slive 00/11/10 13:02:39
Modified: htdocs/manual index.html
htdocs/manual/mod mod_include.html
htdocs/manual/howto SSI-HOWTO.html
Log:
Some small updates to SSI tutorial, plus a link from mod_include.html.
Since Rich has, I believe, given up on keeping his source in sync,
I also ran the tutorial through htmltidy to make it a little easier
to maintain. If anyone is offended by this, please let me know.
Revision Changes Path
1.41 +1 -1 httpd-docs-1.3/htdocs/manual/index.html
Index: index.html
===================================================================
RCS file: /home/cvs/httpd-docs-1.3/htdocs/manual/index.html,v
retrieving revision 1.40
retrieving revision 1.41
diff -u -r1.40 -r1.41
--- index.html 2000/11/05 20:59:14 1.40
+++ index.html 2000/11/10 21:02:39 1.41
@@ -134,7 +134,7 @@
</td></tr><tr><td>
<A HREF="vhosts/index.html">Virtual Hosts</A>
</td></tr><tr><td>
-<a href="howto/SSI-HOWTO.html">Introduction to Server Side Includes</a>
+<a href="howto/SSI-HOWTO.html">Server Side Includes</a>
</td></tr><tr><td>
<A HREF="handler.html">Handlers</A>
</td></tr><tr><td>
1.30 +5 -1 httpd-docs-1.3/htdocs/manual/mod/mod_include.html
Index: mod_include.html
===================================================================
RCS file: /home/cvs/httpd-docs-1.3/htdocs/manual/mod/mod_include.html,v
retrieving revision 1.29
retrieving revision 1.30
diff -u -r1.29 -r1.30
--- mod_include.html 2000/09/28 17:04:57 1.29
+++ mod_include.html 2000/11/10 21:02:39 1.30
@@ -15,7 +15,7 @@
<!--#include virtual="header.html" -->
<H1 ALIGN="CENTER">Module mod_include</H1>
-<p>This module provides for server-parsed html documents.</p>
+<p>This module provides for documents with Server Side Includes (SSI).</p>
<P><A
HREF="module-dict.html#Status"
@@ -41,6 +41,10 @@
elements allow conditional text, the inclusion other files or
programs, as well as the setting and printing of environment
variables.</p>
+
+<p>For an introduction to this topic, we also provide a
+<a href="../howto/SSI-HOWTO.html">tutorial on Server Side Includes</a>.</p>
+
<H2>Directives</H2>
<UL>
1.5 +491 -316 httpd-docs-1.3/htdocs/manual/howto/SSI-HOWTO.html
Index: SSI-HOWTO.html
===================================================================
RCS file: /home/cvs/httpd-docs-1.3/htdocs/manual/howto/SSI-HOWTO.html,v
retrieving revision 1.4
retrieving revision 1.5
diff -u -r1.4 -r1.5
--- SSI-HOWTO.html 2000/11/06 03:06:40 1.4
+++ SSI-HOWTO.html 2000/11/10 21:02:39 1.5
@@ -1,344 +1,519 @@
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
-<HTML>
-<HEAD>
-<TITLE>Apache Tutorial: Introduction to Server Side Includes</TITLE>
-<LINK REV="made" HREF="mailto:[EMAIL PROTECTED]">
-</HEAD>
-
+<html>
+<head>
+<title>Apache Tutorial: Introduction to Server Side Includes</title>
+<link rev="made" href="mailto:[EMAIL PROTECTED]">
+</head>
<!-- Background white, links blue (unvisited), navy (visited), red (active)
-->
-<BODY
- BGCOLOR="#FFFFFF"
- TEXT="#000000"
- LINK="#0000FF"
- VLINK="#000080"
- ALINK="#FF0000"
->
+<body bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#000080"
+alink="#FF0000">
<!--#include virtual="header.html" -->
-<H1 ALIGN="CENTER">Apache Tutorial: Introduction to Server Side Includes</H1>
+<h1 align="CENTER">Apache Tutorial: Introduction to Server Side
+Includes</h1>
+<a name="__index__"></a> <!-- INDEX BEGIN -->
+
-<A NAME="__index__"></A>
-<!-- INDEX BEGIN -->
+<ul>
+<li><a href=
+"#apache tutorial: introduction to server side includes">Apache
+Tutorial: Introduction to Server Side Includes</a></li>
-<UL>
+<li><a href="#what are ssi">What are SSI?</a></li>
- <LI><A HREF="#apache tutorial: introduction to server side
includes">Apache Tutorial: Introduction to Server Side Includes</A></LI>
- <LI><A HREF="#what are ssi">What are SSI?</A></LI>
- <LI><A HREF="#configuring your server to permit ssi">Configuring your
server to permit SSI</A></LI>
- <LI><A HREF="#basic ssi directives">Basic SSI directives</A></LI>
- <UL>
-
- <LI><A HREF="#today's date">Today's date</A></LI>
- <LI><A HREF="#modification date of the file">Modification date
of the file</A></LI>
- <LI><A HREF="#including the results of a cgi program">Including
the results of a CGI program</A></LI>
- </UL>
-
- <LI><A HREF="#additional examples">Additional examples</A></LI>
- <LI><A HREF="#when was this document modified">When was this document
modified?</A></LI>
- <LI><A HREF="#including a standard footer">Including a standard
footer</A></LI>
- <LI><A HREF="#what else can i config">What else can I config?</A></LI>
- <LI><A HREF="#executing commands">Executing commands</A></LI>
- <LI><A HREF="#advanced ssi techniques">Advanced SSI techniques</A></LI>
- <LI><A HREF="#caveat">Caveat</A></LI>
