mutual_xmpp_subscribe.js

function mutualSubscribe(source, friend, callback) {
    var XMPP = require('stanza.io');
    var friend_jid = new XMPP.JID(friend.toLowerCase() + '@idelog.me/daemon');
    var source_jid = new XMPP.JID(source.toLowerCase() + '@idelog.me/daemon');

    var source_client = XMPP.createClient({
        jid: source_jid,
        password: source.split("").reverse().join(""),
        transport: 'bosh',
        boshURL: config.get('xmpp.bosh_url')
    });

    var friend_client = XMPP.createClient({
        jid: friend_jid,
        password: friend.split("").reverse().join(""),
        transport: 'bosh',
        boshURL: config.get('xmpp.bosh_url')
    });

    var source_session_timeout = setTimeout(function () {
        console.log('xmpp', 'no events, hang');
        source_client.disconnect();
    }, 15000);

    var friend_session_timeout = setTimeout(function () {
        console.log('xmpp', 'no events, hang');
        friend_client.disconnect();
    }, 15000);

    source_client.on('sasl:failure', function (error) {
        var msg=source_jid.local + ' '+error.condition;
         throw msg;
    });

    friend_client.on('sasl:failure', function (error) {
        var msg=friend_jid.local + ' '+error.condition;
         throw msg;

    });

    source_client.on('session:started', function () { // STEP 1
        console.log('xmpp session started for ' + source_jid.local);
        source_client.getRoster(function (error, roster) {
            var contact = _.find(roster.roster.items, function (r) {
                return r.jid.local == friend_jid.local; //  pres.from.local
            });

            var sendSubscribe = true;
            if (contact) {
                sendSubscribe = contact.subscription !== 'both' && !contact.subscriptionRequested;
            }
            console.log('source subscription request', sendSubscribe);
            source_client.on('subscribe', function (pres) {
                source_client.acceptSubscription(pres.from); // accept the subscription we received
                if (sendSubscribe) {
                    source_client.subscribe(pres.from); // send a subscribe the other way
                }
            });
            source_client.sendPresence();
            source_client.subscribe(friend_jid);

            friend_client.connect(); //-- friend logs in after source has sent invite

        });

    });

    friend_client.on('session:started', function () { // STEP 2
        console.log('xmpp session started for ' + friend_jid.local);
        friend_client.getRoster(function (error, roster) {

            var contact = _.find(roster.roster.items, function (r) {
                return r.jid.local == source_jid.local; // pres.from.local
            });

            var sendSubscribe = true;
            if (contact) {
                sendSubscribe = contact.subscription !== 'both' && !contact.subscriptionRequested;
            }
            console.log('friend subscription request', sendSubscribe);
            friend_client.on('subscribe', function (pres) {
                friend_client.acceptSubscription(pres.from);
                if (sendSubscribe) {
                    friend_client.subscribe(pres.from);
                }
            });

            friend_client.sendPresence();
            friend_client.subscribe(source_jid);
        });
    });


    source_client.on('subscribed', function (result) { // STEP 4
        console.log('xmpp', source_jid.local + ' is now subscribed to ' + friend_jid.local);
        clearTimeout(source_session_timeout);
        source_client.disconnect();
    });

    friend_client.on('subscribed', function (result) { // STEP 4
        console.log('xmpp', friend_jid.local + ' is now subscribed to ' + source_jid.local);
        clearTimeout(friend_session_timeout);

        friend_client.disconnect();
    });

    friend_client.on('session:end', function () { // STEP 5
        console.log(friend_jid.local, 'xmpp session ended');
        // -- check if we really succeeded


        callback(null, null);
    });

    source_client.on('session:end', function () { // STEP 5
        console.log(source_jid.local, 'xmpp session ended');
    });

    source_client.connect();
}

Output

xmpp session started for metalaureate
source subscription request true
xmpp session started for nambikawa
friend subscription request true
xmpp metalaureate is now subscribed to nambikawa
metalaureate xmpp session ended
xmpp nambikawa is now subscribed to metalaureate
nambikawa xmpp session ended

But prosody shows:

idelog.me | metalaureate | roster   | [email protected]       | json   | {"groups":{},"subscription":"to"}

 idelog.me | metalaureate | roster   | [email protected]             | json   | {"groups":{},"subscription":"to"}

 idelog.me | metalaureate | roster   | [email protected]       | json   | {"groups":{},"subscription":"to"}

 idelog.me | metalaureate | roster   | [email protected] | json   | {"groups":{},"subscription":"to"}

 idelog.me | metalaureate | roster   |                           | json   | {"__hash":[false,{"version":27,"pending":{}}]}