I'm attempting to run ntwitter streaming API to track tweets about a certain hashtag, populating the Mongo collection Tweets with each tweet.
I've hooked it up server side like so:
t = new nTwitter({
consumer_key: credentials.consumer_key,
consumer_secret: credentials.consumer_secret,
access_token_key: credentials.access_token_key,
access_token_secret: credentials.access_token_secret
});
Meteor.methods({
trackTweets: function () {
this.unblock; // this doesn't seem to work
console.log('... ... trackTweets');
var _this = this;
t.stream(
'statuses/filter',
{ track: ['#love'] },
function(stream) {
stream.on('data', function(tweet) {
// app/packages/mongo-livedata/collection.js:247
// throw e;
// ^
// O yes I love her like money
// Error: Meteor code must always run within a Fiber
console.log(tweet.text);
Tweets.insert(tweet.text); // this call blocks
});
stream.on('error', function(error, code) {
console.log("My error: " + error + ": " + code);
});
}
);
}
});
The line: Tweets.insert(tweet.text) throws the must run inside its own Fiber error – and I've tried putting the this.unblock statement in several different places.
What should I do here?
you dont call the function unblock, you need to replace your
this.unblock;
with this:
this.unblock();
if that doesn't work i would think it has something to do with the way ntwitter is getting the data, you could try to add this
if (Meteor.isClient) return false;
so that the method doesn't run on the client, but only on the server
I believe the code you are running server-side needs to be contained within a Fiber.
Some similar examples can be found in these answers:
Meteor code must always run within a Fiber” when calling Collection.insert on server
Stream stdout to Meteor website
Related
When I return the geocode from googles API I'm trying to save it into my database. I've been trying to use the code below, to just insert a Test document with no luck. I think it has something to do with meteor being asynchronous. If I run the insert function before the googleMapsClient.geocode function it works fine. Can someone show me what I'm doing wrong.
Meteor.methods({
'myTestFunction'() {
googleMapsClient.geocode({
address: 'test address'
}, function(err, response) {
if (!err) {
Test.insert({test: 'test name'});
}
});
}
});
I see now where you got the idea to run the NPM library on the client side, but this is not what you really want here. You should be getting some errors on the server side of your meteor instance when you run the initial piece of code you gave us here. The problem is that the google npm library runs in it's own thread, this prevents us from using Meteor's methods. The easiest thing you could do is wrap the function with Meteor.wrapAsync so it would look something like this.
try {
var wrappedGeocode = Meteor.wrapAsync(googleMapsClient.geocode);
var results = wrappedGeocode({ address : "testAddress" });
console.log("results ", results);
Test.insert({ test : results });
} catch (err) {
throw new Meteor.Error('error code', 'error message');
}
You can find more info by looking at this thread, there are others dealing with the same issue as well
You should run the googleMapsClient.geocode() function on the client side, and the Test.insert() function on the server side (via a method). Try this:
Server side
Meteor.methods({
'insertIntoTest'(json) {
Test.insert({results: json.results});
}
});
Client side
googleMapsClient.geocode({
address: 'test address'
}, function(err, response) {
if (!err) {
Meteor.call('insertIntoTest', response.json);
}
});
Meteor Methods should be available on the both the server and client sides. Therefore make sure that your method is accessible by server; via proper importing on /server/main.js or proper folder structuring.
(If a method contains a secret logic run on the server, it should be isolated from the method runs on both server & client, though)
I know that there are several methods to share collections on both the client and server -- namely either in top level lib folder or publish/subscribe model -- but when I try either of these things when using mongodb running at localhost:27017 as my MONGO_URL, I am not reliably getting data on the client. Occasionally console.log(myCollection.findOne({})) will return expected data in the browser but most of the time it returns undefined.
