Ruby on Rails path understanding - ruby-on-rails

Question

I want to update an existing title and a description . My items are called todo, and the database is todos(since I generate with the generate commant) .
The code that i have is
edit.html.erb :
<%= form_for :session, url: todos_path(#todo), method: :patch do |f| %>
<%= f.label :title %>
<%= f.text_field :title %>
<%= f.label :description %>
<%= f.text_field :description %>
<br />
<%= f.submit "Create" %>
<% end %>
routes.rb:
get "/todos", to: "todos#index"
get "/todos/new", to: "todos#new"
post "/todos", to: "todos#create"
delete "/todos/delete" , to: "todos#delete"
get "/todos/three", to: "todos#three"
post "/todos/edit", to: "todos#edit"
patch "/todos/edit", to: "todos#update"
# You can have the root of your site routed with "root"
root 'todos#index'
and finally the controller:
def edit
#todo = Todo.find_by_id(params[:id])
end
def update
todo = Todo.find_by_id(params[:session][:id])
todo.update(:description,params[:session][:description])
end
My problem is : I come from the index page with an ID and the edit function display me the item that I want, then I want to update the title and description field and to hit the f.submit button to update it. My issue is that the parameters don't come, I get todos.2 (which I guess it's the size of that :session hash ?).
I do not with to use <%= button_to %> since I saw it is not needed in all tutorials .
My question is where is my mistake, why don't the parameters come ?

Answer 1

Change in routes:
patch "/todos/:id", to: "todos#update", as: "update_todo"
In form:
<%= form_for #todo, url: update_todo_path(#todo), method: :patch, do |f| %>
In controller:
def update
#todo.update(params.require(:todo).permit(:title, :description))
#todo.save
end
If you want to know all existing routes, you may use:
$ rake routes
It will show table like
Prefix Verb URI Pattern Controller#Action
root GET / posts#index
sign_up GET /sign_up(.:format) users#new
where prefix will be you path url like 'sign_up' it is "sign_up_path" in controller/views.

Answer 2

Change routes to this:
patch "/todos/edit/:id", to: "todos#update", as: :update_todo
then form:
<%= form_for :session, url: update_todo_path(id: #todo.id), method: :patch do |f| %>
and then controller:
def update
todo = Todo.find(params[:id])
todo.update_attributes(params[:session].slice(:description))
end
However, I'd recommend you to stick with the convention instead of writing and defining your own named routes for such purposes.