Handle CURL headers before downloading body

Question

Using PHP and CURL (unless there is a better alternative then CURL in this case), is it possible to have a php function handle the header response before downloading the file?

For example:

I have a script that downloads and processes urls supplied by the user. I would like to add a check so that if the file is not valid for my process (not a text file, too large, etc),the CURL request would be cancelled before the server wastes time downloading the file.

Update: Solution PEAR class HTTP_Request2: http://pear.php.net/package/HTTP%5FRequest2/ Gives you the ability to set observers to the connection and throw exceptions to cancel anytime. Works perfectly for my needs!

Answer 1

Using cURL, do a HTTP HEAD request to check the headers, then if it is valid (the status is 200) do the full HTTP GET request.

The basic option you must set is CURLOPT_NOBODY, which changes the requested to the type HEAD

curl_setopt($ch, CURLOPT_NOBODY, true);

Then after executing the query, you need to check the return status which can be done using curl_getinfo()

$status = curl_getinfo($ch, CURLINFO_HTTP_CODE);

Answer 2

This is an example how you can solve it:

// Include the Auth string in the headers
// Together with the API version being used
$headers = array(
    "Authorization: GoogleLogin auth=" . $auth,
    "GData-Version: 3.0",
);

// Make the request
curl_setopt($curl, CURLOPT_URL, "http://docs.google.com/feeds/default/private/full");
curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);

$response = curl_exec($curl);
curl_close($curl);

// Parse the response
$response = simplexml_load_string($response);

// Output data
foreach($response->entry as $file)
{
       //now you can do what ever if file type is a txt
        //if($file->title =="txt")
        // do something
        else
        // do soething
    echo "File: " . $file->title . "<br />";
    echo "Type: " . $file->content["type"] . "<br />";
    echo "Author: " . $file->author->name . "<br /><br />";
}