Add username replacement API

api/users.rb

@@ -95,3 +95,17 @@
   user.update_attribute(:username, params["retired_username"])
   user.save
 end
+
+post "#{APIPREFIX}/users/:user_id/replace_username" do |user_id|
+  if not params["new_username"]
+    error 500, {message: "Missing new_username param. "}.to_json
+  end
+  begin
+    user = User.find_by(external_id: user_id)
+  rescue Mongoid::Errors::DocumentNotFound
+    error 404, {message: "User not found."}.to_json
+  end
+  user.update_attribute(:username, params["new_username"])
+  user.replace_username_in_all_content(params["new_username"])
+  user.save
+end

models/user.rb

@@ -201,6 +201,36 @@ def retire_all_content(retired_username)
     end
   end
 
+  def replace_comment_username(comment, new_username)
+    # Replace the username of a single comment with the new username
+    data = {
+      username: new_username
+    }
+    comment.without_es do
+      comment.update!(data)
+    end
+    {
+      update: {
+        _index: Content::ES_INDEX_NAME,
+        _type: comment.__elasticsearch__.document_type,
+        _id: comment._id,
+        data: { doc: data }
+      }
+    }
+  end
+
+  def replace_username_in_all_content(new_username)
+    # Replaces the username on all content authored by this user
+    user_comments = all_comments
+    user_comment_threads = all_comment_threads
+    user_content = all_comments + all_comment_threads
+    unless user_content.empty?
+      bulk_data = user_content.map {|comment| replace_comment_username(comment, new_username)}
+      Elasticsearch::Model.client.bulk(body: bulk_data)
+    end
+  end
+
+
   def mark_as_read(thread)
     read_state = read_states.find_or_create_by(course_id: thread.course_id)
     read_state.last_read_times[thread.id.to_s] = Time.now.utc

spec/api/user_spec.rb

@@ -528,5 +528,72 @@ def test_unicode_data(text)
       end
     end
 
+    describe "POST /api/v1/users/:user_id/replace_username" do
+      include_context 'search_enabled'
+
+      describe "with an inactive forums user," do
+        before :each do
+          User.all.delete
+          Content.all.delete
+          create_test_user(1)
+          # No user content
+        end
+
+        it "replaces a user's username" do
+          new_username = "test_username_replacement"
+          user = User.where(external_id: '1').first
+          # User should have original username.
+          expect(user.username).to eq('user1')
+
+          # Replace the username.
+          post "/api/v1/users/#{user.external_id}/replace_username", new_username: new_username
+          expect(last_response).to be_ok
+
+          user.reload
+          # User should have new username.
+          expect(user.username).to eq(new_username)
+        end
+      end
+
+      describe "with an active forums user," do
+        before :each do
+          User.all.delete
+          Content.all.delete
+          init_without_subscriptions
+        end
+
+        it "attempts to replace username without sending new username" do
+          post "/api/v1/users/1/replace_username"
+          expect(last_response.status).to eq(500)
+        end
+
+        it "attempts to replace username of a non-existant user" do
+          post "/api/v1/users/1234/replace_username", new_username: new_username
+          expect(last_response.status).to eq(404)
+        end
+
+        it "attempts to replace username and username on content" do
+          new_username = "test_username_replacement"
+          user = User.where(external_id: '1').first
+          # User should have original username.
+          expect(user.username).to eq('user1')
+
+          # Change the username.
+          post "/api/v1/users/#{user.external_id}/replace_username", new_username: new_username
+          expect(last_response).to be_ok
+
+          user.reload
+          # User should have new username.
+          expect(user.username).to eq(new_username)
+
+          # User's comments should all have new username.
+          comments = user.all_comments + user.all_comment_threads
+          expect(comments.count).should_not eq(0)
+          comments.each do |single_comment|
+            expect(single_comment.author_username).to match(new_username)
+          end
+        end
+      end
+    end
   end
 end