Accepting Data: Handling Form Data

So far, your web server offers a read-only service: it publishes some data but doesn’t accept any… Until now!

Information submitted to a web server can be either form data or JSON data.

Handling form data

Form data comes encapsulated into the HTTP POST request sent by the client to the server. The first server task is to extract this information from the request. The simplest way to do this is to use a specialized npm package, such as multer. Install it with the npm install multer command or directly in your app dependencies.

  "dependencies": {
    ...
    "multer": "^1.3.0"
  },

Once multer is installed, add the following code towards the beginning of your server main file.

  // Load the multer package as a module
  const multer = require("multer");
  
  // Access the exported service
  const upload = multer();

The following route accepts form data sent to the "/animals" route. Notice the use of app.post() instead of app.get() to handle POST HTTP requests, and the addition of upload.array() as a second parameter to add a body object containing the fields of the form to the request object.

  // Handle form data submission to the "/animals" route
  app.post("/animals", upload.array(), (request, response) => {
const name = request.body.name;
const vote = request.body.strongest;
response.send(`Hello ${name}, you voted: ${vote}`);
  });

The values of the name and vote variables are extracted from the request body, and a string is constructed and sent back to the client.