I have chat app, and I load last 5 messages in it , do it like this
{{#if haseMoreMessages}}
<div class="loadmore text-center" id="incLimit">Load More</div>
{{/if}}
{{#each messages}}
{{> message}}
{{/each}}
messages: function(){
var messages = Messages.find({},{sort:{createdAt:1}}); // I can remove {sort:{createdAt:1}} and all ok, nut it's not fit
return messages;
},
haseMoreMessages:function(){
if (Session.get('messageLimit') > Messages.find().count()) return false;
return true;
}
Messages.find({room: Rooms.findOne({users : { $in : [this.userId]}})._id},{ sort: { createdAt: -1 } , limit : limitM});
So when I write new message, for 100ms or more it shows on the top , and after 200ms or more it shows on the bottom, example:
-mes1
-mes2
-mes3
I write mes4
-mes4
-mes1
-mes2
-mes3
And after some ms
-mes1
-mes2
-mes3
-mes4
When I remove {sort:{createdAt:1}} from var messages = Messages.find({},{sort:{createdAt:1}}) all shows ok, whithout delay, BUT when I click show more button all old messages show on bottom, but they must shows on TOP of the page. Thats why I need {sort:{createdAt:1}}
So any idea what can I do ?
According to your comments, the insert happens on the client, but the createdAt field is only populated on the server. Meteor hence uses the local database without the createdAt field at first to show the result of the insert right away. Then, after a round-trip to the server and update to the query, the sorting happens as expected.
Two options: Do the insert completely on the server, or attach the createdAt field already on the client.
Related
Sorry kind of new to the Meteor framework!
I Subscribed to two Publish functions. Even if both publish functions target the same Collection, they both have different functions, that I would like to display in one template. How do I achieve this. I have done allot of research but there doesn't seem to be sufficient information on how to achieve.
Following are the two publish functions in code that I subscribe to:
.server/main.js:
Meteor.publish('MerchantTrending', function (categoryMan){
var currentUser = this.userId;
return buyList.find({ who:"Merchant", ownerId:currentUser, itemCategory: { $in: categoryMan } }, {skip: 0, limit: 3});
});
.server/main.js:
Meteor.publish('myTopViews', function (){
var currentUser = this.userId;
return buyList.find({ newArrivalsExpiryDate : {'$lte': new Date()}}, {ownerId:currentUser }, {skip: 0, limit: 3});
});
Following is the subscription function in code
.client/main.js:
Router.route('/MerchantLandingPage', {
subscriptions: function(){
var categoryMan = Session.get('category');
return Meteor.subscribe('MerchantTrending', categoryMan, 'merchantTopViews')
}
});
Now the helper function in code:
Template.MerchantLandingPage.helpers({
'top3Trending' : function () {
return buyList.find({}).fetch();
},
'myTopViews' : function () {
return buyList.find({}).fetch();
}
});
And now the template in code:
<template name="MerchantLandingPage">
##### *** Top three trending items *** ########
{{#each top3Trending}}
ItemName:: <b>{{itemName}}</b> <br>
Item Category:: <b>{{itemCategory}}</b> <br>
Discription:: <b>{{descriptions}}</b> <br>
Image:: {{this.photo._id}} <br>
Date Created:: {{createdDate}} <br>
{{/each}}
<br><br>
############ *** My top Views *** #############
{{#each myTopViews}}
ItemName:: <b>{{itemName}}</b> <br>
Item Category:: <b>{{itemCategory}}</b> <br>
Discription:: <b>{{descriptions}}</b> <br>
Image:: {{this.photo._id}} <br>
Date Created:: {{createdDate}} <br>
{{/each}}
</template>
Both {{#each myTopViews}} and {{#each top3Trending}} successfully display but not correctly. When the variable categoryMan in
Meteor.subscribe('MerchantTrending', categoryMan, 'merchantTopViews')
changes value, it affects both both the outcome of both {{#each myTopViews}} and {{#each top3Trending}}, when its only supposed to affect {{#each top3Trending}}.
How can I get the subscriptions to NOT have an affect on both {{#each myTopViews}} and {{#each top3Trending}}, but only {{#each myTopViews}} in my template?
Thanks for the help!
Welcome to Meteor!
The solution is straight forward once you understand that:
Subscription is just a stream of your DB documents from server into your client's MiniMongoDB. So your 2 subscriptions (it is perfectly fine having several subs on the same Collection) just fill in your client's buyList local collection.
Use of Collections client side is generally independent from how you subscribe the data. So you should simply use a similar selector and possibly options in your top3Trending and myTopViews helpers as you have done for your publication server side (not the same between the 2 helpers, obviously).
