| <!--#if expr="$FAQMASTER" --> |
| <!--#set var="STANDALONE" value="" --> |
| <!--#set var="INCLUDED" value="YES" --> |
| <!--#if expr="$QUERY_STRING = TOC" --> |
| <!--#set var="TOC" value="YES" --> |
| <!--#set var="CONTENT" value="" --> |
| <!--#else --> |
| <!--#set var="TOC" value="" --> |
| <!--#set var="CONTENT" value="YES" --> |
| <!--#endif --> |
| <!--#else --> |
| <!--#set var="STANDALONE" value="YES" --> |
| <!--#set var="INCLUDED" value="" --> |
| <!--#set var="TOC" value="" --> |
| <!--#set var="CONTENT" value="" --> |
| <!--#endif --> |
| <!--#if expr="$STANDALONE" --> |
| <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> |
| <HTML> |
| <HEAD> |
| <TITLE>Apache Server Frequently Asked Questions</TITLE> |
| </HEAD> |
| <!-- Background white, links blue (unvisited), navy (visited), red (active) --> |
| <BODY |
| BGCOLOR="#FFFFFF" |
| TEXT="#000000" |
| LINK="#0000FF" |
| VLINK="#000080" |
| ALINK="#FF0000" |
| > |
| <!--#include virtual="header.html" --> |
| <H1 ALIGN="CENTER">Apache Server Frequently Asked Questions</H1> |
| <P> |
| $Revision: 1.1 $ ($Date: 1999/06/24 15:02:52 $) |
| </P> |
| <P> |
| The latest version of this FAQ is always available from the main |
| Apache web site, at |
| <<A |
| HREF="http://www.apache.org/docs/misc/FAQ.html" |
| REL="Help" |
| ><SAMP>http://www.apache.org/docs/misc/FAQ.html</SAMP></A>>. |
| </P> |
| <!-- Notes about changes: --> |
| <!-- - If adding a relative link to another part of the --> |
| <!-- documentation, *do* include the ".html" portion. There's a --> |
| <!-- good chance that the user will be reading the documentation --> |
| <!-- on his own system, which may not be configured for --> |
| <!-- multiviews. --> |
| <!-- - When adding items, make sure they're put in the right place --> |
| <!-- - verify that the numbering matches up. --> |
| <!-- - *Don't* use <PRE></PRE> blocks - they don't appear --> |
| <!-- correctly in a reliable way when this is converted to text --> |
| <!-- with Lynx. Use <DL><DD><CODE>xxx<BR>xx</CODE></DD></DL> --> |
| <!-- blocks inside a <P></P> instead. This is necessary to get --> |
| <!-- the horizontal and vertical indenting right. --> |
| <!-- - Don't forget to include an HR tag after the last /P tag --> |
| <!-- but before the /LI in an item. --> |
| <P> |
| If you are reading a text-only version of this FAQ, you may find numbers |
| enclosed in brackets (such as "[12]"). These refer to the list of |
| reference URLs to be found at the end of the document. These references |
| do not appear, and are not needed, for the hypertext version. |
| </P> |
| <H2>The Questions</H2> |
| <OL TYPE="A"> |
| <!--#endif --> |
| <!--#if expr="$TOC || $STANDALONE" --> |
| <LI VALUE="8"><STRONG>URL Rewriting</STRONG> |
| <OL> |
| <LI><A HREF="#rewrite-more-config">Where can I find mod_rewrite rulesets |
| which already solve particular URL-related problems?</A> |
| </LI> |
| <LI><A HREF="#rewrite-article">Where can I find any published information |
| about URL-manipulations and mod_rewrite?</A> |
| </LI> |
| <LI><A HREF="#rewrite-complexity">Why is mod_rewrite so difficult to learn |
| and seems so complicated?</A> |
| </LI> |
| <LI><A HREF="#rewrite-dontwork">What can I do if my RewriteRules don't work |
| as expected?</A> |
| </LI> |
| <LI><A HREF="#rewrite-prefixdocroot">Why don't some of my URLs get |
| prefixed with DocumentRoot when using mod_rewrite?</A> |
| </LI> |
| <LI><A HREF="#rewrite-nocase">How can I make all my URLs case-insensitive |
| with mod_rewrite?</A> |
| </LI> |
| <LI><A HREF="#rewrite-virthost">Why are RewriteRules in my VirtualHost |
| parts ignored?</A> |
| </LI> |
| <LI><A HREF="#rewrite-envwhitespace">How can I use strings with whitespaces |
| in RewriteRule's ENV flag?</A> |
| </LI> |
| </OL> |
| </LI> |
| <!--#endif --> |
| <!--#if expr="$STANDALONE" --> |
| </OL> |
| |
| <HR> |
| |
| <H2>The Answers</H2> |
| <!--#endif --> |
| <!--#if expr="! $TOC" --> |
| |
| <H3>H. URL Rewriting</H3> |
| <OL> |
| |
| <LI><A NAME="rewrite-more-config"> |
| <STRONG>Where can I find mod_rewrite rulesets which already solve |
| particular URL-related problems?</STRONG> |
| </A> |
| <P> |
| There is a collection of |
| <A HREF="http://www.engelschall.com/pw/apache/rewriteguide/" |
| >Practical Solutions for URL-Manipulation</A> |
| where you can |
| find all typical solutions the author of |
| <A HREF="../mod/mod_rewrite.html"><SAMP>mod_rewrite</SAMP></A> |
| currently knows of. If you have more |
| interesting rulesets which solve particular problems not currently covered in |
| this document, send it to |
| <A HREF="mailto:rse@apache.org">Ralf S. Engelschall</A> |
| for inclusion. The |
| other webmasters will thank you for avoiding the reinvention of the wheel. |
| </P> |
| <HR> |
| </LI> |
| |
| <LI><A NAME="rewrite-article"> |
| <STRONG>Where can I find any published information about |
| URL-manipulations and mod_rewrite?</STRONG> |
| </A> |
| <P> |
| There is an article from |
| <A HREF="mailto:rse@apache.org" |
| >Ralf S. Engelschall</A> |
| about URL-manipulations based on |
| <A HREF="../mod/mod_rewrite.html"><SAMP>mod_rewrite</SAMP></A> |
| in the "iX Multiuser Multitasking Magazin" issue #12/96. The |
| german (original) version |
| can be read online at |
| <<A HREF="http://www.heise.de/ix/artikel/9612149/" |
| >http://www.heise.de/ix/artikel/9612149/</A>>, |
| the English (translated) version can be found at |
| <<A HREF="http://www.heise.de/ix/artikel/E/9612149/" |
| >http://www.heise.de/ix/artikel/E/9612149/</A>>. |
| </P> |
| <HR> |
| </LI> |
| |
| <LI><A NAME="rewrite-complexity"> |
| <STRONG>Why is mod_rewrite so difficult to learn and seems so |
| complicated?</STRONG> |
| </A> |
| <P> |
| Hmmm... there are a lot of reasons. First, mod_rewrite itself is a powerful |
| module which can help you in really <STRONG>all</STRONG> aspects of URL |
| rewriting, so it can be no trivial module per definition. To accomplish |
| its hard job it uses software leverage and makes use of a powerful regular |
| expression |
| library by Henry Spencer which is an integral part of Apache since its |
| version 1.2. And regular expressions itself can be difficult to newbies, |
| while providing the most flexible power to the advanced hacker. |
| </P> |
| <P> |
| On the other hand mod_rewrite has to work inside the Apache API environment |
| and needs to do some tricks to fit there. For instance the Apache API as of |
| 1.x really was not designed for URL rewriting at the <TT>.htaccess</TT> |
| level of processing. Or the problem of multiple rewrites in sequence, which |
| is also not handled by the API per design. To provide this features |
| mod_rewrite has to do some special (but API compliant!) handling which leads |
