Rails: Conditional path in form partial - ruby-on-rails

Question

I have two forms for new and edit that I want to extract to a partial, but, to my begginer knowledge in Rails, they need different paths in order to work.
This is my edit form:
<%= simple_form_for [#user, #wiki], url: user_wiki_path do |f| %>
<%= f.input :title %>
<%= f.input :body %>
<%= f.submit class: "btn btn-success" %>
<% end %>
This is my new form:
<%= simple_form_for [#user, #wiki], url: user_wikis_path, method: :post do |f| %>
<%= f.input :title %>
<%= f.input :body %>
<%= f.submit class: "btn btn-success" %>
<% end %>
Can I, and if so, how, combine them into one partial _form.html.erb conditionally specifing the paths?
When I try joining them now I get the error below when trying to edit it:
No route matches [PATCH] "/users/32/wikis"
These are my routes:
Prefix Verb URI Pattern Controller#Action
users_index GET /users/index(.:format) users#index
users_show GET /users/show(.:format) users#show
root GET / pages#index
new_user_session GET /users/sign_in(.:format) devise/sessions#new
user_session POST /users/sign_in(.:format) devise/sessions#create
destroy_user_session DELETE /users/sign_out(.:format) devise/sessions#destroy
user_password POST /users/password(.:format) devise/passwords#create
new_user_password GET /users/password/new(.:format) devise/passwords#new
edit_user_password GET /users/password/edit(.:format) devise/passwords#edit
PATCH /users/password(.:format) devise/passwords#update
PUT /users/password(.:format) devise/passwords#update
cancel_user_registration GET /users/cancel(.:format) devise/registrations#cancel
user_registration POST /users(.:format) devise/registrations#create
new_user_registration GET /users/sign_up(.:format) devise/registrations#new
edit_user_registration GET /users/edit(.:format) devise/registrations#edit
PATCH /users(.:format) devise/registrations#update
PUT /users(.:format) devise/registrations#update
DELETE /users(.:format) devise/registrations#destroy
user_wikis POST /users/:user_id/wikis(.:format) wikis#create
new_user_wiki GET /users/:user_id/wikis/new(.:format) wikis#new
edit_user_wiki GET /users/:user_id/wikis/:id/edit(.:format) wikis#edit
user_wiki PATCH /users/:user_id/wikis/:id(.:format) wikis#update
PUT /users/:user_id/wikis/:id(.:format) wikis#update
DELETE /users/:user_id/wikis/:id(.:format) wikis#destroy
users GET /users(.:format) users#index
POST /users(.:format) users#create
new_user GET /users/new(.:format) users#new
edit_user GET /users/:id/edit(.:format) users#edit
user GET /users/:id(.:format) users#show
PATCH /users/:id(.:format) users#update
PUT /users/:id(.:format) users#update
DELETE /users/:id(.:format) users#destroy
wikis GET /wikis(.:format) wikis#index
wiki GET /wikis/:id(.:format) wikis#show
charges POST /charges(.:format) charges#create
new_charge GET /charges/new(.:format) charges#new
charge PATCH /charges/:id(.:format) charges#update
PUT /charges/:id(.:format) charges#update

Answer 1

You can post local variables into the partial. Something like the following would work:
new.html.erb
<%= render partial: '_form', locals: {url: user_wikis_path, method: :post} %>
edit.html.erb
<%= render partial: '_form', locals: {url: user_wiki_path(#user, #wiki), method: :post} %>
_form.html.erb
<%= simple_form_for [#user, #wiki], url: url, method: method do |f| %>
<%= f.input :title %>
<%= f.input :body %>
<%= f.submit class: "btn btn-success" %>
<% end %>
Or you could set #url and #method as instance variables and access them that way.
Controller
def new
#method = :get
#url = user_wikis_path
...
end
def edit
#method = :post
#url = user_wiki_path(#user, #wiki)
...
end
_form.html.erb
<%= simple_form_for [#user, #wiki], url: url, method: method do |f| %>
...
Or you could have a conditional in the form that accesses the current action, if you use action_name in the view it'll return the name of the current action.

Answer 2

# _form.html.erb
<%= simple_form_for #wiki do |f| %>
<%= f.input :title %>
<%= f.input :body %>
<%= f.submit class: "btn btn-success" %>
<% end %>
and on your wikis#edit and wikis#new, add
...
#user = User.find params[:user_id]
...