As a side note, you do not even need to fetch() the Collection cursor returned by find(), Blaze knows how to handle it directly.
I see a few problems with your code, first of all - your second subscription isn't going to work because your query is wrong:
Meteor.publish('myTopViews', function (){
var currentUser = this.userId;
return buyList.find(
{ ownerId:currentUser, newArrivalsExpiryDate : {'$lte': new Date()}},
{skip: 0, limit: 3}
);
});
You had ownerId: currentUser wrapped in curly braces, it is fixed above.
The way publications/subscriptions work is, if you have two publications sending different data, the template doesn't 'know' the data is coming from two different subscriptions. It will just have access to all of the data being sent by all subscriptions.
For that reason, your two helpers top3trending and myTopViews are returning exactly the same thing. You can delete one of them!
You should move your subscriptions out of the router and in to the Template itself. Here's an article that will help you with that!
There is a package percolate:find-from-publication that permits to filter the data from publications.
I'm struggling with an issue that I will explain giving a simple demo.
There's following very simple document in People Collection.
{
"_id" : "vxmLRndHgNocZouJg",
"fname" : "John" ,
"nicks" : [ "Johnny" , "Jo"]
}
Now let's consider following templates. Basically I display username and a list of nicknames with input field for adding more nicknames.
<head>
<title>test</title>
</head>
<body>
{{> name}}<br/>
{{> nicks}}
</body>
<template name="name">
<input type="text" value="{{fname}}"/>
</template>
<template name="nicks">
{{#each nicks}}
<div>{{this}}</div>
{{else}}
no nicks yet
{{/each}}
<input type="text" name="nicks"/>
<input type="submit"/>
</template>
My client javascript code is as follows:
Template.name.fname = function() {
return People.findOne({"fname" : "John"},{
transform : function(doc) {
return doc.fname;
}
});
}
Template.name.rendered = function() {
console.log('Template "name" rendered!');
}
Template.nicks.nicks = function() {
var john = People.findOne({"fname" : "John"});
if(john) return john.nicks;
}
Template.nicks.events({
'click input[type="submit"]' : function () {
var johnId = People.findOne({"fname" : "John"})._id; // demo code
People.update(johnId,{
$addToSet : {
nicks : $('input[name="nicks"]').val()
}
})
}
});
My problem is that after adding nickname (update of nicks field in a document) template name is re-rendered (I know because I console.log it). When I query People collection to provide data for name template I use transform option so changes in nicks field shouldn't have impact on name template.
Meteor docs supports this:
Cursors are a reactive data source. The first time you retrieve a cursor's documents with fetch, map, or forEach inside a reactive computation (eg, a template or autorun), Meteor will register a dependency on the underlying data. Any change to the collection that changes the documents in a cursor will trigger a recomputation.
Why template name is re-rendered then?
The template is re-rendered because you change the People collection.
When you alter the People collection, Meteor automatically assumes that everything that it provides data to needs to be recalculated. (Which your name template does via Template.name.fname.
Even though you transform the output of the cursor, the People collection has changed in some way. The query is done before the transform is used, in other words, its not the transform that is looked at but the whole collection.
Meteor thinks that perhaps your document with {'fname':'John'} may have some other field that might have changed and it needs to requery it to check (which the nicks field has been altered). The transform is then applied after the requery.
Your HTML might not actually change at this point, only if the cursor returns something different will the html be changed.
If it becomes an issue in any scenario (i.e forms being cleared or DOM being changed when it shouldn't be) you can use the {{#isolate}} {{/isolate}} blocks to ensure that only everything inside them is re-rendered and nothing outside.
I have a collection published on the server and auto-subscribed on the client. I'd like to set the 'selected' item on the session and have the template update to display only the selected item, but it seems this can only be done with a roundtrip to the server (which is totally unnecessary).
Common:
var Missions = new Meteor.Collection('missions');
Client:
Template.missionList.missions = function() {
var currMission = Session.get('selectedMission');
var searchMission = {};
if(currMission)
{
searchMission['_id'] = currMission;
}
return Missions.find(searchMission);
};
Template.missionList.events({
'click div.mission': function (e, t) {
Session.set('selectedMission',
this._id == Session.get('selectedMission') ? null : this._id
);
}
});
Template.mission.isSelected = function() {
return this._id == Session.get('selectedMission');
};
Meteor.autosubscribe(function () {
Meteor.subscribe("missions");
});
Server:
Meteor.publish('missions', function() {
// there are really some filters here, but removed for simplicity
return Missions.find();
});
Template:
<template name="missionList">
<div class="missionList">
{{#each missions}}
{{> mission}}
{{/each}}
</div>
</template>
<template name="mission">
<div class="mission{{#if isSelected}} selected{{/if}}">details</div>
</template>
My requirement is for the Missions.find() in Template.missionList.missions to filter the client-side cached results, rather than to re-request from the server, but I can't seem to find a flag or settings to allow me to tell minimongo to only use the currently available data.