| to difficult processing inside the Apache kernel. While the user usually |
| doesn't see anything of this processing, it can be difficult to find |
| problems when some of your RewriteRules seem not to work. |
| </P> |
| <HR> |
| </LI> |
| |
| <LI><A NAME="rewrite-dontwork"> |
| <STRONG>What can I do if my RewriteRules don't work as expected? |
| </STRONG> |
| </A> |
| <P> |
| Use "<SAMP>RewriteLog somefile</SAMP>" and |
| "<SAMP>RewriteLogLevel 9</SAMP>" and have a precise look at the |
| steps the rewriting engine performs. This is really the only one and best |
| way to debug your rewriting configuration. |
| </P> |
| <HR> |
| </LI> |
| |
| <LI><A NAME="rewrite-prefixdocroot"><STRONG>Why don't some of my URLs |
| get prefixed with DocumentRoot when using mod_rewrite?</STRONG> |
| </A> |
| <P> |
| If the rule starts with <SAMP>/somedir/...</SAMP> make sure that |
| really no <SAMP>/somedir</SAMP> exists on the filesystem if you |
| don't want to lead the URL to match this directory, <EM>i.e.</EM>, |
| there must be no root directory named <SAMP>somedir</SAMP> on the |
| filesystem. Because if there is such a directory, the URL will not |
| get prefixed with DocumentRoot. This behaviour looks ugly, but is |
| really important for some other aspects of URL rewriting. |
| </P> |
| <HR> |
| </LI> |
| |
| <LI><A NAME="rewrite-nocase"> |
| <STRONG>How can I make all my URLs case-insensitive with mod_rewrite? |
| </STRONG> |
| </A> |
| <P> |
| You can't! The reason is: First, case translations for arbitrary |
| length URLs cannot be done <EM>via</EM> regex patterns and |
| corresponding substitutions. One need a per-character pattern like |
| sed/Perl <SAMP>tr|..|..|</SAMP> feature. Second, just making URLs |
| always upper or lower case will not resolve the complete problem of |
| case-INSENSITIVE URLs, because actually the URLs had to be rewritten |
| to the correct case-variant residing on the filesystem because in |
| later processing Apache needs to access the file. And Unix |
| filesystem is always case-SENSITIVE. |
| </P> |
| <P> |
| But there is a module named <CODE>mod_speling.c</CODE> (yes, it is named |
| this way!) out there on the net. Try this one. |
| </P> |
| <HR> |
| </LI> |
| |
| <LI><A NAME="rewrite-virthost"> |
| <STRONG> Why are RewriteRules in my VirtualHost parts ignored?</STRONG> |
| </A> |
| <P> |
| Because you have to enable the engine for every virtual host explicitly due |
| to security concerns. Just add a "RewriteEngine on" to your |
| virtual host configuration parts. |
| </P> |
| <HR> |
| </LI> |
| |
| <LI><A NAME="rewrite-envwhitespace"> |
| <STRONG> How can I use strings with whitespaces in RewriteRule's ENV |
| flag?</STRONG> |
| </A> |
| <P> |
| There is only one ugly solution: You have to surround the complete |
| flag argument by quotation marks (<SAMP>"[E=...]"</SAMP>). Notice: |
| The argument to quote here is not the argument to the E-flag, it is |
| the argument of the Apache config file parser, <EM>i.e.</EM>, the |
| third argument of the RewriteRule here. So you have to write |
| <SAMP>"[E=any text with whitespaces]"</SAMP>. |
| </P> |
| <HR> |
| </LI> |
| |
| </OL> |
| <!--#endif --> |
| <!--#if expr="$STANDALONE" --> |
| <!-- Don't forget to add HR tags at the end of each list item.. --> |
| |
| <!--#include virtual="footer.html" --> |
| </BODY> |
| </HTML> |
| <!--#endif --> |
