Develop Reference

Keeping a client-side sync of Sails.js collection, using sockets

I very much like Meteor's pub/sub. I wonder if there is a way to get a similar workflow, using sails.js or just a socket library in general.
In particular, what I would like to be able to do is something along the lines of:
// Server-side:
App.publish('myCollection', -> collection.find({}))
// Client-side:
let myCollection = App.subscribe('myCollection')
let bob = myCollection.find({name: 'Bob'})
myCollection.insert({name: 'Amelie'}, callback)
All interaction with the server should happen in the background.

I very much like Meteor's pub/sub. I wonder if there is a way to get a similar workflow, using sails.js or just a socket library in general
Basically yes, at least about realtime sync between backend and frontend. Let's review what meteor's have and answer point by point.
Pub/sub
The Pub / Sub concept, as stated by Sabbir, is also supported by sails.js. Though the basics are slightly different :
In meteor, the client can subscribes to everything he wants, and the server control what it receives by only publishing to who he wants;
whereas in sails.js, the server both does subscribe some clients sockets and publish to all binded sockets
Note that, by default:
meteor contains the autopublish package that just notify every client without any kind of filtering. To acheive some filtering, you have to meteor remove autopublish then you can handle what will your client receive by adding a mongo request to it, like explained here.
sails by default, on its automatic "select" blueprints actions, auto-subscribes the calling socket to the events on the objects returned by the "select".
As a server-side conclusion:
Subscribe: just call findor findOne blueprint default action, through a socket (attaching some where filters or not) and your socket will automatically be subscribed to every events concerning returned objects => you don't have to code anything on the server, in most cases, for the Subscribe logic.
Publish: every blueprint default actions (create, update, destroy, add, remove) auto-publish to subscribed sockets => you don't have to code anything on the server, in most cases, for the Publish logic.
(Though, if you find yourself implementing some manual controller actions, sails API helps you publishing and subscribing easily)
Client handling
Therefore, with both meteor and sails, clients only receive what they're supposed to receive. Time for front-end now.
Philosophy
meteor in one hand, with it's isomorphic dimension, does provide a front-end connector by nature, exposing it's data-bound collections.
sails on the other hand, is front-end agnostic, and can be attacked by any http REST connector (JS or not), such as $http, $resource, or more advanced ones like Restangular.
Though, being aware of the complexity using raw sockets on their API (when it comes to session, CORS, CSRF and stuff), they developped a javascript socket.io wrapper called sails.io.js designed to be REST-like-over-socket, and just works like a charm.
Basically, The main difference is that meteor is one step higher-level than sails, because it provides the logic of syncing collections and objects.
All interaction with the server should happen in the background.
sails.io.js, the official front-end component, is just not that high-level. When it comes to Angular.js.
Though, you can find some community connectors that aim to, kinda, provide the same feature as mongo data-bound collections and objects. There is sails-resource, spinnaker or angular resource sails. I tried both of them, and I should say that I was disapointed. The abstraction level is so high that it just becomes annoying, IMHO. For example, with not-very-RESTful-friendly custom actions, like a login, it becomes very hard to adapt it for your needs.
==> I would advice to use a low-level connector, such as angularSails or (my prefered) https://github.com/janpantel/angular-sails, or even raw sails.io.js if you're not using Angular.
Edit: just foun a backbone version, by the sails' creator
It just works great, and believe me, the "keep my collection in sync with that socket" code is so ridiculous, that finding a module for this is just not worth it.
Some code please, stop talking
In particular, what I would like to be able to do is something along the lines of:
Server
Meteor
# Server-side:
App.publish('myCollection', -> collection.find({}))
Sails
//Nothing to do, just sails generate api myCollection
Client
Meteor
# Client-side:
myCollection = App.subscribe('myCollection')
Sails, with sails.io.js
(Here using lodash for convenience)
var myCollection;
sails.io.get('/myCollection').then(
function(res) {
myCollection = res.data;
},
function(err) {
//Handle error
}
);
sails.io.on('myCollection').function(msg) {
switch(msg.verb) {
case 'created':
myCollection.push(msg.data);
break;
case 'updated':
_.extend(_.find(myCollection, 'id', msg.id), msg.data);
break;
case 'destroyed':
_.remove(myCollection, 'id', msg.id);
break;
};
});
(I leave the find where and create to your imagination with [the doc])
All interaction with the server should happen in the background.
Well, Sails, only for angular, with sails ressources
I'm not pretty used to that process, so I leave you reading here or here, but once again I'd choose manual .on()method.

