NoMethodError though method has been defined

Question

I have a Ruby On Rails weblog application and am getting a NoMethodError in PostsController#show issue when opening a post. PostsController is stored under rails/weblog/app/controllers

I get undefined method 'set_current_page' for #<PostsController:0x007fb162831e70> however set_current_page is defined like so:

  private 
   def set_current_page 
      @current_page = params[:page] || 1 
   end
end

and then used in a before_action

before_action :set_current_page, except: [:index]
before_action :set_post, only: [:show, :edit, :update, :destroy]

Full stack trace:

activesupport (5.0.0.1) lib/active_support/callbacks.rb:382:in `block in make_lambda'
activesupport (5.0.0.1) lib/active_support/callbacks.rb:150:in `block (2 levels) in halting_and_conditional'
actionpack (5.0.0.1) lib/abstract_controller/callbacks.rb:12:in `block (2 levels) in <module:Callbacks>'
activesupport (5.0.0.1) lib/active_support/callbacks.rb:151:in `block in halting_and_conditional'
activesupport (5.0.0.1) lib/active_support/callbacks.rb:454:in `block in call'
activesupport (5.0.0.1) lib/active_support/callbacks.rb:454:in `each'
activesupport (5.0.0.1) lib/active_support/callbacks.rb:454:in `call'
activesupport (5.0.0.1) lib/active_support/callbacks.rb:101:in `__run_callbacks__'
activesupport (5.0.0.1) lib/active_support/callbacks.rb:750:in `_run_process_action_callbacks'
activesupport (5.0.0.1) lib/active_support/callbacks.rb:90:in `run_callbacks'
actionpack (5.0.0.1) lib/abstract_controller/callbacks.rb:19:in `process_action'
actionpack (5.0.0.1) lib/action_controller/metal/rescue.rb:20:in `process_action'
actionpack (5.0.0.1) lib/action_controller/metal/instrumentation.rb:32:in `block in process_action'
activesupport (5.0.0.1) lib/active_support/notifications.rb:164:in `block in instrument'
activesupport (5.0.0.1) lib/active_support/notifications/instrumenter.rb:21:in `instrument'
activesupport (5.0.0.1) lib/active_support/notifications.rb:164:in `instrument'
actionpack (5.0.0.1) lib/action_controller/metal/instrumentation.rb:30:in `process_action'
actionpack (5.0.0.1) lib/action_controller/metal/params_wrapper.rb:248:in `process_action'
activerecord (5.0.0.1) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (5.0.0.1) lib/abstract_controller/base.rb:126:in `process'
actionview (5.0.0.1) lib/action_view/rendering.rb:30:in `process'
actionpack (5.0.0.1) lib/action_controller/metal.rb:190:in `dispatch'
actionpack (5.0.0.1) lib/action_controller/metal.rb:262:in `dispatch'
actionpack (5.0.0.1) lib/action_dispatch/routing/route_set.rb:50:in `dispatch'
actionpack (5.0.0.1) lib/action_dispatch/routing/route_set.rb:32:in `serve'
actionpack (5.0.0.1) lib/action_dispatch/journey/router.rb:39:in `block in serve'
actionpack (5.0.0.1) lib/action_dispatch/journey/router.rb:26:in `each'
actionpack (5.0.0.1) lib/action_dispatch/journey/router.rb:26:in `serve'
actionpack (5.0.0.1) lib/action_dispatch/routing/route_set.rb:725:in `call'
rack (2.0.1) lib/rack/etag.rb:25:in `call'
rack (2.0.1) lib/rack/conditional_get.rb:25:in `call'
rack (2.0.1) lib/rack/head.rb:12:in `call'
rack (2.0.1) lib/rack/session/abstract/id.rb:222:in `context'
rack (2.0.1) lib/rack/session/abstract/id.rb:216:in `call'
actionpack (5.0.0.1) lib/action_dispatch/middleware/cookies.rb:613:in `call'
activerecord (5.0.0.1) lib/active_record/migration.rb:552:in `call'
actionpack (5.0.0.1) lib/action_dispatch/middleware/callbacks.rb:38:in `block in call'
activesupport (5.0.0.1) lib/active_support/callbacks.rb:97:in `__run_callbacks__'
activesupport (5.0.0.1) lib/active_support/callbacks.rb:750:in `_run_call_callbacks'
activesupport (5.0.0.1) lib/active_support/callbacks.rb:90:in `run_callbacks'
actionpack (5.0.0.1) lib/action_dispatch/middleware/callbacks.rb:36:in `call'
actionpack (5.0.0.1) lib/action_dispatch/middleware/executor.rb:12:in `call'
actionpack (5.0.0.1) lib/action_dispatch/middleware/remote_ip.rb:79:in `call'
actionpack (5.0.0.1) lib/action_dispatch/middleware/debug_exceptions.rb:49:in `call'
web-console (3.4.0) lib/web_console/middleware.rb:135:in `call_app'
web-console (3.4.0) lib/web_console/middleware.rb:28:in `block in call'
web-console (3.4.0) lib/web_console/middleware.rb:18:in `catch'
web-console (3.4.0) lib/web_console/middleware.rb:18:in `call'
actionpack (5.0.0.1) lib/action_dispatch/middleware/show_exceptions.rb:31:in `call'
railties (5.0.0.1) lib/rails/rack/logger.rb:36:in `call_app'
railties (5.0.0.1) lib/rails/rack/logger.rb:24:in `block in call'
activesupport (5.0.0.1) lib/active_support/tagged_logging.rb:70:in `block in tagged'
activesupport (5.0.0.1) lib/active_support/tagged_logging.rb:26:in `tagged'
activesupport (5.0.0.1) lib/active_support/tagged_logging.rb:70:in `tagged'
railties (5.0.0.1) lib/rails/rack/logger.rb:24:in `call'
sprockets-rails (3.2.0) lib/sprockets/rails/quiet_assets.rb:13:in `call'
actionpack (5.0.0.1) lib/action_dispatch/middleware/request_id.rb:24:in `call'
rack (2.0.1) lib/rack/method_override.rb:22:in `call'
rack (2.0.1) lib/rack/runtime.rb:22:in `call'
activesupport (5.0.0.1) lib/active_support/cache/strategy/local_cache_middleware.rb:28:in `call'
actionpack (5.0.0.1) lib/action_dispatch/middleware/executor.rb:12:in `call'
actionpack (5.0.0.1) lib/action_dispatch/middleware/static.rb:136:in `call'
rack (2.0.1) lib/rack/sendfile.rb:111:in `call'
railties (5.0.0.1) lib/rails/engine.rb:522:in `call'
puma (3.6.0) lib/puma/configuration.rb:225:in `call'
puma (3.6.0) lib/puma/server.rb:578:in `handle_request'
puma (3.6.0) lib/puma/server.rb:415:in `process_client'
puma (3.6.0) lib/puma/server.rb:275:in `block in run'
puma (3.6.0) lib/puma/thread_pool.rb:116:in `block in spawn_thread'

