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<!DOCTYPE document [
<!ENTITY project SYSTEM "project.xml">
]>
<document url="default-servlet.html">
&project;
<properties>
<author email="funkman@apache.org">Tim Funk</author>
<title>Default Servlet Reference</title>
</properties>
<body>
<section name="Table of Contents">
<toc/>
</section>
<section anchor="what" name="What is the DefaultServlet">
The default servlet is the servlet which serves static resources as well
as serves the directory listings (if directory listings are enabled).
</section>
<section anchor="where" name="Where is it declared?">
It is declared globally in <i>$CATALINA_BASE/conf/web.xml</i>.
By default here is it's declaration:
<source>
<servlet>
<servlet-name>default</servlet-name>
<servlet-class>
org.apache.catalina.servlets.DefaultServlet
</servlet-class>
<init-param>
<param-name>debug</param-name>
<param-value>0</param-value>
</init-param>
<init-param>
<param-name>listings</param-name>
<param-value>true</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
...
<servlet-mapping>
<servlet-name>default</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</source>
So by default, the default servlet is loaded at webapp startup and
directory listings are enabled and debugging is turned off.
</section>
<section anchor="change" name="What can I change?">
The DefaultServlet allows the following initParamters:
<table border="1">
<tr>
<th valign='top'>debug</th>
<td valign='top'>
Debugging level. It is not very useful unless you are a tomcat
developer. As
of this writing, useful values are 0, 1, 11, 1000.
</td>
</tr>
<tr>
<th valign='top'>listings</th>
<td valign='top'>
If no welcome file is present, can a directory listing be
shown?
value may be <b>true</b> or <b>false</b>
<br />
Welcome files are part of the servlet api.
<br />
<b>WARNING:</b> Listings of directories containing many entries are
expensive. Multiple requests for large directory listings can consume
significant proportions of server resources.
</td>
</tr>
<tr>
<th valign='top'>readmeFile</th>
<td valign='top'>
If a directory listing is presented, a readme file may also
be presented with the listing. This file is inserted as is
so it may contain HTML. default value is null
</td>
</tr>
<tr>
<th valign='top'>globalXsltFile</th>
<td valign='top'>
If you wish to customize your directory listing, you
can use an XSL transformation. This value is an absolute
file name which be used for all directory listings.
This can be overridden per context and/or per directory. See
<strong>contextXsltFile</strong> and <strong>localXsltFile</strong>
below. The format of the xml is shown below.
</td>
</tr>
<tr>
<th valign='top'>contextXsltFile</th>
<td valign='top'>
You may also customize your directory listing by context by
configuring <code>contextXsltFile</code>. This should be a context
relative path (e.g.: <code>/path/to/context.xslt</code>). This
overrides <code>globalXsltFile</code>. If this value is present but a
file does not exist, then <code>globalXsltFile</code> will be used. If
<code>globalXsltFile</code> does not exist, then the default
directory listing will be shown.
</td>
</tr>
<tr>
<th valign='top'>localXsltFile</th>
<td valign='top'>
You may also customize your directory listing by directory by
configuring <code>localXsltFile</code>. This should be a relative
file name in the directory where the listing will take place.
This overrides <code>globalXsltFile</code> and
<code>contextXsltFile</code>. If this value is present but a file
does not exist, then <code>contextXsltFile</code> will be used. If
<code>contextXsltFile</code> does not exist, then
<code>globalXsltFile</code> will be used. If
<code>globalXsltFile</code> does not exist, then the default
directory listing will be shown.
</td>
</tr>
<tr>
<th valign='top'>input</th>
<td valign='top'>
Input buffer size (in bytes) when reading
resources to be served. [2048]
</td>
</tr>
<tr>
<th valign='top'>output</th>
<td valign='top'>
Output buffer size (in bytes) when writing
resources to be served. [2048]
</td>
</tr>
<tr>
<th valign='top'>readonly</th>
<td valign='top'>
Is this context "read only", so HTTP commands like PUT and
DELETE are rejected? [true]
</td>
</tr>
<tr>
<th valign='top'>fileEncoding</th>
<td valign='top'>
File encoding to be used when reading static resources.
