@fastify/formbody

What is @fastify/formbody?

@fastify/formbody is a Fastify plugin that parses x-www-form-urlencoded bodies. It is useful for handling form submissions in Fastify applications.

What are @fastify/formbody's main functionalities?

Basic Form Body Parsing

This feature allows you to parse form data sent with the 'application/x-www-form-urlencoded' content type. The parsed data is available in the `request.body` object.

const fastify = require('fastify')();
const formbody = require('@fastify/formbody');

fastify.register(formbody);

fastify.post('/submit', (request, reply) => {
  const { name, age } = request.body;
  reply.send({ name, age });
});

fastify.listen(3000, err => {
  if (err) throw err;
  console.log('Server listening on http://localhost:3000');
});

Custom Body Limit

This feature allows you to set a custom limit for the size of the body that can be parsed. In this example, the limit is set to 1 MB.

const fastify = require('fastify')();
const formbody = require('@fastify/formbody');

fastify.register(formbody, { bodyLimit: 1048576 }); // 1 MB limit

fastify.post('/submit', (request, reply) => {
  const { name, age } = request.body;
  reply.send({ name, age });
});

fastify.listen(3000, err => {
  if (err) throw err;
  console.log('Server listening on http://localhost:3000');
});

Handling Nested Objects

This feature allows you to handle nested objects in form data. The nested objects are automatically parsed and available in the `request.body` object.

const fastify = require('fastify')();
const formbody = require('@fastify/formbody');

fastify.register(formbody);

fastify.post('/submit', (request, reply) => {
  const { user } = request.body; // user is an object with nested properties
  reply.send(user);
});

fastify.listen(3000, err => {
  if (err) throw err;
  console.log('Server listening on http://localhost:3000');
});

Other packages similar to @fastify/formbody

body-parser

body-parser is a popular middleware for parsing request bodies in Express applications. It supports various content types including JSON, raw, text, and URL-encoded form data. Compared to @fastify/formbody, body-parser is more versatile but is designed specifically for Express.

qs

qs is a query string parsing and stringifying library with support for nested objects. It can be used to parse URL-encoded form data in various frameworks. While qs is not a Fastify plugin, it can be used in conjunction with Fastify to achieve similar functionality to @fastify/formbody.

formidable

formidable is a Node.js module for parsing form data, especially file uploads. It supports multipart and URL-encoded form data. While formidable is more focused on file uploads, it can also handle URL-encoded data, making it a more comprehensive solution compared to @fastify/formbody.

README

@fastify/formbody

A simple plugin for Fastify that adds a content type parser for the content type application/x-www-form-urlencoded.

Install

npm i @fastify/formbody

Compatibility

Plugin version	Fastify version
^8.x	^5.x
^7.x	^4.x
^6.x	^3.x
^3.x	^2.x
^2.x	^1.x

Please note that if a Fastify version is out of support, then so are the corresponding versions of this plugin in the table above. See Fastify's LTS policy for more details.

Example

Given the following code:

const fastify = require('fastify')()

fastify.register(require('@fastify/formbody'))

fastify.post('/', (req, reply) => {
  reply.send(req.body)
})

fastify.listen({ port: 8000 }, (err) => {
  if (err) throw err
})

And a POST body of:

foo=foo&bar=bar&answer=42

The sent reply would be the object:

{
  foo: 'foo',
  bar: 'bar',
  answer: 42
}

Options

The plugin accepts an options object with the following properties:

• bodyLimit: The maximum amount of bytes to process before returning an error. If the limit is exceeded, a 500 error will be returned immediately. When set to undefined the limit will be set to whatever is configured on the parent Fastify instance. The default value is whatever is configured in fastify (1048576 by default).
• parser: The default parser used is the querystring.parse built-in. You can change this default by passing a parser function e.g. fastify.register(require('@fastify/formbody'), { parser: str => myParser(str) })

Upgrading from 4.x

Previously, the external qs lib was used that did things like parse nested objects. For example:

• Input: foo[one]=foo&foo[two]=bar
• Parsed: { foo: { one: 'foo', two: 'bar' } }

The way this is handled now using the built-in querystring.parse:

• Input: foo[one]=foo&foo[two]=bar
• Parsed: { 'foo[one]': 'foo', 'foo[two]': 'bar' }

If you need nested parsing, you must configure it manually by installing the qs lib (npm i qs), and then configure an optional parser:

const fastify = require('fastify')()
const qs = require('qs')
fastify.register(require('@fastify/formbody'), { parser: str => qs.parse(str) })

License

Licensed under MIT.