately if the value is < 1000 ms with the error "cURL Error (28): Timeout was reached". The explanation for this behavior is:

"If libcurl is built to use the standard system name resolver, that portion of the transfer will still use full-second resolution for timeouts with a minimum timeout allowed of one second."

What this means to PHP developers is "You can't use this function without testing it first, because you can't tell if libcurl is using the standard system name resolver (but you can be pretty sure it is)"

The problem is that on (Li|U)nix, when libcurl uses the standard name resolver, a SIGALRM is raised during name resolution which libcurl thinks is the timeout alarm.

The solution is to disable signals using CURLOPT_NOSIGNAL. Here's an example script that requests itself causing a 10-second delay so you can test timeouts:

if (!isset($_GET['foo'])) {
    // Client
    $ch = curl_init('http://localhost/test/test_timeout.php?foo=bar');
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_NOSIGNAL, 1);
    curl_setopt($ch, CURLOPT_TIMEOUT_MS, 200);
    $data = curl_exec($ch);
    $curl_errno = curl_errno($ch);
    $curl_error = curl_error($ch);
    curl_close($ch);

    if ($curl_errno > 0) {
        echo "cURL Error ($curl_errno): $curl_error\n";
    } else {
        echo "Data received: $data\n";
    }
} else {
    // Server
    sleep(10);
    echo "Done.";
}

From http://www.php.net/manual/en/function.curl-setopt.php#104597

Answer 3

If you are using PHP as a fastCGI application then make sure you check the fastCGI timeout settings. See: PHP curl put 500 error

Answer 4

See documentation: http://www.php.net/manual/en/function.curl-setopt.php

CURLOPT_CONNECTTIMEOUT - The number of seconds to wait while trying to connect. Use 0 to wait indefinitely.
CURLOPT_TIMEOUT - The maximum number of seconds to allow cURL functions to execute.

curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 0); 
curl_setopt($ch, CURLOPT_TIMEOUT, 400); //timeout in seconds

also don't forget to enlarge time execution of php script self:

set_time_limit(0);// to infinity for example

Answer 5

You can't run the request from a browser, it will timeout waiting for the server running the CURL request to respond. The browser is probably timing out in 1-2 minutes, the default network timeout.

You need to run it from the command line/terminal.

Answer 6

Hmm, it looks to me like CURLOPT_TIMEOUT defines the amount of time that any cURL function is allowed to take to execute. I think you should actually be looking at CURLOPT_CONNECTTIMEOUT instead, since that tells cURL the maximum amount of time to wait for the connection to complete.