Im new to Meteor and Im trying to figure out how to run a function after a collection change.
I have a route(iron router) that subscribes to a collection with waitOn. Which just waits for the subscrition to be ready before rendering which is what I want.
waitOn: function () {
return Meteor.subscribe('collection', this.params._id);
},
Any changes to the collection will be updated on all the clients and rendered automatically.
How would I run a function once the collection has changed?
You can use the onData hook, provided that you're returning that data using the data helper. E.g this is what a route may look like
this.route('routename',
path : '/abc',
waitOn: function () {
return Meteor.subscribe('collection', this.params._id);
},
data: function() {
return Collection.findOne({_id: this.params.id});
}
onData: function() {
//Do something when the data found by the above changes
}
});
Related
I am building a chat and based on the chatroom selected by the currentUser, I want to publish messages with this function:
Meteor.publish('messages',function(){
return Messages.find(
{chatId: 'QMMjBgCvLcnLvJPvx'},
sort:{timestamp: -1}
});
});
Now the chatId is still hardcoded, but it needs to be dynamic. The chatId is passed in the URL(e.g..../chat/QMMjBgCvLcnLvJPvx). In the client based code I have used to read the chatId:
var chatId = Router.current().params._id;
Iron Router
But this doesn't work server side. Is there a way to send the chatId from the URL to the server so I use Meteor.publish as mentioned above. Any help appreciated :)
Pass in the variable when you subscribe I.e.
Meteor.subscribe("messages", {chatId: Session.get("current-room")})
In the publication:
Meteor.publish('messages',function(chatId){
return Messages.find(
{chatId: chatId},
sort:{timestamp: -1}
});
});
In your route, you can subscribe to a publication and pass a param inside waitOn which will cause the app to show your loading template until the subscription is ready and the chatId will be reactive.
Configure loading template:
Router.configure({
layoutTemplate:'templateName',
loadingTemplate: 'anotherTemplateName'
});
Your route:
Router.route('/chat/:_id',{
waitOn: function(){
return Meteor.subscribe('messages', this.params._id);
},
action: function(){
//render your template with data
this.render('templateName', {
data: function () {
//will return object to the template which you can use in both HTML and JS. Also necessary for the link.
return Somethings.findOne({_id: this.params._id})
}
})
}
});
Publication:
Meteor.publish("messages", function (chatId) {
//the chatId comes from our subscribe in our route
return Messages.find({chatId: chatId});
});
Thanks for your answers and the hints. After some more modifications I arrived at this, which solved the issue:
var chatId = Router.current().params._id
this.wait(Meteor.subscribe('messages', chatId));
I am doing a find on a collection of nodes and am then storing the info in a variable.
I am then console.logging this data to see the contents of it. The thing is, my data stays an empty array for a split second and then a new console.log is done with an array of data. See my code below:
Template.temperature.helpers({
node() {
let node = Nodes.find({_id:Session.get('selectedNode')});
console.log(node);
return '';
}
});
My console output:
1: []
2: [Object]
What could be the reason for this?
In your router, subscribe within waitOn:
Router.route('/home', {
waitOn: function() {
return [
Meteor.subscribe('nodes'),
];
},
action: function() {
if (this.ready()) {
this.render();
}
},
});
This will ensure that the route will wait until the subscription is completed before executing the route. It uses the meteor loading hook, so the wait will utilize whatever loading screen or animation you ahve setup.
I would to show a list of all users, in my template.
I have:
//publications.js
Meteor.publish('users', function() {
return Meteor.users.find({}, { fields: {username: 1, profile: 1} });
});
//router.js
Router.route('/users/add/:_id?', {name: 'users.add', controller: 'UserAddController'});
UserAddController = RouteController.extend({
subscriptions: function(){
return [ Meteor.subscribe('hospitals'),
Meteor.subscribe('roles'),
Meteor.subscribe('users') ];
},
action: function() {
this.render('addUser', {
data: function(){
return { hospital_id : this.params._id }
}
});
}
});
//client
Template.listUsers.helpers({
users: function() {
return Meteor.users.find({});
}
});
But the list keep showing only the current logged-in user. I have created a list of users using Account.createUser() function What am I doing wrong?
Thanks.
