what are the best practices for letting users upload theme files to my server

I'm trying to make my own framework for my own projects and I would want people to upload themes for their profiles to the database. Letting them theme the look and feel of their accounts.

I first thought of having the files on the server.

A user would log in and the PHP would pick up their user id and other misc details and route the urls to their particular folder and serve the files in that folder.

an example would be a real directory of

http://www.foo.bar/users/me/style.css
http://www.foo.bar/users/me/script.js
http://www.foo.bar/users/me/index.tpl
http://www.foo.bar/users/me/otherPage.tpl

then I was thinking wow, imagine if I have 100's of users? then I would have 100's of folders in my users directory on my server, not to mention duplicate files all over the place taking up space. So ok, while this may be the fasted way to fetch a file maybe loading the markup from the database won't be such a bad idea right?

My server looks cleaner but now my database will get queried a lot more than I would want.

Then comes the major issue i think, is having files that a开发者_运维知识库re particular to a user. For example stylesheets may have background url's with images, so now these images needed to be linked to their real path on the server. Which brings me back to having a dedicated folder for each user to house their theme specific files.

How can i securely and effectively find a way to let users upload themes and have all files images, pdf's, docs, etc. all saved without them potentially being accessed by another account holder or thru simple hacking techniques to pull a file from the server that belongs to another user.

One solution I thought of was to only let users who are logged in view files, append to the file a unique tag that will let the user view the file if the tag matches a session variable. But then what if a user wants to share that file with another person, then tagging the file would bring my back to square 1 with the security thing not letting view the file because they wouldn't be an authorized user.

Well in any case, what would be best practices to get some of my concerns on the right path to being delt with.

P.S. I choose these tags because in my solutions I think they will touch upon some of these aspects.

You can store html or css in a table row but be sure to sanitize the data to avoid hacks, or injections. The easiest way would be to let the user paste the code into a text area or field. If you want to let them upload files, you will need to write a script that parses the data from the uploaded file. This is more complicated as you will have to manage all filtering and sanitizing along with making pulling the data from the file and saving it to the database.

We skin our CMS to work with multiple clients and their own users. But rather than giving them the possibility of changing ANY area or style of the page we allow certain areas such as:

• upload your logo
• set the colour of the banner bar behind your logo (using a smart colour picker and some 'figure out the contrast between the colours' functions)
• set your text colour (using a colour picker)
• and so on for the items you want them to change.

We then store those in the database and serve them up through dynamic stylesheets (I know these don't cache but it's better than having hundreds of files).

I know that MySpace used to let you upload a whole host of HTML and CSS (not sure if they still do) but it's a security nightmare as the potential for XSS is enourmous.

You may want to look at HTML Purifier if you're going to let them add their own custom HTML and full themes -> http://www.htmlpurifier.org