I am trying to build an Admin panel that will connect to another apps database and have the ability to change the data stored there.
var remote = DDP.connect('http://localhost:3000/');
var ServerAItems = new Mongo.Collection('items', { connection: remote });
Meteor.startup(function() {
console.log(remote);
remote.subscribe('smallBatchProducts', function(item){
});
console.log(ServerAItems.find().count(), 'test');
});
ServerAItems.find().count(); //returns 0
I have looked at Meteor: No docs from remote collection in template helper when connecting two apps via DDP and Connect two Meteor applications using DDP , but still can't figure out how to interact with the data and give the client access to it. The publication on localhost:3000 is smallBatchProducts.
I'm planning to have Flow Router handle the routing. Thanks
You should probably just put your console.log into the onReady callback.
Meteor.startup(function() {
remote.subscribe('smallBatchProducts', {
onReady: function(){
console.log(ServerAItems.find().count(), 'test');
},
onError: function(err) {}
});
});
Related
I have two meteor app using database for frontend and backend. Due to some bulk operation. frontend app calls backend server. works fine in many methods. in few method I should check authentication.
frontend
let remote = DDP.connect(<url>);
remote.call('methodName',argument, function(err,res){
});
backend
Meteor.methods({
methodName: function(argument) {
Meteor.user() // null value
}
});
How secure suppose I send userId as parameter?
You have to login in a way or another.
You can do something like this:
var remote = DDP.connect(url);
result = remote.call('login', {
user: user,
password: {digest: SHA256(password), algorithm: 'sha-256' }
});
Sources:
https://forums.meteor.com/t/different-interfaces-based-on-devices/264
You can get user data on server-side by:
var userData = Meteor.users.findOne(Meteor.userId());
I want to create a meteor application that connect meteor server to another tcp server,
that is meteor server is client side and another tcp server is server side.
1.It like WebSocket of browser ,but I want use it on meteor server ,not on meteor client .
WebSocket using like :
var tcpServer = "ws://some.tcpServer.org/";
socket = new WebSocket(tcpServer,options);
socket.onopen = function(evt) { onOpen(evt) };
socket.onclose = function(evt) { onClose(evt) };
socket.onmessage = function(evt) { onMessage(evt) };
socket.onerror = function(evt) { onError(evt) };
2.Maybe as follow :
if (Meteor.isServer) {
Meteor.startup(function () {
var tcpServer = "ws://some.tcpServer.org/";
socket = new socketClient(tcpServer,options);
socket.onopen = function(evt) { onOpen(evt) };
socket.onclose = function(evt) { onClose(evt) };
socket.onmessage = function(evt) { onMessage(evt) };
socket.onerror = function(evt) { onError(evt) };
})
}
3.Or ...
var net = Npm.require('net');
net.createServer(function(socket){...} is for server side , not fit for my idea.
Maybe like net.createClient(function(tcpServer, options ){...} , but no this method.
I had been looking around but i do not see a method for Meteor. Can anyone give any pointers for me to start?
Thank a lot !
There are several problems with what you described.
WebSocket, which works over HTTP, and TCP are completely different protocols. You will not be able to open a WebSocket connection to a TCP server.
To have the Meteor server communicate with another server over TCP, you'll want to use Node's net API. To use this with Meteor, you'll need to use async callbacks in a way that is compatible with Fibers; see this blog post for an overview and https://stackoverflow.com/a/21542356/586086.
Here you have link to working plugin:
websocketify on atmosphere.com
I am building a realtime game with Meteor streams. I need to update only one client - send a room ID from server. Users are not logged in so Meteor.userId() is null and therefore I can't use this: http://arunoda.github.io/meteor-streams/communication-patterns.html#streaming_private_page
There is only one URL (homepage) where all things happen. So I don't use any URL parameters for room. Everything is on the server.
I have tried to use Meteor.uuid() instead of Meteor.userId() but uuid is changed after each emit (which is strange).
In socket.io I would do this:
//clients is an array of connected socket ids
var clientIndex = clients.indexOf(socket.id);
io.sockets.socket(clients[clientIndex]).emit('message', 'hi client');
Is there any way to do this in Meteor streams or Meteor itself?
