| <!--#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="$STANDALONE" --> |
| <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" |
| "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> |
| |
| <html xmlns="http://www.w3.org/1999/xhtml"> |
| <head> |
| <meta name="generator" content="HTML Tidy, see www.w3.org" /> |
| |
| <title>Apache Server Frequently Asked Questions</title> |
| </head> |
| <!-- Background white, links blue (unvisited), navy (visited), red (active) --> |
| |
| <body bgcolor="#FFFFFF" text="#000000" link="#0000FF" |
| vlink="#000080" alink="#FF0000"> |
| <!--#include virtual="header.html" --> |
| |
| <h1 align="CENTER">Apache Server Frequently Asked |
| Questions</h1> |
| |
| <p>$Revision: 1.4 $ ($Date: 2001/10/08 01:26:54 $)</p> |
| |
| <p>The latest version of this FAQ is always available from the |
| main Apache web site, at <<a |
| href="http://httpd.apache.org/docs/misc/FAQ.html" |
| rel="Help"><samp>http://httpd.apache.org/docs/misc/FAQ.html</samp></a>>.</p> |
| <!-- Notes about changes: --> |
| <!-- - If adding a relative link to another part of the --> |
| <!-- documentation, *do* include the ".html" portion. There's a --> |
| <!-- good chance that the user will be reading the documentation --> |
| <!-- on his own system, which may not be configured for --> |
| <!-- multiviews. --> |
| <!-- - When adding items, make sure they're put in the right place --> |
| <!-- - verify that the numbering matches up. --> |
| <!-- - *Don't* use <PRE></PRE> blocks - they don't appear --> |
| <!-- correctly in a reliable way when this is converted to text --> |
| <!-- with Lynx. Use <DL><DD><CODE>xxx<BR>xx</CODE></DD></DL> --> |
| <!-- blocks inside a <P></P> instead. This is necessary to get --> |
| <!-- the horizontal and vertical indenting right. --> |
| <!-- - Don't forget to include an HR tag after the last /P tag --> |
| <!-- but before the /LI in an item. --> |
| |
| <p>If you are reading a text-only version of this FAQ, you may |
| find numbers enclosed in brackets (such as "[12]"). These refer |
| to the list of reference URLs to be found at the end of the |
| document. These references do not appear, and are not needed, |
| for the hypertext version.</p> |
| |
| <h2>The Questions</h2> |
| |
| <ol type="A"> |
| <!--#endif --> |
| <!--#if expr="$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 id="rewrite-more-config" |
| 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 practical solutions that can be |
| found in the |
| <a href="rewriteguide.html">Apache 1.3 URL Rewriting Guide</a>. |
| 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 id="rewrite-article" |
| 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/1996/12/149/">http://www.heise.de/ix/artikel/1996/12/149/</a>>, |
| the English (translated) version can be found at <<a |
| href="http://www.heise.de/ix/artikel/E/1996/12/149/">http://www.heise.de/ix/artikel/E/1996/12/149/</a>>.</p> |
| <hr /> |
| </li> |
| |
| <li> |
| <a id="rewrite-complexity" |
| 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 id="rewrite-dontwork" |
| 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 id="rewrite-prefixdocroot" |
| 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 behavior looks ugly, but is really |
| important for some other aspects of URL rewriting.</p> |
| <hr /> |
| </li> |
| |
| <li> |
| <a id="rewrite-nocase" name="rewrite-nocase"><strong>How |
| can I make all my URLs case-insensitive with |
| mod_rewrite?</strong></a> |
| |
| <p>You can't! The reasons are: first, that, case |
| translations for arbitrary length URLs cannot be done |
| <em>via</em> regex patterns and corresponding |
| substitutions. One needs a per-character pattern like the |
| sed/Perl <samp>tr|..|..|</samp> feature. Second, just |
| making URLs always upper or lower case does not solve the |
| whole problem of case-INSENSITIVE URLs, because URLs |
| actually have to be rewritten to the correct case-variant |
| for the file residing on the filesystem in order to allow |
| Apache to access the file. And the Unix filesystem is |
| always case-SENSITIVE.</p> |
| |
| <p>But there is a module named <code><a |
| href="../mod/mod_speling.html">mod_speling.c</a></code> in |
| the Apache distribution. Try this module to help correct |
| people who use mis-cased URLs.</p> |
| <hr /> |
| </li> |
| |
| <li> |
| <a id="rewrite-virthost" |
| 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 id="rewrite-envwhitespace" |
| 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" --> |
| <!--#endif --> |
| </body> |
| </html> |
| |
