Add a request-token to identify which xblock html was rendered as part of the current request

[STUD-2903]

common/djangoapps/xmodule_modifiers.py

@@ -6,6 +6,7 @@ import datetime
 import json
 import logging
 import static_replace
+import uuid
 
 from django.conf import settings
 from django.utils.timezone import UTC
@@ -32,7 +33,19 @@ def wrap_fragment(fragment, new_content):
     return wrapper_frag
 
 
-def wrap_xblock(runtime_class, block, view, frag, context, usage_id_serializer, display_name_only=False, extra_data=None):  # pylint: disable=unused-argument
+def request_token(request):
+    """
+    Return a unique token for the supplied request.
+    This token will be the same for all calls to `request_token`
+    made on the same request object.
+    """
+    if not hasattr(request, '_xblock_token'):
+        request._xblock_token = uuid.uuid1().get_hex()
+
+    return request._xblock_token
+
+
+def wrap_xblock(runtime_class, block, view, frag, context, usage_id_serializer, request_token, display_name_only=False, extra_data=None):  # pylint: disable=unused-argument
     """
     Wraps the results of rendering an XBlock view in a standard <section> with identifying
     data so that the appropriate javascript module can be loaded onto it.
@@ -44,6 +57,8 @@ def wrap_xblock(runtime_class, block, view, frag, context, usage_id_serializer,
     :param context: The context passed to the view being rendered
     :param usage_id_serializer: A function to serialize the block's usage_id for use by the
         front-end Javascript Runtime.
+    :param request_token: An identifier that is unique per-request, so that only xblocks
+        rendered as part of this request will have their javascript initialized.
     :param display_name_only: If true, don't render the fragment content at all.
         Instead, just render the `display_name` of `block`
     :param extra_data: A dictionary with extra data values to be set on the wrapper
@@ -56,7 +71,7 @@ def wrap_xblock(runtime_class, block, view, frag, context, usage_id_serializer,
 
     data = {}
     data.update(extra_data)
-    css_classes = ['xblock', 'xblock-' + view]
+    css_classes = ['xblock', 'xblock-{}'.format(view)]
 
     if isinstance(block, (XModule, XModuleDescriptor)):
         if view in PREVIEW_VIEWS:
@@ -76,6 +91,7 @@ def wrap_xblock(runtime_class, block, view, frag, context, usage_id_serializer,
         data['runtime-version'] = frag.js_init_version
         data['block-type'] = block.scope_ids.block_type
         data['usage-id'] = usage_id_serializer(block.scope_ids.usage_id)
+        data['request-token'] = request_token
 
     template_context = {
         'content': block.display_name if display_name_only else frag.content,

common/lib/xmodule/xmodule/js/src/conditional/display.coffee

@@ -32,4 +32,6 @@ class @Conditional
           else
             $(element).show()
 
-        XBlock.initializeBlocks @el
+        # The children are rendered with a new request, so they have a different request-token.
+        # Use that token instead of @requestToken by simply not passing a token into initializeBlocks.
+        XBlock.initializeBlocks(@el)

common/lib/xmodule/xmodule/js/src/sequence/display.coffee

@@ -1,5 +1,6 @@
 class @Sequence
   constructor: (element) ->
+    @requestToken = $(element).data('request-token')
     @el = $(element).find('.sequence')
     @contents = @$('.seq_contents')
     @content_container = @$('#seq_content')
@@ -102,7 +103,7 @@ class @Sequence
       current_tab = @contents.eq(new_position - 1)
       @content_container.html(current_tab.text()).attr("aria-labelledby", current_tab.attr("aria-labelledby"))
 
-      XBlock.initializeBlocks(@content_container)
+      XBlock.initializeBlocks(@content_container, @requestToken)
 
       window.update_schematics() # For embedded circuit simulator exercises in 6.002x
 

common/lib/xmodule/xmodule/public/js/split_test_staff.js

@@ -18,7 +18,7 @@ function ABTestSelector(runtime, elem) {
             var child_group_id = $(this).data('group-id').toString();
             if(child_group_id === group_id) {
                 _this.content_container.html($(this).text());
-                XBlock.initializeBlocks(_this.content_container);
+                XBlock.initializeBlocks(_this.content_container, $(elem).data('request-token'));
             }
         });
     }

common/static/coffee/spec/xblock/core_spec.coffee

@@ -2,9 +2,21 @@ describe "XBlock", ->
   beforeEach ->
     setFixtures """
       <div>
-        <div class='xblock' id='vA' data-runtime-version="A" data-runtime-class="TestRuntime" data-init="initFnA" data-name="a-name"/>
+        <div class='xblock'
+             id='vA'
+             data-runtime-version="A"
+             data-runtime-class="TestRuntime"
+             data-init="initFnA"
+             data-name="a-name"
+        />
         <div>
-          <div class='xblock' id='vZ' data-runtime-version="Z" data-runtime-class="TestRuntime" data-init="initFnZ"/>
+          <div class='xblock'
+               id='vZ'
+               data-runtime-version="Z"
+               data-runtime-class="TestRuntime"
+               data-init="initFnZ"
+               data-request-token="req-token-z"
+          />
         </div>
         <div class='xblock' id='missing-version' data-init='initFnA' data-name='no-version'/>
         <div class='xblock' id='missing-init' data-runtime-version="A" data-name='no-init'/>
@@ -25,8 +37,11 @@ describe "XBlock", ->
       @fakeChildren = ['list', 'of', 'children']
       spyOn(XBlock, 'initializeBlocks').andReturn(@fakeChildren)
 
