Could not find devise mapping for path "/sessions/user" devise log in error

Be careful if you nave namespaced routes to declare the devise_scope a little different:

namespace :api, defaults: {format: 'json'} do   namespace :v1 do     devise_scope :api_v1_user do      ...    end  endend

in your routes.rb file, try wrapping your routes inside the scope block as the error message suggests.Here is an example:

devise_scope :user do   get "signup", to: "devise/registrations#new"   get "login", to: "devise/sessions#new"   get "logout", to: "devise/sessions#destroy"end

This will give you nicely named routes.

And by the way, if you are using Rails 4, get rid of the match method. you need to specify the HTTP verb.

OBSOLETE old answer:

(Below is the old obsolete version of the code, shown for reference. Use the code above.)

devise_for :users, path_names: { sign_in: 'login', sign_out: 'logout', sign_up: 'signup' }

AND

match '/sessions/user', to: 'devise/sessions#create', via: :post

This error (AbstractController::ActionNotFound - Could not find devise mapping for path) can arise if devise_scope is passed a plural scope instead of a singular scope.

The devise_for method takes a plural form of model scope (i.e. :users) whereas the devise_scope takes the singular form (i.e. :user).

From the devise documentations (http://www.rubydoc.info/github/plataformatec/devise/ActionDispatch%2FRouting%2FMapper%3Adevise_scope):

Also be aware of that 'devise_scope' and 'as' use the singular form of the noun where other devise route commands expect the plural form. This would be a good and working example.

devise_scope :user do  get "/some/route" => "some_devise_controller"enddevise_for :users