This code in Meteor.
Template.message.helpers({
message: function() {
var message = Messages.findOne({ _id: FlowRouter.getParam('messageId')});
var curTime = new Date();
console.log(message.createdAt.getHours());
return message;
}
});
Gives me this exception:
Exception in template helper: message#http://localhost:3000/app/app.js?hash=0da6be4507e857f169e0cecb7b0874729eae4663:239:13
bindDataContext/<#http://localhost:3000/packages/blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:3051:14
Blaze._wrapCatchingExceptions/<#http://localhost:3000/packages/blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:1715:14
wrapHelper/</<#http://localhost:3000/packages/blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:3103:14
Template._withTemplateInstanceFunc#http://localhost:3000/packages/blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:3744:12
wrapHelper/<#http://localhost:3000/packages/blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:3102:12
Spacebars.dot#http://localhost:3000/packages/spacebars.js?hash=ebf9381e7fc625d41acb0df14995b7614360858a:234:13
template.message.js/Template.message</<#http://localhost:3000/app/app.js?hash=0da6be4507e857f169e0cecb7b0874729eae4663:85:31
doRender#http://localhost:3000/packages/blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:2086:20
viewAutorun/</<#http://localhost:3000/packages/blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:1934:18
Template._withTemplateInstanceFunc#http://localhost:3000/packages/blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:3744:12
viewAutorun/<#http://localhost:3000/packages/blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:1932:14
Blaze._withCurrentView#http://localhost:3000/packages/blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:2271:12
viewAutorun#http://localhost:3000/packages/blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:1931:12
Tracker.Computation.prototype._compute#http://localhost:3000/packages/tracker.js?hash=997515fa2d5b0530ba07741da556c4b36963ef3b:339:5
Tracker.Computation#http://localhost:3000/packages/tracker.js?hash=997515fa2d5b0530ba07741da556c4b36963ef3b:229:5
Tracker.autorun#http://localhost:3000/packages/tracker.js?hash=997515fa2d5b0530ba07741da556c4b36963ef3b:613:11
Blaze.View.prototype.autorun#http://localhost:3000/packages/blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:1944:14
Blaze._materializeView/<#http://localhost:3000/packages/blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:2080:5
Tracker.nonreactive#http://localhost:3000/packages/tracker.js?hash=997515fa2d5b0530ba07741da556c4b36963ef3b:640:12
Blaze._materializeView#http://localhost:3000/packages/blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:2079:3
materializeDOMInner#http://localhost:3000/packages/blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:1532:9
Blaze._materializeDOM#http://localhost:3000/packages/blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:1474:3
Blaze._materializeDOM#http://localhost:3000/packages/blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:1483:7
Blaze._materializeView/<#http://localhost:3000/packages/blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:2113:25
Tracker.nonreactive#http://localhost:3000/packages/tracker.js?hash=997515fa2d5b0530ba07741da556c4b36963ef3b:640:12
Blaze._materializeView#http://localhost:3000/packages/blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:2079:3
Blaze.render#http://localhost:3000/packages/blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:2370:3
_render#http://localhost:3000/packages/kadira_blaze-layout.js?hash=dbd1396d04e62378fc8792cdef18869a1108cedd:204:5
render/</<#http://localhost:3000/packages/kadira_blaze-layout.js?hash=dbd1396d04e62378fc8792cdef18869a1108cedd:77:9
withValue#http://localhost:3000/packages/meteor.js?hash=27829e936d09beae3149ecfbf3332c42ccb1596f:1077:17
withoutInvocation/<#http://localhost:3000/packages/meteor.js?hash=27829e936d09beae3149ecfbf3332c42ccb1596f:464:26
Meteor.bindEnvironment/<#http://localhost:3000/packages/meteor.js?hash=27829e936d09beae3149ecfbf3332c42ccb1596f:1105:17
onGlobalMessage#http://localhost:3000/packages/meteor.js?hash=27829e936d09beae3149ecfbf3332c42ccb1596f:401:11
meteor.js:930:11
It actually gets printed twice but I felt it was large and unnecessary to show here twice.
And line 239 of app.js looks like this (it's line 7 here).
Template.message.helpers({ // 34
message: function () { // 35
var message = Messages.findOne({ // 36
_id: FlowRouter.getParam('messageId') // 36
}); // 36
var curTime = new Date(); // 37
console.log(message.createdAt.getHours()); // 38
return message; // 40
} // 41
But the hours still get printed to the console.
My goal is to use the createdAt date to subtract it from a current Date object and get a time delta. But I never got that far because whatever I try to do with message.createdAt produces this strange exception.
If I just do console.log(message.createdAt) I see TWO ISO formatted dates in the browser console, and two exceptions.
