Regex help?

Killswitch · 02-09-2010, 03:22 AM

I am working on an app and currently looking to create a plugin to quickly display images from a folder using a quick tag.

I figured in order to do so I would replace ...

{gallery=/path/to/images}

In the content page, replacing it with formatted HTML showing the images in the folder specified.

I am no good with regex (still painfully trying to learn though), and was hoping someone could help me with the match to get the /path/to/images portion of the tag and replacing the entire thing with my HTML.

gamer13 · 02-09-2010, 04:45 PM

You could use preg_replace_callback() to replace that part with a gallery:

PHP Code:


			
<?php



function gallery($path_to_images)

{

    // do something and return it:

    return;

}



$text = 'Hello world!

{gallery=/path/to/images}

Another world!';



$new_text = preg_replace_callback('/^{gallery=(.*?)}$/', 'gallery', $text)

Not tested...

Killswitch · 02-09-2010, 06:58 PM

Thanks, I will give that a try. I have put regex off for so long, really need to work with it more.

This is the pattern I had, but it currently is half working...

Code:

"/{gallery=(.*)}/i"

It worked on a basic dummy example I had perfectly, but currently it is not working with content pulled from the database (or I am missing something)...

Code:

// The main file
$this->content->data = preg_replace("/{gallery=(.*)}/is", $this->gallery(), $this->data->content);

// gallery() function
$html = "";
		
		if ( ! preg_match("/{gallery=(.*)}/is", $this->data->content, $matches)) return $html;
		
		// Ensure we have trailing /
		if (substr($matches[0], -1) !== '/') $matches[0] .= '/';
		
		// Trim down unwanted chars from match
		$matches[0] = str_replace("{", "", $matches[0]);
		$matches[0] = str_replace("}", "", $matches[0]);
		$matches[0] = str_replace("gallery=", "", $matches[0]);
		
		// Check if the supplied match is a valid directory
		if ( ! is_dir(DOCROOT.$matches[0])) return $html;
		
		// Get files from the supplied dir
		$files = Kohana::list_files(DOCROOT.$matches[0]);
		
		$count = count($files);
		
		if ( ! $count > 0) return $html;
		
		$html = "<div class=\"gallery\">\n";
		foreach ($files AS $file)
		{	
			$sub = substr($file, -3);
			if ($sub != 'jpg' OR $sub != 'png' OR $sub != 'gif') break;
			
			$html .= "<img src=\"$file\">\n";
		}
		$html .= "</div>\n";
		
		return $html;

I know, the gallery() function is a bit messy, I needed to see if it would work, which it doesn't. This entire bit is actually a hook for Kohana which I am using for a CMS I am building with Kohana. (Small note, the returning HTML bit above is just to overwrite the tag)

A small note, the regex you listed above didn't work until I removed the ^ and $ in the pattern.

delayedinsanity · 02-09-2010, 08:17 PM

Regular expressions are fairly easy to pick up, they're just a little harder to master.

php Code:

header( 'Content-type: text/plain' );

$string = '<html> <test> Some content {gallery=/path/to/images} some more {gallery} </test> </html>';

// This won't work, because if there's more than one, it will get greedy
// $string = preg_replace( '~{gallery=(.*)}~i', 'FOUND ONE!', $string );

// This only matches up to the first brace it finds
$string = preg_replace( '~{gallery=([^}]+)}~i', 'FOUND ONE!', $string );

echo $string;

The above is just an example of one way to improve your expression, I'll leave the insertion of the gallery to you since you seem to have a handle on it. Uncomment the first one using the original pattern (and comment the second) and you'll see what I'm referring to.

.* is powerful, but almost always misused. Try to avoid it while you're learning and you'll pick up tricks that will help you build much more complex patterns down the road.