我正在使用 Rails 4 构建一个简单的 API，但是使用我的“创建”方法时，一切都出错了。

这是我的路线文件的相关部分:

namespace :api, defaults: { format: 'json' } do
         # /api/... Api::
        scope module: :v1, constraints: ApiConstraints.new(version: 1, default: true) do
        resources :users
    end
end

这是 api/v1/users_controller.rb:

class Api::V1::UsersController < ApplicationController

        protect_from_forgery except: :create
        respond_to :json

        def index
            respond_to do |format|
                format.html {render text: "Your data was sucessfully loaded. Thanks"}
                format.json { render text: User.last.to_json }
            end
        end

        def show
            respond_with User.find(params[:id])
        end

        def create
            respond_with User.create(user_params)
        end

        def update
            respond_with User.update(params[:id], params[:users])
        end

        def destroy
            respond_with User.destroy(params[:id])
        end

        private

            def user_params
              params.require(:user).permit(:name, :age, :location, :genre_ids         => [], :instrument_ids => [])
            end
    end

每当我尝试使用 JSON 添加 API 时，我都会收到“{"errors":{"name":["can't be blank"]}}"

它可以用我的常规 Controller 创建用户，但我感觉我的 API Controller 因为强参数而变得一团糟。

关于如何在 Rails 4 中正确执行此操作的任何建议？ 此外，我通过我的用户模型有一些 Has-Many-Through 关系。 API 的用户 Controller 应该能够马上看到，对吧？

谢谢

编辑:

我现在遇到这个错误:

编辑:

{
  "name": "Sally",
  "age": "23",
  "location": "Blue York",
  "genre_ids": [1, 2, 3]
}

再次编辑

即使在我的 JSON 调用中添加了 User 参数，它仍然给我相同的错误:user 参数丢失。我是否错误地使用了强参数？在我的“常规”users_controller 中，我可以使用我设置的表单轻松创建用户，但是使用这个 API Controller ，我似乎无法使用 JSON 创建用户。还有其他建议吗？

再次编辑 这是从开始到出错的日志

rails s
=> Booting WEBrick
=> Rails 4.0.1 application starting in development on http://0.0.0.0:3000
=> Run `rails server -h` for more startup options
=> Ctrl-C to shutdown server
[2013-12-19 14:03:01] INFO  WEBrick 1.3.1
[2013-12-19 14:03:01] INFO  ruby 1.9.3 (2013-02-22) [x86_64-darwin10.8.0]
[2013-12-19 14:03:01] INFO  WEBrick::HTTPServer#start: pid=53778 port=3000


 Started GET "/api/users" for 127.0.0.1 at 2013-12-19 14:03:02 -0500
 ActiveRecord::SchemaMigration Load (0.1ms)  SELECT "schema_migrations".* FROM  "schema_migrations"
 Processing by Api::V1::UsersController#index as JSON
 User Load (0.2ms)  SELECT "users".* FROM "users" ORDER BY "users"."id" DESC LIMIT 1
 Rendered text template (0.0ms)
 Completed 200 OK in 142ms (Views: 27.8ms | ActiveRecord: 0.6ms)
 [2013-12-19 14:03:03] WARN  Could not determine content-length of response body. Set   content-length of the response or set Response#chunked = true
 [2013-12-19 14:03:03] WARN  Could not determine content-length of response body. Set  content-length of the response or set Response#chunked = true


 Started POST "/api/users" for 127.0.0.1 at 2013-12-19 14:03:37 -0500
 Processing by Api::V1::UsersController#create as JSON
 Completed 400 Bad Request in 1ms

 ActionController::ParameterMissing (param not found: user):
 app/controllers/api/v1/users_controller.rb:40:in `user_params'
 app/controllers/api/v1/users_controller.rb:20:in `create'


