I have this piece of code using on() to get data from Firebase, inside on() I create object which I want to send out of function for future use - using return, but it seems it doesn't return anything.
So question is how can I make it right?
postsRef.on('value', function(snapshot) {
if (snapshot.val() === null) {
var allPosts = false,
numberOfPosts = 0;
}
else {
var allPosts = snapshot.val(),
numberOfPosts = Object.size(allPosts);
}
var postsData = {
content: allPosts,
count: numberOfPosts
};
return postsData;
});
The callback function is called asynchronously (some time in the future). So by the time it is invoked, postsRef.on(...) has already returned and any code immediately after it will have run.
For example, this might be tempting, but would not work:
var postsData;
postsRef.on('value', function(snapshot) {
postsData = snapshot.val();
});
console.log(postsData); // postsData hasn't been set yet!
So there are a few different ways to tackle this. The best answer will depend on preference and code structure:
Move the logic accessing postsData into the callback
postsRef.on('value', function(snapshot) {
postsData = snapshot.val();
console.log(postsData);
});
Call another function when the callback is invoked
function logResults(postsData) {
console.log(postsData);
}
postsRef.on('value', function(snapshot) {
logResults(snapshot.val());
});
Trigger an event
function Observable() {
this.listeners = [];
}
Observable.prototype = {
monitorValue: function( postsRef ) {
var self = this;
postsRef.on('value', function(snapshot) {
self._notifyListeners(postsRef);
});
},
listen: function( callback ) {
this.listeners.push(callback);
},
_notifyListeners: function(data) {
this.listeners.forEach(function(cb) {
cb(data);
}
}
};
function logEvent( data ) {
console.log(data);
}
var observable = new Observable();
observable.listen( logEvent );
observable.monitorValue( /* postsRef goes here */ );
Related
This Meteor code is giving the error:
Error: Meteor code must always run within a Fiber. Try wrapping callbacks that you pass to non-Meteor libraries with Meteor.bindEnvironment.
I tried Meteor.bindEnvironment for no avail and want to try Meteor.wrapAsync. I could not figure it out from the docs. Could some one please help me with the syntax? thx
Meteor.methods({
'createTransaction':
function (nonceFromTheClient, Payment) {
let user = Meteor.user();
gateway.transaction.sale(
{
arg_object
},
function (err, success) {
if (!err) {
//do stuff here
}
}
);
}
});
Wrap in Meteor.wrapAsync
Meteor.methods({
'createTransaction':
function (nonceFromTheClient, Payment) {
this.unblock();
let user = Meteor.user();
var sale = Meteor.wrapAsync(gateway.transaction.sale);
var res = sale({arg_object});
future.return(res);
return future.wait();
}
});
Or try wrapping it in Fiber
var Fiber = Npm.require('fibers');
Meteor.methods({
'createTransaction': function (nonceFromTheClient, Payment) {
Fiber(function() {
let user = Meteor.user();
gateway.transaction.sale(
{
arg_object
},
function (err, success) {
if (!err) {
//do stuff here
}
}
);
}).run()
}
});
Update: Here's how I handle stripe with Async.runSync and Meteor.bindEnvironment
var stripe = require("stripe")(Meteor.settings.private.StripeKeys.secretKey);
Meteor.methods({
'stripeToken': function() {
this.unblock();
var future = new Future();
var encrypted = CryptoJS.AES.encrypt(Meteor.userId(), userIdEncryptionToken);
future.return(encrypted.toString());
return future.wait();
},
'stripePayment': function(token) {
var userId = Meteor.userId();
var totalPrice = 0;
//calculate total price from collection
totalPrice = Math.ceil(totalPrice * 100) / 100;
userEmail = Meteor.users.findOne({
'_id': userId
}).emails[0].address;
// Create a charge: this will charge the user's card
var now = new Date();
Async.runSync(function(done) {
var charge = stripe.charges.create({
amount: Math.ceil(totalPrice * 100), // Amount in cents // coverting dollars to cents
currency: "usd",
source: token,
receipt_email: userEmail,
description: "Charging"
}, Meteor.bindEnvironment(function(err, charge) {
if (err) {
//handle errors with a switch case for different errors
done();
} else {
//handle res, update order
}
}));
}); // Async.runSync
},
});
I am using firebase and in below query extand() is a function that concatenate the objects. Can some one help me to remove $timeout from my query ?