//Client side code
Template.controls.onCreated(function controlsOnCreated() {
Meteor.subscribe("myEvents");
Events = new Mongo.Collection("events");
});
//Server side code
Meteor.startup(() => {
Events = new Mongo.Collection("events");
}
Meteor.publish('myEvents', function() {
console.log(Events.find());
return Events.find();
});
UPDATED CODE -- returns Events on server but not client:
//Client
Template.controls.onCreated(function controlsOnCreated() {
this.subscribe("myEvents");
});
//Server
if (Meteor.isServer) {
Meteor.publish("myEvents", function() {
return Events.find();
});
}
// /collections/events.js
Events = new Mongo.Collection("events");
UPDATE 2:
I am attempting to verify the publication in the browser after the page has rendered, calling Events.findOne({}) in the Chrome dev tools console.
on your client:
Template.controls.onCreated(function controlsOnCreated() {
Meteor.subscribe("myEvents");
Events = new Mongo.Collection("events");
});
that is an odd place to define the Events variable. typically, you would put that line of code in a JS file common to both platform. e.g.
collections/events.js:
Events = new Mongo.Collection("events");
when that line runs on the server, it defines the mongo collection and creates a server-side reference to it. when it runs on the client, it creates a collection by that name in mini-mongo and creates a client-side reference to it.
you can write your onCreated like this (note "this" instead of "Meteor"):
Template.controls.onCreated(function() {
this.subscribe("myEvents");
});
you don't say where on the client you ran your console.log with the find(). if you did it in the onCreated(), that's too early. you're seeing the effects of a race condition. typically, you might use it in a helper:
Template.controls.helpers({
events() {
return Events.find({});
}
});
and display the data in the view:
{{#each event in events}}
{{event.name}}
{{/each}}
that helper will run reactively once the data from the publish shows up.
I've created a very simple server using Meteor, to send an email after a timeout. When I use a timeout, the message is successfully sent but an error is thrown: [Error: Can't wait without a fiber].
Here's my code:
if (Meteor.isServer) {
Meteor.startup(function () {
// <DUMMY VALUES: PLEASE CHANGE>
process.env.MAIL_URL = 'smtp://me%40example.com:PASSWORD#smtp.example.com:25';
var to = 'you#example.com'
var from = 'me#example.com'
// </DUMMY>
//
var subject = 'Message'
var message = "Hello Meteor"
var eta_ms = 10000
var timeout = setTimeout(sendMail, eta_ms);
console.log(eta_ms)
function sendMail() {
console.log("Sending...")
try {
Email.send({
to: to,
from: from,
subject: subject,
text: message
})
} catch (error) {
console.log("Email.send error:", error)
}
}
})
}
I understand that I could use Meteor.wrapAsync to create a fiber. But wrapAsync expects there to be a callback to call, and Email.send doesn't use a callback.
What should I do to get rid of the error?
This happens because while your Meteor.startup function runs inside a Fiber (like almost all other Meteor callbacks), the setTimeout you use does not! Due to the nature of setTimeout it will run on the top scope, outside the fiber in which you defined and/or called the function.
To solve, you could use something like Meteor.bindEnvironment:
setTimeout(Meteor.bindEnvironment(sendMail), eta_ms);
And then do so for every single call to setTimeout, which is a painfully hard fact.
Good thing it's not actually true. Simply use Meteor.setTimeout instead of the native one:
Meteor.setTimeout(sendMail, eta_ms);
From the docs:
These functions work just like their native JavaScript equivalents. If you call the native function, you'll get an error stating that Meteor code must always run within a Fiber, and advising to use Meteor.bindEnvironment
Meteor timers just bindEnvironment then delay the call as you wanted.
I've just spent a few hours reading SO with answers such as Meteor: Calling an asynchronous function inside a Meteor.method and returning the result
Unfortunately, I still didn't manage to user fibers, or futures for that matter.
I'm trying to do something fairly simple (I think!).
When creating a user, add a variable to the user object, based on the result of an asynchronous method. So imagine if you will my async method is called on a 3rd party db server called BANK, which could take several seconds to return.
