Paging for LibraryView added with JS tests.

cms/djangoapps/contentstore/views/item.py

@@ -237,12 +237,28 @@ def xblock_view_handler(request, usage_key_string, view_name):
             if view_name == 'reorderable_container_child_preview':
                 reorderable_items.add(xblock.location)
 
+            paging = None
+            try:
+                if request.REQUEST.get('enable_paging', 'false') == 'true':
+                    paging = {
+                        'page_number': int(request.REQUEST.get('page_number', 0)),
+                        'page_size': int(request.REQUEST.get('page_size', 0)),
+                    }
+            except ValueError:
+                log.exception(
+                    "Couldn't parse paging parameters: enable_paging: %s, page_number: %s, page_size: %s",
+                    request.REQUEST.get('enable_paging', 'false'),
+                    request.REQUEST.get('page_number', 0),
+                    request.REQUEST.get('page_size', 0)
+                )
+
             # Set up the context to be passed to each XBlock's render method.
             context = {
                 'is_pages_view': is_pages_view,     # This setting disables the recursive wrapping of xblocks
                 'is_unit_page': is_unit(xblock),
                 'root_xblock': xblock if (view_name == 'container_preview') else None,
-                'reorderable_items': reorderable_items
+                'reorderable_items': reorderable_items,
+                'paging': paging
             }
 
             fragment = get_preview_fragment(request, xblock, context)

cms/static/coffee/spec/main.coffee

@@ -239,6 +239,7 @@ define([
     "js/spec/views/assets_spec",
     "js/spec/views/baseview_spec",
     "js/spec/views/container_spec",
+    "js/spec/views/library_container_spec",
     "js/spec/views/group_configuration_spec",
     "js/spec/views/paging_spec",
     "js/spec/views/unit_outline_spec",

cms/static/js/factories/container.js

 define([
-    'jquery', 'js/models/xblock_info', 'js/views/pages/container',
+    'jquery', 'underscore', 'js/models/xblock_info', 'js/views/pages/container',
     'js/collections/component_template', 'xmodule', 'coffee/src/main',
     'xblock/cms.runtime.v1'
 ],
-function($, XBlockInfo, ContainerPage, ComponentTemplates, xmoduleLoader) {
+function($, _, XBlockInfo, ContainerPage, ComponentTemplates, xmoduleLoader) {
     'use strict';
-    return function (componentTemplates, XBlockInfoJson, action, isUnitPage) {
-        var templates = new ComponentTemplates(componentTemplates, {parse: true}),
-            mainXBlockInfo = new XBlockInfo(XBlockInfoJson, {parse: true});
-
-        xmoduleLoader.done(function () {
-            var view = new ContainerPage({
+    return function (componentTemplates, XBlockInfoJson, action, options) {
+        var main_options = {
                 el: $('#content'),
-                model: mainXBlockInfo,
+                model: new XBlockInfo(XBlockInfoJson, {parse: true}),
                 action: action,
-                templates: templates,
-                isUnitPage: isUnitPage
-            });
+                templates: new ComponentTemplates(componentTemplates, {parse: true})
+            };
+
+        xmoduleLoader.done(function () {
+            var view = new ContainerPage(_.extend(main_options, options));
             view.render();
         });
     };

cms/static/js/factories/library.js

 define([
-    'jquery', 'js/models/xblock_info', 'js/views/pages/container',
+    'jquery', 'underscore', 'js/models/xblock_info', 'js/views/pages/container',
     'js/collections/component_template', 'xmodule', 'coffee/src/main',
     'xblock/cms.runtime.v1'
 ],
-function($, XBlockInfo, ContainerPage, ComponentTemplates, xmoduleLoader) {
+function($, _, XBlockInfo, ContainerPage, ComponentTemplates, xmoduleLoader) {
     'use strict';
-    return function (componentTemplates, XBlockInfoJson) {
-        var templates = new ComponentTemplates(componentTemplates, {parse: true}),
-            mainXBlockInfo = new XBlockInfo(XBlockInfoJson, {parse: true});
+    return function (componentTemplates, XBlockInfoJson, options) {
+        var main_options = {
+            el: $('#content'),
+            model: new XBlockInfo(XBlockInfoJson, {parse: true}),
+            templates: new ComponentTemplates(componentTemplates, {parse: true}),
+            action: 'view'
+        };
 
         xmoduleLoader.done(function () {
-            var view = new ContainerPage({
-                el: $('#content'),
-                model: mainXBlockInfo,
-                action: "view",
-                templates: templates,
-                isUnitPage: false
-            });
+            var view = new ContainerPage(_.extend(main_options, options));
             view.render();
         });
     };

cms/static/js/views/container.js

@@ -123,6 +123,10 @@ define(["jquery", "underscore", "js/views/xblock", "js/utils/module", "gettext",
                 });
             },
 
