This is relatively straightforward. You set up a client-only collection and a subscription in the usual way.
RestData = new Mongo.Collection('rest-data'); // client only
Meteor.subscribe('rest-docs');
On the server, you poll the REST endpoint at a suitable interval within a roll-your-own publication. Something along the lines of:
Meteor.publish('rest-docs', function() {
var init = true;
var self = this;
Meteor.setInterval(function() {
var data = HTTP.get('some url').data; // for JSON
if (init) {
self.added('rest-data', 'unique_doc_id', {stuff:data});
} else {
self.changed('rest-data', 'unique_doc_id', {stuff:data});
}
self.ready();
init = false;
}, 10000);
});
Also, you could look at any-database, which allows you to connect to a REST endpoint.