Why does my form always get submitted with Content-Type:application/x-www-form-urlencoded;

[JohnSmall]

I'm trying to send a form with Content-Type:application/json; I set

`<form data-remote="true" data-type="json">...</form>`

As it says in the documentation.

But it's always sent as Content-Type:application/x-www-form-urlencoded;

Is this a bug or is there a special undocumented gotcha such that setting data-type='json' doesn't actually send json encoded data.

[jeremy]

What are you seeing when you step through in the debugger?

[l4cr0ss]

I have the same problem. With data-remote: true my form is still being submitted as 'Content-Type': 'application/x-www-form-urlencoded'.

See this example repl.it that illustrates the problem. Try and submit the form without any input and notice that www-form-urlencoded is submitted and HTML is returned, even though form has data-remote: true set.

https://repl.it/repls/TriangularEmptyWireframes

[l4cr0ss]

It looks like this could be related to rails/rails#20610. Adding a format.js to the respond block fixes the return type issue (it returns JSON instead of HTML). However, the rails-ujs parser still breaks because it's expecting HTML.

[l4cr0ss]

Setting data type to json fixes the issue, like form_with(..., data: { type: 'json' }) do |form|..

Doing this means you don't have to create a format.js response