If I try something else like message.createdAt.getTime() I get one Unix timestamp.
What the heck is going on?
I was actually able to subtract the date and use it as intended, but the exceptions kept showing up in spite of the code working.
The reason you are seeing the errors is because the helper is being run, attempting to fetch data from a subscription that isn't ready yet. It eventually works because once the subscription is ready, the helper is re-run, and all is well. To fix this, simply wrap you helper with Template.subscriptionsReady:
<template name="message">
{{#if Template.subscriptionsReady}}
{{message}}
{{else}}
{{> SomeLoadingTemplate}}
{{/if}
</template>
NOTE: This template will execute the message helper only when all
template-level subscriptions are "Ready" and instead will show a
loader template executing the else part.
Regarding a comment on the question, to wrap your logic with if (date) {...}: this will get rid of the error, but isn't really solving the problem. The helper is still being run multiple times when it doesn't have to. It seems to be a bit of code smell to hide potential errors like this.
you have a template, a helper, and a local variable all called "message". even if that's not the source of your error, i'd gently suggest making them all different names.
Related
I have a Meteor Helper that does a GET request and am supposed to get response back and pass it back to the Template, but its now showing up the front end. When I log it to console, it shows the value corerctly, for the life of mine I can't get this to output to the actual template.
Here is my helper:
UI.registerHelper('getDistance', function(formatted_address) {
HTTP.call( 'GET', 'https://maps.googleapis.com/maps/api/distancematrix/json? units=imperial&origins=Washington,DC&destinations='+formatted_address+'&key=MYKEY', {}, function( error, response ) {
if ( error ) {
console.log( error );
} else {
var distanceMiles = response.data.rows[0].elements[0].distance.text;
console.log(response.data.rows[0].elements[0].distance.text);
return distanceMiles;
}
});
});
In my template I pass have the following:
{{getDistance formatted_address}}
Again, this works fine and shows exactly what I need in the console, but not in the template.
Any ideas what I'm doing wrong?
I posted an article on TMC recently that you may find useful for such a pattern. In that article the problem involves executing an expensive function for each item in a list. As others have pointed out, doing asynchronous calls in a helper is not good practice.
In your case, make a local collection called Distances. If you wish, you can use your document _id to align it with your collection.
const Distances = new Mongo.collection(); // only declare this on the client
Then setup a function that either lazily computes the distance or returns it immediately if it's already been computed:
function lazyDistance(formatted_address){
let doc = Distances.findOne({ formatted_address: formatted_address });
if ( doc ){
return doc.distanceMiles;
} else {
let url = 'https://maps.googleapis.com/maps/api/distancematrix/json';
url += '?units=imperial&origins=Washington,DC&key=MYKEY&destinations=';
url += formatted_address;
HTTP.call('GET',url,{},(error,response )=>{
if ( error ) {
console.log( error );
} else {
Distances.insert({
formatted_address: formatted_address,
distanceMiles: response.data.rows[0].elements[0].distance.text
});
}
});
}
});
Now you can have a helper that just returns a cached value from that local collection:
UI.registerHelper('getDistance',formatted_address=>{
return lazyDistance(formatted_address);
});
You could also do this based on an _id instead of an address string of course. There's a tacit assumption above that formatted_address is unique.
It's Meteor's reactivity that really makes this work. The first time the helper is called the distance will be null but as it gets computed asynchronously the helper will automagically update the value.
best practice is not to do an async call in a helper. think of the #each and the helper as a way for the view to simply show the results of a prior calculation, not to get started on doing the calculation. remember that a helper might be called multiple times for a single item.
instead, in the onCreated() of your template, start the work of getting the data you need and doing your calculations. store those results in a reactive var, or reactive array. then your helper should do nothing more than look up the previously calculated results. further, should that helper be called more times than you expect, you don't have to worry about all those additional async calls being made.
The result does not show up because HTTP.call is an async function.
Use a reactiveVar in your case.
Depending on how is the formated_address param updated you can trigger the getDistance with a tracker autorun.
Regs
Yann
I am getting a curious error in a template helper and I was hoping someone could lay eyes on it with me. Basically the error I'm getting in the console of the client is that the getArena().height is undefined. However, console.log(getArena().height) returns the correct property value. It appears to be a timing issue causing me to get the error, but my application is actually working. What can I do to alleviate this console error?