[platform default]
</td>
</tr>
<tr>
<th valign='top'>sendfileSize</th>
<td valign='top'>
If the connector used supports sendfile, this represents the minimal
file size in KB for which sendfile will be used. Use a negative value
to always disable sendfile. [48]
</td>
</tr>
<tr>
<th valign='top'>useAcceptRanges</th>
<td valign='top'>
If true, the Accept-Ranges header will be set when appropriate for the
response. [true]
</td>
</tr>
</table>
</section>
<section anchor="dir" name="How do I customize directory listings?">
<p>You can override DefaultServlet with you own implementation and use that
in your web.xml declaration. If you
can understand what was just said, we will assume you can read the code
to DefaultServlet servlet and make the appropriate adjustments. (If not,
then that method isn't for you)
</p>
<p>
You can use either <code>localXsltFile</code> or
<code>globalXsltFile</code> and DefaultServlet will create
an xml document and run it through an xsl transformation based
on the values provided in <code>localXsltFile</code> and
<code>globalXsltFile</code>. <code>localXsltFile</code> is first
checked, followed by <code>globalXsltFile</code>, then default
behaviors takes place.
</p>
<p>
Format:
<source>
<listing>
<entries>
<entry type='file|dir' urlPath='aPath' size='###' date='gmt date'>
fileName1
</entry>
<entry type='file|dir' urlPath='aPath' size='###' date='gmt date'>
fileName2
</entry>
...
</entries>
<readme></readme>
</listing>
</source>
<ul>
<li>size will be missing if <code>type='dir'</code></li>
<li>Readme is a CDATA entry</li>
</ul>
</p>
The following is a sample xsl file which mimics the default tomcat behavior:
<source>
<?xml version="1.0"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="1.0">
<xsl:output method="xhtml" encoding="iso-8859-1" indent="no"/>
<xsl:template match="listing">
<html>
<head>
<title>
Sample Directory Listing For
<xsl:value-of select="@directory"/>
</title>
<style>
h1{color : white;background-color : #0086b2;}
h3{color : white;background-color : #0086b2;}
body{font-family : sans-serif,Arial,Tahoma;
color : black;background-color : white;}
b{color : white;background-color : #0086b2;}
a{color : black;} HR{color : #0086b2;}
</style>
</head>
<body>
<h1>Sample Directory Listing For
<xsl:value-of select="@directory"/>
</h1>
<hr size="1" />
<table cellspacing="0"
width="100%"
cellpadding="5"
align="center">
<tr>
<th align="left">Filename</th>
<th align="center">Size</th>
<th align="right">Last Modified</th>
</tr>
<xsl:apply-templates select="entries"/>
</table>
<xsl:apply-templates select="readme"/>
<hr size="1" />
<h3>Apache Tomcat/6.0</h3>
</body>
</html>
</xsl:template>
<xsl:template match="entries">
<xsl:apply-templates select="entry"/>
</xsl:template>
<xsl:template match="readme">
<hr size="1" />
<pre><xsl:apply-templates/></pre>
</xsl:template>
<xsl:template match="entry">
<tr>
<td align="left">
<xsl:variable name="urlPath" select="@urlPath"/>
<a href="{$urlPath}">
<tt><xsl:apply-templates/></tt>
</a>
</td>
<td align="right">
<tt><xsl:value-of select="@size"/></tt>
</td>
<td align="right">
<tt><xsl:value-of select="@date"/></tt>
</td>
</tr>
</xsl:template>
</xsl:stylesheet>
</source>
</section>
<section anchor="secure" name="How do I secure directory listings?">
Use web.xml in each individual webapp. See the security section of the
Servlet specification.
</section>
</body>
</document>