| 1 | <html><head><META http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><title>Catalina Functional Specifications - Default Servlet</title><meta value="Craig McClanahan" name="author"><meta value="craigmcc@apache.org" name="email"></head><body vlink="#525D76" alink="#525D76" link="#525D76" text="#000000" bgcolor="#ffffff"><table cellspacing="0" width="100%" border="0"><!--PAGE HEADER--><tr><td><!--PROJECT LOGO--><a href="http://tomcat.apache.org/"><img border="0" alt=" | 
|---|
| 2 |       Catalina Functional Specifications | 
|---|
| 3 |     " align="right" src="../../../images/tomcat.gif"></a></td><td><font face="arial,helvetica,sanserif"><h1>Apache Tomcat 6.0</h1></font></td><td><!--APACHE LOGO--><a href="http://www.apache.org/"><img border="0" alt="Apache Logo" align="right" src="../../../images/asf-logo.gif"></a></td></tr></table><table cellspacing="4" width="100%" border="0"><!--HEADER SEPARATOR--><tr><td colspan="2"><hr size="1" noshade></td></tr><tr><!--RIGHT SIDE MAIN BODY--><td align="left" valign="top" width="80%"><table cellspacing="4" width="100%" border="0"><tr><td valign="top" align="left"><h1>Catalina Functional Specifications</h1><h2>Default Servlet</h2></td><td nowrap="true" valign="top" align="right"><img border="0" hspace="0" vspace="0" height="1" width="1" src="../../../images/void.gif"></td></tr></table><table cellpadding="2" cellspacing="0" border="0"><tr><td bgcolor="#525D76"><font face="arial,helvetica.sanserif" color="#ffffff"><a name="Overview"><strong>Overview</strong></a></font></td></tr><tr><td><blockquote> | 
|---|
| 4 |  | 
|---|
| 5 |  | 
|---|
| 6 |   <table cellpadding="2" cellspacing="0" border="0"><tr><td bgcolor="#828DA6"><font face="arial,helvetica.sanserif" color="#ffffff"><a name="Introduction"><strong>Introduction</strong></a></font></td></tr><tr><td><blockquote> | 
|---|
| 7 |  | 
|---|
| 8 |     <p>The purpose of the <strong>Default Servlet</strong> is to serve | 
|---|
| 9 |     static resources of a web application in response to client requests. | 
|---|
| 10 |     As the name implies, it is generally configured as the "default" | 
|---|
| 11 |     servlet for a web application, by being mapped to a URL pattern "/".</p> | 
|---|
| 12 |  | 
|---|
| 13 |   </blockquote></td></tr></table> | 
|---|
| 14 |  | 
|---|
| 15 |  | 
|---|
| 16 |   <table cellpadding="2" cellspacing="0" border="0"><tr><td bgcolor="#828DA6"><font face="arial,helvetica.sanserif" color="#ffffff"><a name="External Specifications"><strong>External Specifications</strong></a></font></td></tr><tr><td><blockquote> | 
|---|
| 17 |  | 
|---|
| 18 |     <p>The following external specifications have provisions which | 
|---|
| 19 |     partially define the correct behavior of the default servlet:</p> | 
|---|
| 20 |     <ul> | 
|---|
| 21 |     <li><a href="http://java.sun.com/products/servlet/download.html"> | 
|---|
| 22 |         Servlet Specification</a> (Version 2.3 PFD2)</li> | 
|---|
| 23 |     <li><a href="http://www.rfc-editor.org/rfc/rfc2046.txt">Multipurpose | 
|---|
| 24 |         Internet Mail Extensions (MIME) Part Two: Media Types</a></li> | 
|---|
| 25 |     <li><a href="http://www.rfc-editor.org/rfc/rfc2616.txt">Hypertext | 
|---|
| 26 |         Transfer Protocol -- HTTP/1.1</a></li> | 
|---|
| 27 |     </ul> | 
|---|
| 28 |  | 
|---|
| 29 |   </blockquote></td></tr></table> | 
|---|
| 30 |  | 
|---|
| 31 |  | 
|---|
| 32 |   <table cellpadding="2" cellspacing="0" border="0"><tr><td bgcolor="#828DA6"><font face="arial,helvetica.sanserif" color="#ffffff"><a name="Implementation Requirements"><strong>Implementation Requirements</strong></a></font></td></tr><tr><td><blockquote> | 
|---|
| 33 |  | 
|---|
| 34 |     <p>The implementation of this functionality shall conform to the | 
|---|
| 35 |     following requirements:</p> | 
|---|
| 36 |     <ul> | 
|---|
| 37 |     <li>Must be implemented as a servlet.</li> | 
|---|
| 38 |     <li>Must support configurable parameters for debugging detail level, | 
|---|
| 39 |         input buffer size, output buffer size, whether or not to produce | 
|---|
| 40 |         directory listings when no welcome file is present, and whether or not | 
|---|