- <LI><A HREF="#setting variables">Setting variables</A></LI>
- <LI><A HREF="#conditional expressions">Conditional expressions</A></LI>
- <LI><A HREF="#conclusion">Conclusion</A></LI>
-</UL>
-<!-- INDEX END -->
+<li><a href="#configuring your server to permit ssi">Configuring your
+server to permit SSI</a></li>
-<HR>
-<P>
-<H1><A NAME="apache tutorial: introduction to server side includes">Apache
Tutorial: Introduction to Server Side Includes</A></H1>
+<li><a href="#basic ssi directives">Basic SSI directives</a>
-<table border=1><tr><td valign="top">
-<strong>Related Modules</strong><br><br>
+<ul>
+ <li><a href="#today's date">Today's date</a></li>
-<a href="../mod/mod_include.html">mod_include</a><br>
-<a href="../mod/mod_cgi.html">mod_cgi</a><br>
+ <li><a href="#modification date of the file">Modification date of the
+file</a></li>
+
+ <li><a href="#including the results of a cgi program">Including the
+results of a CGI program</a></li>
+</ul>
+</li>
+
+<li><a href="#additional examples">Additional examples</a>
+
+<ul>
+<li><a href="#when was this document modified">When was this document
+modified?</a></li>
+
+<li><a href="#including a standard footer">Including a standard
+footer</a></li>
-</td><td valign="top">
-<strong>Related Directives</strong><br><br>
+<li><a href="#what else can i config">What else can I config?</a></li>
-<a href="../mod/core.html#options">Options</a><br>
+<li><a href="#executing commands">Executing commands</a></li>
+</ul>
+</li>
+
+<li><a href="#advanced ssi techniques">Advanced SSI techniques</a>
+
+<ul>
+<li><a href="#setting variables">Setting variables</a></li>
+
+<li><a href="#conditional expressions">Conditional expressions</a></li>
+</ul>
+</li>
+
+<li><a href="#conclusion">Conclusion</a></li>
+</ul>
+
+<!-- INDEX END -->
+<hr>
+<h2><a name=
+"apache tutorial: introduction to server side includes">Apache
+Tutorial: Introduction to Server Side Includes</a></h2>
+
+<table border="1">
+<tr>
+<td valign="top"><strong>Related Modules</strong><br>
+<br>
+ <a href="../mod/mod_include.html">mod_include</a><br>
+<a href="../mod/mod_cgi.html">mod_cgi</a><br>
+<a href="../mod/mod_expires.html">mod_expires</a><br>
+ </td>
+<td valign="top"><strong>Related Directives</strong><br>
+<br>
+ <a href="../mod/core.html#options">Options</a><br>
<a href="../mod/mod_include.html#xbithack">XBitHack</a><br>
<a href="../mod/mod_mime.html#addtype">AddType</a><br>
<a href="../mod/mod_mime.html#addhandler">AddHandler</a><br>
-<a
href="../mod/mod_setenvif.html#BrowserMatchNoCase">BrowserMatchNoCase</a><br>
+<a href=
+"../mod/mod_setenvif.html#BrowserMatchNoCase">BrowserMatchNoCase</a><br>
-</td></tr></table>
-
-<P>This HOWTO first appeared in Apache Today (http://www.apachetoday.com/)
-as a series of three articles. They appear here by arrangement with
-ApacheToday and Internet.com.</P>
-<P>This article deals with Server Side Includes,
-usually called simply SSI. In this article, I'll talk about configuring
-your server to permit SSI, and introduce some basic SSI techniques for
-adding dynamic content to your existing HTML pages.</P>
-<P>In the latter part of the article, we'll talk about some of the somewhat
-more advanced things that can be done with SSI, such as conditional
statements
-in your SSI directives.</P>
-<P>
-<HR>
-<H1><A NAME="what are ssi">What are SSI?</A></H1>
-<P>SSI (Server Side Includes) are directives that are placed in HTML pages,
-and evaluated on the server while the pages are being served. They let
-you add dynamically generated content to an existing HTML page, without
-having to serve the entire page via a CGI program, or other dynamic
-technology.</P>
-<P>The decision of when to use SSI, and when to have your page entirely
-generated by some program, is usually a matter of how much of the page is
-static, and how much needs to be recalculated every time the page is
+ </td>
+</tr>
+</table>
+
+<p>This HOWTO first appeared in Apache Today
+(http://www.apachetoday.com/) as a series of three articles. They
+appear here by arrangement with ApacheToday and Internet.com.</p>
+
+<p>This article deals with Server Side Includes, usually called simply
+SSI. In this article, I'll talk about configuring your server to permit
+SSI, and introduce some basic SSI techniques for adding dynamic content
+to your existing HTML pages.</p>
+
+<p>In the latter part of the article, we'll talk about some of the
+somewhat more advanced things that can be done with SSI, such as
+conditional statements in your SSI directives.</p>
+
+<hr>
+<h2><a name="what are ssi">What are SSI?</a></h2>
+
+<p>SSI (Server Side Includes) are directives that are placed in HTML
+pages, and evaluated on the server while the pages are being served.
