Subj : Registering a MIME type handler in Mozilla's autoconfig
To   : netscape.public.mozilla.xpcom,netscape.public.mozilla.jseng,netscape.public.mozilla.xpfe
From : ALBANI damiano
Date : Fri Jul 30 2004 01:12 pm

Hello,

I am trying to use the autoconfig feature of Mozilla to register new 
MIME handlers at browser *startup*.
To avoid duplicating code, I am using the logic from 
"chrome://communicator/content/pref/overrideHandler.js", the one used by 
the preferences panel dealing with helper applications.
However, as there's no 'include' or 'import' feature in JavaScript, I 
have to fetch the file and then eval() the code.

I also took the glue code from 
"http://lxr.mozilla.org/seamonkey/source/xpfe/components/prefwindow/resources/content/pref-applications-new.js#106" 
onwards.

I can successfully create a HandlerOverride object, but any call on the 
setter/getter of this class fails (silently unfortunately). Where could 
this come from ?

What is strange is that this process works in a <script> included in an 
HTML page (though it needs XPConnect privileges).

I know this is a (bad) trick, but as 
"http://bugzilla.mozilla.org/show_bug.cgi?id=190413" isn't implemented, 
I have no choice.

Follows my code :

//////

function readFile(path)
{
   var ioService = Components.classes["@mozilla.org/network/io-service;1"]
 
..getService(Components.interfaces.nsIIOService);
   var channel = ioService.newChannel(path, null, null);
   var inputStream = channel.open();
   var sInputStream = 
Components.classes["@mozilla.org/scriptableinputstream;1"]
 
..createInstance(Components.interfaces.nsIScriptableInputStream);
   sInputStream.init(inputStream);
   return sInputStream.read(sInputStream.available());
}


var gDS = null;
function addMIMEHandler(mime, extension, description, application)
{
   var gRDF = Components.classes["@mozilla.org/rdf/rdf-service;1"]
                        .getService(Components.interfaces.nsIRDFService);

   var fileLocator = 
Components.classes["@mozilla.org/file/directory_service;1"]
 
..getService(Components.interfaces.nsIProperties);

   var file = fileLocator.get("UMimTyp", Components.interfaces.nsIFile);

   var ioService = Components.classes["@mozilla.org/network/io-service;1"]
 
..getService(Components.interfaces.nsIIOService);

   var fileHandler = ioService.getProtocolHandler("file")
 
..QueryInterface(Components.interfaces.nsIFileProtocolHandler);

   gDS = gRDF.GetDataSource(fileHandler.getURLSpecFromFile(file));

   var js_data = 
readFile("chrome://communicator/content/pref/overrideHandler.js");
   eval(js_data);

// works, a 'for ( i in handler )' sees its methods
   var handler = new HandlerOverride(MIME_URI(mime));

// it works, because mUpdateMode isn't accessed through a setter (?)
   handler.mUpdateMode = true;

   handler.mimeType = mime; // !!! stops/fails here !!!
   handler.description = description;
   handler.addExtension(extension);
   handler.appPath = application;

   handler.isEditable = true;
   handler.saveToDisk = false;
   handler.handleInternal = false;
   handler.alwaysAsk = false;
   handler.appDisplayName = application.split(/[\/\\]/).pop();

   handler.buildLinks();

gDS.QueryInterface(Components.interfaces.nsIRDFRemoteDataSource).Flush();
}


Cheers,

-- 
Damiano

.