+            acknowledgeXBlockDeletion: function(locator){
+                this.notifyRuntime('deleted-child', locator);
+            },
+
             refresh: function() {
                 var sortableInitializedClass = this.makeRequestSpecificSelector('.reorderable-container.ui-sortable');
                 this.$(sortableInitializedClass).sortable('refresh');

cms/static/js/views/library_container.js

+define(["jquery", "underscore", "js/views/xblock", "js/utils/module", "gettext", "js/views/feedback_notification",
+        "js/views/paging_header", "js/views/paging_footer"],
+    function ($, _, XBlockView, ModuleUtils, gettext, NotificationView, PagingHeader, PagingFooter) {
+        var LibraryContainerView = XBlockView.extend({
+            // Store the request token of the first xblock on the page (which we know was rendered by Studio when
+            // the page was generated). Use that request token to filter out user-defined HTML in any
+            // child xblocks within the page.
+            requestToken: "",
+
+            initialize: function(options){
+                var self = this;
+                XBlockView.prototype.initialize.call(this);
+                this.page_size = this.options.page_size || 10;
+                if (options) {
+                    this.page_reload_callback = options.page_reload_callback;
+                }
+                // emulating Backbone.paginator interface
+                this.collection = {
+                    currentPage: 0,
+                    totalPages: 0,
+                    totalCount: 0,
+                    sortDirection: "desc",
+                    start: 0,
+                    _size: 0,
+
+                    bind: function() {},  // no-op
+                    size: function() { return self.collection._size; }
+                };
+            },
+
+            render: function(options) {
+                var eff_options = options || {};
+                if (eff_options.block_added) {
+                    this.collection.currentPage = this.getPageCount(this.collection.totalCount+1) - 1;
+                }
+                eff_options.page_number = typeof eff_options.page_number !== "undefined"
+                    ? eff_options.page_number
+                    : this.collection.currentPage;
+                return this.renderPage(eff_options);
+            },
+
+            renderPage: function(options){
+                var self = this,
+                    view = this.view,
+                    xblockInfo = this.model,
+                    xblockUrl = xblockInfo.url();
+                return $.ajax({
+                    url: decodeURIComponent(xblockUrl) + "/" + view,
+                    type: 'GET',
+                    cache: false,
+                    data: this.getRenderParameters(options.page_number),
+                    headers: { Accept: 'application/json' },
+                    success: function(fragment) {
+                        self.handleXBlockFragment(fragment, options);
+                        self.processPaging({ requested_page: options.page_number });
+                        if (options.paging && self.page_reload_callback){
+                            self.page_reload_callback(self.$el);
+                        }
+                    }
+                });
+            },
+
+            getRenderParameters: function(page_number) {
+                return {
+                    enable_paging: true,
+                    page_size: this.page_size,
+                    page_number: page_number
+                };
+            },
+
+            getPageCount: function(total_count){
+                if (total_count==0) return 1;
+                return Math.ceil(total_count / this.page_size);
+            },
+
+            setPage: function(page_number) {
+                this.render({ page_number: page_number, paging: true });
+            },
+
+            nextPage: function() {
+                var collection = this.collection,
+                    currentPage = collection.currentPage,
+                    lastPage = collection.totalPages - 1;
+                if (currentPage < lastPage) {
+                    this.setPage(currentPage + 1);
+                }
+            },
+
+            previousPage: function() {
+                var collection = this.collection,
+                    currentPage = collection.currentPage;
+                if (currentPage > 0) {
+                    this.setPage(currentPage - 1);
+                }
+            },
+
+            processPaging: function(options){
+                var $element = this.$el.find('.xblock-container-paging-parameters'),
+                    total = $element.data('total'),
+                    displayed = $element.data('displayed'),
+                    start = $element.data('start');
+
+                this.collection.currentPage = options.requested_page;
+                this.collection.totalCount = total;
+                this.collection.totalPages = this.getPageCount(total);
+                this.collection.start = start;
+                this.collection._size = displayed;
+
+                this.processPagingHeaderAndFooter();
+            },
+
+            processPagingHeaderAndFooter: function(){
+                if (this.pagingHeader)
+                    this.pagingHeader.undelegateEvents();
+                if (this.pagingFooter)
+                    this.pagingFooter.undelegateEvents();
+
+                this.pagingHeader = new PagingHeader({
+                    view: this,
+                    el: this.$el.find('.container-paging-header')
+                });
+                this.pagingFooter = new PagingFooter({
+                    view: this,
+                    el: this.$el.find('.container-paging-footer')
+                });
+
+                this.pagingHeader.render();
+                this.pagingFooter.render();
+            },
+
+            xblockReady: function () {
+                XBlockView.prototype.xblockReady.call(this);
+
+                this.requestToken = this.$('div.xblock').first().data('request-token');
+            },
+
+            refresh: function() { },
+
+            acknowledgeXBlockDeletion: function (locator){
+                this.notifyRuntime('deleted-child', locator);
+                this.collection._size -= 1;
+                this.collection.totalCount -= 1;
+                // pages are counted from 0 - thus currentPage == 1 if we're on second page
+                if (this.collection._size == 0 && this.collection.currentPage >= 1) {
+                    this.setPage(this.collection.currentPage - 1);
+                    this.collection.totalPages -= 1;
+                }
+                else {
+                    this.pagingHeader.render();
+                    this.pagingFooter.render();
+                }
+            },
+
+            makeRequestSpecificSelector: function(selector) {
+                return 'div.xblock[data-request-token="' + this.requestToken + '"] > ' + selector;
+            },
+
+            sortDisplayName: function() {
+                return "Date added";  // TODO add support for sorting
+            }
+        });
+
+        return LibraryContainerView;
+    }); // end define();

