@prexjs/body-parser

Node.js body parsing middleware for JSON, URL-encoded, raw buffer, and text HTTP requests.

@prexjs/body-parser parses incoming request bodies in standard HTTP middleware pipelines before handlers receive them, populating req.body with parsed representations. It provides dedicated parsers for JSON, form URL-encoded data, raw binary buffers, and plain text.

Features

• JSON Parser (json): Parses JSON payloads with customizable revivers, strict typing mode, and size limits.
• URL-Encoded Parser (urlencoded): Parses UTF-8 URL-encoded form data with customizable depth and parameter limits.
• Raw Body Parser (raw): Parses incoming payloads into a binary Buffer with strict Content-Type checks.
• Text Parser (text): Parses request streams into string bodies with customizable character set decoders.
• Stream Inflation & Limit Control: Automatically uncompresses gzip/deflate streams and enforces byte limits.
• Standard Middleware Contract: Integrates seamlessly with Prex, Connect, and standard Node.js HTTP servers.

Installation

Install using your preferred package manager:

# npm
npm install @prexjs/body-parser

# pnpm
pnpm add @prexjs/body-parser

# Yarn
yarn add @prexjs/body-parser

# Bun
bun add @prexjs/body-parser

Quick start

import http from 'node:http';
import bodyParser, { json, urlencoded } from '@prexjs/body-parser';

// Create JSON middleware
const parseJson = json({ limit: '1mb' });
const parseUrlencoded = urlencoded({ extended: true });

const server = http.createServer((req: any, res) => {
  parseJson(req, res, (err) => {
    if (err) {
      res.statusCode = 400;
      res.end('Bad Request: Invalid JSON');
      return;
    }

    res.setHeader('Content-Type', 'application/json');
    res.end(JSON.stringify({ received: req.body }));
  });
});

server.listen(3000);

API

json(options?)

Returns middleware that only parses JSON and only looks at requests where the Content-Type header matches the type option.

• limit: Maximum request body size (default: '100kb').
• strict: When true, only accepts arrays and objects (default: true).
• reviver: Reviver function passed to JSON.parse.

urlencoded(options?)

Returns middleware that parses URL-encoded bodies (like HTML forms).

• extended: Parse with advanced query-string parser when true (default: true).
• limit: Maximum request body size (default: '100kb').
• parameterLimit: Maximum number of parameters allowed (default: 1000).

raw(options?)

Returns middleware that parses all bodies as a Buffer.

• limit: Maximum size (default: '100kb').
• type: Content-Type to match (default: 'application/octet-stream').

text(options?)

Returns middleware that parses all bodies as a string.

• limit: Maximum size (default: '100kb').
• defaultCharset: Default character encoding if unspecified in headers (default: 'utf-8').

Compatibility

• Node.js >= 18.0.0
• Supports both ESM and CommonJS
• TypeScript 5.0+

Related Packages

• @prexjs/raw-body: Core stream reader and byte limiter.
• @prexjs/http-errors: Standardized HTTP error generator.
• @prexjs/type-is: Content-Type matcher.

License

MIT