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<?xml version="1.0" encoding="ISO-8859-1"?>
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PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "DTD/xhtml1-strict.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
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<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
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<meta name="robots" content="index,follow" />
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<meta name="author" content="Jos� Luis Gonz�lez Gonz�lez" />
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<meta name="description" content="how to setup MIME handlers for ELinks" />
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<meta name="keywords" content="ELinks MIME handler images view" />
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<title>Basic instructions for MIME configuration</title>
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<h2>What's all this about?</h2>
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At some time along the 0.4 prereleases, ELinks replaced the old Links file
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configuration system with its own one. Now, the configuration is stored
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in <cite>elinks.conf</cite>, much more complete and featuring a new
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syntax. You can set most options from the <acronym title="User
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Interface">UI</acronym> (so usually there is no need to deal with
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<cite>elinks.conf</cite>), and that used to be true for setting MIME
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handlers and extensions as well; but now the associations menu is gone
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temporarily, forcing you to set the handlers from the configuration file.
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The comments provided within <cite>elinks.conf</cite> for the MIME
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options are not much helpful, and those options may seem a bit obscure
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or confusing at first. This document is a basic introduction to setting of
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MIME associations for ELinks. If you want to know how to automatically
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launch a program to view some kind of file (like images), then read
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on. Some basic knowledge of MIME is recommended.
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<h2>Acknowledgements</h2>
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This document was written by <cite>Jos� Luis Gonz�lez
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Gonz�lez</cite> out of despair due to the lack of documentation
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regarding the new way to configure MIME in recent ELinks prereleases.
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You may reach him at <a href="mailto:jlg80@mi.madritel.es">
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jlg80@mi.madritel.es</a>. Suggestions, fixes and contributions are
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I'd like to thank <a href="mailto:zas@norz.org">Laurent Monin</a>,
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who pointed me the syntax for the <code>mime.type</code> and
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<code>mime.handler</code> options. Thanks also to
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<a href="mailto:pasky@ucw.cz">Petr Baudis</a> for suggesting to
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use the Links to ELinks configuration conversion script from
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<cite>contrib/</cite> and in general for keeping up improving ELinks.
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<h1>Handling MIME types, the ELinks way</h1>
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<h2>What are MIME types and why may you want to use them?</h2>
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If, while browsing with ELinks, you need to display files that it can't
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show (like images or PDF documents), then you will likely want to pass
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them to other programs that are suitable for this task. While you may
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do it manually (saving the file to disk, running the auxiliar program to
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show it and then removing the file when finished), ELinks provides a
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method to do this automatically using MIME types.
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ELinks usually knows what the MIME type is for any file (which is a kind
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of description of its format), thus you only need to specify how to
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manage the MIME types for the files you want to open. If you don't tell
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ELinks how to manage a given MIME type then it will show you on screen
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the contents of the file (as if it was ASCII text) instead
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of calling an external program to show them.
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<h2>Associating files to MIME types</h2>
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If the file is fetched from a web server then this web server should
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tell ELinks what its MIME type is, so you should have generally no need to
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care about it. However, the web server might send an incorrect type, or
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you may be retrieving it by <acronym title="File Transfer Protocol">FTP
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</acronym> or from your local filesystem, so sometimes ELinks needs to
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The easiest method to guess a MIME type for a file is to just look at its
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name trusting it was given the right extension. ELinks supports this,
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letting you to specify a type for any given extension.
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<h2>Managing a given MIME type</h2>
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This usually means specifying programs to open files of this type and
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the conditions in which those programs may be used. For instance, you
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may want to use <cite>zgv</cite> (a popular svgalib image viewer) when
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you are using the text console, but <cite>xli</cite> (a image viewer for
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X) when running the X window system.
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<h3>Binding it to a handler</h3>
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Instead of directly attaching a program to a MIME type, ELinks lets you
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associate an abstract <cite>handler</cite> to each type. Then you can
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specify which programs implement the handler and how are they used.
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For instance, you may create an <code>image_viewer</code> handler and
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assign it to MIME types <cite>image/jpeg</cite>, <cite>image/png</cite>
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and <cite>image/gif</cite>. Then you would associate to <code>
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image_viewer</code> the programs you would like to use for viewing
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images and the details on how to use them. This is less cumbersome than
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repeating all these details for each MIME type.
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<h2>Specifying the details for a handler</h2>
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There are three issues to specify for a handler: the program associated
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to it, whether you want confirmation before using it and whether you
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want the terminal to be blocked while it is being used.