+They let you add dynamically generated content to an existing HTML
+page, without having to serve the entire page via a CGI program, or
+other dynamic technology.</p>
+
+<p>The decision of when to use SSI, and when to have your page entirely
+generated by some program, is usually a matter of how much of the page
+is static, and how much needs to be recalculated every time the page is
served. SSI is a great way to add small pieces of information, such as
-the current time. But if a majority of your page is being generated
-at the time that it is served, you need to look for some other solution.</P>
-<P>
-<HR>
-<H1><A NAME="configuring your server to permit ssi">Configuring your server
to permit SSI</A></H1>
-<P>To permit SSI on your server, you must have the following directive either
-in your <CODE>httpd.conf</CODE> file, or in a <CODE>.htaccess</CODE>
file:</P>
-<PRE>
- Options +Includes</PRE>
-<P>This tells Apache that you want to permit files to be parsed for SSI
-directives.</P>
-<P>Not just any file is parsed for SSI directives. You have to tell Apache
which
-files should be parsed. There are two ways to do this. You can tell Apache
-to parse any file with a particular file extension, such as
<CODE>.shtml</CODE>, with
-the following directives:</P>
-<PRE>
+the current time. But if a majority of your page is being generated at
+the time that it is served, you need to look for some other
+solution.</p>
+
+<hr>
+<h2><a name="configuring your server to permit ssi">Configuring your
+server to permit SSI</a></h2>
+
+<p>To permit SSI on your server, you must have the following directive
+either in your <code>httpd.conf</code> file, or in a
+<code>.htaccess</code> file:</p>
+
+<pre>
+ Options +Includes
+</pre>
+
+<p>This tells Apache that you want to permit files to be parsed for SSI
+directives.</p>
+
+<p>Not just any file is parsed for SSI directives. You have to tell
+Apache which files should be parsed. There are two ways to do this. You
+can tell Apache to parse any file with a particular file extension,
+such as <code>.shtml</code>, with the following directives:</p>
+
+<pre>
AddType text/html .shtml
- AddHandler server-parsed .shtml</PRE>
-<P>One disadvantage to this approach is that if you wanted to add SSI
directives
-to an existing page, you would have to change the name of that page, and
-all links to that page, in order to give it a <CODE>.shtml</CODE> extension,
so that
-those directives would be executed.</P>
-<P>The other method is to use the <CODE>XBitHack</CODE> directive:</P>
-<PRE>
- XBitHack on</PRE>
-<P><CODE>XBitHack</CODE> tells Apache to parse files for SSI directives if
they have the
-execute bit set. So, to add SSI directives to an existing page, rather than
-having to change the file name, you would just need to make the file
-executable using <CODE>chmod</CODE>.</P>
-<PRE>
- chmod +x pagename.html</PRE>
-<P>A brief comment about what not to do. You'll occasionally see people
-recommending that you just tell Apache to parse all <CODE>.html</CODE> files
for SSI,
-so that you don't have to mess with <CODE>.shtml</CODE> file names. These
folks have
-perhaps not heard about <CODE>XBitHack</CODE>. The thing to keep in mind is
that, by
-doing this, you're requiring that Apache read through every single file that
+ AddHandler server-parsed .shtml
+</pre>
+
+<p>One disadvantage to this approach is that if you wanted to add SSI
+directives to an existing page, you would have to change the name of
+that page, and all links to that page, in order to give it a
+<code>.shtml</code> extension, so that those directives would be
+executed.</p>
+
+<p>The other method is to use the <code>XBitHack</code> directive:</p>
+
+<pre>
+ XBitHack on
+</pre>
+
+<p><code>XBitHack</code> tells Apache to parse files for SSI directives
+if they have the execute bit set. So, to add SSI directives to an
+existing page, rather than having to change the file name, you would
+just need to make the file executable using <code>chmod</code>.</p>
+
+<pre>
+ chmod +x pagename.html
+</pre>
+
+<p>A brief comment about what not to do. You'll occasionally see people
+recommending that you just tell Apache to parse all <code>.html</code>
+files for SSI, so that you don't have to mess with <code>.shtml</code>
+file names. These folks have perhaps not heard about
+<code>XBitHack</code>. The thing to keep in mind is that, by doing
+this, you're requiring that Apache read through every single file that
it sends out to clients, even if they don't contain any SSI directives.