Since I asked this question, I've learned a few things and some new projects have popped up. I decided against sails.io, because when developing with React.js, most of the community's weight is behind webpack, but sails.io uses gulp. I realize these can be used together and there is even an npm package for this, but I wasn't too keen on making my stack bigger than it had to be, so I went with a simple express.js server that I could tailor to my needs.
In order to sync my data, I'm using rethinkdb which allows me to asynchronously watch the database for changes and then publish the changes to the clients through websockets.
I've set up a simple script where I keep an instance of a baobab tree on both the client and the server.
When the tree gets modified on the server, it sends transaction data to the appropriate clients through the websocket
The client merges the transaction with the tree.
This method does not make use of local storage and keeps the data in memory in the node.js process. The data in the transaction is also quite redundant.
The future plan has always been to set something up using redis and local storage ...
... until yesterday when I found deepstream.io!
This is a tool that does exactly what I want and need! Nothing more, nothing less.
Another project worth mention is meatier: "like meteor, but meatier". It is composed of many other well supported open source projects, so you could even pick and choose.

How to make per user base logging with hapi js

I am using winston logging framework and logging on basis of log level, but now i am facing difficulties in tracking down bugs. So we decided to make logging on per user basis, and this is where i ran into problem.
What i want to acheive?
log file for every user will be generated on every hour. (We can skip every hour constraint in this thread) and every user has unique identifier 'uid'.
What i have?
I have followed architecture as used here 'https://github.com/agendor/sample-hapi-rest-api'. Some additional lib modules exist too.
Currently i am using winston library (but i can afford to replace this if needed).
Brief introduction of flow
Currently, i have access to request object in handler function only, but i want to log events in DAO, library functions too ( on per user basis). 'Uid' is available to me in handler function in request object as i put uid in request in authentication middleware.
My solution (which is not elegant)
pass request object ( or only uid) to every function and log (using winston) event. Custom transport will determine where (in which file, on basis of uid) to put the log.
Certainly, this is not elegant way as every function must have uid parameter in order to log event, which seems bad.
What i want from you?
A better, elegant approach which is scalable too.
Related post: https://github.com/hapijs/discuss/issues/51

Try taking a look at Continuation-Local Storage:
https://github.com/othiym23/node-continuation-local-storage
Heres a good article on implementing it within express:
https://datahero.com/blog/2014/05/22/node-js-preserving-data-across-async-callbacks/

Using the Pusher.com API for client to client events

I have setup an account and app in the pusher.com API dashboard and have experimented with both private and public channels and client->client events - I have no trouble doing this.
My project is using CodeIgniter (latest) PHP framework (+ jQuery latest + pusher latest) and I have access to edit everything - nothing is out of bounds in terms of solutions, this is a non commercial project.
My aim is to have client/socket A send an event/message to client/socket B within 'channelX'.
I would like many people/sockets to be possible within 'channelX' - so for example we could have 10 clients connected to this channel, but within it I would like 2 parties to be able to communicate directly with each other (can be via server or just via pusher api).
At the moment, and where my understanding and research leads me: is that any event triggered in my 'channelX' private channel is sent to all clients - now I have used the 'exclude socket' parameter to make sure the event doesn't trigger on 'socketA' (the person doing the initiating of the event) - and this works when there is only 2 clients/sockets connected to a channel - but add more parties and it gets messy.
The question:
Should a channel ONLY have 2 clients/sockets if the events are only to be shared between two?
Ideally what I would like to do:
Have one master channel which holds all users - then each user should be able to send a 'ping' or 'poke' to one of the other users - without all of the other clients receiving this pusher event/trigger.
I do have code but my question is really theory based and so I'm not expecting bundles of code to come from this question - but the docs on the pusher.com website kind of miss this point (or perhaps I did!)
Thanks for any input

There is an old FAQ article on how to implement 1-to-1 chat that may provide a strategy that suits your needs.

How to customize the OData server using JayData?

I'm quite new to JayData, so this may sound like a stupid question.
I've read the OData server tutorial here: http://jaydata.org/blog/install-your-own-odata-server-with-nodejs-and-mongodb - it is very impressive that one can set up an OData provider just like that. However the tutorial did not go into details about how to customize the provider.
I'd be interested in seeing how I can set it up with a custom database and how I can add a layer of authentication/authorization to the OData server. What I mean is, not every user may have permissions to every entity and not every user has the permission to add new entities.
How would I handle such use cases with JayData?
Thanks in advance for your answers!

