PHP - Debugging Curl

Question

I\'d like to see what the post fields in the request are before I send it. (For debugging purposes).

The PHP library (class) I am using is already made (not by me),

Answer 1

You can enable the CURLOPT_VERBOSE option and log that information to a (temporary) CURLOPT_STDERR:

// CURLOPT_VERBOSE: TRUE to output verbose information. Writes output to STDERR, 
// or the file specified using CURLOPT_STDERR.
curl_setopt($handle, CURLOPT_VERBOSE, true);

$verbose = fopen('php://temp', 'w+');
curl_setopt($handle, CURLOPT_STDERR, $verbose);

You can then read it after curl has done the request:

$result = curl_exec($handle);
if ($result === FALSE) {
    printf("cUrl error (#%d): %s
\n", curl_errno($handle),
           htmlspecialchars(curl_error($handle)));
}

rewind($verbose);
$verboseLog = stream_get_contents($verbose);

echo "Verbose information:\n
", htmlspecialchars($verboseLog), "
\n";

(I originally answered similar but more extended in a related question.)

More information like metrics about the last request is available via curl_getinfo. This information can be useful for debugging curl requests, too. A usage example, I would normally wrap that into a function:

$version = curl_version();
extract(curl_getinfo($handle));
$metrics = <<