koa-body

A full-featured koa body parser middleware. Supports multipart, urlencoded, and json request bodies. Provides the same functionality as Express's bodyParser - multer.

Install

Install with npm

npm install koa-body

Features

can handle requests such as:
- multipart/form-data
- application/x-www-urlencoded
- application/json
- application/json-patch+json
- application/vnd.api+json
- application/csp-report
- text/xml
option for patch to Koa or Node, or either
file uploads
body, fields and files size limiting

Hello World - Quickstart

npm install koa koa-body # Note that Koa requires Node.js 7.6.0+ for async/await support

index.js:

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

const app = new Koa();

app.use(koaBody());
app.use(ctx => {
  ctx.body = `Request Body: ${JSON.stringify(ctx.request.body)}`;
});

app.listen(3000);

node index.js
curl -i http://localhost:3000/users -d "name=test"

Output:

HTTP/1.1 200 OK
Content-Type: text/plain; charset=utf-8
Content-Length: 29
Date: Wed, 03 May 2017 02:09:44 GMT
Connection: keep-alive

Request Body: {"name":"test"}%

For a more comprehensive example, see examples/multipart.js

Usage with koa-router

It's generally better to only parse the body as needed, if using a router that supports middleware composition, we can inject it only for certain routes.

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

router.post('/users', koaBody(),
  (ctx) => {
    console.log(ctx.request.body);
    // => POST body
    ctx.body = JSON.stringify(ctx.request.body);
  }
);

app.use(router.routes());

app.listen(3000);
console.log('curl -i http://localhost:3000/users -d "name=test"');

Usage with unsupported text body type

For unsupported text body type, for example, text/xml, you can use the unparsed request body at ctx.request.body. For the text content type, the includeUnparsed setting is not required.

// xml-parse.js:
const Koa = require('koa');
const koaBody = require('koa-body');
const convert = require('xml-js');

const app = new Koa();

app.use(koaBody());
app.use(ctx => {
  const obj = convert.xml2js(ctx.request.body)
  ctx.body = `Request Body: ${JSON.stringify(obj)}`;
});

app.listen(3000);

node xml-parse.js
curl -i http://localhost:3000/users -H "Content-Type: text/xml" -d '<?xml version="1.0"?><catalog id="1"></catalog>'

Output:

HTTP/1.1 200 OK
Content-Type: text/plain; charset=utf-8
Content-Length: 135
Date: Tue, 09 Jun 2020 11:17:38 GMT
Connection: keep-alive

Request Body: {"declaration":{"attributes":{"version":"1.0"}},"elements":[{"type":"element","name":"catalog","attributes":{"id":"1"}}]}%

Options

Options available for koa-body. Four custom options, and others are from raw-body and formidable.

patchNode {Boolean} Patch request body to Node's ctx.req, default false
patchKoa {Boolean} Patch request body to Koa's ctx.request, default true
jsonLimit {String|Integer} The byte (if integer) limit of the JSON body, default 1mb
formLimit {String|Integer} The byte (if integer) limit of the form body, default 56kb
textLimit {String|Integer} The byte (if integer) limit of the text body, default 56kb
encoding {String} Sets encoding for incoming form fields, default utf-8
multipart {Boolean} Parse multipart bodies, default false
urlencoded {Boolean} Parse urlencoded bodies, default true
text {Boolean} Parse text bodies, such as XML, default true
json {Boolean} Parse JSON bodies, default true
jsonStrict {Boolean} Toggles co-body strict mode; if set to true - only parses arrays or objects, default true
includeUnparsed {Boolean} Toggles co-body returnRawBody option; if set to true, for form encoded and JSON requests the raw, unparsed request body will be attached to ctx.request.body using a Symbol (see details), default false
formidable {Object} Options to pass to the formidable multipart parser
onError {Function} Custom error handle, if throw an error, you can customize the response - onError(error, context), default will throw
strict {Boolean} DEPRECATED If enabled, don't parse GET, HEAD, DELETE requests, default true
parsedMethods {String[]} Declares the HTTP methods where bodies will be parsed, default ['POST', 'PUT', 'PATCH']. Replaces strict option.

A note about `parsedMethods`

see http://tools.ietf.org/html/draft-ietf-httpbis-p2-semantics-19#section-6.3

GET, HEAD, and DELETE requests have no defined semantics for the request body, but this doesn't mean they may not be valid in certain use cases.
koa-body is strict by default, parsing only POST, PUT, and PATCH requests

File Support

Uploaded files are accessible via ctx.request.files.

A note about unparsed request bodies

Some applications require crytopgraphic verification of request bodies, for example webhooks from slack or stripe. The unparsed body can be accessed if includeUnparsed is true in koa-body's options. When enabled, import the symbol for accessing the request body from unparsed = require('koa-body/unparsed.js'), or define your own accessor using unparsed = Symbol.for('unparsedBody'). Then the unparsed body is available using ctx.request.body[unparsed].

Some options for formidable

See node-formidable for a full list of options

maxFields {Integer} Limits the number of fields that the querystring parser will decode, default 1000
maxFieldsSize {Integer} Limits the amount of memory all fields together (except files) can allocate in bytes. If this value is exceeded, an 'error' event is emitted, default 2mb (2 * 1024 * 1024)
uploadDir {String} Sets the directory for placing file uploads in, default os.tmpDir()
keepExtensions {Boolean} Files written to uploadDir will include the extensions of the original files, default false
hash {String} If you want checksums calculated for incoming files, set this to either 'sha1' or 'md5', default false
multiples {Boolean} Multiple file uploads or no, default true
onFileBegin {Function} Special callback on file begin. The function is executed directly by formidable. It can be used to rename files before saving them to disk. See the docs

Changelog

Please see the Changelog for a summary of changes.

Tests

$ npm test

License

The MIT License, 2014 Charlike Mike Reagent (@tunnckoCore) and Daryl Lau (@daryllau)

glintik/koa-body