UPDATE:
Here are two posts that will get you started:
How to use the odata-server npm module
How to set up authentication/authorization
The $data.createODataServer method frequently used in the posts is a convenience method that hides the connect/express pipleline from you. To interact with the pipeline examine the method body of $data.createODataServer function found in node_modules/odata-server folder.
Disregard text below
Authentication must be solved with the connect pipeline there are planty of middleware for that.
For authorization EntityContext constructor accepts an authorization function that must be promise aware.
The all-allow authorizator looks like this.
function checkPerm(access, user, entitysets, callback) {
var pHandler = new $data.PromiseHandler();
var clbWrapper = pHandler.createCallback(callback);
var pHandlerResult = pHandler.getPromise();
clbWrapper.success(true); // this grants a joker rw permission to everyone
//consult user, entitySet and acces to decide on success/error
//since you return a promise you can call async stuff (will not be fast though)
return pHandlerResult;
}
I have to consult with one of the team members on the syntax that let you pass this into the build up process - but I can confirm this is doable and is supported. I'll get back with the answer ASAP.
Having authenticated the user you can also use EntityContext Level Events to intercept Read/Update/Create/Delete operations.
$data.EntityContext.extend({
MySet: { type: $data.EntitySet, elementType: Foobar,
beforeDelete: function(items) {
//if delete was in batch you'll get multiple items
//check items here,access this.request.user
return false // deny access
}
});
And there is a declarative way, you can annotate Role names with permissions on entity sets, this requirest that your user object actually has a roles field with an array of role names.

I too have been researching oData recently and as we develop our platform in both node and C# naturally looked at JayStorm. From my understanding of the technical details of JayStorm the whole capability of Connect and Express are available to make this topic possible. We use Restify to provide the private API of our platform and there we have written numerous middleware modules for exactly this case.

We are using JayData for our OData Service layer also, and i have implemnment a very simple basic authentication with it.
Since the JayData is using Express, so we can leverage Express' features. For Basic Auth, the simplest way is:
app.use(c.session({ secret: 'session key' }));
// Authenticator
app.use(c.basicAuth('admin', 'admin'));
app.use("/odata.svc", $data.JayService.OData.Utils.simpleBodyReader());
you also can refer to this article for more detail for authentication with Express: http://blog.modulus.io/nodejs-and-express-basic-authentication
Thanks.

I wrote that blogpost, I work for JayData.
What do you mean by custom database?
We have written a middleware for authentication and authorization but it is not open source. We might release it later.
We have a service called JayStorm, it has a free version, maybe that is good for you.
We probably will release an appliance version of it.

Publish data from browser app without writing my own server

I need users to be able to post data from a single page browser application (SPA) to me, but I can't put server-side code on the host.
Is there a web service that I can use for this? I looked at Amazon SQS (simple queue service) but I can't call their REST APIs from within the browser due to cross origin policy.
I favour ease of development over robustness right now, so even just receiving an email would be fine. I'm not sure that the site is even going to catch on. If it does, then I'll develop a server-side component and move hosts.

