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:
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, '/')?
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?
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?
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.?
Can I send the user only the changed, dynamically created html file, and not send again unchanged .js and .css files?
Does every user who opens the home page (GET, '/') create a new connection to the server using WebSocket / socket.io?
I will try to answer some of your questions:
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.
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!
Related
I'm relatively new to react and wanted to create an app that uses the Bigcommerce API to change product data submitted by the user through a form. My idea is to have a simple form for the user to input a quantity, for example. Once the user submits the quantity the want to change, the new number will be reflected on the product page on Bigcommerce Admin pages.
I have already created the same kind of app with Node with no front end. The app I made reads a csv file and calls the proper APIs to update their quantities. I wanted to create sort of the same app but in React with no csv reading abilities. I am having trouble with CORS errors now for some reason. I tried creating a backend with Node for this React app but I still get the same error.
I tried some other API. one that does not require authentication and that worked fine. I was able to see results when I do the console.log(data).
It seems that this Bigcommerce API won't work because it requires authentication, which I already have made on their backend several times to double check my work. I'm confused and not convinced that there is no way for a react app to fetch data from a remote server with credentials.
I figured it out, but I'm still convinced that I can do this with only a front end application in React. Without Node, However.
What I did was create an endpoint with Express using Node as the backend. Installed cors modules, then allowed requests coming from the front end URL address. Also, pay attention to whether you are using localhost:PORT# or 127.0.0.1:PORT#
to the browser these are different. Make sure they're the same when you open up the browser.
I have developed and hosted few react applications but I'm still confused about the word server side rendering. So, I'm curious to know what is the benefit of serving my react applications from an express server.
Thank you as I look forward to your response.
Please consider clarifying your question, because I don't know also if you use next.js or nuxt.js.
Angular, React, Vue.js are JavaScript frontend frameworks/libraries, which means they are using JavaScript language.
The websites on the Internet contain HTML, CSS, JavaScript Vanilla code.
The application you developed using React.js needs to use React.js library source code, and then you need the React.js code to be compiled to JavaScript Vanilla code because the browser at the end needs a JavaScript native code that it can read.
When I need to see your hosted website, I need to write the domain name to see it, so the HTTP request at the end goes to the server which is hosting your react app, thus if your react application contains just a static content, for example, a landing HTML page, then there is no need for server-side rendering from Express(Node.js), Ruby, PHP, Java,...
What I mean by static content is content that doesn’t change in response to different users, all of them will get the same content.
Notice you can host a static website in Github and you still don't need any server-side rendering...
Let's have a small application for a better explanation:
If you developed a Portfolio that contains a description of yourself, images of your projects, skills, then here there is no need for a server-side rendering.
But if you developed a system that lets a user who has permission to create a short link from a full URL, then you need a backend server(like Java, Ruby, C#, PHP,...) to host the logic code in order to generate a tiny URL from the full URL, and then save it in a Database, that way any user can click the generated tiny URL then this request goes to your backend server which needs to redirect the user with correct full URL, an application like this cannot be done using React.js alone, you need a server to handle the logic.
Returning to your answering your question: "So, I'm curious to know what is the benefit of serving my react applications from an express server."
If you have static content you can avoid using Express, but if you think your application needs some backend logic in the future, then Express or any other backend framework will help you in that.
*Notice when you have a static website, and you tried to edit the content of it, the users which already visited your website, their browser might cached your website content unless (they disabled this option in their browser), so if your website is cached in users' browsers they might not get the updated content unless you changed the static website file name for example by adding ?092130123 to file name in order to let the users' browser download the updated data
Context:
I'm making a React website that draws information from the Google Sheets API and formats specific rows into a data visualization. There are columns I don't want to share because of sensitivity of information, and fortunately there are ways to share only specified columns, but that isn't why I'm asking the following:
Problem:
I want to have a Node API that handles requests from a React front-end, but whose code isn't available on the client's browser (for example, in the bundle.js file created during build).
