Sending POST data using cURL, by scanning QR code - php

Question

I'm trying to pass some data (JSON) to another page by scanning a QR code.
The page where the data is send to, contains a HTML form. I want to use that form as a last chance to correct the data before sending it to the database.
I found here at S.O. a way to pass the data using cURL: (https://stackoverflow.com/a/15643608/2131419)
QR code library:
http://phpqrcode.sourceforge.net
I use the QR code execute this function:
function passData () {
$url = 'check.php';
$data = array('name' => 'John', 'surname' => 'Doe');
$ch = curl_init( $url );
# Setup request to send json via POST.
$payload = json_encode($data);
curl_setopt( $ch, CURLOPT_POSTFIELDS, $payload );
curl_setopt( $ch, CURLOPT_HTTPHEADER, array('Content-Type:application/json'));
# Return response instead of printing.
curl_setopt( $ch, CURLOPT_RETURNTRANSFER, true );
# Send request.
$result = curl_exec($ch);
curl_exec($ch);
curl_close($ch);
# Print response.
return $result;
}
Create QR code:
QRcode::png(passData(), $tempDir.'007_4.png', QR_ECLEVEL_L, 4);
echo '<img src="'.$tempDir.'007_4.png" />';
Check.php
<?php $data = json_decode(file_get_contents("php://input"), true); ?>
<form method="post" action="handle.php">
<input type="text" name="name" value="<?php echo $data['name'];?>" /><br />
<input type="text" name="surname" value="<?php echo $data['surname'];?>" /><br />
<input type="submit" />
</form>
Problem:
I can pass the data to check.php, but it's returning plain text instead of a useable HTML form.
Hope someone can help!
EDIT
Some clarification:
What I actually want is, to scan the QR code, which executes the passData() function. Then the 'QR code scanner app', needs to open a browser, which shows check.php with the form AND the passed data as the values of the input fields.
Now, I get only the response of check.php (plain text).
When I pass an URL instead of the passData() function like:
QRcode::png("http://www.google.com", $tempDir.'007_4.png', QR_ECLEVEL_L, 4);
The app asks if I want to go to http://www.google.com.

Answer 1

QR codes cannot execute code. The only executable type of data you can put in a QR code is a URL. That is why using google.com as a URL opens a web browser to that URL. The QR code itself does not render anything.
What your code is doing is fetching the check.php page when the QR code is generated and then storing the output as the raw data. It isn't a webpage, it is a string like you are seeing in your question. You may be able to pass a javascript URL similar to a bookmarklet but its execution would depend on the QR code reader being used.
bookmarklet example
<?php
function passData() {
// javascript code in a heredoc, you may need to url encode it
return <<<JS
javascript:(function() {
//Statements returning a non-undefined type, e.g. assignments
})();
JS;
}
A better way to do it would be to have your QR code generate a URL like: http://your-site.com/check.php?name=John&surname=Doe and host check.php on your machine. You can use the $_GET data to populate your form and then use javascript to automatically post it as Jah mentioned.

Answer 2

Not the best way but you can do something like this.
Check.php:
<?php
$data = '<form method="post" action="handle.php">
<input type="text" name="name" value="name" /><br />
<input type="text" name="surname" value="surname" /><br />
<input type="submit" />
</form>';
$html = str_replace(PHP_EOL, ' ', $data);
$html = preg_replace('/[\r\n]+/', "\n", $html);
$html = preg_replace('/[ \t]+/', ' ', $html);
$html = str_replace('> <', '><', $html);
?>
<div id="placeholder">
Write HTML here
</div>
<script type="text/javascript">
function write_html(id,data){
var formHtml = data;
document.getElementById(id).innerHTML = formHtml;
}
</script>