#TernopilJS

MeteorJS

Лекція 8. Publish/Subscribe

Лектор - Михайло

Код - github.com/ternopiljs

Презентації - slides.com/ternopiljs

Новини - vk.com/ternopiljs

Observe

Posts.find().observe({
    added: function (doc) {
        console.log('Post\'s added', doc);
    },
    changed: function (doc) {
        console.log('Post\'s changed', doc);
    },
    removed: function (doc) {
        console.log('Post\'s removed', doc);
    }
});

Observe

Posts.find().observeChanges({
    added: function (id, fields) {
        console.log('Post\'s added', id, fields);
    },
    changed: function (id, doc) {
        console.log('Post\'s changed', id, fields);
    },
    removed: function (id, doc) {
        console.log('Post\'s removed', id, fields);
    }
});

Observe

var handle = Posts.find().observeChanges({
    added: function (id, fields) {
        console.log('Post\'s added', id, fields);
    },
    changed: function (id, doc) {
        console.log('Post\'s changed', id, fields);
    },
    removed: function (id, doc) {
        console.log('Post\'s removed', id, fields);
    }
});

handle.stop(); // stops observing

Publish

Meteor.publish('publish-name', function(argument1, argument2) {
  return Collection.find({field1: argument1, field2: argument2});
});

Meteor.subscribe('publish-name', argument1, argument2);

Subscribe

Publish. Low-level interface

Meteor.publish('publish-name', function() {
  var self = this;
  var handle = SomeCollection.find().observe({
    added: function (doc) {
      self.added('collection-name', doc._id, doc);
    },
    changed: function (doc) {
      self.changed('collection-name', doc._id, doc);
    },
    removed: function (oldDoc) {
      self.removed('collection-name', oldDoc._id);
    }
  });
  self.ready();
 
  self.onStop(function () {
    handle.stop();
  });
});

Meteor.subscribe('publish-name', argument1, argument2, {
    onReady: function () {},
    onStop: function () {}
});

Subscribe handle

var handle = Meteor.subscribe('publish-name', argument1, argument2, {
    onReady: function () {},
    onStop: function () {}
});

handle.stop() // зупиняє підписку
handle.ready() // реактивне джерело
// True, якщо метод ready був викликаний в публікації

Reactive Subscribe

Tracker.autorun(function () {
  Meteor.subscribe("images", Session.get("limit"));
});

Allow

Posts.allow({
  insert: function (userId, doc) {
    // the user must be logged in, and the document must be owned by the user
    return (userId && doc.owner === userId);
  },
  update: function (userId, doc, fields, modifier) {
    // can only change your own documents
    return doc.owner === userId;
  },
  remove: function (userId, doc) {
    // can only remove your own documents
    return doc.owner === userId;
  },
  fetch: ['owner']
});

Deny

Posts.deny({
  insert: function (userId, doc) {
    return !!userId;
  },
  update: function (userId, doc, fields, modifier) {
    return doc.owner !== userId;
  },
  remove: function (userId, doc) {
    return false;
  },
  fetch: ['owner']
});

• Methods

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