I'm also not entirely sure if this is what I should be doing, I started out just using jQuery to hide the non-selected missions but getting my head round Meteor and it seems a natural fit to use the data and reactivity to drive selection/local-filtering.
Is there any way the roundtrip can be avoided or am I just using it wrong?
By setting up a publish / subscribe relationship, you are creating a simplified form of database replication. Minimongo will have a copy of the data locally and execute the find() locally without a server roundtrip. If you are seeing network activity or calls to the server code, it is because meteor is regularly working behind the scenes to keep the subscription in sync with the server, not for your specific find.
This also means you have to wary of sending too much data to the client, so your server side publish function may want to filter by the specific fields needed by client, in addition to existing your selection criteria.
I've got a meteor collection on the client side
Friends = new Meteor.Collection("Friends");
Meteor.subscribe("Friends");
I have a user authenticate with facebook and I want to grab a list of their friends:
FB.api("/me/friends? auth_token="+response.authResponse.accessToken,
function(response){
for (i = 0; i<response.data.length;i++){
Friends.insert(response.data[i]);
}
);
I have a function to get that list:
Template.Friends.all_friends = function(){
return Friends.find();
}
I have a template that would like to display all the friends on the screen:
<template name="Friends">
{{#each all_friends}}
<div id="{{id}}" class="friend">
<img src="http://graph.facebook.com/{{id}}/picture" />
{{name}}
</div>
{{/each}}
</template>
What appears to be happening on the page is that all the friends DO flash up on the screen for a split second then immediately the screen flashes back to blank.
In the javascript console the message appears once per friend I have (yes, it is more than zero, thanks for asking)
insert failed: 404 -- Method not found
So! What have I missed? Anyone?
You need that Collection declaration on both the client and the server.
// common code, do not put under /client or inside Meteor.is_client test
Friends = new Meteor.Collection("Friends");
If you want to use Collection only on Client side and you don't need to save that data to server you can declare your collection in "client" folder or in .isClient() function by passing null to the constructor like this:
if(Meteor.isClient()){
// Some other code
...
onlyClientCollection = new Meteor.Collection(null);
// Some other code
...
}
Meteor promises reactive updates, so that views are auto-updated when data changes. The included leaderboard example demonstrates this. It runs fine when I test it: data is updated across several browsertabs in different browsers, as expected.
All set and go, I started coding with meteor and progress was being made, but when I tested for reactive updates across browertabs, I noticed that only after a short while the updates across tabs stopped.
I boiled down the problem to the following code, based on a new empty meteor project:
updatebug.html
<head>
<title>updatebug</title>
</head>
<body>
{{> form}}
</body>
<template name="form">
<form onsubmit="return false;">
{{#each items}}
{{> form_item }}
{{/each}}
</form>
</template>
<template name="form_item">
<div>
<label>{{name}}
<input type="text" name="{{name}}" value="{{value}}">
</label>
</div>
</template>
updatebug.js:
Items = new Meteor.Collection("items");
if (Meteor.is_client) {
Template.form.items = function () {
return Items.find();
};
Template.form_item.events = {
'blur input': function(e) {
var newValue = $(e.target).val();
console.log('update', this.name, this.value, newValue);
Items.update({_id: this._id}, {$set: {value: newValue}});
},
};
}
if (Meteor.is_server) {
Meteor.startup(function () {
if (Items.find().count() === 0) {
Items.insert({name: 'item1', value: 'something'});
}
});
}
Run in multiple browsertabs, start changing the value of the input in one tab. The other tabs will reflect the change. Goto the next tab and change the value. Repeat a couple of times.
After a while, no more updates are received by any other tabs. It seems that once a tab has changed the value, it does not receive/show any more updates.
Differences compared to the leaderboard example (since it's very similar):
The leaderboard uses no form controls
The leaderboard example does an increment operation on update, not a set
I am about to file a bug report, but want to be sure I am not doing anything stupid here, or missing an essential part of the Meteor Collection mechanics (yes, autopublish package is installed).
The issue here is input element preservation. Meteor will preserve the input state of any form field with an id or name attribute across a template redraw. The redraw is preserving the old text in your form element, because you wouldn't want to interrupt another user typing in the same field. If you remove the name attribute from the text box, each tab will update on blur.
In fact, I'm not sure why the first update works in your example. That may actually be the bug!
You can see it's not a data problem by opening the console in each browser. On each blur event you will get an updated document in every open tab. (Type Items.find().fetch())