Clarification: I have noticed that when running most Node-React application examples locally and when building them with webpack, you end up with one bundle.js file that contains Node request-handling code being delivered to the browser on page load.
Proposal:
Do I need to deploy two separate apps (one for Node, the other for React), or can I keep them together without the server code being visible to the client?
EDIT POST ANSWER:
you end up with one bundle.js file that contains Node request-handling code being delivered to the browser on page load.
This was untrue. The code I had assumed to be request-handling code was client side request-calling code.
It is already decoupled. There is nothing you need to do.
Note that the security of your node.js server code depends on your server configuration, not node.js. If you access your server via unencrypted file sharing or FTP then your node server code is still not safe.
Even when using encryption, avoid compromised protocols such as SSL or TLSv1.0 (use TLSv1.3 instead for things like FTPS)
You can add a simple authentication system. There are plenty packages out there for Node already, so no need to implement it yourself.
Specifically, this would prevent the backend from sending sensitive data to a unauthorized request.
EDIT: Just for clarification, code run on a Node.js server is not sent out publicly, it will run on your server and send its output to the frontend.
EDIT 2: Looks like I misunderstood your question.
If your code is not decoupled at the moment it will need to be. All code of a React.js project is sent to the browser. Since there is no backend to handle any kind of access logic, any such logic would have to be in the frontend (React.js), where it could easily be circumvented.
Have small app (My first Node js App), where I want add changing real-time content.
For example I have a common url which have list of content link, when user click on particular link it will open its correspondence link.
I have teacher and student role in the app so if teacher open the specific content(From the common url page) then it will automatically open that content for all student who have common url.
Please give me any Idea to implement this functionality and please tell me any plugin who have same functionality for real time content change.
One way, probably the easiest would be to use websockets, an easily manageable choice is socket.io npm package. What makes websockets different from http requests is the direction of the data flow. While http is pull based, meaning that a request has to be made to the server in order to get a response, websockets - once the connection is established - are or at least can be push based, meaning that the server could push out content without having to get a request from the client. In your situation, the teacher and the studens would all have an active websocket connection with the server. When the teacher clicked on a certain view, it would push the view’s data requirements to the students without any interaction from their side and the view would update on their screens according to the pushed data.
Look into how websockets work and try to experiment with a basic socket.io setup.
I'm new at Firebase, I'm starting making a project which has to include Firebase and angular2, but I am such confused about how to implement them. I don't know if a there's the need to have a Back-end implementation (like Java or NodeJs) to handle some security issues (like form validation, authentication, routing etc), or it's enough just implementing Angular2 to handle all these issues. I would be so Thankful about any helpful advice how I could implement these both technologies to build my project successfully. Thanks
first firebase is something like your backend firebase can safe get and send request as your backend apps...
and angular js will do the rest like you just said andd all the backend stuff you can handle by firebase :)
This is my simple explanation on how this 2 works together
Always keep in mind that Angular works only in front-end. Its domain is the look and feel, application events, sending data to server and anything else that has something to do with displaying data is coded in this area.
Backend services in the other hand interacts with your database, creating business logic, handling authentications, saving / sending of data and other stuff that interacts with the database is coded from here.
Now how these two interact is done by the frontend service to send HTTP requests to the Server which is the backend service. This is done by using Angulars $http service or the so called jQuery AJAX or the infamous XMLHttpRequest JavaScript native. New technologies today utilizes Web Sockets which is being used by Firebase and some other frameworks, Web Sockets offers a faster way sending / fetching data from server.
The server then interprets the data being sent and send appropriate response. For example getting user list, saving profile, getting reports, logging in, etc.. It would work in this workflow.
1) Angular sends http request to server to get list of users.
2) Backend service installed in the server then interprets the data being sent.
3) Backend service then gets list of users from the database.
4) Backend then sends the data back to the frontend service.
5) Frontend then recieves server response and displays the data to the view.
Also these two is coded separately. To have more detailed explations research about how frontend and backend services interact you can find so much resouces in Google.