nsIProtocolHandler

nsIProtocolHandler.js

var {classes: Cc, interfaces: Ci, utils: Cu, results: Cr, manager: Cm} = Components; //can make this const if not in scratchpad
Cm.QueryInterface(Ci.nsIComponentRegistrar);
Cu.import('resource://gre/modules/Services.jsm');
Cu.import('resource://gre/modules/XPCOMUtils.jsm');

var nsIProtocolHandler = Ci.nsIProtocolHandler; //const

var unloaders = [];

function makeProtocolHandler(aProtocol, aClassID, aDefaultPort) {
    var obj = {
        classID: Components.ID(aClassID),
        classDescription: 'blah blah blah',
        contractID: '@mozilla.org/network/protocol;1?name=' + aProtocol,
        QueryInterface: XPCOMUtils.generateQI([nsIProtocolHandler]),
        scheme: aProtocol,
        defaultPort: aDefaultPort,
        protocolFlags: nsIProtocolHandler.URI_NORELATIVE | nsIProtocolHandler.URI_NOAUTH | nsIProtocolHandler.URI_LOADABLE_BY_ANYONE, //You must specify either URI_LOADABLE_BY_ANYONE, URI_DANGEROUS_TO_LOAD, URI_IS_UI_RESOURCE, or URI_IS_LOCAL_FILE in order for your protocol to work.
        newURI: function(aSpec, aOriginCharset, aBaseURI) {
            var uri = Cc['@mozilla.org/network/simple-uri;1'].createInstance(Ci.nsIURI);
            uri.spec = aSpec;
            console.log('uri=', uri);
            return uri;
        },

        newChannel: function(aURI) {
            //throw Cr.NS_ERROR_NOT_IMPLEMENTED;
            /* Get twitterName from URL */
            var postProtocolPath = aURI.spec.split(":")[1];
            var uri = Services.io.newURI("http://twitter.com/" + postProtocolPath, null, null);
            var channel = Services.io.newChannelFromURI(uri); //, null).QueryInterface(Ci.nsIHttpChannel); //i dont think i need to QI nsIHttpChannel
            /* Determines whether the URL bar changes to the URL */
            //channel.setRequestHeader("X-Moz-Is-Feed", "1", false);
            channel.originalURI = aURI;
            return channel;
        },
        getURIFlags: function(aURI) 0 // i dont think i need this? do I?
    };

    if (aDefaultPort == undefined || aDefaultPort == null) {
        aDefaultPort = -1;
    } else {
        obj.allowPort = function(port, scheme) {
            return port == aDefaultPort;
        };
    }

    return obj;
}

var myComponents = [myCustomBlah];

function myCustomBlah() {}
myCustomBlah.prototype = makeProtocolHandler('mycustomblah', 'b14c2b67-8680-4c11-8d63-9403c7d4f757');

//const NSGetFactory = XPCOMUtils.generateNSGetFactory(components);


function registerComponents() {
    for (let [y, cls] in Iterator(myComponents)) {
        console.info('y: ', y, 'cls: ', cls);
        try {
            var factory = {
                _cls: cls,
                createInstance: function(outer, iid) {
                    if (outer) {
                        throw Cr.NS_ERROR_NO_AGGREGATION;
                    }
                    return new cls();
                }
            };
            Cm.registerFactory(cls.prototype.classID, cls.prototype.classDescription, cls.prototype.contractID, factory);
            unloaders.push(function() {
                Cm.unregisterFactory(factory._cls.prototype.classID, factory);
            });
        } catch (ex) {
            console.warn('failed to register module: ', cls.name, 'exception thrown: ', ex);
        }
    }
}

function unregisterComponents() {
    for (var i = 0; i < unloaders.length; i++) {
        unloaders[i]();
    }
}

registerComponents(); //run this to make it work. once this is run follwoing examples above: typing "about:yabba" will take you to bings homepage
//unregisterComponents(); //do this to remove it //after running this typing about:yabba will take you to problem loading page

README

Rev1

• Copied from MDN which was copied from mozCentral: https://github.com/mozilla/releases-comm-central/blob/1f2a40ec2adb448043de0ae96d93b44a9bfefcd1/mailnews/compose/src/nsSMTPProtocolHandler.js#L10

Rev2

• Changed from smtp to mycustomblah but using the same class id

Rev3

• Beautified

Rev4

• Copy and paste, it works. If you type mycustomblah:rawr it will do a twitter lookup on user rawr.