//My template helper function
yGrids: function() {
console.log(getArena);
console.log(getArena().height);
var yArray = [];
for (var i=0;i<(getArena().height);i++){
yArray.push({});
}
return yArray;
},
// The console results
function getArena() { // 50
return Arenas.findOne(Session.get('arena_id')); …
Exception in template helper: TypeError: Cannot read property 'height' of undefined
at Object.yGrids (http://localhost:3000/app/app.js?hash=c17abf51d6af6541e868fa3fd0b26e34eea2df28:94:35)
at http://localhost:3000/packages/blaze.js?hash=ef41aed769a8945fc99ac4954e8c9ec157a88cea:2994:16
at http://localhost:3000/packages/blaze.js?hash=ef41aed769a8945fc99ac4954e8c9ec157a88cea:1653:16
at http://localhost:3000/packages/blaze.js?hash=ef41aed769a8945fc99ac4954e8c9ec157a88cea:3046:66
at Function.Template._withTemplateInstanceFunc (http://localhost:3000/packages/blaze.js?hash=ef41aed769a8945fc99ac4954e8c9ec157a88cea:3687:12)
at http://localhost:3000/packages/blaze.js?hash=ef41aed769a8945fc99ac4954e8c9ec157a88cea:3045:27
at Object.Spacebars.call (http://localhost:3000/packages/spacebars.js?hash=65db8b6a8e3fca189b416de702967b1cb83d57d5:172:18)
at http://localhost:3000/app/app.js?hash=c17abf51d6af6541e868fa3fd0b26e34eea2df28:24:22
at .<anonymous> (http://localhost:3000/packages/blaze.js?hash=ef41aed769a8945fc99ac4954e8c9ec157a88cea:2754:17)
at http://localhost:3000/packages/blaze.js?hash=ef41aed769a8945fc99ac4954e8c9ec157a88cea:1875:20
function getArena() { // 50
return Arenas.findOne(Session.get('arena_id')); …
2
This is a very common issue in Meteor helpers when referring to a collection which may not yet have been loaded via a subscription. In general you want to show a loading template instead of your actual layout until your subscription is ready. Or (less elegant) you can defend yourself with:
var arena = getArena();
var height = arena && arena.height;
Whatever getArena() returns you ought to store it in the reactive variable by setting the reactive variable and you can access the reactive var in helper by get() method
In Meteor, how do I properly return a value from a property (in this case response) from a collection so that I can send it to a data propert? I have tried the following function:
Responses: function(answer) {
return Responses.findOne({answerId: answer.hash.answer});
}
Which I call in the spacebars template as:
data-selected="{{Responses answer=_id}}
When I look at the HTML it says that the data-selected="[object object]" which is not super surprising but I can't figure out how to return just the response value from the match. I can add .response onto the end and it works but gives an expected 'undefined' error I know that it is not reactive. I have seen people use wrapasync but that was for methods, not subscriptions. I should note that there are several responses, so the code would have to be suitable inside a #for loop of answers which the responses variable is keeping track of the input from each user separately.
Thanks!
I'm not sure about data-selected="{{Responses answer=_id}}". Since you're already inside a for loop your html code can simply look like this:
data-selected="{{Responses}}"
Inside your helper function you can then say:
var myResponse = Responses.findOne({answerId: this._id}).response;
if (myResponse != null){
return myResponse;
else {
return "";
}
When the page is still loading and the data is not yet available, myResponse is still null, so the helper returns the empty string "". Shortly thereafter the data becomes available and your data gets returned, without any error in your console.
I have a fairly simple Meteor application.
I tried to send newsletter to about 3000 users in my list and things went wrong. A random set of users got multiple emails (between 41 to 1).
I shut the server down as soon I noticed this behavior. around 1300 emails were sent to 210 users. I am trying to figure out what happened and why.
Here is the code flow:
SendNow (client clode) --> SendNow (server method) --> populateQue (server function) --> processQue(server function) --> sendEmails (server method)
Client side code :
'click .sendNow': function(){
/* code that forms data object */
Meteor.call('sendNow',data);
}
Server code : server/method.js
Meteor.methods({
'sendNow' : function(data){
if(userWithPermission()){
var done = populateQue(data);
if(done)
processQue();
return {'method':'sendNow','status':'ok'}
},
'sendEmails': function(data){
this.unblock();
var result = Mandrill.messages('send', data);// using external library
SentEmails.insert(data);//Save sent emails in a collection
}
});
Function on server : server/utils.js
populateQue = function(data) {
/* code to get all users in to array */
MessageQue.remove();//Remove all documents from the Que
for (var i=0; i<users.length; i++) {
MessageQue.insert({userId: users[i]._id});
}
return true;
}
processQue = function(){
var messageQue = MessageQue.find({}).fetch();
for(i=0; i < messageQue.length; i++){
Meteor.call('sendEmails', data);
MessageQue.remove({_id: messageQue[i]._id});//Remove sent emails from the Que
}
}
My first hunch was MessageQue got messed up as I am removing items while processQue is using it but i was wrong. I am unable to simulate this behavior again after few tests
Test 1 : replaced Mandrill.message('send',data) with Meteor._sleepForMs(1000); - Only one email/person was seen in SentEmails collection.
