Hello, I am building some custom urls for finding images online. These are like:

 www.website.com/images/123456789.jpg

 Usually these are isbns or upc codes for products or books.

I am currently doing string replacement by php, for substituting the number by an expression and replacing that expression with whatver number, when I do a search.

For example

www.website.com/images/{REPLACEMENT}.jpg

 and then I replace this with the actual product number.

This works fine but some sites store the numbers as such:

www.website.com/images/978/9789731234.jpg

or

www.website.com/images/1/2/3/123456789.jpg

In this case, I must create the query with the first, second, third character of the search number and THEN the number + .jpg

This works fine with PHP, and there are multiple possible combinations. Since I want to do this script database-driven, I can't store in the database, obviously, the substring function which I use in PHP. How can I write a regex to help with this?

So, for example on this website:

http://isbn.abebooks.com/mz/39/67/0679728139.jpg

this book has the last two numbers, then the first two, without the 0 and then the isbn itself.

In the database I want to store something like:

http://isbn.abebooks.com/mz/[substr|-2|2]/[substr|1|2]/[str].jpg

and then my code would replace these things between [ and ] with the appropriate characters in a query.

Any help would be so much appreciated.

Thanks