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<?xml version="1.0" encoding="ISO-8859-1"?><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head><!-- XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX This file is generated from xml source: DO NOT EDIT XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX --><title>Apache Tutorial: Introduction to Server Side Includes - Apache HTTP Server</title><link href="../style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" /><link href="../style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" /><link href="../style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" /><link href="../images/favicon.ico" rel="shortcut icon" /></head><body id="manual-page"><div id="page-header"><p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="../faq/">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p><p class="apache">Apache HTTP Server Version 2.0</p><img alt="" src="../images/feather.gif" /></div><div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div><div id="path"><a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.0</a> > <a href="./">How-To / Tutorials</a></div><div id="page-content"><div id="preamble"><h1>Apache Tutorial: Introduction to Server Side Includes</h1><div class="toplang"><p><span>Available Languages: </span><a href="../en/howto/ssi.html" title="English"> en </a> |<a href="../ja/howto/ssi.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |<a href="../ko/howto/ssi.html" hreflang="ko" rel="alternate" title="Korean"> ko </a></p></div><p>Server-side includes provide a means to add dynamic content toexisting HTML documents.</p></div><div id="quickview"><ul id="toc"><li><img alt="" src="../images/down.gif" /> <a href="#related">Introduction</a></li><li><img alt="" src="../images/down.gif" /> <a href="#what">What are SSI?</a></li><li><img alt="" src="../images/down.gif" /> <a href="#configuring">Configuring your server to permit SSI</a></li><li><img alt="" src="../images/down.gif" /> <a href="#basic">Basic SSI directives</a></li><li><img alt="" src="../images/down.gif" /> <a href="#additionalexamples">Additional examples</a></li><li><img alt="" src="../images/down.gif" /> <a href="#config">What else can I config?</a></li><li><img alt="" src="../images/down.gif" /> <a href="#exec">Executing commands</a></li><li><img alt="" src="../images/down.gif" /> <a href="#advanced">Advanced SSI techniques</a></li><li><img alt="" src="../images/down.gif" /> <a href="#conclusion">Conclusion</a></li></ul></div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div><div class="section"><h2><a name="related" id="related">Introduction</a></h2> <table class="related"><tr><th>Related Modules</th><th>Related Directives</th></tr><tr><td><ul><li><code class="module"><a href="../mod/mod_include.html">mod_include</a></code></li><li><code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code></li><li><code class="module"><a href="../mod/mod_expires.html">mod_expires</a></code></li></ul></td><td><ul><li><code class="directive"><a href="../mod/core.html#options">Options</a></code></li><li><code class="directive"><a href="../mod/mod_include.html#xbithack">XBitHack</a></code></li><li><code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code></li><li><code class="directive"><a href="../mod/core.html#setoutputfilter">SetOutputFilter</a></code></li><li><code class="directive"><a href="../mod/mod_setenvif.html#browsermatchnocase">BrowserMatchNoCase</a></code></li></ul></td></tr></table> <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></div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div><div class="section"><h2><a name="what" id="what">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></div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div><div class="section"><h2><a name="configuring" id="configuring">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><div class="example"><p><code> Options +Includes</code></p></div> <p>This tells Apache that you want to permit files to be parsed for SSI directives. Note that most configurations contain multiple <code class="directive"><a href="../mod/core.html#options">Options</a></code> directives that can override each other. You will probably need to apply the <code>Options</code> to the specific directory where you want SSI enabled in order to assure that it gets evaluated last.</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><div class="example"><p><code> AddType text/html .shtml<br /> AddOutputFilter INCLUDES .shtml</code></p></div> <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 class="directive"><a href="../mod/mod_include.html#xbithack">XBitHack</a></code> directive:</p><div class="example"><p><code> XBitHack on</code></p></div> <p><code class="directive"><a href="../mod/mod_include.html#xbithack">XBitHack</a></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><div class="example"><p><code> chmod +x pagename.html</code></p></div> <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 class="directive"><a href="../mod/mod_include.html#xbithack">XBitHack</a></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>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 <code class="module"><a href="../mod/mod_expires.html">mod_expires</a></code> to set an explicit expiration time on your files, thereby letting browsers and proxies know that it is acceptable to cache them.</li> </ol></div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div><div class="section"><h2><a name="basic" id="basic">Basic SSI directives</a></h2> <p>SSI directives have the following syntax:</p><div class="example"><p><code> <!--#element attribute=value attribute=value ... --></code></p></div> <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="todaysdate" id="todaysdate">Today's date</a></h3><div class="example"><p><code> <!--#echo var="DATE_LOCAL" --></code></p></div> <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><div class="example"><p><code> <!--#config timefmt="%A %B %d, %Y" --><br /> Today is <!--#echo var="DATE_LOCAL" --></code></p></div><h3><a name="lastmodified" id="lastmodified">Modification date of the file</a></h3><div class="example"><p><code> This document last modified <!--#flastmod file="index.html" --></code></p></div> <p>This element is also subject to <code>timefmt</code> format configurations.</p><h3><a name="cgi" id="cgi">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><div class="example"><p><code> <!--#include virtual="/cgi-bin/counter.pl" --></code></p></div></div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div><div class="section"><h2><a name="additionalexamples" id="additionalexamples">Additional examples</a></h2> <p>Following are some specific examples of things you can do in your HTML documents with SSI.</p><h3><a name="docmodified" id="docmodified">When was this documentmodified?</a></h3> <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><div class="example"><p><code> <!--#config timefmt="%A %B %d, %Y" --><br /> This file last modified <!--#flastmod file="ssi.shtml" --></code></p></div> <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><div class="example"><p><code>⌨️ 快捷键说明
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