Dynamically creating preg pattern?

Question

Hello.

I want to try and make a BBCode parser, and as far as I know, preg functions are the most convenient to find and replace bbcode with html.

In the past I have used a lot of str_replace over and over, which isn't very efficient.

I want to create a BBCode and store it in the DB, so given the BBCode structure:

[image]{URL}[/image]

and the HTML: <img src="{URL}" alt="" .. />

How can I use PHP to compare these two inputs and find the necessary preg pattern to use when parsing the BBcode in content?

What I want to achieve is the DB also storing this pattern, and when it is time to parse a large text for bbcodes, it will know exactly how to do it. No hardcoding.

I searched a bit to try and find relevant topics on this, but I could only find exact patterns on how to resolve url bbcode etc, so pardon me if this really does exist somewhere.

Answer 1

Store the regexp and replacement patterns in the DB:

regExp: \[image\](.*?)\[/image\]
replacement: <img src="$1"/>

Then later retrieve these from the database and call preg_replace() with them as arguments. Note that you should be able to do it with a single call, since you can specify the regexp and replacement as arrays, and it will perform all of them at once.