-      @vABlock = XBlock.initializeBlock($('#vA')[0])
-      @vZBlock = XBlock.initializeBlock($('#vZ')[0])
+      @vANode = $('#vA')[0]
+      @vZNode = $('#vZ')[0]
+
+      @vABlock = XBlock.initializeBlock(@vANode, 'req-token-a')
+      @vZBlock = XBlock.initializeBlock(@vZNode)
       @missingVersionBlock = XBlock.initializeBlock($('#missing-version')[0])
       @missingInitBlock = XBlock.initializeBlock($('#missing-init')[0])
 
@@ -35,8 +50,8 @@ describe "XBlock", ->
       expect(TestRuntime.vZ).toHaveBeenCalledWith()
 
     it "loads the right init function", ->
-      expect(window.initFnA).toHaveBeenCalledWith(@runtimeA, $('#vA')[0])
-      expect(window.initFnZ).toHaveBeenCalledWith(@runtimeZ, $('#vZ')[0])
+      expect(window.initFnA).toHaveBeenCalledWith(@runtimeA, @vANode)
+      expect(window.initFnZ).toHaveBeenCalledWith(@runtimeZ, @vZNode)
 
     it "loads when missing versions", ->
       expect(@missingVersionBlock.element).toBe($('#missing-version'))
@@ -53,15 +68,29 @@ describe "XBlock", ->
       expect(@vZBlock.name).toBeUndefined()
 
     it "attaches the element to the block", ->
-      expect(@vABlock.element).toBe($('#vA')[0])
-      expect(@vZBlock.element).toBe($('#vZ')[0])
+      expect(@vABlock.element).toBe(@vANode)
+      expect(@vZBlock.element).toBe(@vZNode)
       expect(@missingVersionBlock.element).toBe($('#missing-version')[0])
       expect(@missingInitBlock.element).toBe($('#missing-init')[0])
 
+    it "passes through the request token", ->
+      expect(XBlock.initializeBlocks).toHaveBeenCalledWith($(@vANode), 'req-token-a')
+      expect(XBlock.initializeBlocks).toHaveBeenCalledWith($(@vZNode), 'req-token-z')
+
+
   describe "initializeBlocks", ->
-    it "initializes children", ->
+    beforeEach ->
       spyOn(XBlock, 'initializeBlock')
 
+      @vANode = $('#vA')[0]
+      @vZNode = $('#vZ')[0]
+
+    it "initializes children", ->
       XBlock.initializeBlocks($('#jasmine-fixtures'))
-      expect(XBlock.initializeBlock).toHaveBeenCalledWith($('#vA')[0])
-      expect(XBlock.initializeBlock).toHaveBeenCalledWith($('#vZ')[0])
+      expect(XBlock.initializeBlock).toHaveBeenCalledWith(@vANode, undefined)
+      expect(XBlock.initializeBlock).toHaveBeenCalledWith(@vZNode, undefined)
+
+    it "only initializes matching request tokens", ->
+      XBlock.initializeBlocks($('#jasmine-fixtures'), 'req-token-z')
+      expect(XBlock.initializeBlock).not.toHaveBeenCalledWith(@vANode, jasmine.any(Object))
+      expect(XBlock.initializeBlock).toHaveBeenCalledWith(@vZNode, 'req-token-z')

common/static/coffee/src/xblock/core.coffee

@@ -1,9 +1,16 @@
 @XBlock =
   Runtime: {}
 
-  initializeBlock: (element) ->
+  ###
+  Initialize the javascript for a single xblock element, and for all of it's
+  xblock children that match requestToken. If requestToken is omitted, use the
+  data-request-token attribute from element, or use the request-tokens specified on
+  the children themselves.
+  ###
+  initializeBlock: (element, requestToken) ->
     $element = $(element)
-    children = @initializeBlocks($element)
+    requestToken = requestToken or $element.data('request-token')
+    children = @initializeBlocks($element, requestToken)
     runtime = $element.data("runtime-class")
     version = $element.data("runtime-version")
     initFnName = $element.data("init")
@@ -26,7 +33,17 @@
     $element.addClass("xblock-initialized")
     block
 
-  initializeBlocks: (element) ->
-    $(element).immediateDescendents(".xblock").map((idx, elem) =>
-      @initializeBlock elem
+  ###
+  Initialize all XBlocks inside element that were rendered with requestToken.
+  If requestToken is omitted, and element has a 'data-request-token' attribute, use that.
+  If neither is available, then use the request tokens of the immediateDescendent xblocks.
+  ###
+  initializeBlocks: (element, requestToken) ->
+    requestToken = requestToken or $(element).data('request-token')
+    if requestToken
+      selector = ".xblock[data-request-token='#{requestToken}']"
+    else
+      selector = ".xblock"
+    $(element).immediateDescendents(selector).map((idx, elem) =>
+      @initializeBlock(elem, requestToken)
     ).toArray()