| 41 |         modifications are supported via DELETE and PUT.</li> | 
|---|
| 42 |     <li>Log debugging and operational messages (suitably internationalized) | 
|---|
| 43 |         via the <code>getServletContext().log()</code> method.</li> | 
|---|
| 44 |     </ul> | 
|---|
| 45 |  | 
|---|
| 46 |   </blockquote></td></tr></table> | 
|---|
| 47 |  | 
|---|
| 48 |  | 
|---|
| 49 | </blockquote></td></tr></table><table cellpadding="2" cellspacing="0" border="0"><tr><td bgcolor="#525D76"><font face="arial,helvetica.sanserif" color="#ffffff"><a name="Dependencies"><strong>Dependencies</strong></a></font></td></tr><tr><td><blockquote> | 
|---|
| 50 |  | 
|---|
| 51 |  | 
|---|
| 52 |   <table cellpadding="2" cellspacing="0" border="0"><tr><td bgcolor="#828DA6"><font face="arial,helvetica.sanserif" color="#ffffff"><a name="Environmental Dependencies"><strong>Environmental Dependencies</strong></a></font></td></tr><tr><td><blockquote> | 
|---|
| 53 |  | 
|---|
| 54 |     <p>The following environmental dependencies must be met in order for | 
|---|
| 55 |     the default servlet to operate correctly:</p> | 
|---|
| 56 |     <ul> | 
|---|
| 57 |     <li>The default servlet must be registered in the application deployment | 
|---|
| 58 |         descriptor (or the default deployment descriptor in file | 
|---|
| 59 |         <code>$CATALINA_BASE/conf/web.xml</code>) using a "default servlet" | 
|---|
| 60 |         servlet mapping, signified by URL pattern "/".</li> | 
|---|
| 61 |     </ul> | 
|---|
| 62 |  | 
|---|
| 63 |   </blockquote></td></tr></table> | 
|---|
| 64 |  | 
|---|
| 65 |  | 
|---|
| 66 |   <table cellpadding="2" cellspacing="0" border="0"><tr><td bgcolor="#828DA6"><font face="arial,helvetica.sanserif" color="#ffffff"><a name="Container Dependencies"><strong>Container Dependencies</strong></a></font></td></tr><tr><td><blockquote> | 
|---|
| 67 |  | 
|---|
| 68 |     <p>Correct operation of the default servlet depends on the following | 
|---|
| 69 |     specific features of the surrounding container:</p> | 
|---|
| 70 |     <ul> | 
|---|
| 71 |     <li>The container shall provide a servlet context attribute that | 
|---|
| 72 |         lists the welcome file names that have been defined for this | 
|---|
| 73 |         web application.</li> | 
|---|
| 74 |     <li>The container shall provide a servlet context attribute that | 
|---|
| 75 |         contains a <code>javax.naming.directory.DirContext</code> | 
|---|
| 76 |         implementation representing the static resources of this | 
|---|
| 77 |         web application.</li> | 
|---|
| 78 |     </ul> | 
|---|
| 79 |  | 
|---|
| 80 |   </blockquote></td></tr></table> | 
|---|
| 81 |  | 
|---|
| 82 |  | 
|---|
| 83 | </blockquote></td></tr></table><table cellpadding="2" cellspacing="0" border="0"><tr><td bgcolor="#525D76"><font face="arial,helvetica.sanserif" color="#ffffff"><a name="Functionality"><strong>Functionality</strong></a></font></td></tr><tr><td><blockquote> | 
|---|
| 84 |  | 
|---|
| 85 |  | 
|---|
| 86 |   <table cellpadding="2" cellspacing="0" border="0"><tr><td bgcolor="#828DA6"><font face="arial,helvetica.sanserif" color="#ffffff"><a name="Initialization Functionality"><strong>Initialization Functionality</strong></a></font></td></tr><tr><td><blockquote> | 
|---|
| 87 |  | 
|---|
| 88 |     <p>The following processing must be performed when the <code>init()</code> | 
|---|
| 89 |     method of the invoker servlet is called:</p> | 
|---|
| 90 |     <ul> | 
|---|
| 91 |     <li>Process and sanity check configuration parameters.</li> | 
|---|
| 92 |     </ul> | 
|---|
| 93 |  | 
|---|
| 94 |   </blockquote></td></tr></table> | 
|---|
| 95 |  | 
|---|
| 96 |  | 
|---|
| 97 |   <table cellpadding="2" cellspacing="0" border="0"><tr><td bgcolor="#828DA6"><font face="arial,helvetica.sanserif" color="#ffffff"><a name="Per-Request Functionality"><strong>Per-Request Functionality</strong></a></font></td></tr><tr><td><blockquote> | 
|---|
| 98 |  | 
|---|
| 99 |  | 
|---|
| 100 |     <p>For all HTTP request methods, the resource path is determined from | 
|---|
| 101 |     the path information provided to this request, either as request attribute | 
|---|
| 102 |     <code>javax.servlet.include.path_info</code> (for a request dispatcher | 
