XF 2.0 Having trouble extending \XF\FileWrapper. Can anyone spot my problem?

[Earl]

• What I'm trying to do is:

I wanna add some metadata to a file and modify it as soon as it uploads as an attachment. (before hash calculations etc)

So I thought overriding beforeNewAttachment method in AbstractHandler would do the trick.

XF\Attachment\AbstractHandler

public function beforeNewAttachment(\XF\FileWrapper $file, array &$extra = [])
{
   return;
}

As you can see that method uses \XF\FileWrapper class

Then again, Having my code inside of new method called "addMetaData" in \XF\FileWrapper class would allow me to execute my code.

I mean by doing something like this (I will use attachment handler in XenForo Resource Manager to illustrate the idea here):
MyAddon\XFRM\Attachment\ResourceUpdate

namespace MyAddon\XFRM\Attachment;

class ResourceVersion extends XFCP_ResourceUpdate
{
    /**
     * @param \MyAddon\XF\FileWrapper $file
     * @param array $extra
     */
    public function beforeNewAttachment(\XF\FileWrapper $file, array &$extra = [])
    {
        parent::beforeNewAttachment($file, $extra);
        $file->addMetaData();
    }
}

MyAddon/XF/FileWrapper

namespace MyAddon\XF;


class FileWrapper extends XFCP_FileWrapper
{
    /**
     * Add watermark to images
     * @return $this|bool
     */
    public function addMetaData()
    {

        //my code here

    }

Would allow me to run my code in each "attachment handlers" as opposed to repeating my code inside of beforeNewAttachment method in every attachment handlers (you can't extend abstract classes)

• My problem:

Problem: My Class Extension for MyAddon/XF/FileWrapper doesn't seem work.
But Class Extionsionfor MyAddon\XFRM\Attachment\ResourceUpdate works perfectly. (in my case MyAddon\XF\Attachment\Post)

When I call addMetaData() method (as in first code)
$file->addMetaData(); //after this line

It jumps into an error
Debug screenshots:


Then after pressing f7 (Jump into) next line:



Exception: Call to undefined method XF\FileWrapper::addMetaData()



Strange right?
Namespace looks fine:

And class extensions in admincp:


The craziest thing is:
I tried adding breakpoints to extension.php too



As you can see, it loads both class extensions in __construct method of \XF\Extension class when I debug.

and It only loads the attachment handler class extension with the class proxy system, But not the FileWrapper extension when I running the debugger here:

\XF\Extension

// XFCP = XenForo Class Proxy, in case you're wondering


$nsSplit = strrpos($extendClass, '\\');

if ($nsSplit !== false && $ns = substr($extendClass, 0, $nsSplit))

{

   $proxyClass = $ns . '\\XFCP_' . substr($extendClass, $nsSplit + 1);

}

else

{

   $proxyClass = 'XFCP_' . $extendClass;

}


// TODO: there may be a situation where this fails. If we've changed the extensions after classes have

// been loaded, it's possible these classes will already be loaded with a different config. Figure out

// how to handle that if possible. Remains to be seen if it comes up (mostly relating to add-on imports).

 

[Chris D]

The XF\FileWrapper class isn't designed to be extended and therefore isn't run through the class extension system.

You would have to find somewhere else to add your custom code.

 

[Earl]

The XF\FileWrapper class isn't designed to be extended and therefore isn't run through the class extension system.

You would have to find somewhere else to add your custom code.

Oohhh I see. so there are classes that we can't extend. I lost lots of hair when I was trying to extend this class
How do we find if a class is extensible or not?
And Thank you for the fast response. Truly appreciate it.

 

[Chris D]

Easiest way is to search the XF files for instances of the class name.

In this case, you'll find it is instantiated directly inside the Upload object:

$wrapper = new \XF\FileWrapper($this->tempFile, $this->fileName);

If it was extendable, we'd run the class name through the extendClass method first, similar to this:

$class = \XF::extendClass('XF\FileWrapper');
$wrapper = new $class($this->tempFile, $this->fileName);

 

[Earl]

Easiest way is to search the XF files for instances of the class name.

In this case, you'll find it is instantiated directly inside the Upload object:

$wrapper = new \XF\FileWrapper($this->tempFile, $this->fileName);

If it was extendable, we'd run the class name through the extendClass method first, similar to this:

$class = \XF::extendClass('XF\FileWrapper');
$wrapper = new $class($this->tempFile, $this->fileName);

Got it. Thank you for helping me out with this one. Really appreceate your support.