Move reblogged_by and favourited_by actions out of api/v1/statuses and into unique controllers (#3646)

* Add specs for api statuses routes

* Update favourited_by and reblogged_by api routes

* Move methods into new controllers

* Use load_accounts methods to simplify index actions

* Clean up load_accounts methods

* Clean up link header generation

* Check for link headers in specs

* Remove unused actions from api/v1/statuses controller

* Remove specs for moved actions

3 files changed, 163 insertions, 32 deletions

diff --git a/app/controllers/api/v1/statuses/favourited_by_accounts_controller.rb b/app/controllers/api/v1/statuses/favourited_by_accounts_controller.rb
new file mode 100644
index 000000000..e58184939
--- /dev/null
+++ b/app/controllers/api/v1/statuses/favourited_by_accounts_controller.rb
@@ -0,0 +1,82 @@
+# frozen_string_literal: true
+
+class Api::V1::Statuses::FavouritedByAccountsController < Api::BaseController
+  include Authorization
+
+  before_action :authorize_if_got_token
+  before_action :set_status
+  after_action :insert_pagination_headers
+
+  respond_to :json
+
+  def index
+    @accounts = load_accounts
+    render 'api/v1/statuses/accounts'
+  end
+
+  private
+
+  def load_accounts
+    default_accounts.merge(paginated_favourites).to_a
+  end
+
+  def default_accounts
+    Account
+      .includes(:favourites)
+      .references(:favourites)
+      .where(favourites: { status_id: @status.id })
+  end
+
+  def paginated_favourites
+    Favourite.paginate_by_max_id(
+      limit_param(DEFAULT_ACCOUNTS_LIMIT),
+      params[:max_id],
+      params[:since_id]
+    )
+  end
+
+  def insert_pagination_headers
+    set_pagination_headers(next_path, prev_path)
+  end
+
+  def next_path
+    if records_continue?
+      api_v1_status_favourited_by_index_url pagination_params(max_id: pagination_max_id)
+    end
+  end
+
+  def prev_path
+    unless @accounts.empty?
+      api_v1_status_favourited_by_index_url pagination_params(since_id: pagination_since_id)
+    end
+  end
+
+  def pagination_max_id
+    @accounts.last.favourites.last.id
+  end
+
+  def pagination_since_id
+    @accounts.first.favourites.first.id
+  end
+
+  def records_continue?
+    @accounts.size == limit_param(DEFAULT_ACCOUNTS_LIMIT)
+  end
+
+  def set_status
+    @status = Status.find(params[:status_id])
+    authorize @status, :show?
+  rescue Mastodon::NotPermittedError
+    # Reraise in order to get a 404 instead of a 403 error code
+    raise ActiveRecord::RecordNotFound
+  end
+
+  def authorize_if_got_token
+    request_token = Doorkeeper::OAuth::Token.from_request(request, *Doorkeeper.configuration.access_token_methods)
+    doorkeeper_authorize! :read if request_token
+  end
+
+  def pagination_params(core_params)
+    params.permit(:limit).merge(core_params)
+  end
+end
diff --git a/app/controllers/api/v1/statuses/reblogged_by_accounts_controller.rb b/app/controllers/api/v1/statuses/reblogged_by_accounts_controller.rb
new file mode 100644
index 000000000..43593d3c5
--- /dev/null
+++ b/app/controllers/api/v1/statuses/reblogged_by_accounts_controller.rb
@@ -0,0 +1,79 @@
+# frozen_string_literal: true
+
+class Api::V1::Statuses::RebloggedByAccountsController < Api::BaseController
+  include Authorization
+
+  before_action :authorize_if_got_token
+  before_action :set_status
+  after_action :insert_pagination_headers
+
+  respond_to :json
+
+  def index
+    @accounts = load_accounts
+    render 'api/v1/statuses/accounts'
+  end
+
+  private
+
+  def load_accounts
+    default_accounts.merge(paginated_statuses).to_a
+  end
+
+  def default_accounts
+    Account.includes(:statuses).references(:statuses)
+  end
+
+  def paginated_statuses
+    Status.where(reblog_of_id: @status.id).paginate_by_max_id(
+      limit_param(DEFAULT_ACCOUNTS_LIMIT),
+      params[:max_id],
+      params[:since_id]
+    )
+  end
+
+  def insert_pagination_headers
+    set_pagination_headers(next_path, prev_path)
+  end
+
+  def next_path
+    if records_continue?
+      api_v1_status_reblogged_by_index_url pagination_params(max_id: pagination_max_id)
+    end
+  end
+
+  def prev_path
+    unless @accounts.empty?
+      api_v1_status_reblogged_by_index_url pagination_params(since_id: pagination_since_id)
+    end
+  end
+
+  def pagination_max_id
+    @accounts.last.statuses.last.id
+  end
+
+  def pagination_since_id
+    @accounts.first.statuses.first.id
+  end
+
+  def records_continue?
+    @accounts.size == limit_param(DEFAULT_ACCOUNTS_LIMIT)
+  end
+
+  def set_status
+    @status = Status.find(params[:status_id])
+    authorize @status, :show?
+  rescue Mastodon::NotPermittedError
+    # Reraise in order to get a 404 instead of a 403 error code
+    raise ActiveRecord::RecordNotFound
+  end
+
+  def authorize_if_got_token
+    request_token = Doorkeeper::OAuth::Token.from_request(request, *Doorkeeper.configuration.access_token_methods)
+    doorkeeper_authorize! :read if request_token
+  end
+
+  def pagination_params(core_params)
+    params.permit(:limit).merge(core_params)
+  end
+end
diff --git a/app/controllers/api/v1/statuses_controller.rb b/app/controllers/api/v1/statuses_controller.rb
index 53fb1619e..7227a6536 100644
--- a/app/controllers/api/v1/statuses_controller.rb
+++ b/app/controllers/api/v1/statuses_controller.rb
@@ -5,8 +5,8 @@ class Api::V1::StatusesController < Api::BaseController
 