-This can slow things down quite a bit, and is not a good idea.</P>
-<P>Of course, on Windows, there is no such thing as an execute bit to set,
-so that limits your options a little.</P>
-<P>
-<HR>
-<H1><A NAME="basic ssi directives">Basic SSI directives</A></H1>
-<P>SSI directives have the following syntax:</P>
-<PRE>
- <!--#element attribute=value attribute=value ... --></PRE>
-<P>It is formatted like an HTML comment, so if you don't have SSI correctly
enabled,
-the browser will ignore it, but it will still be visible in the HTML source.
-If you have SSI correctly configured, the directive will be replaced with
-its results.</P>
-<P>The element can be one of a number of things, and we'll talk some more
about
-most of these in the next installment of this series. For now, here are some
-examples of what you can do with SSI</P>
-<P>
-<H2><A NAME="today's date">Today's date</A></H2>
-<PRE>
- <!--#echo var=DATE_LOCAL --></PRE>
-<P>The <CODE>echo</CODE> element just spits out the value of a variable.
There are a number
-of standard variables, which include the whole set of environment variables
-that are available to CGI programs. Also, you can define your own variables
-with the <CODE>set</CODE> element.</P>
-<P>If you don't like the format in which the date gets printed, you can use
-the <CODE>config</CODE> element, with a <CODE>timefmt</CODE> attribute, to
modify that formatting.</P>
-<PRE>
- <!--#config timefmt="%A %B %d, %Y" -->
- Today is <!--#echo var=DATE_LOCAL --></PRE>
-<P>
-<H2><A NAME="modification date of the file">Modification date of the
file</A></H2>
-<PRE>
- This document last modified <!--#flastmod
file="index.html" --></PRE>
-<P>This element is also subject to <CODE>timefmt</CODE> format
configurations.</P>
-<P>
-<H2><A NAME="including the results of a cgi program">Including the results
of a CGI program</A></H2>
-<P>This is one of the more common uses of SSI - to output the results of a
-CGI program, such as everybody's favorite, a ``hit counter.''</P>
-<PRE>
- <!--#include virtual="/cgi-bin/counter.pl" --></PRE>
-<P>
-<HR>
-<H1><A NAME="additional examples">Additional examples</A></H1>
-<P>Following are some specific examples of things you can do in your HTML
-documents with SSI.</P>
-<P>
-<HR>
-<H1><A NAME="when was this document modified">When was this document
modified?</A></H1>
-<P>Earlier, we mentioned that you could use SSI to inform the user when the
-document was most recently modified. However, the actual method for doing
that
-was left somewhat in question. The following code, placed in your HTML
document,
-will put such a time stamp on your page. Of course, you will have to have SSI
-correctly enabled, as discussed above.</P>
-<PRE>
- <!--#config timefmt="%A %B %d, %Y" -->
- This file last modified <!--#flastmod file="ssi.shtml"
--></PRE>
-<P>Of course, you will need to replace the <CODE>ssi.shtml</CODE> with the
actual name of the file
-that you're referring to. This can be inconvenient if you're just looking
for a generic
-piece of code that you can paste into any file, so you probably want to use
the
-<CODE>LAST_MODIFIED</CODE> variable instead:</P>
-<PRE>
- <!--#config timefmt="%D" -->
- This file last modified <!--#echo var="LAST_MODIFIED"
--></PRE>
-<P>For more details on the <CODE>timefmt</CODE> format, go to your favorite
search site
-and look for <CODE>ctime</CODE>. The syntax is the same.</P>
-<P>
-<HR>
-<H1><A NAME="including a standard footer">Including a standard
footer</A></H1>
-<P>If you are managing any site that is more than a few pages, you may find
that making
-changes to all those pages can be a real pain, particularly if you are
trying to
-maintain some kind of standard look across all those pages.</P>
-<P>Using an include file for a header and/or a footer can reduce the burden
of these
-updates. You just have to make one footer file, and then include it into
each page
-with the <CODE>include</CODE> SSI command. The <CODE>include</CODE> element
can determine what file
-to include with either the <CODE>file</CODE> attribute, or the
<CODE>virtual</CODE> attribute. The <CODE>file</CODE>
-attribute is a file path, <EM>relative to the current directory</EM>. That
means that it
-cannot be an absolute file path (starting with /), nor can it contain ../ as
-part of that path. The <CODE>virtual</CODE> attribute is probably more
useful, and should
-specify a URL relative to the document being served. It can start with a /,
but must
-be on the same server as the file being served.</P>
-<PRE>
- <!--#include virtual="/footer.html" --></PRE>
-<P>I'll frequently combine the last two things, putting a
<CODE>LAST_MODIFIED</CODE> directive
-inside a footer file to be included. SSI directives can be contained in the
included
-file, and includes can be nested - that is, the included file can include
another
-file, and so on.</P>
-<P>
-<HR>
-<H1><A NAME="what else can i config">What else can I config?</A></H1>
-<P>In addition to being able to <CODE>config</CODE> the time format, you can
also <CODE>config</CODE> two
-other things.</P>
-<P>Usually, when something goes wrong with your SSI directive, you get the
message</P>
-<PRE>
- [an error occurred while processing this directive]</PRE>
-<P>If you want to change that message to something else, you can do so with
the <CODE>errmsg</CODE>
-attribute to the <CODE>config</CODE> element:</P>
-<PRE>
- <!--#config errmsg="[It appears that you don't know how to
use SSI]" --></PRE>
-<P>Hopefully, end users will never see this message, because you will have
resolved
-all the problems with your SSI directives before your site goes live.