|---|
| 103 |     access to a static resource) or by calling | 
|---|
| 104 |     <code>request.getPathInfo()</code> directly.</p> | 
|---|
| 105 |  | 
|---|
| 106 |     <p>On each HTTP DELETE request processed by this servlet, the following | 
|---|
| 107 |     processing shall be performed:</p> | 
|---|
| 108 |     <ul> | 
|---|
| 109 |     <li>If modifications to the static resources are not allowed (set by a | 
|---|
| 110 |         configuration parameter), return HTTP status 403 (forbidden).</li> | 
|---|
| 111 |     <li>If an attempt is made to delete a resource from <code>/META-INF</code> | 
|---|
| 112 |         or <code>/WEB-INF</code>, return HTTP status 403 (forbidden).</li> | 
|---|
| 113 |     <li>If the requested resource does not exist, return HTTP status 404 | 
|---|
| 114 |         (not found)</li> | 
|---|
| 115 |     <li>Unbind the resource from the directory context containing the | 
|---|
| 116 |         static resources for this web application.  If successful, return | 
|---|
| 117 |         HTTP status 204 (no content).  Otherwise, return HTTP status 405 | 
|---|
| 118 |         (method not allowed).</li> | 
|---|
| 119 |     </ul> | 
|---|
| 120 |  | 
|---|
| 121 |  | 
|---|
| 122 |     <p>On each HTTP GET request processed by this servlet, the following | 
|---|
| 123 |     processing shall be performed:</p> | 
|---|
| 124 |     <ul> | 
|---|
| 125 |     <li>If the request is for a resource under <code>/META-INF</code> or | 
|---|
| 126 |         <code>/WEB-INF</code>, return HTTP status 404 (not found).</li> | 
|---|
| 127 |     <li>If the requested resource does not exist, return HTTP status 404 | 
|---|
| 128 |         (not found).</li> | 
|---|
| 129 |     <li>If the requested resource is not a directory, but the resource | 
|---|
| 130 |         path ends in "/" or "\", return HTTP status 404 (not found).</li> | 
|---|
| 131 |     <li>If the requested resource is a directory: | 
|---|
| 132 |         <ul> | 
|---|
| 133 |         <li>If the request path does not end with "/", redirect to a | 
|---|
| 134 |             corresponding path with "/" appended so that relative references | 
|---|
| 135 |             in welcome files are resolved correctly.</li> | 
|---|
| 136 |         <li>If one of the specified welcome files exists, redirect to the | 
|---|
| 137 |             path for that welcome file so that it will be served explicitly. | 
|---|
| 138 |             </li> | 
|---|
| 139 |         </ul></li> | 
|---|
| 140 |     <li>If the request being processed contains an <code>If-Range</code> | 
|---|
| 141 |         header, perform the processing described in the HTTP/1.1 specification | 
|---|
| 142 |         to determine whether the client's information is up to date.</li> | 
|---|
| 143 |     <li>Determine the content type of the response, by looking up the | 
|---|
| 144 |         corresponding MIME type in our servlet context.</li> | 
|---|
| 145 |     <li>If the requested resource is a directory: | 
|---|
| 146 |         <ul> | 
|---|
| 147 |         <li>If directory listings are suppressed, return HTTP status 404 | 
|---|
| 148 |             (not found).</li> | 
|---|
| 149 |         <li>Set the content type to <code>text/html</code>.</li> | 
|---|
| 150 |         </ul></li> | 
|---|
| 151 |     <li>Determine the range(s) to be returned, based on the existence of | 
|---|
| 152 |         any <code>If-Range</code> and <code>Range</code> headers.</li> | 
|---|
| 153 |     <li>If the requested resource is a directory, include an <code>ETag</code> | 
|---|
| 154 |         header in the response, with the value calculated based on the content | 
|---|
| 155 |         of the directory.</li> | 
|---|
| 156 |     <li>Include a <code>Last-Modified</code> header in the response documenting | 
|---|
| 157 |         the date/time that the resource was last modified.</li> | 
|---|
| 158 |     <li>Unless we are processing a HEAD request, include the appropriate | 
|---|
| 159 |         content (or content ranges) in the response.</li> | 
|---|
| 160 |     </ul> | 
|---|
| 161 |  | 
|---|
| 162 |     <p>On each HTTP HEAD request processed by this servlet, the following | 
|---|
