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a body parser for koa


A body parser for koa, base on co-body. support json, form and text type body.

var koa = require('koa');
var bodyParser = require('koa-bodyparser');
var app = koa();
app.use(function *() {
  // the parsed body will store in this.request.body 
  // if nothing was parsed, body will be an empty object {} 
  this.body = this.request.body;
  • enableTypes: parser will only parse when request type hits enableTypes, default is ['json', 'form'].

  • encode: requested encoding. Default is utf-8 by co-body.

  • formLimit: limit of the urlencoded body. If the body ends up being larger than this limit, a 413 error code is returned. Default is 56kb.

  • jsonLimit: limit of the json body. Default is 1mb.

  • textLimit: limit of the text body. Default is 1mb.

  • strict: when set to true, JSON parser will only accept arrays and objects. Default is true. See strict mode in co-body. In strict mode, this.request.body will always be an object(or array), this avoid lots of type judging. But text body will always return string type.

  • detectJSON: custom json request detect function. Default is null.

      detectJSON: function (ctx) {
        return /\.json$/i.test(ctx.path);
  • extendTypes: support extend types:

      extendTypes: {
        json: ['application/x-javascript'] // will parse application/x-javascript type body as a JSON string 
  • onerror: support custom error handle, if koa-bodyparser throw an error, you can customize the response like:

      onerror: function (err, ctx) {
        ctx.throw('body parse error', 422);

To use koa-bodyparser with koa@2, please use

npm install koa-bodyparser@next --save