Add the ability to request a thread without its responses.

For cases where we don't need or want the responses on a thread at all,
like getting some metadata about a thread, we should be able to request
it without the responses.  This exists in the ThreadPresenter but didn't
exist as an option that could be passed in the API call itself.

We've added this as an option now -- with_responses -- that defaults to
true, which preserves the existing behavior but does in fact allow
toggling.

This gives us a backwards-compatible upgrade path to allow changes to be
made the LMS so that requests which don't need the responses, or do need
the responses, can be explicit about what they want.

api/comment_threads.rb

@@ -49,7 +49,7 @@ get "#{APIPREFIX}/threads/:thread_id" do |thread_id|
   else
     resp_limit = nil
   end
-  presenter.to_hash(true, resp_skip, resp_limit, bool_recursive).to_json
+  presenter.to_hash(bool_with_responses, resp_skip, resp_limit, bool_recursive).to_json
 end
 
 put "#{APIPREFIX}/threads/:thread_id" do |thread_id|

lib/helpers.rb

 require 'new_relic/agent/method_tracer'
 
 helpers do
-
   def commentable
     @commentable ||= Commentable.find(params[:commentable_id])
   end
@@ -10,7 +9,7 @@ helpers do
     raise ArgumentError, t(:user_id_is_required) unless @user || params[:user_id]
     @user ||= User.find_by(external_id: params[:user_id])
   end
-  
+
   def thread
     @thread ||= CommentThread.find(params[:thread_id])
   end
@@ -56,7 +55,7 @@ helpers do
     obj.save
     obj.reload.to_hash.to_json
   end
-  
+
   def un_flag_as_abuse(obj)
     raise ArgumentError, t(:user_id_is_required) unless user
     if params["all"]
@@ -66,7 +65,7 @@ helpers do
     else
       obj.abuse_flaggers.delete user.id
     end
-    
+
     obj.save
     obj.reload.to_hash.to_json
   end
@@ -78,7 +77,6 @@ helpers do
     end
     obj.reload.to_hash.to_json
   end
-  
 
   def pin(obj)
     raise ArgumentError, t(:user_id_is_required) unless user
@@ -86,16 +84,14 @@ helpers do
     obj.save
     obj.reload.to_hash.to_json
   end
-  
+
   def unpin(obj)
     raise ArgumentError, t(:user_id_is_required) unless user
     obj.pinned = nil
     obj.save
     obj.reload.to_hash.to_json
-  end  
-  
-  
-  
+  end
+
   def value_to_boolean(value)
     !!(value.to_s =~ /^true$/i)
   end
@@ -104,6 +100,10 @@ helpers do
     value_to_boolean params["recursive"]
   end
 
+  def bool_with_responses
+    value_to_boolean params["with_responses"] || "true"
+  end
+
   def bool_mark_as_read
     value_to_boolean params["mark_as_read"]
   end
@@ -142,7 +142,6 @@ helpers do
     per_page,
     context=:course
   )
-
     context_threads = comment_threads.where({:context => context})
 
     if not group_ids.empty?
@@ -158,7 +157,7 @@ helpers do
         comment_ids = Comment.where(:course_id => course_id).
           where(:abuse_flaggers.ne => [], :abuse_flaggers.exists => true).
           collect{|c| c.comment_thread_id}.uniq
-          
+
         thread_ids = comment_threads.where(:abuse_flaggers.ne => [], :abuse_flaggers.exists => true).
           collect{|c| c.id}
 
@@ -171,7 +170,7 @@ helpers do
         endorsed_thread_ids = Comment.where(:course_id => course_id).
           where(:parent_id.exists => false, :endorsed => true).
           collect{|c| c.comment_thread_id}.uniq
-          
+
         comment_threads = comment_threads.where({"thread_type" => :question}).nin({"_id" => endorsed_thread_ids})
       end
     end
@@ -228,7 +227,7 @@ helpers do
         page = [1, page].max
         threads = comment_threads.paginate(:page => page, :per_page => per_page).to_a
       end
-      
+
       if threads.length == 0
         collection = []
       else
@@ -328,11 +327,11 @@ helpers do
       current_thread = thread_map[c.comment_thread_id]
 
       #do not include threads or comments who have current or historical abuse flags
-      if current_thread.abuse_flaggers.to_a.empty? and 
-        current_thread.historical_abuse_flaggers.to_a.empty? and 
-        c.abuse_flaggers.to_a.empty? and 
+      if current_thread.abuse_flaggers.to_a.empty? and
+        current_thread.historical_abuse_flaggers.to_a.empty? and
+        c.abuse_flaggers.to_a.empty? and
         c.historical_abuse_flaggers.to_a.empty?
-        
+
           user_ids = subscriptions_map[c.comment_thread_id.to_s]
           user_ids.each do |u|
             if not notification_map.keys.include? u
@@ -365,7 +364,6 @@ helpers do
     end
 
     notification_map.to_json
-
   end
 
   def filter_blocked_content body
@@ -382,7 +380,7 @@ helpers do
       error 503, [msg].to_json
     end
   end
-  
+
   include ::NewRelic::Agent::MethodTracer
   add_method_tracer :user
   add_method_tracer :thread
@@ -390,5 +388,4 @@ helpers do
   add_method_tracer :flag_as_abuse
   add_method_tracer :un_flag_as_abuse
   add_method_tracer :handle_threads_query
-
 end

presenters/thread.rb

@@ -23,7 +23,7 @@ class ThreadPresenter
     @is_endorsed = is_endorsed
   end
 
-  def to_hash with_responses=false, resp_skip=0, resp_limit=nil, recursive=true
+  def to_hash(with_responses=false, resp_skip=0, resp_limit=nil, recursive=true)
     raise ArgumentError unless resp_skip >= 0
     raise ArgumentError unless resp_limit.nil? or resp_limit >= 1
     h = @thread.to_hash

spec/api/comment_thread_spec.rb

@@ -513,6 +513,18 @@ describe "app" do
         check_thread_result_json(nil, thread, parsed)
       end
 
+      context 'when requesting the thread for informational purposes' do
+        subject do
+          get "/api/v1/threads/#{thread.id}", with_responses: false # we're asking for no responses here.
+        end
+
+        it 'should have no children' do
+          expect(subject).to be_ok
+          parsed = parse(subject.body)
+          expect(parsed).not_to include('children')
+        end
+      end
+
       context 'when marking as read' do
         subject do
           get "/api/v1/threads/#{thread.id}", {:user_id => thread.author.id, :mark_as_read => true}