# Module mod_imap

This module is contained in the `mod_imap.c` file, and is compiled in by default. It provides for `.map` files, replacing the functionality of the `imagemap` CGI program. Any document with mime type `application/x-httpd-imap` will be processed by this module.

## Summary

In order to use server-parsed imagemap files, you must first compile the module into your server, and add the following line to the server configuration file. This entry indicates that imagemap files will be named with a `.map` extension.

> `AddType application/x-httpd-imap map`

## New Features

The imagemap module adds some new features that were not possible with previously distributed imagemap programs.

- URL references relative to the Referer: information.
- Default <BASE> assignment through a new map directive `base`.
- No need for `imagemap.conf` file.
- Point references.
- Configurable generation of imagemap menus.

## Configuration Directives

- ImapMenu
- ImapDefault
- ImapBase

### ImapMenu

Syntax: ImapMenu `{none, formatted, semiformatted, unformatted}`
Context: server config, virtual host, directory, .htaccess
Override: Indexes
Module: mod_imap.c

The ImapMenu directive determines the action taken if an imagemap file is called without valid coordinates.

`none`
  If ImapMenu is `none`, no menu is generated, and the `default` action is performed.
`formatted`
  A `formatted` menu is the simplest menu. Comments in the imagemap file are ignored. A level one header is printed, then an hrule, then the links each on a separate line. The menu has a consistent, plain look close to that of a directory listing.
`semiformatted`
  In the `semiformatted` menu, comments are printed where they occur in the imagemap file. Blank lines are turned into HTML breaks. No header or hrule is printed, but otherwise the menu is the same as a `formatted` menu.
`unformatted`
  Comments are printed, blank lines are ignored. Nothing is printed that does not appear in the imagemap file. All breaks and headers must be included as comments in the imagemap file. This gives you the most flexibility over the appearance of your menus, but requires you to treat your map files as HTML instead of plaintext.

### ImapDefault

Syntax: ImapDefault `{error, nocontent, map, referer, URL}`
Context: server config, virtual host, directory, .htaccess
Override: Indexes
Module: mod_imap.c

The ImapDefault directive sets the default `default` used in the imagemap files. It's value is overridden by a `default` directive within the imagemap file. If not present, the `default` action is `nocontent`, which means that a `204 No Content` is sent to the client. In this case, the client should continue to display the original page.

### ImapBase

Syntax: ImapBase `{map, referer, URL}`
Context: server config, virtual host, directory, .htaccess
Override: Indexes
Module: mod_imap.c

The ImapBase directive sets the default `base` used in the imagemap files. It's value is overridden by a `base` directive within the imagemap file. If not present, the `base` defaults to `http://servername/`.

## Imagemap File

The lines in the imagemap files can have one of several formats:

> `directive value [x,y ...]`
> `directive value "Menu text" [x,y ...]`
> `directive value x,y ... "Menu text"`

The directive is one of `base`, `default`, `poly`, `circle`, `rect`, or `point`. The value is an absolute or relative URL, or one of the special values listed below. The coordinates are `x,y` pairs seperated by whitespace. The quoted text is used as the text of the link if a imagemap menu is generated. Lines beginning with '#' are comments.

### Imagemap File Directives

There are six directives allowed in the imagemap file. The directives can come in any order, but are processed in the order they are found in the imagemap file.

`base` Directive
  Has the effect of `<BASE href="value">`. The non-absolute URLs of the mapfile are taken relative to this value. The `base` directive overrides ImapBase as set in a .htaccess file or in the server configuration files. In the absence of an ImapBase configuration directive, `base` defaults to `http://server_name/`.
  `base_uri` is synonymous with `base`. Note that a trailing slash on the URL is significant.

`default` Directive
  The action taken if the coordinates given do not fit any of the `poly`, `circle` or `rect` directives, and there are no `point` directives. Defaults to `nocontent` in the absence of an ImapDefault configuration setting, causing a status code of `204 No Content` to be returned. The client should keep the same page displayed.

`poly` Directive
  Takes three to one-hundred points, and is obeyed if the user selected coordinates fall within the polygon defined by these points.

`circle`
  Takes the center coordinates of a circle and a point on the circle. Is obeyed if the user selected point is with the circle.

`rect` Directive
  Takes the coordinates of two opposing corners of a rectangle. Obeyed if the point selected is within this rectangle.

`point` Directive
  Takes a single point. The point directive closest to the user selected point is obeyed if no other directives are satisfied. Note that `default` will not be followed if a `point` directive is present and valid coordinates are given.

### Values

The values for each of the directives can any of the following:

a URL
  The URL can be relative or absolute URL. Relative URLs can contain '..' syntax and will be resolved relative to the `base` value.
  `base` itself will not resolved according to the current value. A statement `base mailto:` will work properly, though.

`map`
  Equivalent to the URL of the imagemap file itself. No coordinates are sent with this, so a menu will be generated unless ImapMenu is set to 'none'.

`menu`
  Synonymous with `map`.

`referer`
  Equivalent to the URL of the refering document. Defaults to `http://servername/` if no Referer: header was present.

`nocontent`
  Sends a status code of `204 No Content`, telling the client to keep the same page displayed. Valid for all but `base`.

`error`
  Fails with a `500 Server Error`. Valid for all but `base`, but sort of silly for anything but `default`.

### Coordinates

`0,0 200,200`
  A coordinate consists of an `x` and a `y` value separated by a comma. The coordinates are separated from each other by whitespace. To accomodate the way Lynx handles imagemaps, should a user select the coordinate `0,0`, it is as if no coordinate had been selected.

### Quoted Text

`"Menu Text"`
  After the value or after the coordinates, the line optionally may contain text within double quotes. This string is used as the text for the link if a menu is generated:
  `<a href="http://foo.com/">Menu text</a>`
  If no quoted text is present, the name of the link will be used as the text:
  `<a href="http://foo.com/">http://foo.com</a>`
  It is impossible to escape double quotes within this text.

## Example Mapfile

> `#Comments are printed in a 'formatted' or 'semiformatted' menu.
> #And can contain html tags. <hr>
> base referer
> poly map "Could I have a menu, please?" 0,0 0,10 10,10 10,0
> rect .. 0,0 77,27 "the directory of the referer"
> circle http://www.inetnebr.com/lincoln/feedback/ 195,0 305,27
> rect another_file "in same directory as referer" 306,0 419,27
> point http://www.zyzzyva.com/ 100,100
> point http://www.tripod.com/ 200,200
> rect mailto:nate@tripod.com 100,150 200,0 "Bugs?"
> `

## Referencing your mapfile

> `<A HREF="/maps/imagmap1.map">
> <IMG ISMAP SRC="/images/imagemap1.gif">
> </A>`