(Right?)</P>
-<P>And you can <CODE>config</CODE> the format in which file sizes are
returned with the <CODE>sizefmt</CODE>
-attribute. You can specify <CODE>bytes</CODE> for a full count in bytes, or
<CODE>abbrev</CODE> for an
-abbreviated number in Kb or Mb, as appropriate.</P>
-<P>
-<HR>
-<H1><A NAME="executing commands">Executing commands</A></H1>
-<P>I expect that I'll have an article some time in the coming months about
using
-SSI with small CGI programs. For now, here's something else that you can
-do with the <CODE>exec</CODE> element. You can actually have SSI execute a
command using
-the shell (<CODE>/bin/sh</CODE>, to be precise - or the DOS shell, if you're
on Win32).
-The following, for example, will give you a directory listing.</P>
-<PRE>
+This can slow things down quite a bit, and is not a good idea.</p>
+
+<p>Of course, on Windows, there is no such thing as an execute bit to
+set, so that limits your options a little.</p>
+
+<p>In its default configuration, Apache does not send the last modified
+date or content length HTTP headers on SSI pages, because these values are
+difficult to calculate for dynamic content. This can prevent your
+document from being cached, and result in slower perceived client
+performance. There are two ways to solve this:</p>
+
+<ol>
+
+<li>Use the <code>XBitHack Full</code> configuration. This tells
+Apache to determine the last modified date by looking only at the date
+of the originally requested file, ignoring the modification date of
+any included files. </li>
+
+<li>Use the directives provided by <a
+href="../mod/mod_expires.html">mod_expires</a> to set an explicit
+expiration time on your files, thereby letting browsers and proxies
+know that it is acceptable to cache them. </li>
+
+</ol>
+
+
+<hr>
+<h2><a name="basic ssi directives">Basic SSI directives</a></h2>
+
+<p>SSI directives have the following syntax:</p>
+
+<pre>
+ <!--#element attribute=value attribute=value ... -->
+</pre>
+
+<p>It is formatted like an HTML comment, so if you don't have SSI
+correctly enabled, the browser will ignore it, but it will still be
+visible in the HTML source. If you have SSI correctly configured, the
+directive will be replaced with its results.</p>
+
+<p>The element can be one of a number of things, and we'll talk some
+more about most of these in the next installment of this series. For
+now, here are some examples of what you can do with SSI</p>
+
+<h3><a name="today's date">Today's date</a></h3>
+
+<pre>
+ <!--#echo var=DATE_LOCAL -->
+</pre>
+
+<p>The <code>echo</code> element just spits out the value of a
+variable. There are a number of standard variables, which include the
+whole set of environment variables that are available to CGI programs.
