Controller method #show getting called

Question

I have a link on my #index view:

<%= link_to 'Export Calendar (ICS)', { controller: :tickets, action: :ics_export, format: :ics }, class: "class-needed right" %>

routes.rb that pertains to this:

resources :tickets
get 'tickets/calendar' => 'tickets#ics_export'
post 'tickets' => 'tickets#index'
patch 'tickets/:id/close' => 'tickets#close', as: 'close_ticket'
post 'tickets/:id' => 'ticket_comments#create'

My TicketsController that pertains:

before_action :set_ticket, only: [:show, :edit, :destroy, :update, :close]

def show
  @ticket_comment = TicketComment.new
end

def ics_export
  tickets = Ticket.all
  respond_to do |format|
    format.html
    format.ics do
      cal = Icalendar::Calendar.new
      tickets.each do |ticket|
        event = Icalendar::Event.new
        event.dtstart = ticket.start
        event.description = ticket.summary
        cal.add_event(event)
      end
      cal.publish
      render :text =>  cal.to_ical
    end
  end
end

private
def set_ticket
  @ticket = Ticket.find(params[:id])
end

And when I click the link, it takes me to /tickets/calendar.ics which is correct but I get the following error:

ActiveRecord::RecordNotFound in TicketsController#show

Couldn't find Ticket with 'id'=calendar

Extracted source (around line #83):

 private
 def set_ticket
   @ticket = Ticket.find(params[:id])
 end

The @ticket = Ticket.find(params[:id]) is highlighted. Which make sense that it is failing to call a ticket with an id of calendar.

Request has parameters:

{"id"=>"calendar", "format"=>"ics"}

How do I fix this error? Why is it calling the show action?

Answer 1

There is a footnote in the canonical Rails Routing from the Outside In to the effect:

Rails routes are matched in the order they are specified, so if you have a resources :photos above a get 'photos/poll' the show action's route for the resources line will be matched before the get line. To fix this, move the get line above the resources line so that it is matched first.

As commented, the fix is to specify get 'tickets/calendar' => ... ahead of resources :tickets. If the order of routes is in question, you can run rake routes, which, to the best of my knowledge, should render your routes in the order they are checked.