{"id":1045,"date":"2009-07-27T13:12:57","date_gmt":"2009-07-27T19:12:57","guid":{"rendered":"http:\/\/bililite.nfshost.com\/blog\/?p=1045"},"modified":"2009-07-27T15:56:25","modified_gmt":"2009-07-27T21:56:25","slug":"things-i-learned-about-htaccess","status":"publish","type":"post","link":"https:\/\/bililite.com\/blog\/2009\/07\/27\/things-i-learned-about-htaccess\/","title":{"rendered":"Things I Learned About .htaccess"},"content":{"rendered":"

All I wanted was to get a better 404 page for the bililite.com site<\/a> and to use mod_rewrite<\/a> to standardize my pages<\/a>. Of course, nothing is ever simple and mod_rewrite is voodoo<\/a>. So it took a week of experimenting, pulling my hair and staring at a lot of 500 errors<\/a>, but I think I got things where I wanted them (still don't have a very elegant 404 page, though!). To make sure I didn't have to go through this again, and to help anyone else out there, here are the things I wish I had known:<\/p>\r\n

askApache<\/a> is my new best friend<\/h3>\r\n

There are lots of mod_rewrite tutorials out there<\/a> on the web, but once you get past the simple stuff, nothing is obvious. askApache<\/a> digs deeper and explains more of the hack-y stuff that you need to know in order to actually use<\/em> your .htaccess<\/code> file, especially his Crazy Advanced Mod_Rewrite Tutorial<\/a>, Highly recommended.<\/p>\r\n

Know the difference between Redirect<\/code> and Rewrite<\/code><\/h3>\r\n

Both of these involve changing a URL to a different one. Redirecting, however, tells the browser that it changed (generally by sending a 301 status code<\/a>) while rewriting (or \"internally redirecting\") keeps it a secret. Thus if I internally use URL's like \/\/example.com\/index.php?main=foo&part=bar<\/code> but publicly I want them to look like \/\/example.com\/foo\/bar<\/code> I'll rewrite:<\/p>\r\n

