ruby-on-rails undefined method `id' for nil：rails中的NilClass错误

hs1ihplo 于 2023-05-13 发布在 Ruby

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Rails returns NoMethodError in Bookings#create Showing /home/mwenyewe/TOP/Fullstack_Ruby_on_Rails/Ruby_on_Rails/flight-booker/app/views/bookings/new.html.erb where line #3 raised：undefined method `id' for nil：NilClass当我尝试提交乘客详细信息时。这是我的Booking new.html.erb

<%= form_with model: @booking do |form| %>
  <%= form.label :flight, 'Flight ID' %>
  <%= form.text_field :flight, value: @flight.id, readonly: true, disabled: true %>
  <%= form.hidden_field :flight_id, value: @flight.id %>
  
  <%= form.label :date, 'Date' %>
  <%= form.text_field :date, value: @flight.start, readonly: true, disabled: true %><br>

  <%= form.label :departure_airport, 'Departure Airport' %>
  <%= form.text_field :departure_airport, value: @flight.departure_airport.code, readonly: true, disabled: true %>
  
  <%= form.label :arrival_airport, 'Arrival Airport' %>
  <%= form.text_field :arrival_airport, value: @flight.arrival_airport.code, readonly: true, disabled: true %><br>

  <% @booking.passengers.each do |passenger| %>
    <%= form.fields_for :passengers_attributes, passenger do |p| %>
      <%= p.hidden_field :id, value: p.object.id %>

      <%= p.label :name %>
      <%= p.text_field :name %>
        
      <%= p.label :email %>
      <%= p.email_field :email %><br><br>  
    <% end %>
  <% end %>
  <%= form.submit %><br>
<% end %>

表格的第一部分应该显示乘客选择的航班细节。第二个表单允许用户输入乘客详细信息。这是我的控制器：

class BookingsController < ApplicationController
  def new
    @booking = Booking.new
    @flight = Flight.find(params[:flight_id])
    params[:tickets].to_i.times{ @booking.passengers.build }
  end

  def create
    @booking = Booking.new(booking_params)

    if @booking.save
      redirect_to flights_path
    else
      render :new, status: :unprocessable_entity
    end
  end

  private

  def booking_params
    params.require(:booking).permit(:flight_id, passengers_attributes: [:id, :name, :email])
  end
end

下面是Flight索引视图，它应该发送flight_id：

<%= form_with url: new_booking_path, method: :get do |f| %>
      <% @found_flights.each do |flight| %>
        <%= f.radio_button :flight_id, flight.id %>
        <%= f.label "flight_#{flight.id}" do %>
        
          From: <%= flight.departure_airport.code %>
          To: <%= flight.arrival_airport.code %>
          Date: <%= flight.start.to_fs(:long) %>
          Tickets: <%= request.query_parameters[:flight][:tickets] %>
        <% end %>
        <%= f.hidden_field :tickets, value: request.query_parameters[:flight][:tickets] %>
      <% end %>
    <%= f.submit 'Select Flight' %>
    <% end %>

我已经试着按照参数传递，但一切似乎都在做它的工作。即使没有传递flight_id，它也会向用户显示航班的详细信息。

ruby-on-rails

来源：https://stackoverflow.com/questions/76229510/undefined-method-id-for-nilnilclass-error-in-rails

1条答案

按热度按时间

oymdgrw71#

我发现我的模特们都很臃肿，是罪魁祸首，虽然我不知道是怎么回事，但我还没有找到答案。以下是我编辑之前的模型：

<---app/models/booking.rb--->
class Booking < ApplicationRecord
  belongs_to :flight, class_name: 'Flight', foreign_key: 'flight_id'
  has_many :passengers, class_name: 'Passenger', foreign_key: 'booking_id'
  accepts_nested_attributes_for :passengers
end

<---app/models/flight.rb--->
class Flight < ApplicationRecord
  belongs_to :departure_airport, class_name: "Airport", foreign_key: "departure_airport_id"
  belongs_to :arrival_airport, class_name: "Airport", foreign_key: "arrival_airport_id"
  has_many :bookings, class_name: "Booking", foreign_key: "flight_id"
end

<---app/models/passenger.rb--->
class Passenger < ApplicationRecord
  belongs_to :booking, class_name: 'Booking', foreign_key: 'booking_id'
end

现在这里是之后：

<---app/models/booking.rb--->
class Booking < ApplicationRecord
  belongs_to :flight, class_name: 'Flight', foreign_key: 'flight_id'
  has_many :passengers
  accepts_nested_attributes_for :passengers
end

<---app/models/flight.rb--->
class Flight < ApplicationRecord
  belongs_to :departure_airport, class_name: "Airport", foreign_key: "departure_airport_id"
  belongs_to :arrival_airport, class_name: "Airport", foreign_key: "arrival_airport_id"
  has_many :bookings
end

<---app/models/passenger.rb--->
class Passenger < ApplicationRecord
  belongs_to :booking
end

正如你所看到的，我把它修剪下来，试图找到bug。我仍然不知道它是如何导致的错误，但我喜欢我的应用程序没有错误。如果有经验的人能告诉我是什么导致了这个bug，我将不胜感激。

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ruby-on-rails undefined method `id' for nil：rails中的NilClass错误

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