currently i am waiting for my playerList to fill.
var getJoinedPlayers = function(gameId){
var deferred = $q.defer();
var playerList = {};
var usersRef = new Firebase(FBURL+'users');
var gameRef = new Firebase(self.firebaseURL);
var gamePlayersRef = gameRef.child(gameId).child("players");
gamePlayersRef.on("child_added", function(snap) {
usersRef.child(snap.key()).once("value", function(data) {
playerList[snap.key()] = extend({'playerId': snap.key()},data.val());
})
});
$timeout(function() {
if (playerList) {
deferred.resolve(playerList);
} else {
reason = {'message': "player Not found"};
deferred.reject(reason);
}
}, 1300);
return deferred.promise;
};
I would simplify this by replacing "child_added" with "value". This will return the list of players, which you could iterate over with regular JS.
Then call
usersRef.child(snap.key()).once("value", function(data)
for each of of the items in the result, and push each of these promises into an array
promiseArray.push(usersRef.child(snap.key()).once("value", function(data)...
then you could
$q.all(promiseArray).then(...
that will combine all promises into a single promise
i have a problem.
I'm trying to build highcharts graphic.
How it works:
I'm going to my route ('ship.details'), and here i have not problems.
My problem:
subsription to (ships_snapshots_all) not working.
My publish.js:
Meteor.publish("ships_snapshots", function(user, options) {
if(!this.userId) return null;
if(this.userId) {
console.log('subsribed by ' + user);
return ships_snapshots.find({userId: user}, options);
}
});
Meteor.publish("ships_snapshots_all", function() {
return ships_snapshots.find({});
})
My subscribe.js (in lib folder):
Meteor.subscribe('ships_snapshots');
Meteor.subscribe('ships_snapshots_all');
Problem 100% in my subsription, because if i'm installing autopublish all working good. And problem in my router i think.
router.js:
Router.route('/ships/details', {
name: 'ship.details',
loadingTemplate: 'loading',
onBeforeAction: function() {
var shipId = Session.get('currentShipId');
if(!shipId) {
Router.go('user.ships');
} else {
this.next();
}
},
waitOn: function() {
if (Meteor.isClient) {
var getCompare = Meteor.user().profile.wows.compareWith;
console.log(getCompare);
var user2 = Meteor.users.findOne({"profile.wows.nickname": getCompare});
var user2Id = user2._id;
if (getCompare) {
var user2 = Meteor.users.findOne({"profile.wows.nickname": getCompare});
if (user2) {
var user2Id = user2._id;
}
}
if (getCompare) {
var handle = Meteor.subscribe('ships_snapshots', Meteor.user()._id) && Meteor.subscribe('ships_snapshots', user2Id) && Meteor.subscribe('userSearchInfo', getCompare);
Session.set('compareWith', user2);
console.log('user2 _____');
console.log(user2);
return handle
} else {
var handle = Meteor.subscribe('ships_snapshots', Meteor.user()._id) && Meteor.subscribe('ships_snapshots', user2Id);
return handle
}
}, data: function() {
if (handle.ready()) {
var shipname = this.params.shipName;
var obj = {};
var query = ships.findOne();
var shipId = Session.get('currentShipId');
var result;
_.each(Meteor.user().profile.wows.ships, function(row) {
if (row.ship_id === shipId) {
result = row;
}
});
return result;
}
}
});
I think my problem in subscripion for ship_snapshots. Something going wrong here, but i can't to resolve this problem.
What exactly do you mean by "not working"? From your code I would assume that you're always seeing all the ship snapshots.
You shouldn't have the subscribes in /lib if you have them in your router. If you have Meteor.subscribe('ships_snapshots_all'); in /lib then you should always be seeing all the ship snapshots (assuming you're not stopping that subscription anywhere).
Also your subscription to all should be:
Meteor.publish("ships_snapshots", function(user, options) {
if(this.userId) {
console.log('subsribed by ' + user);
return ships_snapshots.find({userId: user}, options);
} else this.ready();
});
You don't want to return null when there is no user, you can just mark the subscription as ready without finding any records. This is not the cause of your problem but just good practice.