Not only there are Web Services, but nowadays there are robust systems that provide a way to server-side some logic on your applications. They are called BaaS or Backend as a Service providers, usually to provide some backbone to your front end applications.
Although they have multiple uses, I'm going to list the most common in my opinion:
For mobile applications - Instead of having to learn an API for each device you code to, you can use an standard platform to store logic and data for your application.
For prototyping - If you want to create a slick application, but you don't want to code all the backend logic for the data -less dealing with all the operations and system administration that represents-, through a BaaS provider you only need good Front End skills to code the simplest CRUD applications you can imagine. Some BaaS even allow you to bind some Reduce algorithms to calls your perform to their API.
For web applications - When PaaS (Platform as a Service) came to town to ease the job for Backend End developers in order to avoid the hassle of System Administration and Operations, it was just logic that the same was going to happen to the Backend. There are many clones that showcase the real power of this strategy.
All of this is amazing, but I have yet to mention any of them. I'm going to list the ones that I know the most and have actually used in projects. There are probably many, but as far as I know, this one have satisfied most of my news, whether it's any of the previously ones mentioned.
Parse.com
Parse's most outstanding features target mobile devices; however, nowadays Parse contains an incredible amount of API's that allows you to use it as full feature backend service for Javascript, Android and even Windows 8 applications (Windows 8 SDK was introduced a few months ago this year).
How does a Parse code looks in Javascript?
Parse works through classes and objects (ain't that beautiful?), so you first create a specific class (can be done through Javascript, REST or even the Data Browser manager) and then you add objects to specific classes.
First, add up Parse as a script tag in javascript:
<script type="text/javascript" src="http://www.parsecdn.com/js/parse-1.1.15.min.js"></script>
Then, through a given Application ID and a Javascript Key, initialize Parse.
Parse.initialize("APPLICATION_ID", "JAVASCRIPT_KEY");
From there, it's all object manipulation
var Person = Parse.Object.extend("Person"); //Person is a class *cof* uppercase *cof*
var personObject = new Person();
personObject.save({name: "John"}, {
success: function(object) {
console.log("The object with the data "+ JSON.stringify(object) + " was saved successfully.");
},
error: function(model, error) {
console.log("There was an error! The following model and error object were provided by the Server");
console.log(model);
console.log(error);
}
});
What about authentication and security?
Parse has a User based authentication system, which pretty much allows you to store a base of users that can manipulate the data. If map the data with User information, you can ensure that only a given user can manipulate specific data. Plus, in the settings of your Parse application, you can specify that no clients are allowed to create classes, to ensure innecesary calls are performed.
Did you REALLY used in a web application?
Yes, it was my tool of choice for a medium fidelity prototype.
Firebase.com
Firebase's main feature is the ability to provide Real Time to your application without all the hassle. You don't need a MeteorJS server in order to bring Push Notifications to your software. If you know Javascript, you are half way through to bring Real Time magic to your users.
How does a Firebase looks in Javascript?
Firebase works in a REST fashion, and I think they do an amazing job structuring the Glory of REST. As a good example, look at the following Resource structure in Firebase:
https://SampleChat.firebaseIO-demo.com/users/fred/name/first
You don't need to be a rocket scientist to know that you are retrieve the first name of the user "Fred", giving there's at least one -usually there should be a UUID instead of a name, but hey, it's an example, give me a break-.
In order to start using Firebase, as with Parse, add up their CDN Javascript
<script type='text/javascript' src='https://cdn.firebase.com/v0/firebase.js'></script>
Now, create a reference object that will allow you to consume the Firebase API
var myRootRef = new Firebase('https://myprojectname.firebaseIO-demo.com/');
From there, you can create a bunch of neat applications.
var USERS_LOCATION = 'https://SampleChat.firebaseIO-demo.com/users';
var userId = "Fred"; // Username
var usersRef = new Firebase(USERS_LOCATION);
usersRef.child(userId).once('value', function(snapshot) {
var exists = (snapshot.val() !== null);
if (exists) {
console.log("Username "+userId+" is part of our database");
} else {
console.log("We have no register of the username "+userId);
}
});
What about authentication and security?
You are in luck! Firebase released their Security API about two weeks ago! I have yet to explore it, but I'm sure it fills most of the gaps that allowed random people to use your reference to their own purpose.
Did you REALLY used in a web application?
Eeehm... ok, no. I used it in a Chrome Extension! It's still in process but it's going to be a Real Time chat inside a Chrome Extension. Ain't that cool? Fine. I find it cool. Anyway, you can browse more awesome examples for Firebase in their examples page.
What's the magic of these services? If you read your Dependency Injection and Mock Object Testing, at some point you can completely replace all of those services for your own through a REST Web Service provider.
Since these services were created to be used inside any application, they are CORS ready. As stated before, I have successfully used both of them from multiple domains without any issue (I'm even trying to use Firebase in a Chrome Extension, and I'm sure I will succeed soon).
Both Parse and Firebase have Data Browser managers, which means that you can see the data you are manipulating through a simple web browser. As a final disclaimer, I have no relationship with any of those services other than the face that James Taplin (Firebase Co-founder) was amazing enough to lend me some Beta access to Firebase.

You actually CAN use SQS from the browser, even without CORS, as long as you only need the browser to send messages, not receive them. Warning: this is a kludge that would make my CS professors cry.
When you perform a GET request via javascript, the browser will always perform the request, however, you'll only get access to the response if it was from the same origin (protocol, host, port). This is your ticket to ride, since messages can be posted to an SQS queue with just a GET, and who really cares about the response anyways?
Assuming you're using jquery, your queue is https://sqs.us-east-1.amazonaws.com/71717171/myqueue, and allows anyone to post a message, the following will post a message with the body "HITHERE" to the queue:
$.ajax({
url: 'https://sqs.us-east-1.amazonaws.com/71717171/myqueue' +
'?Action=SendMessage' +
'&Version=2012-11-05' +
'&MessageBody=HITHERE'
})
The'll be an error in the console saying that the request failed, but the message will show up in the queue anyways.

Have you considered JSONP? That is one way of calling cross-domain scripts from javascript without running into the same origin policy. You're going to have to set up some script somewhere to send you the data, though. Javascript just isn't up to the task.

Depending in what kind of data you want to send, and what you're going to do with it, one way of solving it would be to post the data to a Google Spreadsheet using Ajax. It's a bit tricky to accomplish though.Here is another stackoverflow question about it.
If presentation isn't that important you can just have an embedded Google Spreadsheet Form.

What about mailto:youremail#goeshere.com ? ihihi
Meantime, you can turn on some free hostings like Altervista or Heroku or somenthing else like them .. so you can connect to their server , if i remember these free services allows servers p2p, so you can create a sort of personal web services and push ajax requests as well, obviously their servers are slow for free accounts, but i think it's enought if you do not have so much users traffic, else you should turn on some better VPS or Hosting or Cloud solution.

Maybe CouchDB can provide what you're after. IrisCouch provides free CouchDB instances. Lock it down so that users can't view documents and have a sensible validation function and you've got yourself an easy RESTful place to stick your data in.