Configuring the Web Server to Support Additional MIME Types

When a browser attempts to open a file attachment, the browser invokes a viewer based on the MIME (Multipurpose Internet Mail Extensions) type sent in the response header from the web server. For example, if the user tried to view an MP3 file, the response header sent to the browser by the web server would indicate the audio/MPEG content type:

HTTP/1.1 200 OK 
Server: Microsoft-IIS/5.0 
Date: Mon, 01 Oct 2001 21:25:51 GMT 
Content-Type: audio/mpeg 
Accept-Ranges: bytes 
Last-Modified: Mon, 01 Oct 2001 21:00:26 GMT 
ETag: "78e21918bc4ac11:cc8" 
Content-Length: 60

Notice that the content-type is audio/mpeg. The browser uses this MIME type to determine that the viewer for audio/MPEG is the appropriate application to open this attachment. If the web server did not send this content-type header, the browser would not be able to determine the nature of the file being transmitted, and it would be unable to invoke the correct viewer application. The browser would try to display the file as text/plain, which is often the wrong behavior.

The web server maps file extensions to MIME types through entries in a web.xml configuration file. A copy of web.xml is deployed to each web server instance when it is installed. After a web server instance is created, edit its deployed copy to add any additional MIME types.

The location of the deployment copies varies depending on the web server:

Web Server	Location of Deployment Copy
WebLogic	PS_HOME/webserv/web_server/applications/peoplesoft/PORTAL.war/WEB-INF/web.xml

See your web server documentation for the name and location of the master copy of this configuration file.

This file contains definitions similar to the following:

  <mime-mapping> 
    <extension> 
      doc 
    </extension> 
    <mime-type> 
       application/msword 
    </mime-type> 
  </mime-mapping> 
  <mime-mapping> 
    <extension> 
      xls 
    </extension> 
    <mime-type> 
       application/vnd.ms-excel 
    </mime-type> 
  </mime-mapping>

Let's say you want to add a mapping that causes .log files to be interpreted as regular text files. To determine the correct MIME type, check RFC (Request for Comments) documents 2045, 2046, 2047, 2048, and 2077, which discuss internet media types and the internet media type registry.

After checking the RFCs, you determine that the correct MIME type is text/plain. The following is an example of code you would add to the previous section of the configuration file:

  <mime-mapping> 
    <extension> 
      log 
    </extension> 
    <mime-type> 
       text/plain 
    </mime-type> 
  </mime-mapping> 

Once you save the file, the .log extension is associated with the content type of text/plain.

Note:

You must restart your web server before these changes are recognized.

Note:

When trying to view the objects, the extension must exactly match what is set up in the web.xml file. This value is case-sensitive. Therefore, if the PreserveCase parameter has been used when uploading files, it will be necessary to add a MIME type entry for each case-permutation of the file extension in question. If the object view appears garbled, chances are that either the extension is not set up in the web.xml file or there is a case mismatch.

Also see the documentation for your web server.