Rails 4 not changing post method to patch

Question

I am trying to submit a form, but if I just put form_for @classroom I get a \"No route matches [POST]\" error.

Now with the code posted below, I get th

Answer 1

After some more trial and error, I realised I had left some plain input tags in a deeper nested level of the form (instead of going with the normal fields_for and separate builders for each level). I guess that somehow screwed up the relations and affected the method of the parent form.

That was such a mind blending mess up.

Edit: Andylee's answer is right. What I and Jeremy mention was probably the actual issue going on and not what was originally assumed to be the problem (as mentioned in the title).

Answer 2

form_for takes an object as first argument, and its usually better to keep the REST-like way of rails handling the update method.

The action of you html form displays "/classrooms/23/edit" so yes it won't work.

form_for(@classroom, url: update_classroom_path(@classroom), method: "patch")

Answer 3

To add a bit of specificity, to Tashow's answer above (which set me on the right track), I had some hidden fields that look'd like this, in a nested form.:

<%= hidden_field_tag("Classroom[classroom_teachers_attributes][]", nil) %>
<%= hidden_field_tag("Classroom[classroom_teachers_attributes][]", '') %>

Once I got rid of these, everything began working properly again. (There still remained similar-looking <input> tags generated by fields_for, etc.)

Answer 4

Just to answer your question from title, I think your form method is "PATCH" indeed. Refer to the guide http://guides.rubyonrails.org/form_helpers.html about how rails makes a patch form.

The Rails framework encourages RESTful design of your applications, which means you'll be making a lot of "PATCH" and "DELETE" requests (besides "GET" and "POST"). However, most browsers don't support methods other than "GET" and "POST" when it comes to submitting forms.

Rails works around this issue by emulating other methods over POST with a hidden input named "_method", which is set to reflect the desired method: