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.
@fastify/formbody
A simple plugin for Fastify that adds a content type parser for
the content type application/x-www-form-urlencoded
.
This branch targets Fastify v3. Please refer to this branch and related versions for Fastify ^2.0.0
compatibility.
Example
Given the following code:
const fastify = require('fastify')()
fastify.register(require('@fastify/formbody'))
fastify.post('/', (req, reply) => {
reply.send(req.body)
})
fastify.listen(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