The posts_controller.rb file:

class PostsController < ApplicationController
    before_action :set_current_page, except: [:index]
    before_action :set_post, only: [:show, :edit, :update, :destroy]

    # GET /posts
    # GET /posts.json
    def index
        @posts = Post.paginate(page: params[:page],
                            per_page: params[:per_page])
                            .order('title, user_id')
    end

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

    # GET /posts/new
    def new
        @post = Post.new
    end

    # GET /posts/1/edit
    def edit
    end

    # POST /posts
    # POST /posts.json
    def create
        @post = Post.new(post_params)
        @post.user = User.find_by email: params[:email]

        respond_to do |format|
            if @post.save
                format.html { redirect_to (post_url(@post, page: @current_page)), notice: 'Post was successfully created.' }
                format.json { render :show, status: :created, location: @post }
            else
                format.html { render :new }
                format.json { render json: @post.errors, status: :unprocessable_entity }
            end
        end
    end

    # PATCH/PUT /posts/1
    # PATCH/PUT /posts/1.json
    def update
        @post.user = User.find_by email: params[:email]
        respond_to do |format|
            if @post.update(post_params)
                format.html { redirect_to (post_url(@post, page: @current_page)), notice: 'Post was successfully updated.' }
                format.json { render :show, status: :ok, location: @post }
            else
                format.html { render :edit }
                format.json { render json: @post.errors, status: :unprocessable_entity }
            send
        end
    end

    # DELETE /posts/1
    # DELETE /posts/1.json
    def destroy
        @post.destroy
        respond_to do |format|
            format.html { redirect_to posts_url(page: @current_page), notice: 'Post was successfully destroyed.' }
            format.json { head :no_content }
        end
    end

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

        def set_current_page
            @current_page = params[:page] || 1
        end

        # Never trust parameters from the scary internet, only allow the white list through.
        def post_params
            params.require(:post).permit(:title, :body, :page)
        end
    end
end

Answer 1

You have a typo in your update action - send instead of end.

This means Ruby is interpreting everything after it as part of that update method - and it is not defined outside the method.

In combination with the extra end that's been included after your list of private methods this means you have the correct number of ends so don't see a syntax error, but the class is not interpreted in the way you expect.