 Rendered /usr/local/rvm/gems/ruby-1.9.3-p392/gems/actionpack-  4.0.1/lib/action_dispatch/middleware/templates/rescues/_source.erb (0.7ms)
 Rendered /usr/local/rvm/gems/ruby-1.9.3-p392/gems/actionpack-4.0.1/lib/action_dispatch/middleware/templates/rescues/_trace.erb (1.0ms)
 Rendered /usr/local/rvm/gems/ruby-1.9.3-p392/gems/actionpack-4.0.1/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb (0.8ms)
 Rendered /usr/local/rvm/gems/ruby-1.9.3-p392/gems/actionpack-  4.0.1/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb within rescues/layout   (31.6ms)

编辑#6 这是我的“真实”users_controller，它存在于我的应用程序中而不是我的 API 中。该表单从该 Controller 而非 API Controller 创建用户。

class UsersController < ApplicationController

  def index
    @users = User.all
    @genres = Genre.all
    @instruments = Instrument.all

    render json: @users
  end

  def new
    @user = User.new
  end

  def show
    @user = User.find(params[:id])
  end

  def create
    @user = User.new(user_params)

    if @user.save
      render json: @user, status: :created, location: @user
    else
      render json: @user.errors, status: :unprocessable_entity
    end
  end

  private

    def user_params
      params.require(:user).permit(:name, :age, :location, :genre_ids => [], :instrument_ids => [])
    end
end

另外 - 用户表单

<div class="row">
<div class="span6 offset3">
    <%= form_for(@user) do |f| %>

        <%= f.label :name %>
        <%= f.text_field :name %>

        <%= f.label :age %>
        <%= f.text_field :age %>

        <%= f.label :email %>
        <%= f.text_field :email %>

        <%= f.label :location %>
        <%= f.text_field :location %>

        <br>

        <% Genre.all.each do |genre| %>
            <%= check_box_tag "user[genre_ids][]", genre.id %>
            <%= genre.name %><br>
        <% end %>

        <br>

        <% Instrument.all.each do |instrument| %>
            <%= check_box_tag "user[instrument_ids][]", instrument.id %>
            <%= instrument.name %><br>
        <% end %>

        <%= f.submit "Create My Account!" %>
    <% end %>
   </div>
  </div>

 <%= users_path %>

这是我的 user.rb 文件

class User < ActiveRecord::Base

validates :name, presence: true, length: { maximum: 50 }
has_many :generalizations
has_many :genres, through: :generalizations

has_many :instrumentations
has_many :instruments, through: :instrumentations

end

这是我的路由文件中的内容:

namespace :api do
   namespace :v1 do
      resources :users
   end
end

我的 POST 请求

POST/api/v1/users HTTP/1.1 主机:本地主机:3000 缓存控制:无缓存

{ "user": { "name": "Sally", "age": "23", "location": "Blue York", "genre_ids": [1, 2, 3] } }

更新

我将我的强参数更改为:

def user_params
    params.require(:user).permit(:name, :age, :location, :genre_ids => [],   :instrument_ids => []) if params[:user]
end

所以末尾的“if”语句使错误消失，但每当我发布到我的 API 时，它都会返回“null”。所以这可能是与以前相同的问题，但以不同的方式显示。但与此同时，这可能是进步!

这是上次更新的日志

Started POST "/api/v1/users" for 127.0.0.1 at 2013-12-21 11:38:03 -0500
Processing by API::V1::UsersController#create as */*
(0.1ms)  begin transaction
[deprecated] I18n.enforce_available_locales will default to true in the future. If you really want to skip validation of your locale you can set I18n.enforce_available_locales = false to avoid this message.
(0.1ms)  rollback transaction
User Load (0.1ms)  SELECT "users".* FROM "users" ORDER BY "users"."id" DESC LIMIT 1
Rendered text template (0.0ms)
Completed 200 OK in 20ms (Views: 0.3ms | ActiveRecord: 0.6ms)

最终更新 我遗漏了一些东西，但最主要的是我遗漏了“Content-Type - application/json”作为我的标题。 我觉得很有成就感!感谢大家的帮助!

最佳答案

根据您发布的 JSON 中的代码参数，您应该在 params[:user] 中。所以 JSON 应该是这样的:

{
  "user": {
    "name": "Sally",
    "age": "23",
    "location": "Blue York",
    "genre_ids": [1, 2, 3]
  }
}

关于ruby-on-rails - 具有强参数的 Rails 4 API？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/20667404/