| 163 |     processing shall be performed:</p> | 
|---|
| 164 |     <ul> | 
|---|
| 165 |     <li>Processed identically to an HTTP GET request, except that the data | 
|---|
| 166 |         content is not transmitted after the headers.</li> | 
|---|
| 167 |     </ul> | 
|---|
| 168 |  | 
|---|
| 169 |     <p>On each HTTP POST request processed by this servlet, the following | 
|---|
| 170 |     processing shall be performed:</p> | 
|---|
| 171 |     <ul> | 
|---|
| 172 |     <li>Processed identically to an HTTP GET request.</li> | 
|---|
| 173 |     </ul> | 
|---|
| 174 |  | 
|---|
| 175 |  | 
|---|
| 176 |     <p>On each HTTP PUT request processed by this servlet, the following | 
|---|
| 177 |     processing shall be perfomred:</p> | 
|---|
| 178 |     <ul> | 
|---|
| 179 |     <li>If modifications to the static resources are not allowed (set by a | 
|---|
| 180 |         configuration parameter), return HTTP status 403 (forbidden).</li> | 
|---|
| 181 |     <li>If an attempt is made to delete a resource from <code>/META-INF</code> | 
|---|
| 182 |         or <code>/WEB-INF</code>, return HTTP status 403 (forbidden).</li> | 
|---|
| 183 |     <li>Create a new resource from the body of this request.</li> | 
|---|
| 184 |     <li>Bind or rebind the specified path to the new resource (depending on | 
|---|
| 185 |         whether it currently exists or not).  Return HTTP status as follows: | 
|---|
| 186 |         <ul> | 
|---|
| 187 |         <li>If binding was unsuccessful, return HTTP status 409 (conflict). | 
|---|
| 188 |             </li> | 
|---|
| 189 |         <li>If binding was successful and the resource did not previously | 
|---|
| 190 |             exist, return HTTP status 201 (created).</li> | 
|---|
| 191 |         <li>If binding was successful and the resource previously existed, | 
|---|
| 192 |             return HTTP status 204 (no content).</li> | 
|---|
| 193 |         </ul></li> | 
|---|
| 194 |     </ul> | 
|---|
| 195 |  | 
|---|
| 196 |   </blockquote></td></tr></table> | 
|---|
| 197 |  | 
|---|
| 198 |  | 
|---|
| 199 |   <table cellpadding="2" cellspacing="0" border="0"><tr><td bgcolor="#828DA6"><font face="arial,helvetica.sanserif" color="#ffffff"><a name="Finalization Functionality"><strong>Finalization Functionality</strong></a></font></td></tr><tr><td><blockquote> | 
|---|
| 200 |  | 
|---|
| 201 |     <p>No specific processing is required when the <code>destroy()</code> | 
|---|
| 202 |     method is called:</p> | 
|---|
| 203 |  | 
|---|
| 204 |   </blockquote></td></tr></table> | 
|---|
| 205 |  | 
|---|
| 206 |  | 
|---|
| 207 | </blockquote></td></tr></table><table cellpadding="2" cellspacing="0" border="0"><tr><td bgcolor="#525D76"><font face="arial,helvetica.sanserif" color="#ffffff"><a name="Testable Assertions"><strong>Testable Assertions</strong></a></font></td></tr><tr><td><blockquote> | 
|---|
| 208 |  | 
|---|
| 209 |   <p>In addition the the assertions implied by the functionality requirements | 
|---|
| 210 |   listed above, the following additional assertions shall be tested to | 
|---|
| 211 |   validate the behavior of the invoker servlet:</p> | 
|---|
| 212 |   <ul> | 
|---|
| 213 |   <li>Requests for resources that do not exist in the web application must | 
|---|
| 214 |       return HTTP status 404 (not found).</li> | 
|---|
| 215 |   <li>The default servlet must operate identically for web applications that | 
|---|
| 216 |       are run out of a WAR file directly, or from an unpacked directory | 
|---|
| 217 |       structure.</li> | 
|---|
| 218 |   <li>If the web application is running out of an unpacked directory | 
|---|
| 219 |       structure, the default servlet must recognize cases where the resource | 
|---|
| 220 |       has been updated through external means.</li> | 
|---|
| 221 |   </ul> | 
|---|
| 222 |  | 
|---|
| 223 | </blockquote></td></tr></table></td></tr><!--FOOTER SEPARATOR--><tr><td colspan="2"><hr size="1" noshade></td></tr><!--PAGE FOOTER--><tr><td colspan="2"><div align="center"><font size="-1" color="#525D76"><em> | 
|---|
| 224 |         Copyright © 1999-2008, Apache Software Foundation | 
|---|
| 225 |         </em></font></div></td></tr></table></body></html> | 
|---|