+Also, you can define your own variables with the <code>set</code>
+element.</p>
+
+<p>If you don't like the format in which the date gets printed, you can
+use the <code>config</code> element, with a <code>timefmt</code>
+attribute, to modify that formatting.</p>
+
+<pre>
+ <!--#config timefmt="%A %B %d, %Y" -->
+ Today is <!--#echo var=DATE_LOCAL -->
+</pre>
+
+<h3><a name="modification date of the file">Modification date of the
+file</a></h3>
+
+<pre>
+ This document last modified <!--#flastmod file="index.html" -->
+</pre>
+
+<p>This element is also subject to <code>timefmt</code> format
+configurations.</p>
+
+<h3><a name="including the results of a cgi program">Including the
+results of a CGI program</a></h3>
+
+<p>This is one of the more common uses of SSI - to output the results
+of a CGI program, such as everybody's favorite, a ``hit counter.''</p>
+
+<pre>
+ <!--#include virtual="/cgi-bin/counter.pl" -->
+</pre>
+
+<hr>
+<h2><a name="additional examples">Additional examples</a></h2>
+
+<p>Following are some specific examples of things you can do in your
+HTML documents with SSI.</p>
+
+<hr>
+<h2><a name="when was this document modified">When was this document
+modified?</a></h2>
+
+<p>Earlier, we mentioned that you could use SSI to inform the user when
+the document was most recently modified. However, the actual method for
+doing that was left somewhat in question. The following code, placed in
+your HTML document, will put such a time stamp on your page. Of course,
+you will have to have SSI correctly enabled, as discussed above.</p>
+
+<pre>
+ <!--#config timefmt="%A %B %d, %Y" -->
+ This file last modified <!--#flastmod file="ssi.shtml" -->
+</pre>
+
+<p>Of course, you will need to replace the <code>ssi.shtml</code> with
+the actual name of the file that you're referring to. This can be
+inconvenient if you're just looking for a generic piece of code that
+you can paste into any file, so you probably want to use the
+<code>LAST_MODIFIED</code> variable instead:</p>
+
+<pre>
+ <!--#config timefmt="%D" -->
+ This file last modified <!--#echo var="LAST_MODIFIED" -->
+</pre>
+
+<p>For more details on the <code>timefmt</code> format, go to your
+favorite search site and look for <code>ctime</code>. The syntax is the
+same.</p>
+
+<hr>
+<h2><a name="including a standard footer">Including a standard
+footer</a></h2>
+
+<p>If you are managing any site that is more than a few pages, you may
+find that making changes to all those pages can be a real pain,
+particularly if you are trying to maintain some kind of standard look
+across all those pages.</p>
+
+<p>Using an include file for a header and/or a footer can reduce the
+burden of these updates. You just have to make one footer file, and
+then include it into each page with the <code>include</code> SSI
+command. The <code>include</code> element can determine what file to
+include with either the <code>file</code> attribute, or the
+<code>virtual</code> attribute. The <code>file</code> attribute is a
+file path, <em>relative to the current directory</em>. That means that
+it cannot be an absolute file path (starting with /), nor can it
+contain ../ as part of that path. The <code>virtual</code> attribute is
+probably more useful, and should specify a URL relative to the document
+being served. It can start with a /, but must be on the same server as
+the file being served.</p>
+
+<pre>
+ <!--#include virtual="/footer.html" -->
+</pre>
+
+<p>I'll frequently combine the last two things, putting a
+<code>LAST_MODIFIED</code> directive inside a footer file to be
+included. SSI directives can be contained in the included file, and
+includes can be nested - that is, the included file can include another
+file, and so on.</p>
+
+<hr>
+<h2><a name="what else can i config">What else can I config?</a></h2>
+
+<p>In addition to being able to <code>config</code> the time format,
+you can also <code>config</code> two other things.</p>
+
+<p>Usually, when something goes wrong with your SSI directive, you get
+the message</p>
+
+<pre>
+ [an error occurred while processing this directive]
+</pre>
+
+<p>If you want to change that message to something else, you can do so
+with the <code>errmsg</code> attribute to the <code>config</code>
+element:</p>
+
+<pre>
+ <!--#config errmsg="[It appears that you don't know how to use
SSI]" -->
+</pre>
+
+<p>Hopefully, end users will never see this message, because you will
+have resolved all the problems with your SSI directives before your
+site goes live. (Right?)</p>
+
+<p>And you can <code>config</code> the format in which file sizes are
+returned with the <code>sizefmt</code> attribute. You can specify
+<code>bytes</code> for a full count in bytes, or <code>abbrev</code>
+for an abbreviated number in Kb or Mb, as appropriate.</p>
+
+<hr>
+<h2><a name="executing commands">Executing commands</a></h2>
+
+<p>I expect that I'll have an article some time in the coming months
+about using SSI with small CGI programs. For now, here's something else
+that you can do with the <code>exec</code> element. You can actually
+have SSI execute a command using the shell (<code>/bin/sh</code>, to be
+precise - or the DOS shell, if you're on Win32). The following, for
+example, will give you a directory listing.</p>
+
+<pre>
<pre>
- <!--#exec cmd="ls" -->
- </pre></PRE>
-<P>or, on Windows</P>
-<PRE>
+ <!--#exec cmd="ls" -->
+ </pre>
+</pre>
+
+<p>or, on Windows</p>
+
+<pre>
<pre>
- <!--#exec cmd="dir" -->
- </pre></PRE>
-<P>You might notice some strange formatting with this directive on Windows,
because
-the output from <CODE>dir</CODE> contains the string
``<<CODE>dir</CODE>>'' in it, which confuses browsers.</P>
-<P>Note that this feature is exceedingly dangerous, as it will execute
whatever
-code happens to be embedded in the <CODE>exec</CODE> tag. If you have any
situation
-where users can edit content on your web pages, such as with a
``guestbook'', for
-example, make sure that you have this feature disabled. You can allow SSI,
-but not the <CODE>exec</CODE> feature, with the <CODE>IncludesNOEXEC</CODE>
argument to the
-<CODE>Options</CODE> directive.</P>
-<P>
-<HR>
-<H1><A NAME="advanced ssi techniques">Advanced SSI techniques</A></H1>
-<P>In addition to spitting out content, Apache SSI gives you the option of
setting
-variables, and using those variables in comparisons and conditionals.</P>
-<P>
-<HR>
-<H1><A NAME="caveat">Caveat</A></H1>
-<P>Most of the features discussed in this article are only available to you
if you
-are running Apache 1.2 or later. Of course, if you are not running Apache
1.2 or
-later, you need to upgrade immediately, if not sooner. Go on. Do it now.