You have to subscribe to a publication using this.subscribe() in subscriptions hook:
// a place to put your subscriptions
subscriptions: function() {
this.subscribe('items');
// add the subscription to the waitlist
this.subscribe('item', this.params._id).wait();
}
Or use waitOn:
// Subscriptions or other things we want to "wait" on. This also
// automatically uses the loading hook. That's the only difference between
// this option and the subscriptions option above.
waitOn: function () {
return Meteor.subscribe('post', this.params._id);
}
By default, Meteor publishes the current user. I see that you have a addUser template and a listUsers template. The problem is that while addUser is subscribed to the users publication, listUsers is not (this would depend on what else you have in your router of course). To fix this, change the call to this.render to render the listUsers template. Then, your users helper should work, and you can render the information however you like.
I tested this with my own app (the Microscope project from DiscoverMeteor) and it worked for me. Hope it works for you too. Comment here if not, and be sure to accept this answer if it worked. =)
Can someone see why the route is not subscribing to the publication. Profiles = new Meteor.Collection('profiles');
The mongo database does have documents in this collection, but the browser console still has a count of 0 in Profiles collection.
I am trying to tell the router, "subscribe to user-profile publication, when you are ready, render the 'profile' template. I also named the route 'profile.'
Now I have noticed that after typingsub = Meteor.subscribe('user-profile'); and then sub.ready(); I get the count of the collection. Otherwise the path is not subscribed. This behaviour has not occurred before.
lib/router.js
Router.plugin('loading', {loadingTemplate: 'Loading'});
Router.route('user/profile', {
name: 'profile',
waitOn: function () {
// return one handle, a function, or an array
return Meteor.subscribe('user-profile');
},
action: function () {
// this.ready() is true if all items returned from waitOn are ready
if (this.ready())
this.render('profile');
else
this.render('Loading');
}
});
server.js:
Meteor.publish('user-profile', function () {
return Profiles.find({userId: this.userId});
});
userId is a field in the Profiles collection. This profiles doc id is stored within the user.profile.experiences array for reference.
Meteor.userId is a function which returns the _id, not the _id itself, and you can't pass a function over DDP anyway. It should be:
waitOn: function () {
return Meteor.subscribe('user-profile', Meteor.userId());
}
In my Meteor app I have some collections I would like to subscribe to immediately upon login, and other collections I would like to subscribe to when the user visits or revisits the initial home page, but not otherwise.
The first set of collections should always be subscribed to throughout, but the second set should be turned off and on as the user leaves and returns to the initial screen.
I have the following code:
Meteor.startup(function () {
Meteor.subscribe('collection_one', Meteor.user().profile.setting_one);
Meteor.subscribe('collection_two', Meteor.user().profile.setting_two);
});
Router.route('/', {
name: 'home',
path: '/',
template: 'home',
waitOn: function() {
return [
Meteor.subscribe('collection_three', Meteor.user().profile.setting_three),
Meteor.subscribe('collection_four', Meteor.user().profile.setting_four),
]
}
});
My problem is that immediately upon startup and immediately upon going to the home page, Meteor.user() returns undefined. I would like to wait until Meteor.user() is defined, and then take these actions. How can I do this?
Meteor.startup() does not run code as a reactive computation, so even though Meteor.user() is a reactive data source it won't trigger a computation.
The reactivity section of the docs has a list of functions that run code as reactive computations.
You can use Tracker (previously called 'Deps') to create a reactive computation, like this:
Tracker.autorun(function () {
if (Meteor.user()) {
Meteor.subscribe('collection_one', Meteor.user().profile.setting_one);
Meteor.subscribe('collection_two', Meteor.user().profile.setting_two);
}
});
But it looks like you're using Iron Router so you could also set a global waitOn() with Router.configure to solve it, like this:
Router.configure({
layoutTemplate: 'MasterLayout',
loadingTemplate: 'Loading',
notFoundTemplate: 'NotFound',
templateNameConverter: 'upperCamelCase',
routeControllerNameConverter: 'upperCamelCase',
// This method will re-run when ever Meteor.user() changes.
waitOn: function () {
// Making sure setting_one and setting_two are available (which they won't be initially)
var setting_one = Meteor.user() && Meteor.user().profile && Meteor.user().profile.setting_one;
var setting_two = Meteor.user() && Meteor.user().profile && Meteor.user().profile.setting_one;
// Subscribe to the published version of the server side collections
return [
Meteor.subscribe('collection_one', setting_one),
Meteor.subscribe('collection_two', setting_two)
];
}
});
The key is to use Tracker.autorun()
import { Meteor } from 'meteor/meteor';
import { Tracker } from 'meteor/tracker';
let username = ''
Tracker.autorun( function(currentComputation) {
if (Meteor.user()) {
username = Meteor.user().username
if (username) // do something with username
return
}
})
currentComputation is optional