Question

我使用“rails generate scaffold project”来创建一个新的Web应用程序。我已经在Linux和Mac OSX上运行了其他版本的rails和ruby并且一切正常，但这次我正在使用Windows 7.这是我的环境

C:\Users\user1\Company>ruby -v
ruby 2.0.0p451 (2014-02-24) [x64-mingw32]

C:\Users\user1\Company>rails -v
DL is deprecated, please use Fiddle
Rails 4.1.0

C:\Users\user1\Company>

运行scaffold命令后，我运行了rake db：migrate，我能够成功创建我的第一个项目。然后我可以编辑项目，但是当我点击更新时，我收到以下错误消息

ArgumentError (When assigning attributes, you must pass a hash as an argument.):

完整服务器日志消息

Started PATCH "/projects/1" for 127.0.0.1 at 2014-04-29 05:16:33 -0700
Processing by projectsController#update as HTML
  Parameters: {"utf8"=>"√", "authenticity_token"=>"gST6BUQNwOZQDYVj60DXLuFANv1JsM02YAIM+xYwt/M=", "commit"=>"Update project", "id"=>"1"}
  project Load (0.0ms)  SELECT  "projects".* FROM "projects"  WHERE "projects"."id"= ? LIMIT 1  [["id", 1]]
   (1.0ms)  begin transaction
   (0.0ms)  rollback transaction
Completed 500 Internal Server Error in 10ms

ArgumentError (When assigning attributes, you must pass a hash as an argument.):

  app/controllers/projects_controller.rb:44:in `block in update'
  app/controllers/projects_controller.rb:43:in `update'

  Rendered C:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/actionpack-4.1.0/lib/action_dispatch/middleware/templates/rescues/_source.erb (2.0ms)
  Rendered C:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/actionpack-4.1.0/lib/action_dispatch/middleware/templates/rescues/_trace.html.erb (2.0ms)
  Rendered C:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/actionpack-4.1.0/lib/action_dispatch/middleware/templates/rescues/_request_and_response.html.erb (2.0ms)
  Rendered C:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/actionpack-4.1.0/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb within rescues/layout (104.0ms)

这是我的“更新”方法（由scaffold命令自动创建）

# PATCH/PUT /projects/1
# PATCH/PUT /projects/1.json
def update
  respond_to do |format|
    if @project.update(project_params)
      format.html { redirect_to @project, notice: 'Update Successful!' }
      format.json { render :show, status: :ok, location: @project }
    else
      format.html { render :edit }
      format.json { render json: @project.errors, status: :unprocessable_entity }
    end
  end
end

我尝试删除“PATCH /”关键字，但没有运气。我用以下内容替换了整个方法（这适用于我的其他应用程序，但这次不适用于Windows）

# PATCH/PUT /projects/1
# PATCH/PUT /projects/1.json
def update
  @project = Project.find(params[:id])

  if @project.update_attributes(params[:project])
    flash[:notice] = "Update Successful!"
  end
  respond_with(@project)
end

但这没有任何区别。

我也尝试过（我通过浏览SO找到了这个）

# PUT /projects/1
# PUT /projects/1.json
def update
  @project = Project.find(params[:id])

  respond_to do |format|
    if @project.update_attributes(params[:project])
      format.html { redirect_to @project, notice: 'Update Successful!' }
      format.json { head :ok }
    else
      format.html { render action: "edit" }
      format.json { render json: @project.errors, status: :unprocessable_entity }
    end
  end

但没有成功

以下是其他工作方法（全部由“rails generate scaffold”命令自动生成，并且它们都能正常工作）

# GET /projects
# GET /projects.json
def index
  @projects = project.all
end

# GET /projects/1
# GET /projects/1.json
def show
end

# GET /projects/new
def new
  @project = project.new
end

# GET /projects/1/edit
def edit
end

# POST /projects
# POST /projects.json
def create
  @project = project.new(project_params)

  respond_to do |format|
    if @project.save
      format.html { redirect_to @project, notice: 'Creation Successful!' }
      format.json { render :show, status: :created, location: @project }
    else
      format.html { render :new }
      format.json { render json: @project.errors, status: :unprocessable_entity }
    end
  end
end

为什么“rails generate scaffold”命令无法在Windows上运行并在Linux和Mac OSX上正常运行？

更新1

以下是“rails generate scaffold”命令

自动创建的其他方法

class ProjectsController < ApplicationController
  before_action :set_project, only: [:show, :edit, :update, :destroy]

  <other methods listed above : index, show, new, edit, create, update, and destroy>

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_project
      @project = Project.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def project_params
      params[:project]
    end
end

在进行Kirti Thorat建议的更改后的工作代码

这对我有用

# PATCH/PUT /projects/1
# PATCH/PUT /projects/1.json
def update

@project = Project.find(params[:id])

  respond_to do |format|
    if @project.update(project_params)
      format.html { redirect_to @project, notice: 'Project was successfully updated.' }
      format.json { render :show, status: :ok, location: @project }
    else
      format.html { render :edit }
      format.json { render json: @project.errors, status: :unprocessable_entity }
    end
  end
end

private
  # Use callbacks to share common setup or constraints between actions.
  def set_project
    @project = Project.find(params[:id])
  end

  # Never trust parameters from the scary internet, only allow the white list through.
  def project_params
    params.require(:project).permit(:UnitMgtAddress)
  end

Answer 1

您刚刚创建了一个没有任何其他字段的脚手架。因此，您的projects表只有3个默认字段id，created_at和updated_at。因为您在执行update时采取了以下措施：

if @project.update(project_params)

或者

if @project.update_attributes(params[:project])

您收到错误update而update_attributes需要Hash作为参数，params[:project]为零。查看服务器日志中的params哈希

{"utf8"=>"√", "authenticity_token"=>"gST6BUQNwOZQDYVj60DXLuFANv1JsM02YAIM+xYwt/M=", "commit"=>"Update project", "id"=>"1"}

它没有密钥project。

可能的解决方案

不添加新字段

如果您不打算在projects表格中添加任何新字段，那么在您更新的字段上进行update操作毫无意义吗？

添加新字段

您可以根据自己的要求向projects表添加新字段，例如name，duration等（通过创建迁移来添加新字段）。

在此之后，您只需要更新project_params方法，如下所示：

def project_params
  params.require(:project).permit(:name, :duration)
end

rails生成脚手架命令在Windows上导致ArgumentError

1 个答案:

可能的解决方案