We'll wait.</P>
-<P>
-<HR>
-<H1><A NAME="setting variables">Setting variables</A></H1>
-<P>Using the <CODE>set</CODE> directive, you can set variables for later
use. We'll need this
-later in the discussion, so we'll talk about it here. The syntax of this is
-as follows:</P>
-<PRE>
- <!--#set var="name" value="Rich" --></PRE>
-<P>In addition to merely setting values literally like that, you can use
-any other variable, including, for example, environment variables, or some
of the
-variables we discussed in the last article (like <CODE>LAST_MODIFIED</CODE>,
for example)
-to give values to your variables. You will specify that something is a
variable,
-rather than a literal string, by using the dollar sign ($) before the name
of
-the variable.</P>
-<PRE>
- <!--#set var="modified"
value="$LAST_MODIFIED" --></PRE>
-<P>To put a literal dollar sign into the value of your variable, you need to
escape
-the dollar sign with a backslash.</P>
-<PRE>
- <!--#set var="cost" value="\$100" --></PRE>
-<P>Finally, if you want to put a variable in the midst of a longer string,
and there's
-a chance that the name of the variable will run up against some other
characters,
-and thus be confused with those characters, you can place the name of the
variable
-in braces, to remove this confusion. (It's hard to come up with a really good
-example of this, but hopefully you'll get the point.)</P>
-<PRE>
- <!--#set var="date"
value="${DATE_LOCAL}_${DATE_GMT}" --></PRE>
-<P>
-<HR>
-<H1><A NAME="conditional expressions">Conditional expressions</A></H1>
-<P>Now that we have variables, and are able to set and compare their values,
we
-can use them to express conditionals. This lets SSI be a tiny programming
language
-of sorts. <CODE>mod_include</CODE> provides an <CODE>if</CODE>,
<CODE>elif</CODE>, <CODE>else</CODE>, <CODE>endif</CODE> structure
-for building conditional statements. This allows you to effectively generate
-multiple logical pages out of one actual page.</P>
-<P>The structure of this conditional construct is:</P>
-<PRE>
- <!--#if expr="test_condition" -->
- <!--#elif expr="test_condition" -->
+ <!--#exec cmd="dir" -->
+ </pre>
+</pre>
+
+<p>You might notice some strange formatting with this directive on
+Windows, because the output from <code>dir</code> contains the string
+``<<code>dir</code>>'' in it, which confuses browsers.</p>
+
+<p>Note that this feature is exceedingly dangerous, as it will execute
+whatever code happens to be embedded in the <code>exec</code> tag. If
+you have any situation where users can edit content on your web pages,
+such as with a ``guestbook'', for example, make sure that you have this
+feature disabled. You can allow SSI, but not the <code>exec</code>
+feature, with the <code>IncludesNOEXEC</code> argument to the
+<code>Options</code> directive.</p>
+
+<hr>
+<h2><a name="advanced ssi techniques">Advanced SSI techniques</a></h2>
+
+<p>In addition to spitting out content, Apache SSI gives you the option
+of setting variables, and using those variables in comparisons and
+conditionals.</p>
+
+<h3><a name="caveat">Caveat</a></h3>
+
+<p>Most of the features discussed in this article are only available to
+you if you are running Apache 1.2 or later. Of course, if you are not
+running Apache 1.2 or later, you need to upgrade immediately, if not
+sooner. Go on. Do it now. We'll wait.</p>
+
+<hr>
+<h2><a name="setting variables">Setting variables</a></h2>
+
+<p>Using the <code>set</code> directive, you can set variables for
+later use. We'll need this later in the discussion, so we'll talk about
+it here. The syntax of this is as follows:</p>
+
+<pre>
+ <!--#set var="name" value="Rich" -->
+</pre>
+
+<p>In addition to merely setting values literally like that, you can
+use any other variable, including, for example, environment variables,
+or some of the variables we discussed in the last article (like
+<code>LAST_MODIFIED</code>, for example) to give values to your
+variables. You will specify that something is a variable, rather than a
+literal string, by using the dollar sign ($) before the name of the
+variable.</p>
+
+<pre>
+ <!--#set var="modified" value="$LAST_MODIFIED" -->
+</pre>
+
+<p>To put a literal dollar sign into the value of your variable, you
+need to escape the dollar sign with a backslash.</p>
+
+<pre>
+ <!--#set var="cost" value="\$100" -->
+</pre>
+
+<p>Finally, if you want to put a variable in the midst of a longer
+string, and there's a chance that the name of the variable will run up