Accounts.onCreateUser(function(options,user){
var Fiber = Npm.require("fibers");
Fiber(function() {
BANK.getBalance(function(err, theBalance) {
if (err) return console.log(err);
_.extend(user,{
balance: theBalance;
});
});
}).run();
return user;
});
So what happens in the above is that the BANK method is called, but by the time it returns the code has already moved on and _.extend is never invoked.
I tried placing the return call inside the Fiber, that only made things worse: it never return user. Well it did, but 3 seconds too late so by then everything downstream was bailing out.
Thank you for any help!
Answering my own question which hopefully will help some people in the future. This is based on the excellent advice of Avital Oliver and David Glasser to have a look at Mike Bannister's meteor-async.md. You can read it here: https://gist.github.com/possibilities/3443021
Accounts.onCreateUser(function(options,user){
_.extend(user,{
balance: getBalance(),
});
return user;
});
function getBalance() {
var Future = Npm.require("fibers/future");
var fut = new Future();
BANK.getBalance(function(err, bal) {
if (err) return console.log(err);
fut.return(bal);
});
return fut.wait();
}
I believe there's an even better way to handle this, which is directly by wrapping the BANK API in Futures within the npm package itself, as per this example (from Avital Oliver): https://github.com/avital/meteor-xml2js-npm-demo/blob/master/xml2js-demo.js
I hope it helps!
Use this.unblock() on server side code.
From Meteor 1.0 documentation: "Allow subsequent method from this client to begin running in a new fiber.On the server, methods from a given client run one at a time. The N+1th invocation from a client won't start until the Nth invocation returns. However, you can change this by calling this.unblock. This will allow the N+1th invocation to start running in a new fiber."
Meteor.methods({checkTwitter: function (userId) {
check(userId, String);
this.unblock();
try {
var result = HTTP.call("GET", "http://api.twitter.com/xyz",
{params: {user: userId}});
return true;
} catch (e) {
// Got a network error, time-out or HTTP error in the 400 or 500 range.
return false;
}
}});
method calls use the sync style (see 'sync call' here http://docs.meteor.com/#meteor_call) on the server side, which is where this create user method runs - you should be able to do something like
Accounts.onCreateUser(function(options, user) {
user.balance = Meteor.call('getBankBalance', params);
return user;
});
Thanks yo so much that's work, This solution its better for Meteor projects, because Fibers module installed by default. mrt add npm has a method for this too -> Meteor.sync . For any nodeJS projects there is a other module based on Fibers, its name is Fibrous
Reference:https://github.com/goodeggs/fibrous
I am just starting to build a new Meteor app. The only thing I have done so far is add one Collection. It will start, run fine for about 5 minutes, and then give me the error message "Failed to receive keepalive! Exiting."
What is failing to receive keepalive from what? I assume this has something to do with Mongo since that is the only thing I have added. Googling the error message turns up nothing except Meteor sites that are just showing this error message instead of the their app.
My MongoDB collection already had data in it that was not created by Meteor and it is over 4GB if that makes any difference.
This is the complete app.
pitches_sum = new Meteor.Collection( 'pitches_sum' );
if (Meteor.is_client) {
Template.hello.greeting = function () {
return "Welcome to my site.";
};
Template.hello.events = {
'click input' : function () {
// template data, if any, is available in 'this'
if (typeof console !== 'undefined')
console.log("You pressed the button");
}
};
}
if (Meteor.is_server) {
Meteor.startup(function () {
console.log( '**asdf**' );
});
}
If I comment out the pitches_sum = new Meteor.Collection( 'pitches_sum' ); line, then I don't think I will get the error message any more.
This was being caused by my large data set and autopublish. Since autopublish was on, Meteor was trying to send the whole 4GB collection down to the client. Trying to process all the data prevented the client from responding to the server's keep alive pings. Or something to that effect.
Removing autopublish with meteor remove autopublish and then writing my own publish and subscribe functions fixed the problem.