RewriteRule ^([^\/\\.]+)\/([^\/\\.]+)$ index.php?main=$1&part=$2 [QSA,L]<\/code><\/pre>\r\n
But to publicly change a URL, say from \/\/example.com\/oldname.html<\/code> to \/\/example.com\/newname.html<\/code> I'll redirect:<\/p>\r\n
Redirect Permanent \/oldname.html \/newname.html\r\n# or\r\nRewriteRule ^oldname.html$ newname.html [R]<\/code><\/pre>\r\n
Note that it's usually easier to use Redirect<\/code><\/a> or RedirectMatch<\/code><\/a> rather than RewriteRule<\/code><\/a> with the [R] flag. Note also that the Redirect<\/code> pattern starts with the \/<\/code> (or whatever the per-directory prefix is) while RewriteRule<\/code> patterns strip the \/<\/code> out. I've been burned by this! (this is true for .htaccess<\/code> only; the per-server configuration file httpd.conf<\/code> uses the entire URL. But I'm on a cheap shared server; I can't touch httpd.conf<\/code>).<\/p>\r\n
Use Redirect<\/code> to append a slash to directories<\/h3>\r\n
Generally, if you use a URL like \/\/example.com\/foo<\/code> you really want \/\/example.com\/foo\/<\/code>. Apache does this automatically<\/a> for real directories. But if you're doing the \/foo\/bar<\/code> to \/index.php?main=foo&part=bar<\/code> and \/foo<\/code> to \/index.php?main=foo<\/code>, you really want \/foo<\/code> to be redirected<\/em> to \/foo\/<\/code>, then \/foo\/ rewritten<\/em> to \/index.php?main=foo<\/code>. If you don't, then relative URL's won't work. If the file returned by \/foo<\/code> contains a link <a href=\"bar\"><\/code> you want the browser to interpret that href as \/foo\/bar<\/code>. But it won't. It thinks the file has the URL \/foo<\/code>, so its directory is \/<\/code> and the relative URL bar refers to \/bar<\/code>. Redirecting \/foo<\/code> to \/foo\/<\/code> lets the browser know that foo<\/code> is to be treated as a directory, so bar<\/code> refers to \/foo\/bar<\/code>. Example:\r\n
RedirectMatch Permanent ^\/([^\/\\.]+)$ \/$1\/\r\nRewriteRule ^([^\/\\.]+)\/$ index.php?main=$1 [QSA,L]\r\nRewriteRule ^([^\/\\.]+)\/([^\/\\.]+)$ index.php?main=$1&part=$2 [QSA,L]<\/code><\/pre>\r\n
ErrorDocument<\/code> should rewrite, not redirect<\/h3>\r\n
It's incredibly annoying to type in \/\/example.com\/long\/complicated\/urk.html<\/code> (note the typo!) and have the address bar turn into \/\/example.com\/404.html. I want the address bar to stay the same so I can edit what I wrote! The ErrorDocument<\/a> directive uses redirection if a complete URL is specified. This is bad. Just start the URL with a slash and it will use internal redirection (what I'm calling rewriting) and the browser's address bar will remain untouched.\r\n
ErrorDocument 404 \/404.php\r\n#NOT ErrorDocument 404 http:\/\/example.com\/404.php\r\n<\/code><\/pre>\r\n
1&1 gets it wrong<\/h3>\r\n
I use the cheapest shared-server plan from 1&1<\/a> and I've been pretty happy with it: no frills, straight classic LAMP stack<\/a>, reliable enough for me. But they \"hijack\" the ErrorDocument<\/code> for active pages (.php, .cgi, .pl and I assume others) to their own advertising-laden page. That I can understand (again, it's a cheap plan) but they redirect so you can't correct the URL. So I need to do an end run around them by catching nonexistent files first:\r\n
RewriteCond %{REQUEST_FILENAME} \\.php$\r\nRewriteCond %{REQUEST_FILENAME} !-f\r\nRewriteRule . \/404.php [L]\r\n<\/code><\/pre>\r\n
RewriteCond -f<\/code> is case sensitive<\/h3>\r\n
This burned me badly before I figured it out. The -f<\/code> test for RewriteCond<\/code><\/a> uses the underlying operating system to find the file, which means that on a Linux system, it's case-sensitive. No way around it; the [NC]<\/code> flag doesn't help. So when I create gif's on my Windows machine in Paint and save it, it automatically names the file whatever.GIF<\/code> and remains that way when I copy it to the Linux server. Now Apache will do fine finding the file if I request it with <img src=\"whatever.gif\"\/><\/code>, but if my .htaccess<\/code> has a line RewriteCond %{REQUEST_FILENAME} !-f<\/code> it will return true since whatever.gif<\/code> doesn't exist; whatever.GIF<\/code> does.<\/p>\r\n
Hope this saves someone some time (and hair).<\/p>","protected":false},"excerpt":{"rendered":"All I wanted was to get a better 404 page for the bililite.com site and to use mod_rewrite to standardize my pages. Of course, nothing is ever simple and mod_rewrite is voodoo. So it took a week of experimenting, pulling my hair and staring at a lot of 500 errors, but I think I got […]","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[20],"tags":[],"_links":{"self":[{"href":"https:\/\/bililite.com\/blog\/wp-json\/wp\/v2\/posts\/1045"}],"collection":[{"href":"https:\/\/bililite.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/bililite.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/bililite.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/bililite.com\/blog\/wp-json\/wp\/v2\/comments?post=1045"}],"version-history":[{"count":23,"href":"https:\/\/bililite.com\/blog\/wp-json\/wp\/v2\/posts\/1045\/revisions"}],"predecessor-version":[{"id":1068,"href":"https:\/\/bililite.com\/blog\/wp-json\/wp\/v2\/posts\/1045\/revisions\/1068"}],"wp:attachment":[{"href":"https:\/\/bililite.com\/blog\/wp-json\/wp\/v2\/media?parent=1045"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/bililite.com\/blog\/wp-json\/wp\/v2\/categories?post=1045"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/bililite.com\/blog\/wp-json\/wp\/v2\/tags?post=1045"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}