Just found a really great article / example about using PHP/Curl to access the google docs API:
Google Docs API: Client Login with PHP and Curl
Here is a code sample:
// Construct an HTTP POST request
$clientlogin_url = "https://www.google.com/accounts/ClientLogin";
$clientlogin_post = array(
"accountType" => "HOSTED_OR_GOOGLE",
"Email" => "[email protected]",
"Passwd" => "yourgooglepassword",
"service" => "writely",
"source" => "your application name"
);
// Initialize the curl object
$curl = curl_init($clientlogin_url);
// Set some options (some for SHTTP)
curl_setopt($curl, CURLOPT_POST, true);
curl_setopt($curl, CURLOPT_POSTFIELDS, $clientlogin_post);
curl_setopt($curl, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
// Execute
$response = curl_exec($curl);
// Get the Auth string and save it
preg_match("/Auth=([a-z0-9_-]+)/i", $response, $matches);
$auth = $matches[1];
echo "The auth string is: " . $auth;