Exploring Long Polling, SSE, and WebSockets

We take a look at different methods for real-time communication in a simple notification system using Node.js and React

Overview

This article is for anyone who wants to add a real time feature to their application, but does not need the full functionality of a serverless platform like Firebase or library like socket.io. Long polling, SSE (Server-Sent Events), and WebSockets provide a more simple and lightweight alternative that is built into all modern web browsers.

Setup

The client generates a key that uniquely identifies itself. This key is used in a request to the server which contains the notification message.

An internal messaging system is used to pass the message to the appropriate endpoint which in turn sends the message back to the client. I recommend using a tool like Postman to send the request.

So for the purposes of the demo, we are manually sending the request. But, you can think of this action as mocking another client or backend service that is trying to send real time data to a specific client.

app.post('/create-notification', (req, res) => {

  const { type, forClientId, message } = req.body

  switch(type) {
    case 'long-polling':
      eventEmitter.emit('notification-long-polling', forClientId, message)
      break
    case 'sse':
      eventEmitter.emit('sse',forClientId, message)
    case 'socket':
      eventEmitter.emit('socket',forClientId, message)
    default:
      break
  }
  res.send()
})

#websocket #nodejs #react #programming

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Exploring Long Polling, SSE, and WebSockets

We take a look at different methods for real-time communication in a simple notification system using Node.js and React

Overview

This article is for anyone who wants to add a real time feature to their application, but does not need the full functionality of a serverless platform like Firebase or library like socket.io. Long polling, SSE (Server-Sent Events), and WebSockets provide a more simple and lightweight alternative that is built into all modern web browsers.

Setup

The client generates a key that uniquely identifies itself. This key is used in a request to the server which contains the notification message.

An internal messaging system is used to pass the message to the appropriate endpoint which in turn sends the message back to the client. I recommend using a tool like Postman to send the request.

So for the purposes of the demo, we are manually sending the request. But, you can think of this action as mocking another client or backend service that is trying to send real time data to a specific client.

app.post('/create-notification', (req, res) => {

  const { type, forClientId, message } = req.body

  switch(type) {
    case 'long-polling':
      eventEmitter.emit('notification-long-polling', forClientId, message)
      break
    case 'sse':
      eventEmitter.emit('sse',forClientId, message)
    case 'socket':
      eventEmitter.emit('socket',forClientId, message)
    default:
      break
  }
  res.send()
})

#websocket #nodejs #react #programming

Poll UI Design using HTML CSS & JavaScript

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What is LONG coin (LONG)?

Brief and simple:

LONG COIN - Cryptocurrency and Social Blockchain Network

We have added the ability to send a string of 256 characters to blockchain transactions. That is, through the blockchain, you can send / receive messages (a kind of twitter) and build more complex structures such as blockchain stores, social networks, lotteries, games, etc.

About privacy:

All messages are also encrypted and the developer has no keys. You encrypt with your private key and the recipient’s public key, which is its address. Where is the best place to hide a needle? In a haystack? No. Best in a stack of other needles. The entire blockchain is flooded with messages and it is not possible to track and decipher yours. (Encryption algorithm - ecdh and aes cbc)

Specification

Coin name: LONG COIN

Coin Ticker: LONG

Hash Algorithm: SHA-256

Message encryption algorithm: ecdh and aes cbc

Coin Type: POW

Block time: 2 minutes

Premine: 0

Confirmation period: 30 blocks

Block Reward: 10,000

Fixed commission: 1 LONG / KB

• SMS — 1 LONG

• Standard financial transactions - 1 LONG

• Limit on the volume of data transactions - 64kB (max commission 64 LONG)

Multicast transactions with simultaneous transmission of coins and messages

How and Where to Buy LONG ?

LONG has been listed on a number of crypto exchanges, unlike other main cryptocurrencies, it cannot be directly purchased with fiats money. However, You can still easily buy this coin by first buying Bitcoin, ETH, USDT from any large exchanges and then transfer to the exchange that offers to trade this coin, in this guide article we will walk you through in detail the steps to buy LONG

You will have to first buy one of the major cryptocurrencies, usually either Bitcoin (BTC), Ethereum (ETH), Tether (USDT)…

We will use Binance Exchange here as it is one of the largest crypto exchanges that accept fiat deposits.

Binance is a popular cryptocurrency exchange which was started in China but then moved their headquarters to the crypto-friendly Island of Malta in the EU. Binance is popular for its crypto to crypto exchange services. Binance exploded onto the scene in the mania of 2017 and has since gone on to become the top crypto exchange in the world.

Once you finished the KYC process. You will be asked to add a payment method. Here you can either choose to provide a credit/debit card or use a bank transfer, and buy one of the major cryptocurrencies, usually either Bitcoin (BTC), Ethereum (ETH), Tether (USDT)

☞ SIGN UP ON BINANCE

Step by Step Guide : What is Binance | How to Create an account on Binance (Updated 2021)

Next step - Transfer your cryptos to an Altcoin Exchange

Since LONG is an altcoin we need to transfer our coins to an exchange that LONG can be traded. Below is a list of exchanges that offers to trade LONG in various market pairs, head to their websites and register for an account.

Once finished you will then need to make a BTC/ETH/USDT deposit to the exchange from Binance depending on the available market pairs. After the deposit is confirmed you may then purchase LONG from the exchange.

Exchange: WhiteBIT, and STEX

Apart from the exchange(s) above, there are a few popular crypto exchanges where they have decent daily trading volumes and a huge user base. This will ensure you will be able to sell your coins at any time and the fees will usually be lower. It is suggested that you also register on these exchanges since once LONG gets listed there it will attract a large amount of trading volumes from the users there, that means you will be having some great trading opportunities!

Top exchanges for token-coin trading. Follow instructions and make unlimited money

☞ Binance ☞ Bittrex ☞ Poloniex ☞ Bitfinex ☞ Huobi ☞ MXC ☞ ProBIT ☞ Gate.io ☞ Coinbase

Find more information LONG

☞  Website
☞  Explorer
☞  Source Code
☞ Social Channel
☞  Coinmarketcap

Would you like to earn LONG right now! ☞ CLICK HERE

Thank for visiting and reading this article! I’m highly appreciate your actions! Please share if you liked it!

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Comparative and Sample Coded Expression

Of course, there is never a single truth during software development. We always come up with multiple options and try to determine which one suits us the best according to the requirements we have.
For example, there may be an exchange of information between “client” and “server” at times. However, the information needed by the client may not be ready there yet.
Sample Scenario
If you say what are such scenarios, the simplest example I can give is the messaging application. Let’s call “Jake 👨‍💼(Client1)” to the person who sends the message in the messaging application and “Emily 👩 (Client2)” to the person who receives the message. Jake and Emily have both phones in their hands, messaging with each other. In this case, when Jake sends a message to the messaging app, Emily should be able to receive it in near real-time. Likewise, Emily should be able to receive the message sent by Jake near real-time. Imagine that you are designing a messaging application and rolled-up sleeves to meet this need. In this case, what solutions could we produce?

#tutorial #websocket #long-polling #nodejs #socketio