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63

How to parse multipart/form-data body with Koa?

rated 0 times [ 70] [ 7] / answers: 1 / hits: 33172 / 9 Years ago, tue, november 17, 2015, 12:00:00

Because I spent some (too much) time figuring out this simple requirement. I am documenting here the way to achieve multipart/form-data body parsing with Koa.

In my case, the reason of the confusion was the number of alternatives available out there:

koa-body

koa-better-body

koa-body-parser

koa-bodyparser

And I wanted to find the most minimalist/close to express/koa/node way/philosophy of doing things.

So here it is. Below. In accepted answer. Hope this helps.

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lamontm

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1 Year ago

answered 9 Years ago blaisep · Accepted Answer

You have to use koa-multer as stated in the official Koa wiki.

So a simple setup would look like:

const koa = require('koa');

const multer = require('koa-multer');



const app = koa();



app.use(multer());



app.use(function *() {

  this.body = this.req.body;

});

A couple of notes:

Multer will only parse bodies of requests of type multipart/form-data

Notice the use of this.req.body instead of Koa's supercharged this.request (not sure if this is intentional but this is confusing for sure... I would expect the parsed body to be available on this.request...)

And sending this HTML form as FormData:

<form>

  <input type=hidden name=topsecret value=1>

  <input type=text name=area51[lat] value=37.235065>

  <input type=text name=area51[lng] value=-115.811117>

  ...

</form>

Would give you access to nested properties as expected:

// -> console.log(this.req.body)

{

  topsecret: 1,

  area51: {

    lat: 37.235065,

    lng: -115.811117,

  }

}