Rails: NoMethodError in Users#show - ruby-on-rails

Question

I'm new to Rails and I've been wandering aimlessly around stackoverflow trying to find a solution to my problem but can't seem to figure it out. I'm doing chapter 10 of Michael Hartl's tutorial and when I try to view the profile of a specific user the localhost:3000 page I get the following error messages:
"NoMethodError in Users#show"
followed by
"undefined method `name' for nil:NilClass".
The source is listed as the first line of my show.html.erb file but I can't see anything wrong with the code.
The home page works fine and the users index is viewable but beyond that it doesn't work. I understand that this could mean that the #user object is nil but I'm not sure how to fix this. My Rspec tests are also failing hard - any help would be greatly appreciated.
My users_controller.rb file:
class UsersController < ApplicationController
before_filter :signed_in_user, only: [:index, :edit, :update, :destroy]
# Arranges for a particular method to be called before the given actions.
before_filter :correct_user, only: [:edit, :update]
before_filter :admin_user, only: :destroy # Restricts the destroy action to admins.
def new
#user = User.new
end
def create
#user = User.new(params[:user])
if #user.save
sign_in #user
flash[:success] = "Welcome to the Sample App!"
redirect_to #user
else
render 'new'
end
end
def index
#users = User.paginate(page: params[:page])
end
def edit
# #user = User.find(params[:id])
end
def update
# #user = User.find(params[:id])
if #user.update_attributes(params[:user])
flash[:success] = "Profile updated"
sign_in #user
redirect_to #user
else
render 'edit'
end
end
def destroy
User.find(params[:id]).destroy
flash[:success] = "User destroyed."
redirect_to users_url
end
private
# def signed_in_user
# unless signed_in?
# store_location
# redirect_to signin_url, notice: "Please sign in."
# end
# end
def correct_user
#user = User.find(params[:id])
redirect_to(root_path) unless current_user?(#user)
end
def admin_user
redirect_to(root_path) unless current_user.admin?
end
def show
#user = User.find(params[:id])
#microposts = #user.microposts.paginate(page: params[:page])
end
end
My show.html.erb file:
<% provide(:title, #user.name) %>
<div class="row">
<aside class="span4">
<section>
<h1>
<%= gravatar_for #user %>
<%= #user.name %>
</h1>
</section>
</aside>
<div class="span8">
<% if #user.microposts.any? %>
<h3>Microposts (<%= #user.microposts.count %>)</h3>
<ol class="microposts">
<%= render #microposts %>
</ol>
<%= will_paginate #microposts %>
<% end %>
</div>
</div>
And users_helper.rb
module UsersHelper
# Returns the Gravatar (http://gravatar.com/) for the given user.
def gravatar_for(user, options = { size: 50 })
gravatar_id = Digest::MD5::hexdigest(user.email.downcase)
size = options[:size]
gravatar_url = "https://secure.gravatar.com/avatar/#{gravatar_id}?s=#{size}"
image_tag(gravatar_url, alt: user.name, class: "gravatar")
end
end

Answer 1

Here #user is nil. Because there is no record with the id (params[:id]). Thats why this error is coming.
<h1>
<%= gravatar_for #user %>
<%= !#user.nil? #user.name : "" %>
</h1>
It will check whether the #user having any record, if its having it will display it's name else it will display empty.

Answer 2

Your query doesn't find a user:
#user = User.find(params[:id])
does apparently return nil.
Please check that a user with the given ID exists. Additionally, you should make your actions fail safely when no object(s) are found:
<% if #user.nil? %>
<% provide(:title, 'Not found') %>
No user with that ID has been found.
<% else %>
<!-- Contents of your current show.html.erb -->
<% end %>