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Tomcat example source code file (fs-default.xml)

This example Tomcat source code file (fs-default.xml) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Tomcat tags/keywords

dependencies, dependencies, functionality, functionality, get, http, http, license, license, mime, see, servlet, version, you

The Tomcat fs-default.xml source code

<?xml version="1.0"?>
<!--
  Licensed to the Apache Software Foundation (ASF) under one or more
  contributor license agreements.  See the NOTICE file distributed with
  this work for additional information regarding copyright ownership.
  The ASF licenses this file to You under the Apache License, Version 2.0
  (the "License"); you may not use this file except in compliance with
  the License.  You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
-->
<!DOCTYPE document [
  <!ENTITY project SYSTEM "project.xml">
]>
<document url="fs-default.html">

  &project;

  <properties>
    <author email="craigmcc@apache.org">Craig McClanahan
    <title>Default Servlet
    <revision>$Id: fs-default.xml 562814 2007-08-05 03:52:04Z markt $
  </properties>

<body>


<section name="Overview">


  <subsection name="Introduction">

    <p>The purpose of the Default Servlet is to serve
    static resources of a web application in response to client requests.
    As the name implies, it is generally configured as the "default"
    servlet for a web application, by being mapped to a URL pattern "/".</p>

  </subsection>


  <subsection name="External Specifications">

    <p>The following external specifications have provisions which
    partially define the correct behavior of the default servlet:</p>
    <ul>
    <li>
        Servlet Specification</a> (Version 2.3 PFD2)
    <li>Multipurpose
        Internet Mail Extensions (MIME) Part Two: Media Types</a>
    <li>Hypertext
        Transfer Protocol -- HTTP/1.1</a>
    </ul>

  </subsection>


  <subsection name="Implementation Requirements">

    <p>The implementation of this functionality shall conform to the
    following requirements:</p>
    <ul>
    <li>Must be implemented as a servlet.
    <li>Must support configurable parameters for debugging detail level,
        input buffer size, output buffer size, whether or not to produce
        directory listings when no welcome file is present, and whether or not
        modifications are supported via DELETE and PUT.</li>
    <li>Log debugging and operational messages (suitably internationalized)
        via the <code>getServletContext().log() method.
    </ul>

  </subsection>


</section>


<section name="Dependencies">


  <subsection name="Environmental Dependencies">

    <p>The following environmental dependencies must be met in order for
    the default servlet to operate correctly:</p>
    <ul>
    <li>The default servlet must be registered in the application deployment
        descriptor (or the default deployment descriptor in file
        <code>$CATALINA_HOME/conf/web.xml) using a "default servlet"
        servlet mapping, signified by URL pattern "/".</li>
    </ul>

  </subsection>


  <subsection name="Container Dependencies">

    <p>Correct operation of the default servlet depends on the following
    specific features of the surrounding container:</p>
    <ul>
    <li>The container shall provide a servlet context attribute that
        lists the welcome file names that have been defined for this
        web application.</li>
    <li>The container shall provide a servlet context attribute that
        contains a <code>javax.naming.directory.DirContext
        implementation representing the static resources of this
        web application.</li>
    </ul>

  </subsection>


</section>


<section name="Functionality">


  <subsection name="Initialization Functionality">

    <p>The following processing must be performed when the init()
    method of the invoker servlet is called:</p>
    <ul>
    <li>Process and sanity check configuration parameters.
    </ul>

  </subsection>


  <subsection name="Per-Request Functionality">


    <p>For all HTTP request methods, the resource path is determined from
    the path information provided to this request, either as request attribute
    <code>javax.servlet.include.path_info (for a request dispatcher
    access to a static resource) or by calling
    <code>request.getPathInfo() directly.

<p>On each HTTP DELETE request processed by this servlet, the following processing shall be performed:</p> <ul> <li>If modifications to the static resources are not allowed (set by a configuration parameter), return HTTP status 403 (forbidden).</li> <li>If an attempt is made to delete a resource from /META-INF or <code>/WEB-INF, return HTTP status 403 (forbidden). <li>If the requested resource does not exist, return HTTP status 404 (not found)</li> <li>Unbind the resource from the directory context containing the static resources for this web application. If successful, return HTTP status 204 (no content). Otherwise, return HTTP status 405 (method not allowed).</li> </ul> <p>On each HTTP GET request processed by this servlet, the following processing shall be performed:</p> <ul> <li>If the request is for a resource under /META-INF or <code>/WEB-INF, return HTTP status 404 (not found). <li>If the requested resource does not exist, return HTTP status 404 (not found).</li> <li>If the requested resource is not a directory, but the resource path ends in "/" or "\", return HTTP status 404 (not found).</li> <li>If the requested resource is a directory: <ul> <li>If the request path does not end with "/", redirect to a corresponding path with "/" appended so that relative references in welcome files are resolved correctly.</li> <li>If one of the specified welcome files exists, redirect to the path for that welcome file so that it will be served explicitly. </li> </ul> <li>If the request being processed contains an If-Range header, perform the processing described in the HTTP/1.1 specification to determine whether the client's information is up to date.</li> <li>Determine the content type of the response, by looking up the corresponding MIME type in our servlet context.</li> <li>If the requested resource is a directory: <ul> <li>If directory listings are suppressed, return HTTP status 404 (not found).</li> <li>Set the content type to text/html. </ul> <li>Determine the range(s) to be returned, based on the existence of any <code>If-Range and Range headers. <li>If the requested resource is a directory, include an ETag header in the response, with the value calculated based on the content of the directory.</li> <li>Include a Last-Modified header in the response documenting the date/time that the resource was last modified.</li> <li>Unless we are processing a HEAD request, include the appropriate content (or content ranges) in the response.</li> </ul> <p>On each HTTP HEAD request processed by this servlet, the following processing shall be performed:</p> <ul> <li>Processed identically to an HTTP GET request, except that the data content is not transmitted after the headers.</li> </ul> <p>On each HTTP POST request processed by this servlet, the following processing shall be performed:</p> <ul> <li>Processed identically to an HTTP GET request. </ul> <p>On each HTTP PUT request processed by this servlet, the following processing shall be perfomred:</p> <ul> <li>If modifications to the static resources are not allowed (set by a configuration parameter), return HTTP status 403 (forbidden).</li> <li>If an attempt is made to delete a resource from /META-INF or <code>/WEB-INF, return HTTP status 403 (forbidden). <li>Create a new resource from the body of this request. <li>Bind or rebind the specified path to the new resource (depending on whether it currently exists or not). Return HTTP status as follows: <ul> <li>If binding was unsuccessful, return HTTP status 409 (conflict). </li> <li>If binding was successful and the resource did not previously exist, return HTTP status 201 (created).</li> <li>If binding was successful and the resource previously existed, return HTTP status 204 (no content).</li> </ul> </ul> </subsection> <subsection name="Finalization Functionality"> <p>No specific processing is required when the destroy() method is called:</p> </subsection> </section> <section name="Testable Assertions"> <p>In addition the the assertions implied by the functionality requirements listed above, the following additional assertions shall be tested to validate the behavior of the invoker servlet:</p> <ul> <li>Requests for resources that do not exist in the web application must return HTTP status 404 (not found).</li> <li>The default servlet must operate identically for web applications that are run out of a WAR file directly, or from an unpacked directory structure.</li> <li>If the web application is running out of an unpacked directory structure, the default servlet must recognize cases where the resource has been updated through external means.</li> </ul> </section> </body> </document>
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