Making viewing external files a happier experience


Some of you have been wondering how to change the viewers that are used for external files. Doing so requires changing the s:.mailcap file, and, under some circumstances, the s:.mime.types file.

The S:.Mailcap file

How to change the mailcap file should be reasonably evident. It consists of type action pairs, on separate lines, with general types (with * in them) being overridden by specific ones, if they exist. The action is the name of the program to run to display the external data, with %s being a place holder for the filename.

The most common change you might want to make is to remove the public screen parameters if you intend to run mosaic on the workbench. The second most common change would be to replace calls to multiview by calls to more specific viewers, such as viewtek or oplay, which you may preferm, or by calls to arexx scripts with more powerful capabilities (you may, for example, want to write a script that gives you the option of saving the external file after you have viewed it).

Note that the .mailcap file supplied is a simple example, and that you are encouraged to improve upon it and share your improvements with others.

The s:.mime.types file

Mosaic uses three methods of determining the type of a file to be displayed:

  1. If the file is served by an HTTP server (i.e. the url starts http://), then the server on the remote host tells Mosaic what type the file is. The server's opinion is presumed to be correct. The .mime.types file is ignored in this case. (actually, it has to be an http server running httpd V1.0 or greater - most do).
  2. If the file is served by an FTP, GOPHER or WAIS server, then the Mosaic client uses the s:.mime.types file to attempt to determine the file type from its file extension. You may edit the s:.mime.types file to increase the number of files correctly handled this way. Remember, you will not change the type of files served via http.
  3. If the file type is not given by the server or the s:.mime.types file, defaults built into mosaic are used.

(c) 1993 Michael Witbrock