Well, this can be easily done if you decided to use database, but I guess it is not the best option if you have a large number of clients.
So another way to achieve this - without database - is to make a good use of the Meteor's publish/subscribe mechanism. Basically the way it could work is the following:
1. client asks server for a communication token (use Meteor.methods)
2. client subscribes to some (abstract) data set using that token
3. server publishes the required data based on the received token
So you will need to define a method - say getToken - on the server that generates tokens for new users (since you don't want to use accounts). This could be something more or less like this:
var clients = {}
Meteor.methods({
getToken: function () {
var token;
do {
token = Random.id();
} while (clients[token]);
clients[token] = {
dependency: new Deps.Dependency(),
messages: [],
};
return token;
},
});
A new client will need to ask for token and subscribe to the data stream:
Meteor.startup(function () {
Meteor.call('getToken', function (error, myToken) {
// possibly use local storage to save the token for further use
if (!error) {
Meteor.subscribe('messages', myToken);
}
});
});
On the server you will need to define a custom publish method:
Meteor.publish('messages', function (token) {
var self = this;
if (!clients[token]) {
throw new Meteor.Error(403, 'Access deniend.');
}
send(token, 'hello my new client');
var handle = Deps.autorun(function () {
clients[token].dependency.depend();
while (clients[token].messages.length) {
self.added('messages', Random.id(), {
message: clients[token].messages.shift()
});
}
});
self.ready();
self.onStop(function () {
handle.stop();
});
});
and the send function could defined as follows:
var send = function (token, message) {
if (clients[token]) {
clients[token].messages.push(message);
clients[token].dependency.changed();
}
}
That's a method I would use. Please check if it works for you.
I think using Meteor.onConnection() like a login would enable you to do what you want pretty easily in a publish function.
Something like this:
Messages = new Meteor.Collection( 'messages' );
if ( Meteor.isServer ){
var Connections = new Meteor.Collection( 'connections' );
Meteor.onConnection( function( connection ){
var connectionMongoId = Connections.insert( connection );
//example Message
Message.insert( {connectionId: connection.id, msg: "Welcome"});
//remove users when they disconnect
connection.onClose = function(){
Connections.remove( connectionMongoId );
};
});
Meteor.publish( 'messages', function(){
var self = this;
var connectionId = self.connection.id;
return Messages.find( {connectionId: connectionId});
});
}
if ( Meteor.isClient ){
Meteor.subscribe('messages');
Template.myTemplate.messages = function(){
//show all user messages in template
return Messages.find();
};
}
I have used database backed collections here since they are the default but the database is not necessary. Making Messages a collection makes the reactive publishing easy whenever a new message is inserted.
One way that this is different from streams is that all the messages sent to all clients will end up being kept in server memory as it tries to keeps track of all data sent. If that is really undesirable then you could use a Meteor.method so send data instead and just use publish to notify a user a new message is available so call the method and get it.
Anyway this is how I would start.
On the introducing article of DDP, I read that anything can be published, but I've read somewhere ( for example in this Stackoverflow comment Publish arbitrary data and automatically update HTML ) that only Collections can be published.
So where is the truth? If we can publish other things than Collections, I would liek to see an example as I can't find one so far.
From the docs: http://docs.meteor.com/#meteor_publish
Publish functions can return a Collection.Cursor, in which case Meteor will publish that cursor's documents. You can also return an array of Collection.Cursors, in which case Meteor will publish all of the cursors.
So at the moment you can only return a Collection via a cursor (result of a Collection.find()).
To return other data you need to hack into the sockjs stream (the socket library meteor uses to communicate to the server). Be aware this does not guarantee compatibility with future versions of meteor. Sockjs is the library used for meteor to communicate between the server (the wire)
from Publish arbitrary data and automatically update HTML*
client side js
sc = new Meteor._Stream('/sockjs');
sc.on('message', function(payload) {
var msg = JSON.parse(payload);
Session.set('a_random_message', JSON.stringify(msg.data));
});
Template.hello.greeting = function () {
return Session.get('a_random_message');
};
server side js
ss = new Meteor._StreamServer();
ss.register(function (socket) {
var data = {socket: socket.id, connected: new Date()}
var msg = {msg: 'data', data: data};
// Send message to all sockets (which will be set in the Session a_random_message of the client
_.each(ss.all_sockets(), function(socket) {
socket.send(JSON.stringify(msg));
});
});
You can also look at Meteor Streams too. See below.
