Newbie .htaccess Tutorial
by billy
| send those evil hotlinkers to picture hell..... |
| "What is that .htaccess thing?" .htaccess is a ascii text file used to over-ride your Apache web-servers configuration and has many weird, wonky and wonderful uses! This tutorial focues on preventing thiefs from hotlinking your images and those "chat-room" folks who like to pretend they are your favourite model by posting the url to one of your images. note: when creating your .htaccess file, it must be saved with no file type extension! If your text editor won't allow you to save a file without an extension, most FTP clients will let you remove it after you've uploaded it to your server. "Where do you put that thing?" Wherever it's needed! You can have a single .htaccess file protecting your entire domain, protecting a single directory(eg. images/), or, have many .htaccess files. each protecting a different directory. Sometimes simple is better, using a single .htaccess file to protect your image directory will help you avoid problems managing/changing multiple files across your domains. I normally use a single .htaccess file in my document root directory and sometimes put niche-specific .htaccess files in some sub-directories. "Show me that thing!"
"What do those things do?" AuthUserFile /dev/null AuthGroupFile /dev/null No passwords are required for individual users or groups of users RewriteEngine On Have to turn it on, before it will work....... :) RewriteCond %{HTTP_REFERER} !^http://www.newbie.com/.*$ [NC] If the referring url "HTTP_REFERER" does not start with your domain "http://www.newbie.com/", then this conditional statement is true and the next "RewriteRule" encountered will be executed. Since Unix is case sensitive, the [NC] flag makes the statement case insensitive. The ".*$" at the end will match any string, allowing access from any location on your domain ReWriteRule .*\.jpg$ http://www.hotlinker-hell.com [R,L] If the preceding Rewrite condition was true, and the request was for any url .* ending with .jpg we'll send them to the hotlinker-hell url. This is accomplished with the [R,L] flag. R forces a redirect of the url, while L says this is the last rule, don't bother checking any more. Since Unix is case sensitive, you should modify the RewriteRule to handle upper-case extenstions if you use them and you might want to include protection for gif files. ReWriteRule .*\.(jpg|JPG|gif|GIF)$ http://www.hotlinker-hell.com [R,L] Would protect images ending in ".jpg", or, "JPG", or "gif", or "GIF" If you use mixed-case in your image file names, the following rule could be used to protect strings ending in "JPG","JPg","JpG",Jpg"......,or, "GIF","GIf","GiF","Gif"...... RewriteRule .*[Jj][Pp][Gg]$|.*[Gg][Ii][Ff]$ http://www.hotlinker-hell.com [R,L] "Show me a bigger thing!" Its a good idea to include error document handlers in your .htaccess files and additional Rewrite conditions to handle most variations of your domains.
note: there is an implied AND between each of the RewriteCond statements above. "Some handy variations of ReWritecond..."
note: this could have an effect on friendly search engine spiders!
"Some other handy things...."
You can create ReWriteCond statements that use almost any of your server's environmental variables including: cookies, DNS, IP's. Check the Apache document links on the left, if you need something special. :) "I want them to hotlink me...." If a search engine caches your page, the surfer clicking on your link won't see any of your images, or banners. This is a scenario where you might want the the search engine to be able to hotlink at least your banners so the surfer would only see it. billy |
Funny Symbols ! - negation ^ - start of string $ - end of string . - any character ? - repetition [0,1] * - repetition [0,..,n] + - repetition [1,..,n] \ - escape character [NC] - ignore case [R,L] - redirect, last Regular Expressions simple examples... Advanced Students URL Rewriting Guide URL Rewriting Engine Apache HTTP Server .htaccess testing! www.hotlinking.com It doesn't work? Common problems... Things that crawl Friendly Spiders |
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by billy
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