Sunday, 16 December 2012

PHP, Wkhtmltopdf and Win 7: Eleven steps

Proof of Concept tutorial

This is a barebones guide on getting HTML to PDF / HTML to Image conversion using Windows 7, PHP and Wkhtmltopdf. This is a POC only; this tutorial does not describe server installation or configuration (using a package like WAMP makes it easy anyway). I might add those in a later revision or an extended version of this guide.

The steps
  1. Download wkhtmltopdf
  2. Installation step 1
  3. Installation step 2
  4. Installation step 3
  5. Start WampServer
  6. Open www-directory
  7. Create a test file
  8. Call the test file
  9. Examine generated
  10. Compare file contents

Download wkhtmltopdf


Download and run the "wkhtmltox" installer, that contains both wkhtmltopdf and wkhtmltoimage.

Installation step 1


After running the executable read the license agreement and click "I agree" if you do.

Installation step 2


Choose the installer to install both wkhtmltopdf and wkhtmltoimage but don't let it modify path because it breaks the PATH variable. If you want it to be in %PATH%, add it yourself.

Installation step 3


Choose the destination folder. I like the simple custom path C:\wkhtmltopdf.

Start your WWW Server

I use WAMP. It is very simple, easy to install, has sensible defaults but it's also very configurable.

Open www-directory


Wampserver opens with an icon in the system tray. Use it or otherwise navigate to your www root directory.

Create a test file


Create the following or similar test page and save it into your www root directory. The only PHP function used here is shell_exec(...); that executes the command given. The 2>>err1.txt forwards the standard error stream (stderr) to a file called err1.txt, which will be created if it doesn't exist. The 1>>out1.txt likewise forwards standard output stream (stdout) to the out1.txt file. Capturing both errors and normal output is useful in debugging. You need to call wkhtmltopdf but it's full path because it's not included in your environment PATH variable. Add it there and you can omit the folder.


<?php
// Test correct and failed output
shell_exec('c:\wkhtmltopdf\wkhtmltopdf --asdasdsadsad 2>> err1.txt 1>> out1.txt');
shell_exec('c:\wkhtmltopdf\wkhtmltopdf --version 2>> err2.txt 1>> out2.txt');
?>
<html>
<head>
</head>
<body>
<p>Magical ponies!</p>
</body>
</html>

Here we are intentionally forcing an error with the bogus parameter -asdasddas so we can test that we indeed do get stderr output.

Call the test file


Examine generated


Compare file contents


Examine your various outputs. The first test generated an almost empty file from standard output, but did generate some text in the error log err1.txt.
shell_exec('c:\wkhtmltopdf\wkhtmltopdf --asdasdsadsad 2>> err1.txt 1>> out1.txt');

 The second test generated the standard version output as expected and nothing to standard error output.
shell_exec('c:\wkhtmltopdf\wkhtmltopdf --version 2>> err2.txt 1>> out2.txt');

 If this is not the case, you need to check that you are pointing to the right path when calling wkhtmltopdf and that your PHP server is configured correctly. If you get no errors, check that PHP error reporting is on and check what the Apache and PHP error logs say. If your WAMP is installed into C:\wamp, your Apache log will by default be at C:\wamp\logs\apache_error.log and your PHP log will be at C:\wamp\logs\php_error.log.

Finally

This sort of testing is a proof of concept and is not directly usable in a production environment. Remember to validate your inputs and to keep a tight watch on security but this is a method that will get you wkhtmltopdf up and running. You will likely need to play with the stderr and stdout streams a little to get it to work like you wish but after you do a few experiments it really isn't that complicated. Working with streams in PHP is a different issue.
Posted by at
Labels: , ,

5 comments:

  1. Tifanix11 January 2013 at 07:07

    Thank you for this, I was driving crazy tring to configure it in windows, it turned out to be so easy! :)

    ReplyDelete
  2. Tifanix11 January 2013 at 07:16

    I have another question, I got this working correctly and converting to pdf, but how can i use the wkhtmltopdf comands, like:

    $pdf->output(Wkhtmltopdf::MODE_DOWNLOAD, "test.pdf");

    Thanks!

    ReplyDelete
    Replies
    1. Joel11 October 2013 at 05:29

      Hi, sorry for the late answer! That looks like a wrapper library that's using wkhtmltopdf so that you don't use it directly like I did in the examples. I don't know which one it is. It looks a little like the standard one provided at https://code.google.com/p/wkhtmltopdf/wiki/IntegrationWithPhp but it could also be Snappy, which is found at https://github.com/KnpLabs/snappy . I hope this helps if you still have this issue.

      Delete
  3. Unknown24 May 2013 at 00:16

    Hi great tutorial, but where's the output pdf file?

    ReplyDelete
    Replies
    1. Joel11 October 2013 at 05:27

      Sorry to answer so late! None of the commands I used actually produce a PDF file. You would use something like this: shell_exec('c:\wkhtmltopdf\wkhtmltopdf www.google.com google.pdf');

      This is meant to be a simple proof of concept and a starting point, converting live pages is a little more complicated and depends a lot on your website so it's hard to do a generic one.

      Delete

Subscribe to: Post Comments (Atom)