   before_action :authorize_if_got_token, except:            [:create, :destroy, :reblog, :unreblog, :favourite, :unfavourite, :mute, :unmute]
   before_action -> { doorkeeper_authorize! :write }, only:  [:create, :destroy, :reblog, :unreblog, :favourite, :unfavourite, :mute, :unmute]
-  before_action :require_user!, except:  [:show, :context, :card, :reblogged_by, :favourited_by]
-  before_action :set_status, only:       [:show, :context, :card, :reblogged_by, :favourited_by, :mute, :unmute]
+  before_action :require_user!, except:  [:show, :context, :card]
+  before_action :set_status, only:       [:show, :context, :card, :mute, :unmute]
   before_action :set_conversation, only: [:mute, :unmute]
 
   respond_to :json
@@ -33,36 +33,6 @@ class Api::V1::StatusesController < Api::BaseController
     render_empty if @card.nil?
   end
 
-  def reblogged_by
-    @accounts = Account.includes(:statuses)
-                       .references(:statuses)
-                       .merge(Status.where(reblog_of_id: @status.id)
-                                    .paginate_by_max_id(limit_param(DEFAULT_ACCOUNTS_LIMIT), params[:max_id], params[:since_id]))
-                       .to_a
-
-    next_path = reblogged_by_api_v1_status_url(pagination_params(max_id: @accounts.last.statuses.last.id))     if @accounts.size == limit_param(DEFAULT_ACCOUNTS_LIMIT)
-    prev_path = reblogged_by_api_v1_status_url(pagination_params(since_id: @accounts.first.statuses.first.id)) unless @accounts.empty?
-
-    set_pagination_headers(next_path, prev_path)
-
-    render :accounts
-  end
-
-  def favourited_by
-    @accounts = Account.includes(:favourites)
-                       .references(:favourites)
-                       .where(favourites: { status_id: @status.id })
-                       .merge(Favourite.paginate_by_max_id(limit_param(DEFAULT_ACCOUNTS_LIMIT), params[:max_id], params[:since_id]))
-                       .to_a
-
-    next_path = favourited_by_api_v1_status_url(pagination_params(max_id: @accounts.last.favourites.last.id))     if @accounts.size == limit_param(DEFAULT_ACCOUNTS_LIMIT)
-    prev_path = favourited_by_api_v1_status_url(pagination_params(since_id: @accounts.first.favourites.first.id)) unless @accounts.empty?
-
-    set_pagination_headers(next_path, prev_path)
-
-    render :accounts
-  end
-
   def create
     @status = PostStatusService.new.call(current_user.account,
                                          status_params[:status],