koa-body

What is koa-body?

koa-body is a middleware for Koa that parses incoming request bodies in various formats, including JSON, URL-encoded, and multipart forms. It simplifies handling file uploads and form submissions in Koa applications.

What are koa-body's main functionalities?

JSON Body Parsing

This feature allows you to parse JSON bodies from incoming requests. The middleware automatically parses the JSON and makes it available in `ctx.request.body`.

const Koa = require('koa');
const koaBody = require('koa-body');
const app = new Koa();

app.use(koaBody());

app.use(async ctx => {
  if (ctx.method === 'POST') {
    ctx.body = `Received JSON data: ${JSON.stringify(ctx.request.body)}`;
  } else {
    ctx.body = 'Send a POST request with JSON data';
  }
});

app.listen(3000);

URL-encoded Body Parsing

This feature allows you to parse URL-encoded bodies from incoming requests. The middleware automatically parses the URL-encoded data and makes it available in `ctx.request.body`.

const Koa = require('koa');
const koaBody = require('koa-body');
const app = new Koa();

app.use(koaBody({ urlencoded: true }));

app.use(async ctx => {
  if (ctx.method === 'POST') {
    ctx.body = `Received URL-encoded data: ${JSON.stringify(ctx.request.body)}`;
  } else {
    ctx.body = 'Send a POST request with URL-encoded data';
  }
});

app.listen(3000);

Multipart Form Parsing

This feature allows you to parse multipart form data, which is commonly used for file uploads. The middleware automatically parses the multipart data and makes it available in `ctx.request.files`.

const Koa = require('koa');
const koaBody = require('koa-body');
const app = new Koa();

app.use(koaBody({ multipart: true }));

app.use(async ctx => {
  if (ctx.method === 'POST') {
    const files = ctx.request.files;
    ctx.body = `Received files: ${JSON.stringify(files)}`;
  } else {
    ctx.body = 'Send a POST request with multipart form data';
  }
});

app.listen(3000);

Other packages similar to koa-body

koa-bodyparser

koa-bodyparser is a middleware for Koa that parses JSON and URL-encoded request bodies. It is simpler and more lightweight compared to koa-body, but it does not support multipart form data parsing.

koa-multer

koa-multer is a middleware for handling multipart/form-data, which is primarily used for uploading files. It is similar to koa-body in terms of file upload capabilities but does not handle JSON or URL-encoded bodies.

koa-better-body

koa-better-body is a more feature-rich alternative to koa-body, supporting JSON, URL-encoded, and multipart form data parsing. It also offers additional features like custom body parsers and file renaming.

README