How to make a form-data request with koa? - node.js

Question

I am trying to replicate a login form's behaviour through koa.
The login form does:
<form id="loginForm" method="post" action="http://myaddress:3000/auth" enctype="multipart/form-data">
I'm using the koa request and form-data modules:
var form = new FormData();
form.append('identification', 'userId');
form.append('password', 'userPassword');
var options = {
url: DB_SERVER_URL + 'auth',
method: 'POST',
formData: form
};
var response = yield request(options);
console.log('response.statusCode: ' + response.statusCode);
But I always get a 400 response.
I've tried just using form.submit(DB_SERVER_URL + 'auth', function(err, res) { ... } which works, but I like koa's yield functionality and ideally I want to avoid having to deal with callbacks.
Any ideas?

Answer 1

Koa accepts multiple yield inputs that can be obtained from your current code more or less easily depending on your current setup:
a promise. As form-data doesn't seem to use them, we'll create one with Q
var Q = require('q');
var promise = Q.ninvoke(form, "submit", DB_SERVER_URL + 'auth');
var response = yield promise;
console.log('response.statusCode: ' + response.statusCode);
or a thunk, a wrapper function as you used in your answer, but there are libraries that can handle the wrapping for you (here, thunkify-wrap):
var thunkify = require('thunkify-wrap');
var submit = thunkify(form.submit, form); // the context is needed in this case
var response = yield submit(DB_SERVER_URL + 'auth');
console.log('response.statusCode: ' + response.statusCode);

Answer 2

I ended up using form.submit(DB_SERVER_URL + 'auth', function(err, res) { ... }, but wrapped the callbacks so I could use yield to maintain a synchronous control flow.
Here's my wrapper for the callback to the form.submit to receive the response:
function makeLoginRequest(formData) {
var form = new FormData();
form.append('identification', formData.identification);
form.append('password', formData.password);
var DB_SERVER_URL = 'http://myurl:3000/';
return function(callback) {
form.submit(DB_SERVER_URL + 'auth', function(error, response) {
callback(error, response);
});
}
}
And here's my wrapper for the callback for receiving the response body:
function getLoginResponseData(response) {
return function(callback) {
response.on("data", function(chunk) {
callback(null, chunk);
});
}
}
This lets me use yield to maintain a synchronous control flow:
var response = yield makeLoginRequest(this.request.body);
console.log('response.statusCode: ' + response.statusCode);
var chunk = yield getLoginResponseData(response);
console.log("BODY: " + chunk);
I'm a node and koa beginner, so if you have a better way please let me know!

Answer 3

If you are using koa-request I was able to do this.
const request = require('koa-request');
const response = yield request({
method: 'POST',
url: 'https://whatsever.com',
form: {
itema: 'vala',
itemb: 'valb',
},
headers: {
'Content-type': 'application/x-www-form-urlencoded'
}
});
this.body = response.body;
If you need multipart look here: https://www.npmjs.com/package/request#multipartform-data-multipart-form-uploads.
Remember that koa-request wraps therequest module