PHP Printing with Google Cloud Print - php

Question

I am currently adding the ability to a php back-end system to allow it to print directly and I am trying to get things working with Google's Cloud Print. Imagine the app as an online shopping cart and I want it to print picking notes (completed orders) without the need for someone to login. The server is remote and the destination has Cloud Ready Printers.
So far I have been successful in getting it to print using the interfaces, as long as I am simply passing HTML, plain text or a URL to a PDF. I am able to set the print to color, marginless and the print quality.
However where I have hit a problem is, the PDF which the system creates are not publicly accessible, hence I can't pass a URL to the file, I need to pass the contents of the file.
I have been trying with no success to modify one of the examples I have found on the web HERE. However I don't know the language so am struggling with it.
Another example in python HERE again I have been trying without success!
I'm using PHP and the Zend framework to work with the interface. Here is one sample I have tried, cut down to where I am trying to prepare the file to send, like I say I'm not really sure on translating from python to php, or if the python script even works, but this is what I came up with:
<?php
// Test print a job:
$b64_pathname = PDF_PATH.'ec22c3.pdf'.'.b64';
$fileType = "application/pdf";
// Open the original file and base64 encode it:
$dataHandle = fopen(PDF_PATH.'ec22c3.pdf', "rb");
$dataContent = fread($dataHandle, filesize(PDF_PATH.'ec22ed167763a15e8591a3776f3c65c3.pdf'));
fclose($dataHandle);
$b64data = $fileType.base64_encode($dataContent);
// Store the base64 encoded file:
$ourFileHandle = fopen($b64_pathname, 'w');
fwrite($ourFileHandle, $b64data);
fclose($ourFileHandle);
// Read the contents of the base64 encoded file and delete it:
$fileHandle = fopen($b64_pathname, "rb");
$fileContent = fread($fileHandle, filesize($b64_pathname));
fclose($fileHandle);
unlink($b64_pathname);
// URL encode the file contents:
$file = urlencode($fileContent);
// Add the file and send to the printer:
$client->setParameterPost('content', $file);
$client->setParameterPost('contentType', $fileType);
$client->request(Zend_Http_Client::POST);
?>

Answer 1

Here's a method in php using cUrl (note, I have object level variables called _auth, _username, _password & _printerId).
First, build a function to post with cUrl:
function processRequest($url, $postFields, $referer) {
$ret = "";
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL,$url);
curl_setopt($ch, CURLOPT_USERAGENT, "");
if(!is_null($postFields)) {
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS,
$postFields);
// http_build_query() will properly escape the fields and
// build a query string.
}
if(strlen($this->_auth) > 0) {
$headers = array(
"Authorization: GoogleLogin auth=". $this->_auth,
//"GData-Version: 3.0",
"X-CloudPrint-Proxy", "yourappname"
);
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
}
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
curl_setopt($ch, CURLOPT_REFERER, $referer);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
$ret = curl_exec ($ch);
curl_close ($ch);
return $ret;
}
Then, a function to authorize against Google:
public function authorize() {
$url = "https://www.google.com/accounts/ClientLogin";
$post = array("accountType" => "HOSTED_OR_GOOGLE",
"Email" => $this->_username,
"Passwd" => $this->_password,
"service" => "cloudprint",
"source" => "yourappname");
$resp = $this->processRequest($url, $post, "");
preg_match("/Auth=([a-z0-9_\-]+)/i", $resp, $matches);
$this->_auth = $matches[1];
}
Finally, build a function to submit to the cloud printer:
function printDocument($title, $docBytes)
{
$url = "http://www.google.com/cloudprint/submit?printerid=". $this->_printerId."&output=json";
$post = array(
"printerid" => $this->_printerId,
"capabilities" => "",
"contentType" => "dataUrl",
"title" => $title,
"content" => 'data:application/pdf;base64,'. base64_encode($docBytes)
);
$ret = $this->processRequest($url, $post, "");
echo $ret;
}
In use, call authorize() to get the authentication token. Then just read your file (from wherever) into a variable and pass it to printDocument with the title.

Answer 2

In order to send base64 encoded content you need to send another parameter in submit request:
$client->setParameterPost('contentTransferEncoding', 'base64');