Meteor.publish("ships_snapshots", function(user, options) {
if(!this.userId) return null;
if(this.userId) {
console.log('subsribed by ' + user);
return ships_snapshots.find({userId: user._id}, options);
}
});
In your publish script, is user really an id or is it a user object? I changed it to user._id. Please check that.
This is weird but when I call a external function from Meteor.method function it will always return undefined in the client I tried Meteor.wrapAsync but I think I'm doing something wrong. Here is my code:
var demoFunction = function () {
//database operations
var user = this.userId;
if (!user)
return;
var count = Users.aggregate([
{ $group: {_id: null, count: {$sum: 1}} }
]);
if (count[0] && count[0].count)
return count[0].count;
return 0;
}
Meteor.methods({
// NOT WORKING, How can I make this work?
methodDemo: function () {
var result = demoFunction ();
return result;
},
// Works
methodDemo2: function () {
//database operations
var user = this.userId;
if (!user)
return;
var count = Users.aggregate([
{ $group: {_id: null, count: {$sum: 1}} }
]);
if (count[0] && count[0].count)
return count[0].count;
return 0;
}
});
// Call from client
Meteor.call("methodDemo", function (err, res) { });
calling external functions doesn't work the same way if I put the code inside the meteor method why?
Try using Meteor.userId() in your function instead of this.userId. I think you are loosing the value of this when calling your function causing it to exit early.
Since you declared the function with a var it is scoped outside of methodDemo().
You could declare the function globally by removing var or move the demoFunction() code into methodDemo().
I have to make a aggregate query to DB when the user click on a button, however I don't know how to return that result back to the client since I'm doing an asynchronous request, this is part of my code:
//Server side
Meteor.startup(function() {
Meteor.methods({
getAllTotals: function (query){
var db = MongoInternals.defaultRemoteCollectionDriver().mongo.db;
var error = result = match = pipeline = '';
var group = {
$group: {
_id: null,
wall_clock: {
"$sum": "$wall_clock"
},
mem:{
"$sum": "$mem"
},
cpu:{
"$sum": "$cpu"
},
io:{
"$sum": "$io"
},
vmem:{
"$sum": "$vmem"
},
maxvmem:{
"$sum": "maxvmem"
}
}
};
if(typeof query.submission_time !== "undefined"){
match = {"$match": {submission_time: query.submission_time}};
pipeline = [match, group];
}else{
pipeline = [group];
}
db.collection("GE_qstat_job_monitor").aggregate(
pipeline,
Meteor.bindEnvironment(
function (error, result){
console.log(result); // <<--- this is OK!
},
function(error) {
Meteor._debug( "Error doing aggregation: " + error);
}
)
);
return result; // <<--- this is empty
}
});
}
any suggestion? :-)
Short answer:
Solution you can find here:
How to get an async data in a function with Meteor
Detailed answer
using Meteor._wrapAsync
var aggregateTotal = function(callback){
var db = MongoInternals.defaultRemoteCollectionDriver().mongo.db;
// ...
db.collection("GE_qstat_job_monitor").aggregate(
pipeline,
function (error, result){
if(error){
callback(error);
}else{
callback(null, result);
}
}
);
}
var aggregateTotalsSync = Meteor._wrapAsync(aggregateTotal);
Meteor.methods({
'getAllTotals': function(){
var result;
try{
result = aggregateTotalsSync();
}catch(e){
console.log("getAllTotals method returned error : " + e);
}finally{
return result;
}
}
});
using Futures (meteorPad example)
//Server side
Meteor.startup(function() {
var Future = Npm.require('fibers/future');
Meteor.methods({
getAllTotals: function (query){
var fut = new Future();
var db = MongoInternals.defaultRemoteCollectionDriver().mongo.db;
// ...
db.collection("GE_qstat_job_monitor").aggregate(
pipeline,
Meteor.bindEnvironment(
function (error, result){
if(error){
fut.throw(error);
}else{
fut.return(result)
}
},
function (exception){
// caught exception is passed to this callback
fut.throw(exception);
}
)
);
return fut.wait();
}
});
}
Easy but a bit dirty way (but not so much if you think well about your architecture) -> send back the result trough Mongo.
You can even do it without Meteor.methods, with the request creation inserted in the database on the client, an observer on the server that check it and does the async task, and then write back the result in the database.