add course and sub-account count to accounts API

closes FOO-4553
closes GH-2380
flag = none

test plan:
- Exercise the following API's
  - GET /api/v1/accounts
  - GET /api/v1/accounts/:account_id/sub_accounts
  - include[]=course_count,sub_account_count
- Verify that the response includes the `course_count` and
  `sub_account_count` fields for each account and that the counts
  reflect reality for active courses and sub-accounts that are
  direct descendants

Change-Id: I54bfe72e08fc695728d08a6c71ea04cd06a0b49f
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/351652
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: Michael Hulse <michael.hulse@instructure.com>
QA-Review: August Thornton <august@instructure.com>
Product-Review: August Thornton <august@instructure.com>

app/controllers/accounts_controller.rb

@@ -87,6 +87,16 @@
 #           "example": "12",
 #           "type": "integer"
 #         },
+#         "course_count": {
+#           "description": "The number of courses directly under the account (available via include)",
+#           "example": "10",
+#           "type": "integer"
+#         },
+#         "sub_account_count": {
+#           "description": "The number of sub-accounts directly under the account (available via include)",
+#           "example": "10",
+#           "type": "integer"
+#         },
 #         "lti_guid": {
 #           "description": "The account's identifier that is sent as context_id in LTI launches.",
 #           "example": "123xyz",
@@ -314,12 +324,14 @@ class AccountsController < ApplicationController
   # Typically, students and even teachers will get an empty list in response,
   # only account admins can view the accounts that they are in.
   #
-  # @argument include[] [String, "lti_guid"|"registration_settings"|"services"]
+  # @argument include[] [String, "lti_guid"|"registration_settings"|"services"|"course_count"|"sub_account_count"]
   #   Array of additional information to include.
   #
   #   "lti_guid":: the 'tool_consumer_instance_guid' that will be sent for this account on LTI launches
   #   "registration_settings":: returns info about the privacy policy and terms of use
   #   "services":: returns services and whether they are enabled (requires account management permissions)
+  #   "course_count":: returns the number of courses directly under each account
+  #   "sub_account_count":: returns the number of sub-accounts directly under each account
   #
   # @returns [Account]
   def index
@@ -538,6 +550,12 @@ class AccountsController < ApplicationController
   #   this account will be returned (though still paginated). If false, only
   #   direct sub-accounts of this account will be returned. Defaults to false.
   #
+  # @argument include[] [String, "course_count"|"sub_account_count"]
+  #   Array of additional information to include.
+  #
+  #   "course_count":: returns the number of courses directly under each account
+  #   "sub_account_count":: returns the number of sub-accounts directly under each account
+  #
   # @example_request
   #     curl https://<canvas>/api/v1/accounts/<account_id>/sub_accounts \
   #          -H 'Authorization: Bearer <token>'
@@ -569,8 +587,11 @@ class AccountsController < ApplicationController
                              api_v1_sub_accounts_url,
                              total_entries: recursive ? nil : @accounts.count)
 
+    supported_includes = %w[course_count sub_account_count]
+    includes = (supported_includes.any? { |i| params[:include]&.include?(i) }) ? supported_includes : []
+
     ActiveRecord::Associations.preload(@accounts, [:root_account, :parent_account])
-    render json: @accounts.map { |a| account_json(a, @current_user, session, []) }
+    render json: @accounts.map { |a| account_json(a, @current_user, session, includes) }
   end
 
   # @API Get the Terms of Service

app/models/account.rb

@@ -1841,11 +1841,11 @@ class Account < ActiveRecord::Base
   end
 
   def course_count
-    courses.active.count
+    courses.active.size
   end
 
   def sub_account_count
-    sub_accounts.active.count
+    sub_accounts.active.size
   end
 
   def user_count

lib/api/v1/account.rb

@@ -68,6 +68,8 @@ module Api::V1::Account
       if includes.include?("services") && account.grants_right?(user, session, :manage_account_settings)
         hash["services"] = Account.services_exposed_to_ui_hash(nil, user, account).keys.index_with { |k| account.service_enabled?(k) }
       end
+      hash["course_count"] = account.course_count if includes.include?("course_count")
+      hash["sub_account_count"] = account.sub_account_count if includes.include?("sub_account_count")
 
       hash["global_id"] = account.global_id if includes.include?("global_id")
 

spec/apis/v1/accounts_api_spec.rb

@@ -195,6 +195,29 @@ describe "Accounts API", type: :request do
                                         "Account 2"]
     end
 
+    it "includes course count if requested" do
+      2.times { course_factory(active_all: true, account: @a1.sub_accounts.find_by(name: "subby")) }
+      json = api_call(:get,
+                      "/api/v1/accounts/#{@a1.id}/sub_accounts?include[]=course_count",
+                      { controller: "accounts",
+                        action: "sub_accounts",
+                        account_id: @a1.id.to_s,
+                        format: "json",
+                        include: ["course_count"] })
+      expect(json.pluck("course_count")).to match_array([2, 0, 0, 0])
+    end
+
+    it "includes sub-account count if requested" do
+      json = api_call(:get,
+                      "/api/v1/accounts/#{@a1.id}/sub_accounts?include[]=sub_account_count",
+                      { controller: "accounts",
+                        action: "sub_accounts",
+                        account_id: @a1.id.to_s,
+                        format: "json",
+                        include: ["sub_account_count"] })
+      expect(json.pluck("sub_account_count")).to match_array([0, 0, 3, 3])
+    end
+
     it "adds sub account" do
       previous_sub_count = @a1.sub_accounts.size
       api_call(:post,
@@ -332,6 +355,23 @@ describe "Accounts API", type: :request do
       expect(json[0]["lti_guid"]).to eq "hey"
     end
 
+    it "includes course count if requested" do
+      2.times { course_factory(active_all: true, account: @a1) }
+      json = api_call(:get,
+                      "/api/v1/accounts?include[]=course_count",
+                      { controller: "accounts", action: "index", format: "json", include: ["course_count"] },
+                      {})
+      expect(json.pluck("course_count")).to match_array([2, 0])
+    end
+
+    it "includes sub-account count if requested" do
+      json = api_call(:get,
+                      "/api/v1/accounts?include[]=sub_account_count",
+                      { controller: "accounts", action: "index", format: "json", include: ["sub_account_count"] },
+                      {})
+      expect(json.pluck("sub_account_count")).to match_array([0, 2])
+    end
+
     context "when the includes query param includes 'global_id'" do
       it "includes the account's global ID" do
         json = api_call(