当错误相关时从控制器显示错误的正确方法

Question

我的项目模型与用户（成员）有多对多的关系。我有一个邀请表，允许用户输入电子邮件以将成员添加到项目中。如果用户输入了无效的电子邮件地址或与数据库中的用户不相关的电子邮件，则不会显示错误。我想提供一条错误消息。实现这一目标的最佳方法是什么？

我在项目模型上创建了invite 方法，并且仅当邀请控制器中存在@user 时才运行它。我想提供一条错误消息，指出由于用户不存在而未添加成员。

邀请函

<%= form_with(url: "/projects/#{@project.id}/invitation", method: "post") do %>
  <div class="mb-3">
    <%= text_field_tag :email, nil, class: "border border-gray rounded w-ful py-2 px-3", placeholder: "Email Address", autofocus: true %>
  </div>
  <%= submit_tag("Invite", class: 'button') %>
<% end %>

邀请控制器

module Projects
  class InvitationController < ApplicationController
    before_action :set_user

    # POST /projects/{id}/invitation
    # POST /projects/{id}/invitation.json
    def create
      @project = Project.find(params[:project_id])
      if @user
        @project.invite(@user)
      end
      respond_to do |format|
        if @project.save
          format.html { redirect_to @project, notice: "User was successfully added." }
          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

    private

    def set_user
      @user = User.with_email(params[:email]).first
    end
  end
end

项目模型

class Project < ApplicationRecord
  include ActivityRecorder
  belongs_to :user
  has_many :tasks
  has_many :activities, -> { order(created_at: :desc) }
  has_many :subjects, -> { order(created_at: :desc) }, as: 'subject'
  has_and_belongs_to_many :members,
                          class_name: 'User',
                          join_table: "members_projects",
                          foreign_key: "projects_id",
                          association_foreign_key: "users_id"

  validates_presence_of :title, :description, :user

  def invite(user)
    self.members << user unless self.members.include?(user)
  end
end

用户模型

class User < ApplicationRecord
  # Include default devise modules. Others available are:
  # :confirmable, :lockable, :timeoutable, :trackable and :omniauthable
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :validatable

  has_many :projects
  has_and_belongs_to_many :projects_as_member,
                          class_name: 'Project',
                          join_table: "members_projects",
                          foreign_key: "users_id",
                          association_foreign_key: "projects_id"

  scope :with_email, ->(email) { where("email = ?", email) }

  def get_md5_email
    Digest::MD5.hexdigest(self.email)
  end

end

项目控制器

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

  # GET /projects
  # GET /projects.json
  def index
   @projects = Project.where(user: current_user).or(Project.where(id: current_user)).order('updated_at DESC')
  end

  # GET /projects/1
  # GET /projects/1.json
  def show
    @task = Task.new
  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)
    @project.user = current_user
    respond_to do |format|
      if @project.save
        format.html { redirect_to @project, notice: "Project was successfully created." }
        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

  # 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: "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

  # DELETE /projects/1
  # DELETE /projects/1.json
  def destroy
    @project.destroy
    respond_to do |format|
      format.html { redirect_to projects_url, notice: "Project was successfully destroyed." }
      format.json { head :no_content }
    end
  end

  private

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

  # Only allow a list of trusted parameters through.
  def project_params
    params.require(:project).permit(:title, :description, :notes)
  end

  def verify_project_access
    if @project.user != current_user
      flash[:danger] = "You don't have access this project"
      redirect_to projects_url
    end
  end
end

Answer 1

我希望有更好的方法来做到这一点，但我只是简单地结束了：

if @user
  @project.invite(@user)
else
  redirect_to @project, alert: "Invalid user was entered"
  return
end

邀请控制器

module Projects
  class InvitationController < ApplicationController
    before_action :set_user

    # POST /projects/{id}/invitation
    # POST /projects/{id}/invitation.json
    def create
      @project = Project.find(params[:project_id])
      if @user
        @project.invite(@user)
      else
        redirect_to @project, alert: "Invalid user was entered"
        return
      end
      respond_to do |format|
        if @project.save
          format.html { redirect_to @project, notice: "User was successfully added." }
          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

    private

    def set_user
      @user = User.with_email(params[:email]).first
    end
  end
end