The content handlers system is used to configure Conkeror's behavior for content types which are not supported internally by Mozilla. Note that before Conkeror gets a chance to handle a given document with these content handlers, Mozilla first looks for plugins such as Acrobat, Flash, Java, et cetera. Plugins can be disabled in the Plugins tab of the Extensions window (M-x extensions).

For versions of Conkeror older than October 12, 2009, see MimeTypeHandlers instead.

1. content_handlers

When you browse to a document of a content-type that Mozilla cannot view internally, Conkeror normally prompts you for an action to take on the content. You can customize this on a per-mime-type basis to automatically do what you like by registering a content handler:

content_handlers.set("application/pdf", content_handler_open);

content_handlers is a mime-type table associating mime-types and mime-type patterns with content handler functions. The following handlers are predefined for your convenience:

content_handler_save

Save the document, prompting for path.

content_handler_open

Open the document, promting for a command.

content_handler_open_default_viewer

Open the document in the viewer registered in external_content_handlers for this mime-type, or prompt if none.

content_handler_open_url

Prompt for a command, and run it with the URL of the document as its argument.

content_handler_copy_url

Copy the URL of the document.

content_handler_view_internally

content_handler_view_as_text

content_handler_prompt

The default prompt---the same as if no handler was defined.

If you set a give null instead of a content handler to content_handlers.set, it will unset the handler for the given mime type.

You can also use the mime-type wildcard "*". A mime-type of "*" will match any mime-type. A mime-type of, for example, "application/*" will match any mime type whose major type is "application".

2. external_content_handlers

This variable is a mime-type table that associates mime types with command names of viewer programs. Manipulation of the table works just as for content_handlers.

external_content_handlers.set("application/pdf", "xpdf");
external_content_handlers.set("image/*", "display");

The default table is:

{
    "*": getenv("EDITOR"),
    text: { "*": getenv("EDITOR") },
    image: { "*": "feh" },
    video: { "*": "mplayer" },
    audio: { "*": "mplayer" },
    application: {
        pdf: "evince",
        postscript: "evince",
        "x-dvi": "evince"
    }
}

If you want to discard the defaults and set the entire table in one go, you can do that as follows:

external_content_handlers =
    {
        "*": "gvim",
        text: { "*": "kate" },
        image: { "*": "display" },
        application: {
            pdf: "xpdf",
            postscript: "gv",
            "x-dvi": "xdvi"
        }
    };

That trick works for content_handlers too.

2.1. Temporary Files and Forking

As a measure of basic garbage collecting, by default, Conkeror deletes temporary files as soon as the handler program completes. This can cause problems if the handler program forks immediately because it dispatches to another program. Examples include urxvtc, emacsclient with the -n flag, or the OS X's open command without the -W flag.

If you are using urxvtc, or a similar program, just use the non-client version (urxvt) instead. If you are using emacsclient, don't pass the -n flag. If you are using OS X's open command, make sure to pass the -W flag.

Another option is to write a wrapper script that runs your forking handler, but does not exit until the viewer or editor is done viewing or editing.

As a last result, you can disable the early deletion of temporary files altogether by setting delete_temporary_files_for_command = false;.