als-body-parser

als-body-parser is a flexible middleware for parsing incoming request bodies in a Node.js environment, making it easy to integrate with frameworks like Express or with the native HTTP server. It adds a req.body property to the incoming request object, which can be a JSON object, URL-encoded string, or plain text, depending on the Content-Type of the request.

Installation

Install using npm:

npm install als-body-parser

Basic Usage

With Native HTTP Server

const http = require('http');
const bodyParser = require('als-body-parser')({});

// Create HTTP server and use bodyParser middleware
http.createServer((req, res) => {
  bodyParser(req, res, () => {
    if (req.body) {
      // Send parsed body back as JSON
      res.writeHead(200, { 'Content-Type': 'application/json' });
      res.end(JSON.stringify(req.body));
    } else {
      // Handle cases where no body could be parsed
      res.writeHead(400);
      res.end('No body parsed');
    }
  });
}).listen(3000);

With Express

const express = require('express');
const bodyParser = require('als-body-parser')({});

const app = express();
app.use(bodyParser);

app.post('/data', (req, res) => {
  res.json(req.body);
});

app.listen(3000);

Advanced Usage

Configuration Options

als-body-parser can be customized with several options:

• supportedMethods: Array of HTTP methods to parse (default: ['POST', 'PUT', 'PATCH']).
• supportedCt: Array of supported content types (default: ['application/x-www-form-urlencoded', 'application/json', 'text/plain']).
• limit: Maximum allowed size of the request body in bytes (default: 1048576).
• timeout: Timeout in milliseconds for receiving the request body (default: 5000).
• logger: Function to log errors (default: console.log).
• httpErrorHandler: Function to handle HTTP errors, expects (res, status, message) (default handles by setting response headers and ending the request).

Customizing Behavior

Changing Supported Methods and Content Types

const bodyParser = require('als-body-parser')({
  supportedMethods: ['POST'],
  supportedCt: ['application/json']
});

app.use(bodyParser);

Custom Error Handling and Logging

const bodyParser = require('als-body-parser')({
  httpErrorHandler: (res, status, message) => {
    res.status(status).send({ error: message });
  },
  logger: (error) => customLogger.error(error)
});

app.use(bodyParser);

Status Codes

The middleware can terminate the request with the following status codes under certain conditions:

• 413 (Content Too Large): If the body exceeds the specified limit.
• 400 (Bad Request): If the body cannot be parsed correctly (e.g., malformed JSON).
• 408 (Request Timeout): If the full body is not received within the specified timeout.

req.body

Depending on the Content-Type, req.body may be:

• An object, for JSON requests.
• A string, for URL-encoded or plain text requests.
• Undefined, if the content type is not supported or no body data is provided.