I am coming from the world of SPA's and REST/GraphQl API's. Now I am building personal project with Next.js library for SSR(Server Side Rendered) React App.
Since I used Redux in all of my single page Apps, I'm now wondering how should I manage user state when every route user visits, a new link is loaded and the page has been refreshed.
I found some info about sessions and cookies, but neither of those are familiar to me. I looked at some online articles about using Redux with Next.js but it seems complicated.
Let's simplify how Next works, browser sends a request to the server, Next renders on server side, returns an html, then, Next re-hydrate the page, and from now it behaves as SPA.
Next has an example folder basically for every technology including redux.
Checkout the redux example.
If you're used to doing it in a route-based way, this may help understand:
the whole app (_app.js) is wrapped in the Provider for redux, so all pages and components in the app can access the store.
according to the docs:
otherwise different user data can be mixed up. On the client side the
same store is used, even between page changes.```
So your app will recreate the store on every request, but pass the request, the url, and possibly even the results (of the request) into the initial state of the store, so each page and component can utilize the store before rendering.
also checkout getInitialProps which will perform some sideEffect before the components on a page renders, and provide data to the page's props.
some resources:
https://github.com/zeit/next.js/tree/canary/examples/with-redux
https://medium.com/#bhavikbamania/a-beginner-guide-for-redux-with-next-js-4d018e1342b2
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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
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!
Given that we can do routing with Express on the server, why do need a client side router?
What are the benefits, and is it only significant to SPA?
Client side routing is required to keep your application in sync with the browser URL.
It is mainly useful for Single Page Applications where the backend will be used for RESTful API calls via XHR or AJAX calls.
Being a SPA uses can book mark your URL and when they hit the URL again , your application should load that page with the data and its state.
The main difference between Server side routing and client side routing:
1. In Server Side routing you download(serve) the entire page.
2. In client Side routing along with the entire page, you can serve a specific portion of a page, reuse the DOM, manually manage the URL and history states. eg.
www.something.com/page1/tab1 will show tab1 in the UI
www.something.com/page1.tab2 will show tab2 in the UI
In this way the url can get more complex and you can have sub-routes with states.
Those who need a client-side router, need it for state management. Say you have server-rendered pages, but with some client-side widgets - e.g. a calendar, set of filters or collapsed or open sidebar. Router helps you initialize these components of the page in the exact state you want them. Granted, you could do most of it and all of the use cases I've named on the server, too. But it's usually a lot easier to handle these on the client. You might render it faster on the server, but sometimes, especially when doing partial page updates, it's cheaper and faster to handle that client-side.
So, I have been searching everywhere and can't find any hints on this.
I have a REST API built with express that will be consumed by a website and in the future a mobile app.
I have to build the website and want to use react/redux, and I'm struggling to understand how to avoid the initial state to be render from server because I will have nested components and a lot of async data, and it will become a mess to maintain code both client- and server-side. Is there any solution/alternative for this?
Thanks in advance.
You don't necessarily need server-side rendering to solve this problem. You can make your components load with a blank state and then immediately fetch your data.
According to the React docs, your ajax requests should be made in the componentDidMount() lifecycle method, which fires once as soon as your initial render is complete.
If you want to ... send AJAX requests, perform those
operations in this method.
For example, you don't load your app if a user isn't authenticated, or you put up loading spinners to indicate that data is being fetched.
I've recently dived into React+Flux on the front-end, and I love it! But I want to also be able to use React on the back-end to avoid having to duplicate views and rendering logic.
I've seen that React supports server-side rendering if you use Node, but I do not use Node for my back-end logic.
So I'm wondering, can I set up a daemon written in Node that just renders HTML based on the data it receives and the root React component?
What I have in mind is to have my back-end application call this daemon with data already prepared (so that domain logic can live on my main back-end application), get HTML, and return that to the front-end.
Is this approach feasible? Has this been done before? I'd love some feedback!
I see that it's been a month and there are still no comments, I will share some of my understandings.
We can use this setup:
An API written in PHP or something similar that serves data.
Isomorphic React components - render on the server, attach event listeners on the client.
Server-side (Node) - the React component uses AJAX calls to get its props from the API and embeds them into a <script id="props" /> tag in the HTML as a JSON string.
Client-side - the component checks the script tag for props. If there is data, then it uses that to skip the re-rendering; if not (due to a server error or something), it can still use AJAX to get its props.
The main idea is that the website is isomorphic (server and client share the same code), so your existing front-end can be easily adapted to this setup.
A good place to start is a simple example about isomorphic React components. This tutorial can also provide an overview to this subject.