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When specifying any of these issues, you must tell ELinks the situation
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in which it gets applied, which is typically either the text console or
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the X window sytem. So you can specify that you don't want confirmation
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before running the program when running X, and that you want it
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otherwise. Similarly, when you are attaching a program (name it
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<cite>foo</cite>) to this handler you must tell if it's for X or not
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(you can attach a second program for the other choice if you want).
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<h3>Attaching a program to it</h3>
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You must tell ELinks the exact command for running it (with any options
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you wish). In place of the filename you must enter <kbd>%</kbd>.
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<h3>Choosing whether you want confirmation before applying it</h3>
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This is rather simple. If you choose not to do so, then the handler
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will be automatically called upon when you demand ELinks to show
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something attached to this handler. Otherwise, if you ask for
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confirmation, you will be prompted to open it with a external program,
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with additional choices that include cancelling the operation and
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viewing it with ELinks. E.g: you may use this option for programs
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written in <cite title="the C programming language">C</cite> so that you
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may always choose if you want to read the source with ELinks, or if you
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want to save it, or if you want to use <cite title="The indent program
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beautifier">indent</cite> to display it with less.
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<h3>Choosing whether to block the terminal</h3>
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If you don't want to allow going back to ELinks (or any other program
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from the same terminal) before the external program ends, then you
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should ask to block the terminal.
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<h1>Setting up <cite>elinks.conf</cite></h1>
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If you have old configuration files from old ELinks versions or from
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Links, then you may use the <cite>conf-links2elinks.pl</cite> script
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(which is placed at <cite>contrib/conv/</cite> on the source
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distribution) to convert them to the new format. If you don't use it
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you will need to edit the configuration file, and here you will find
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<h2>Associating a file extension to a MIME type</h2>
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You can still do this with the <acronym>UI</acronym>, from the the
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<cite>Setup→File Extensions</cite> submenu.
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If you want to do so from the configuration file, enter <kbd>set
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mime.extension.<var>ext</var> = "<var>type</var>"</kbd>, replacing
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<var>ext</var> with the appropiate file extension, and <var>type</var>
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with its MIME type. E.g. you may want to have <samp>set
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mime.extension.jpg = "image/jpeg"</samp>.
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<h2>Defining a handler</h2>
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For each handler you must define three items, specifying in what
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context the value of the item should be applied. You must enter <kbd>set
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mime.handler.<var>handler-name</var>.<var>item</var>.<var>context</var>
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= <var>value</var></kbd>, replacing <var>handler-name</var> with the
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name for the handler you are defining, <var>item</var> with the item you
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are defining for this handler, <var>context</var> with the context this
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item value is to be applied, and <var>value</var> with the value you
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want to assign to the item. You must do so for each of the available
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items: <code>program</code>, <code>ask</code> and <code>block</code>.
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The value for <code>program</code> is a string with the exact command
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you want to be issued to view the file, placing <kbd>%</kbd> were you
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would put the file name. The values for <code>ask</code> and
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<code>block</code> are either 0 (no) or 1 (yes). Available contexts
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include <code>unix</code> and <code>unix-xwin</code>, which mean UNIX text
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terminal and X respectively (others can be os2, win32, beos, riscos, ...).
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The latter does not mean you are running ELinks from X, just that the
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<code>DISPLAY</code> variable is set so
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that ELinks may run an X program.
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To illustrate it, here is an example. Suppose you want to define the
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<cite>image_viewer</cite> handler which should be used to view images.
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The configuration file may look like this:
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set mime.handler.image_viewer.unix.ask = 1
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set mime.handler.image_viewer.unix-xwin.ask = 0
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set mime.handler.image_viewer.unix.block = 1
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set mime.handler.image_viewer.unix-xwin.block = 0
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set mime.handler.image_viewer.unix.program = "zgv %"
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set mime.handler.image_viewer.unix-xwin.program = "xli %"
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In this example the <cite>image_viewer</cite> handler uses the
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<cite>svgalib</cite> image viewer <cite>zgv</cite> when X is not
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available, and the X image viewer <cite>xli</cite> when it is.
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The terminal would be blocked when X is not available and it would not
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be when it's available. Finally, ELinks would ask for confirmation
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before using the handler only with X not available.
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<h2>Associating a MIME type to a handler</h2>
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Just enter <kbd>set mime.type.<var>class</var>.<var>name</var> =
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"<var>handler</var>"</kbd>, replacing <var>class</var> with the class
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for the mime type, <var>name</var> with the specific name within that
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class, and <var>handler</var> with the name for the handler you want to
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assign to the MIME type. E.g. you may want to have <samp>set
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mime.type.image.jpeg = "image_viewer"</samp>.
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<tt>$Id: mime.html,v 1.4 2002/11/26 23:14:52 pasky Exp $</tt>
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