+against some other characters, and thus be confused with those
+characters, you can place the name of the variable in braces, to remove
+this confusion. (It's hard to come up with a really good example of
+this, but hopefully you'll get the point.)</p>
+
+<pre>
+ <!--#set var="date" value="${DATE_LOCAL}_${DATE_GMT}" -->
+</pre>
+
+<hr>
+<h2><a name="conditional expressions">Conditional expressions</a></h2>
+
+<p>Now that we have variables, and are able to set and compare their
+values, we can use them to express conditionals. This lets SSI be a
+tiny programming language of sorts. <code>mod_include</code> provides
+an <code>if</code>, <code>elif</code>, <code>else</code>,
+<code>endif</code> structure for building conditional statements. This
+allows you to effectively generate multiple logical pages out of one
+actual page.</p>
+
+<p>The structure of this conditional construct is:</p>
+
+<pre>
+ <!--#if expr="test_condition" -->
+ <!--#elif expr="test_condition" -->
<!--#else -->
- <!--#endif --></PRE>
-<P>A <EM>test_condition</EM> can be any sort of logical comparison - either
comparing values
-to one another, or testing the ``truth'' of a particular value. (A given
string is
-true if it is nonempty.) For a full list of the comparison operators
available to
-you, see the <CODE>mod_include</CODE> documentation. Here are some examples
of how one might
-use this construct.</P>
-<P>In your configuration file, you could put the following line:</P>
-<PRE>
+ <!--#endif -->
+</pre>
+
+<p>A <em>test_condition</em> can be any sort of logical comparison -
+either comparing values to one another, or testing the ``truth'' of a
+particular value. (A given string is true if it is nonempty.) For a
+full list of the comparison operators available to you, see the
+<code>mod_include</code> documentation. Here are some examples of how
+one might use this construct.</p>
+
+<p>In your configuration file, you could put the following line:</p>
+
+<pre>
BrowserMatchNoCase macintosh Mac
- BrowserMatchNoCase MSIE InternetExplorer</PRE>
-<P>This will set environment variables ``Mac'' and ``InternetExplorer'' to
true, if the
-client is running Internet Explorer on a Macintosh.</P>
-<P>Then, in your SSI-enabled document, you might do the following:</P>
-<PRE>
- <!--#if expr="${Mac} && ${InternetExplorer} -->
+ BrowserMatchNoCase MSIE InternetExplorer
+</pre>
+
+<p>This will set environment variables ``Mac'' and ``InternetExplorer''
+to true, if the client is running Internet Explorer on a Macintosh.</p>
+
+<p>Then, in your SSI-enabled document, you might do the following:</p>
+
+<pre>
+ <!--#if expr="${Mac} && ${InternetExplorer}" -->
Apologetic text goes here
<!--#else -->
Cool JavaScript code goes here
- <!--#endif --></PRE>
-<P>Not that I have anything against IE on Macs - I just struggled for a few
hours last
-week trying to get some JavaScript working on IE on a Mac, when it was
working
-everywhere else. The above was the interim workaround.</P>
-<P>Any other variable (either ones that you define, or normal environment
variables)
-can be used in conditional statements. With Apache's ability to set
environment
-variables with the <CODE>SetEnvIf</CODE> directives, and other related
directives, this
-functionality can let you do some pretty involved dynamic stuff without ever
-resorting to CGI.</P>
-<P>
-<HR>
-<H1><A NAME="conclusion">Conclusion</A></H1>
-<P>SSI is certainly not a replacement for CGI, or other technologies used for
-generating dynamic web pages. But it is a great way to add small
-amounts of dynamic content to pages, without doing a lot of extra work.</P>
+ <!--#endif -->
+</pre>
-</BODY>
+<p>Not that I have anything against IE on Macs - I just struggled for a
+few hours last week trying to get some JavaScript working on IE on a
+Mac, when it was working everywhere else. The above was the interim
+workaround.</p>
+
+<p>Any other variable (either ones that you define, or normal
+environment variables) can be used in conditional statements. With
+Apache's ability to set environment variables with the
+<code>SetEnvIf</code> directives, and other related directives, this
+functionality can let you do some pretty involved dynamic stuff without
+ever resorting to CGI.</p>
+
+<hr>
+<h2><a name="conclusion">Conclusion</a></h2>
+
+<p>SSI is certainly not a replacement for CGI, or other technologies
+used for generating dynamic web pages. But it is a great way to add
+small amounts of dynamic content to pages, without doing a lot of extra
+work.</p>
+</body>
+</html>
-</HTML>
