AngularJS + Socket.io

AngularJS provides a very interactive user experience, just like Socket.io. When you combine them in a single page application awesomeness is squared.

But some of the AngularJS mechanics produce buggy behavior for Socket.io.

For example if you subscribe to an event in your controller and then go to another view scope this controller is destroyed, but event subscription is still stored in a global socket.io object. So when you go back and controller is reinstanciated you get a second subscription. After a while of you going back and forth there's a chaos!

You don't want to receive 2+ messages from 1 event in your let's say chat application. So how can we deal we it?

I'll let code and comments speak for itself (coffeescript):

And here's how you use it:

Some use case for using reconnect (it's so simple I should't have included it):

Popular posts from this blog

HTTP server in Ruby 3 - Fibers & Ractors

Image
This is part #2. Head over to part #1 to learn about HTTP in Ruby. Motivation Historically Ruby's been lacking in the concurrency department. Ruby has "native" threads (prior to 1.9 there were only "green"), which means there can be multiple threads controlled by an OS, but only 1 thread can be executed at a time, this is managed via Global Interpreter Lock (GIL). However, native calls and I/O calls can be executed in parallel. During an I/O call, a thread gives up control and waits for a signal that the I/O has finished. This means I/O heavy applications can benefit from multiple threads. In this article we are going to explore different concurrency modes for our HTTP server: Single-threaded Multi-threaded Fibers Ractors Single-threaded Let's start simple and see how a single threaded HTTP server could look like ( full code ): def start socket = TCPServer.new(HOST, PORT) sock...
Read more

Next.js: restrict pages to authenticated users

Image
Many websites have pages that need to be restricted to authenticated users, for example profile pages or dashboards. Next.js web framework comes with a lot of functionality built-in JS compilation, rendering code on server and caching. When it comes to most other aspecs, it's up to a programmer to build, including such needed functionality as restricting access to some pages only to authenticated users. In this article we are going to build just that: a function that augments a page object, that could be used like that: Here's the implementation in TypeScript: In order to make it work on server we are going to need one more utility function fetchWithCookies . When making HTTP request from inside a Web Browser, the browser automatically sends cookies with each requests and then stores new cookies if a response comes in with set-cookie header. On server-side we need to build this feature ourselves, because neither Next.js nor NodeJS make any a...
Read more

Migration locks for TypeORM

Image
Schema migrations is a must-have functionality for any DB framework. TypeORM provides decent utilities for dealing with migrations, however having a decade of experience in Ruby on Rails I got really spoiled and take some features for granted. One of these features is locking a database while a migration going on so 2 processes running concurrently don't step on each other's toes. This is also important when you run migrations in Kubernetes before launching your app. I was really surprised to find out that this basic feature is not supported , so decided to implement it on my own. Implementation // typeormMigrationUtils.ts import { Connection, createConnection } from 'typeorm' import config from '../ormconfig' import CRC32 from 'crc-32' const MIGRATOR_SALT = 2053462845 async function withAdvisoryLock( connection: Connection, callback: () => Promise<void> ): Promise<boolean> { // generate a unique lock...
Read more