Include pdfjs in preferred_plugins array

Instead of sending a separate param to canvadocs for pdfjs as
a preferred plugin, just put it in the preferred_plugins array (which
used to be called preferred_renders)

Refs CNVS-30582

Test Plan:

    - This is very difficult to test manually, particularly without
      changing any code.  The reason for this is that canvadocs doesn't
      currently do anything with the pdfjs preferred plugin so you can't
      just check for that behavior.  However, this is something you can
      do even tho it isn't ideal (and this is how I tested this patch in
      development):
      - get canvas working with a canvadocs instance on which you can
        modify code.  By modifying the canvadocs instead of the canvas,
        the integrity of this patch is maintained for test purposes.
      - In the canvadocs session controller
        (app/controllers/session_controller.js), add a log statement to
        display what comes in in the body of the request.  Something
        like:
        - console.log('Request body: ')
        - console.dir(req.body)
      - Submit an assignment to a course as a student.
      - As a teacher, open speedgrader from that assignment.  This will
        cause a new canvadocs viewing session to be created.
      - In the console output of the canvadocs instance, see that the
        body did not include a preferred_plugin of pdfjs.
      - Toggle the feature flag to enable new annotations.
      - Repeat opening speedgrader but this time observe that the body
        includes pdfjs in the list of preferred_plugins.

Change-Id: Ie3e16e1331fcdd757e96888f033e8341e7d6a0bc
Reviewed-on: https://gerrit.instructure.com/86549
Tested-by: Jenkins
QA-Review: Caleb Guanzon <cguanzon@instructure.com>
Reviewed-by: Brad Horrocks <bhorrocks@instructure.com>
Product-Review: Benjamin Porter <bporter@instructure.com>

app/controllers/canvadoc_sessions_controller.rb

@@ -36,8 +36,17 @@ class CanvadocSessionsController < ApplicationController
       if @domain_root_account.settings[:canvadocs_prefer_office_online]
         opts[:preferred_plugins].unshift Canvadocs::RENDER_O365
       end
+
+      # We can't set the pdfjs preference here during upload because with
+      # only an attachment object we lack the requisite context
       attachment.submit_to_canvadocs(1, opts) unless attachment.canvadoc_available?
-      url = attachment.canvadoc.session_url(user: @current_user)
+
+      if pdfjs_feature_flag_enabled?(attachment.try(:canvadoc))
+        # Office 365 should take priority over pdfjs
+        index = opts[:preferred_plugins].first == Canvadocs::RENDER_O365 ? 1 : 0
+        opts[:preferred_plugins].insert(index, Canvadocs::RENDER_PDFJS)
+      end
+      url = attachment.canvadoc.session_url(opts.merge(user: @current_user))
 
       # For the purposes of reporting student viewership, we only
       # care if the original attachment owner is looking
@@ -54,4 +63,13 @@ class CanvadocSessionsController < ApplicationController
     render :text => "Service is currently unavailable. Try again later.",
            :status => :service_unavailable
   end
+
+  private
+
+  def pdfjs_feature_flag_enabled?(canvadoc)
+    course = Course.find(canvadoc.preferred_plugin_course_id)
+    return course.feature_enabled?(:new_annotations)
+  rescue NoMethodError, ActiveRecord::RecordNotFound => e
+    false
+  end
 end

app/models/canvadoc.rb

@@ -29,7 +29,6 @@ class Canvadoc < ActiveRecord::Base
     url = attachment.authenticated_s3_url(:expires => 1.day)
 
     opts.delete(:annotatable) unless Canvadocs.annotations_supported?
-    opts[:preferred_plugin] = preferred_plugin
 
     response = Canvas.timeout_protection("canvadocs") {
       canvadocs_api.upload(url, opts)
@@ -50,7 +49,6 @@ class Canvadoc < ActiveRecord::Base
   def session_url(opts = {})
     user = opts.delete(:user)
     opts.merge! annotation_opts(user)
-    opts[:preferred_plugin] = preferred_plugin
 
     Canvas.timeout_protection("canvadocs", raise_on_timeout: true) do
       session = canvadocs_api.session(document_id, opts)
@@ -58,16 +56,6 @@ class Canvadoc < ActiveRecord::Base
     end
   end
 
-  def preferred_plugin
-    begin
-      course = Course.find(self.preferred_plugin_course_id)
-      return course.feature_enabled?(:new_annotations) ? 'pdfjs' : nil
-    rescue ActiveRecord::RecordNotFound => e
-    end
-    nil
-  end
-  private :preferred_plugin
-
   def annotation_opts(user)
     return {} if !user || !has_annotations?
 

lib/canvadocs.rb

@@ -4,9 +4,10 @@ require 'net/https'
 require 'json'
 
 module Canvadocs
-  RENDER_O365 = 'office_365'
-  RENDER_BOX = 'box_view'
+  RENDER_O365     = 'office_365'
+  RENDER_BOX      = 'box_view'
   RENDER_CROCODOC = 'crocodoc'
+  RENDER_PDFJS    = 'pdfjs'
 
   # Public: A small ruby client that wraps the Box View api.
   #

spec/models/canvadoc_spec.rb

@@ -87,42 +87,4 @@ describe 'Canvadoc' do
       expect(@doc).not_to be_available
     end
   end
-
-  describe '#preferred_plugin' do
-    let(:course) { Course.create! }
-
-    let(:set_preferred_plugin_course_id) do
-      ->(course_id = course.id) do
-        @doc.preferred_plugin_course_id = course_id
-        @doc.save!
-      end
-    end
-
-    let(:feature_name) { 'new_annotations' }
-
-    let(:set_feature_flag) do
-      ->(enabled) do
-        course.account.set_feature_flag!(feature_name, enabled ? 'on' : 'off')
-        course.set_feature_flag!(feature_name, enabled ? 'on' : 'off')
-      end
-    end
-
-    it 'has a preferred plugin of nil when new annotations are disabled' do
-      set_preferred_plugin_course_id.call
-      set_feature_flag.call(false)
-      expect(@doc.send(:preferred_plugin)).to be_nil
-    end
-
-    it 'has a preferred plugin of nil when preferred_plugin_course_id is nil' do
-      set_preferred_plugin_course_id.call(nil)
-      set_feature_flag.call(true)
-      expect(@doc.send(:preferred_plugin)).to be_nil
-    end
-
-    it 'has a preferred plugin of "pdfjs" when new annotations are enabled' do
-      set_preferred_plugin_course_id.call
-      set_feature_flag.call(true)
-      expect(@doc.send(:preferred_plugin)).to eq('pdfjs')
-    end
-  end
 end