assume you have added meteor streams via atmosphere - mrt add streams
sc = new Meteor.Stream('hello');
if(Meteor.isServer) {
Meteor.setInterval(function() {
sc.emit('a_random_message', 'Random Message: ' + Random.id());
}, 2000);
Meteor.permissions.read(function() { return true });
}
if(Meteor.isClient) {
sc.on('a_random_message', function(message) {
Session.set('a_random_message', message);
});
Template.hello.greeting = function () {
return Session.get('a_random_message');
};
}
I'm trying to see how can I invoke a js function after the client gets a result from a Meteor method call. The only thing I was able to get is to invoke the function myFunc only on the client that made the actual method call.
Any thoughts how i can invoke the function on all the currently subscribed clients?
here is the code:
function myFunc(error, result) {
alert(result);
}
if (Meteor.is_client) {
Template.container.events = {
'click input' : function () {
Meteor.call('someMethod',myFunc);
if (typeof console !== 'undefined')
console.log("You pressed the button");
}
};
}
if (Meteor.is_server) {
Meteor.startup(function () {
// code to run on server at startup
});
}
Meteor.methods({
someMethod: function() {
//console.log(!this.is_simulation);
return "something";
}
})
Thanks
Currently you can't broadcast a method call to all clients directly. At least as far as I can tell. But a work around would be to create a collection called Alerts and monitor it for changes. Then when you want to send a message to all your users you can change the document in Alerts:
Client:
Alerts = new Meteor.Collection("alerts")
Meteor.autosubscribe(function() {
Alerts.find().observe({
added: function(item){
alert(item.message);
}
});
});
Server:
Alerts = new Meteor.Collection("alerts")
Meteor.publish("alerts", function(){
Alerts.find();
});
Alerts.remove({}); // remove all
Alerts.insert({message: "Some message to show on every client."});
Another option is using Meteor Stream package which purpose is to avoid using a mongodb collection on the server side. It does supports client to clients, server to clients, client to server AND server to servers messaging, including a support for Meteor Cluster
If you want to stay with meteor only using collections, the following code allows you to either broadcast a message from the client to all the clients or a message from the server to all the subscribed clients. Just use this mechanism to then fire a function on the client side once the right message is received. The code is made in such a way that you will never have useless items remaining into the collection.
Messages = new Meteor.Collection("messages");
if (Meteor.isClient) {
Meteor.subscribe("messages");
var query = Messages.find({});
var handle = query.observe({
added: function(document)
{
console.log(document.message);
}
});
// Test the mechanism from the client side
Meteor.call("client talked");
}
if (Meteor.isServer) {
Meteor.startup(function() {
Messages.remove({});
});
Meteor.publish("messages", function()
{
// you might add an optional filter in order to broadcast only the messages you want to the client
return Messages.find();
});
function talk(message)
{
var id = Messages.insert({"message":message});
Messages.remove(id);
}
Meteor.methods(
{
talk: function(message)
{
// you might filter here if the clients can talk using this.userId
talk(message);
}
});
// test the mechanism from the server side
talk("server talked");
}
I like what Zeke said, but for people who uses Meteor 0.5.0+, use Deps.autorun instead of autosubscribe... details at:
https://groups.google.com/forum/#!topic/meteor-core/mTa81RLvhbY
and
http://www.meteor.com/blog/2013/02/14/meteor-055-devshop-code-and-community-contributions
I simple approach to call a JavaScript client-side function would be to add a script tag in your html template that is bound by your collection. Anytime a new item is inserted, this tag would be inserted into the client would run your function. I have a collection call uploads with some properties such as name. The following template triggers drawpoints() client-side function upon receipt of a new item in Uploads collection:
{{#each uploads}}
<tr>
<td>{{name}}</td>
<td>
<div class="alert alert-success">Download Here</div>
</td>
</tr>
<script>drawpoints();</script>
{{/each}}