Express server using npm in node.JS and handling routes.
Published in
3 min readMay 24, 2021
1) How to create a basic server using express in node.JS
- first, we have to create a package.json file into our project by using the following command:- “npm init”
- after creating the package.json file we have to install express using npm and have to make its entry into the package.json file by using the command as following: “ npm install express - -save ”.
- now we just have to import the express module by requiring it. after that, we have to create a new variable and store the value returned by express().see in the image below:-
- once the steps above are done, then we have to call listen to a method which accepts 1st parameter as the port on which server is to be deployed. and call back function as a second optional parameter
— — In this way the basic server is created using Express in node.js
2) Handle routes in Express.
- Suppose we have to handle “ GET ” method on route “ / ”(index route).
- we can use methods in app variable to handle route as below:-
- as shown above we have to use app.[method_name] () method to handle any method we want.
- as in the above example, it accepts 2 parameters:
1) Route.
2) call back function.
- call back function accepts two parameters “request” and “response”.
- we can use “res.send()” or “res.sendFile()” methods inside call back function to end the response.
Note:- res.sendFile() accepts only absolute path of the file.
3) How to handle CSS files and image routes in Express.
- to handle CSS files and images in the project we have to use express.static() method.
- express offers us a very simple way to handle CSS files and image Requests and we don't need to create a separate route for everything.
- First, we have to move all our assets into one folder suppose “ public ” folder.
- Now to check the request method and request URL of the coming request we can use middleware to Console.log() on every route as shown in the below image.
- now we can use express.static() method inside middleware which accepts the only absolute path of the public folder.
- Now we are done .now we don't have to handle routes for images and CSS files.
5) Access the data Coming from the body of the URL.
- we can use middleware to fetch body data of URL.
- express offers“ express.json() ” and “express.urlencoded()” method .
- express.json() :- this method is used when the incoming data is in JSON format.
- express.urlencoded() :- this method is used when data is in URL string format.
- after that, we can access that data while handling routes using the req object “ req.body ”.
- refer image below:-