Allow staff users to impersonate your normal users: see what they see, only do what they can do.

This concept and code was extracted from Engine Yard Cloud, which we use when we want to help support a customer remotely.

This Rails engine currently supports the following Rails authentication systems:

• Devise

When you are impersonating a user you see what they see, with a header section above:

Add the gem to your Rails application's Gemfile and run bundle:

gem "user_impersonate"

Run the (sort of optional) generator:

bundle
rails g user_impersonate

This adds the following line within your config/routes.rb:

mount UserImpersonate::Engine => "/impersonate", as: "impersonate_engine"

Include in your layout files support for flash[:error] and flash[:notice], such as:

<p class="notice"><%= flash[:notice] %></p>
<p class="alert"><%= flash[:error] %></p>

Next, add the impersonation header to your layouts:

<% if current_staff_user %>
  <%= render 'user_impersonate/header' %>
<% end %>

Next, add staff concept to your User model.

To test the engine out, make all users staff!

# app/models/user.rb

def staff?
  true
end

# String to represent a user (email, name, etc)
def to_s
  email
end

You can now go to http://localhost:3000/impersonate to see the list of users, except your own user account. If you impersonate one you will see the magic!

To support this Rails engine, you need to add some things.

• current_user helper within controllers & helpers
• current_user.staff? - your User model needs a staff? to identify if the current user is allowed to impersonate other users; if missing, no user can access impersonation system

One way to add this helper is to add a column to your User model:

rails g migration add_staff_flag_to_users staff:boolean
rake db:migrate db:test:prepare

You can override the bright red header by creating a app/views/user_impersonate/_header.html.erb file (or whatever template system you like).

For example, the Engine Yard Cloud uses a header that looks like:

The app/views/user_impersonate/_header.html.haml HAML partial for this header would be:

%div#impersonating
  .impersonate-controls.page
    .impersonate-info.grid_12
      You (
      %span.admin_name= current_staff_user
      ) are impersonating
      %span.user_name= link_to current_user, url_for([:admin, current_user])
      ( User id:
      %span.user_id= current_user.id
      )
      - if current_user.no_accounts?
        ( No accounts )
      - else
        ( Account name:
        %span.account_id= link_to current_user.accounts.first, url_for([:admin, current_user.accounts.first])
        , id:
        %strong= current_user.accounts.first.id
        )
    .impersonate-buttons.grid_12
      = form_tag url_for([:ssh_key, :admin, current_user]), :method => "put" do
        %span Support SSH Key
        = select_tag 'public_key', options_for_select(current_staff_user.keys.map {|k| k})
        %button{:type => "submit"} Install SSH Key
      or
      = form_tag [:admin, :revert], :method => :delete, :class => 'revert-form' do
        %button{:type => "submit"} Revert to admin

By default, when you impersonate and when you stop impersonating a user you are redirected to the root url.

Configure alternate paths in config/initializers/user_impersonate.rb, which is created by the generator above.

# config/initializers/user_impersonate.rb
module UserImpersonate
  class Engine < Rails::Engine
    config.redirect_on_impersonate = "/"
    config.redirect_on_revert = "/impersonate"
  end
end

By default, it assumes the User model is User, that you use User.find(id) to find a user, and aUser.id to get the related id value.

You can fix this default behavior in config/initializers/user_impersonate.rb, which is created by the generator above.

# config/initializers/user_impersonate.rb
module UserImpersonate
  class Engine < Rails::Engine
    config.user_class           = "User"
    config.user_finder          = "find"   # User.find
    config.user_id_column       = "id"     # Such that User.find(aUser.id) works
    config.user_is_staff_method = "staff?" # current_user.staff?
  end
end