CODEWITHSUNDEEP
node.jsdatabaseamazon-web-servicesexpressamazon-dynamodb
roadtosleep
roadtosleep

Reputation: 15

Recommended practices when developing full-stack applications based on Node.js and AWS

I've been working on the front-end so far, now I'm going to create my first full-stack application. I want to use node.js, express and AWS for this. At the design stage, I already encountered a few problems. Therefore, I have a few questions and I am asking you for help:

  1. Can I send a message (simple JSON or database value) from the server to all clients who have already opened my home page in a simple and cheap way? I'm not talking about logged in users, but all who downloaded the main page (GET, '/')?
  2. Using the admin panel ('www.xxxxxxxxx/admin'), I want to send a message to the server once a day. Then I want to change the HTML to display this message. I was thinking to use EJS for this and download this message from the database. Can I make it better? If someone visits my home page (GET, '/'), EJS will download the message from the database each time! Even though its value is the same for 24 hours. Can I get the value once and then use it until the value is changed? How to store the message? As a JSON on the server? Or maybe in the .env file?
  3. If the user refreshes the page, do I have to pay for calling all AWS functions to build the page each time? Even if nothing has changed in the files?
  4. How to check if the page has new content and then send it to the user, instead of sending the unchanged page files: .html, .js, .css, etc.?
  5. Can I send the user only the changed, dynamically created html file, and not send again unchanged .js and .css files?
  6. Does every user who opens the home page (GET, '/') create a new connection to the server using WebSocket / socket.io?

Upvotes: 0

Views: 87

Answers (1)

Antonio Tripiana
Antonio Tripiana

Reputation: 29

I will try to answer some of your questions:

  1. Can I send a message (simple JSON or database value) from the server to all clients who have already opened my home page in a simple and cheap way? I'm not talking about logged in users, but all who downloaded the main page (GET, '/')?

I guess you mean sending push notifications from the server to the user. This can be done with different services depending on what are you trying to build.

  • If you are planning to use GraphQL, you already have GraphQL subscriptions out of the box. If you are using AWS, go for Appsync, which is the AWS service for GraphQL.
  • If you are using REST and a WebApp (not a mobile app), go for AWS IoT using lambdas. Here is a good resource using Serverless Framework (API Gateway + lambdas + IoT) for unauthenticated users: https://www.serverless.com/blog/serverless-notifications-on-aws
  • If you are planning to use notifications on a mobile app, you can go for SNS, the "de facto" service for push notifications in AWS world.
  1. Using the admin panel ('www.xxxxxxxxx/admin'), I want to send a message to the server once a day. Then I want to change the HTML to display this message. I was thinking to use EJS for this and download this message from the database. Can I make it better? If someone visits my home page (GET, '/'), EJS will download the message from the database each time! Even though its value is the same for 24 hours. Can I get the value once and then use it until the value is changed? How to store the message? As a JSON on the server? Or maybe in the .env file?

Yes, this is the way it's expected to work. The HTML is changed dynamically using frontend code in Javascript; which makes calls (using axios for example) to the backend every time you get into, i.e. "/" path. You can store this data in frontend variables, or even use state management in the frontend using REDUX, VUEX, etc. Remember the frontend code will always run in the browser of your users, not on your servers!

If the user refreshes the page, do I have to pay for calling all AWS functions to build the page each time? Even if nothing has changed in the files?

What you can do is store all your HTML, CSS, Javascript in an S3 bucket and serve from there (this is super cheap, even free till a certain limit). If you want to use Server Side Rendering (SSR), then yes, you'll need to serve your users every time they make a GET request for example. If you use lambda, the first million request per month are free. If you have an EC2 instance to serve your content, then a t2.micro is also free. If you need more than that, you'll need to pay.

How to check if the page has new content and then send it to the user, instead of sending the unchanged page files: .html, .js, .css, etc.?

I think you need to understand how JS (or frameworks like React, Vue or Angular) do this. Basically you download the js code on the client, and the js makes all the functionality to update backend and frontend accordingly. In order to connect frontend with backend, use Axios for example.

Can I send the user only the changed, dynamically created html file, and not send again unchanged .js and .css files?

See answer above. Use frameworks like React or Vue, will help you a lot.

Does every user who opens the home page (GET, '/') create a new connection to the server using WebSocket / socket.io?

Depends on what you code. But by default what happens is the user will make a new GET request everytime he accesses your domain, and that's it. (It's not establishing any connection if you don't tell the code to do so).

Hope this helps!! Happy coding!

Upvotes: 1

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