Test 2 : Put Mandrill in Test mode (had to use different API key) and re ran the code with couple of log statements. - Only one email/person was seen in SentEMails and also in Mandrill's interface.
It's definitely not external library. its somewhere in my code or in the way I understood meteor to work.
Only one thing I noticed is an error occurred while accessing SentEmails collection through another view code. I have a view that displays SentEmails on the client with date as filter.
Here is the error :
Exception from sub sentEmailDocs id 9LTq6mMD4xNcre4YX Error:
Exception while polling query
{
"collectionName":"sent_emails",
"selector":{"date":{"$gt":"2015-07-09T05:00:00.000Z","$lt":"2015-07-11T05:00:00.000Z"}},
"options":{"transform":null,"sort":{"date":-1}}
}:
Runner error: Overflow sort stage buffered data usage of 33565660 bytes exceeds internal limit of 33554432 bytes
Is this the smoking gun? Would this have caused the random behavior?
I have put couple checks to prevent this from happening but I am puzzled on what might have caused and why? I will be happy to provide more information. Thanks in advance to who ever is willing to spend few mins on this.
Shot in the dark here, but the remove method takes an object, otherwise it doesn't do anything. MessageQue.remove() probably didn't clear the queue. You need MessageQue.remove({}). Test the theory by doing an if (MessageQue.find().count() > 0)... after the remove.
If you're set on having a separate collection for the queue, and I'm not saying that's a bad thing, I'd set the _id to be the userId. That way you can't possibly send someone the same message twice.
I'm doing a simple insert into a meteor collection that appears work, but leaves the collection empty.
The collection is defined properly on the server:
Meteor.publish("comments", function () {
return Comments.find();
});
Subscribed to properly in the client.js:
Meteor.subscribe("commments");
And set up properly on the model.js:
Comments = new Meteor.Collection("comments");
The insert code is as follows:
Meteor.methods({
addComment: function (options) {
check(options.post_id, String);
check(options.comment, NonEmptyString);
if (! this.userId)
throw new Meteor.Error(403, "You must be logged in to comment.");
if (options.comment.length > 1000)
throw new Meteor.Error(413, "Comment is too long");
var post = Posts.findOne(options.post_id);
if (! post)
throw new Meteor.Error(404, "No such post");
// add new comment
var timestamp = (new Date()).getTime();
console.log('Comment: ' + options.comment);
console.log('Post: ' + options.post_id);
console.log('UserId: ' + this.userId);
var saved = Comments.insert({
owner: this.userId,
post_id: options.post_id,
timestamp: timestamp,
text: options.comment});
console.log('Saved: ' + saved);
}
});
Once the insert is called, the console prints out the following:
Comment: Something
Post: xRjqaBBEMa6qjGnDm
UserId: SCz9e6zrpcQrKXYWX
Saved: FCxww9GsrDsjFQAGF
> Comments.find().count()
0
I have inserts into several other collections that work just fine (Posts being one of them as you can see the post ID in the code). In the docs ist said that if the insert errors out it will print to the console, but as you can see it appears to be working, yet is actually empty.
Thanks.
UPDATE: I did find that the data is being put into the database, but for some reason is not showing up. I'm not sure why the data is not being published properly since there are no filters on the find().
I'm not sure exactly what's wrong, but there's a few things to check here.
• First, this:
Meteor.publish("comments", function () {
return Comments.find();
});
directs the server to publish the Collection, but doesn't actually establish the collection server side.
You should have Comments = new Meteor.Collection("comments"); available on both the client and the server. I tend to put in a file called model.js like the examples tend to do.
• Second possibility, you don't have a subscribe function shown above, such as Meteor.subscribe("comments"); If you don't have a subscribe function, your client isn't going to know about it, even though it does exist in the collection.
You can test this theory by typing meteor mongo in the shell (with your Meteor app running), and db.comments.find() to see if your comments are actually in the database but not subscribed to.
Verify you do not have an error in your client code. With Meteor.call, if you do not initialize a variable you can have an error condition that will block reactive updating in your templates but continue to write fine to your console just before hand.
I've made that mistake which I talk about here:
http://doctormehmet.blogspot.com/2013/07/revoltdc-hackathon-20130622-iteration-3.html
Specifically I had something like
Template.mytemplate.helpers({
somevar: function({
if (some_session_var_set_by_a_call.party){
//do something
}
}
Now the somevar function gets called on render, before the Meteor.call returns. Therefore the variable some_session_var_set_by_a_call isn't set yet. The whole thing stops client side on the undefined error.