cms/static/js/views/pages/container.js

@@ -3,10 +3,10 @@
  * This page allows the user to understand and manipulate the xblock and its children.
  */
 define(["jquery", "underscore", "gettext", "js/views/pages/base_page", "js/views/utils/view_utils",
-        "js/views/container", "js/views/xblock", "js/views/components/add_xblock", "js/views/modals/edit_xblock",
+        "js/views/container", "js/views/library_container", "js/views/xblock", "js/views/components/add_xblock", "js/views/modals/edit_xblock",
         "js/models/xblock_info", "js/views/xblock_string_field_editor", "js/views/pages/container_subviews",
         "js/views/unit_outline", "js/views/utils/xblock_utils"],
-    function ($, _, gettext, BasePage, ViewUtils, ContainerView, XBlockView, AddXBlockComponent,
+    function ($, _, gettext, BasePage, ViewUtils, ContainerView, PagedContainerView, XBlockView, AddXBlockComponent,
               EditXBlockModal, XBlockInfo, XBlockStringFieldEditor, ContainerSubviews, UnitOutlineView,
               XBlockUtils) {
         'use strict';
@@ -27,6 +27,10 @@ define(["jquery", "underscore", "gettext", "js/views/pages/base_page", "js/views
 
             initialize: function(options) {
                 BasePage.prototype.initialize.call(this, options);
+                this.enable_paging = options.enable_paging || false;
+                if (this.enable_paging) {
+                    this.page_size = options.page_size || 10;
+                }
                 this.nameEditor = new XBlockStringFieldEditor({
                     el: this.$('.wrapper-xblock-field'),
                     model: this.model
@@ -35,11 +39,7 @@ define(["jquery", "underscore", "gettext", "js/views/pages/base_page", "js/views
                 if (this.options.action === 'new') {
                     this.nameEditor.$('.xblock-field-value-edit').click();
                 }
-                this.xblockView = new ContainerView({
-                    el: this.$('.wrapper-xblock'),
-                    model: this.model,
-                    view: this.view
-                });
+                this.xblockView = this.getXBlockView();
                 this.messageView = new ContainerSubviews.MessageView({
                     el: this.$('.container-message'),
                     model: this.model
@@ -75,6 +75,28 @@ define(["jquery", "underscore", "gettext", "js/views/pages/base_page", "js/views
                 }
             },
 
+            getXBlockView: function(){
+                var self = this,
+                    parameters = {
+                        el: this.$('.wrapper-xblock'),
+                        model: this.model,
+                        view: this.view
+                    };
+
+                if (this.enable_paging) {
+                    parameters = _.extend(parameters, {
+                        page_size: this.page_size,
+                        page_reload_callback: function($element) {
+                            self.renderAddXBlockComponents();
+                        }
+                    });
+                    return new PagedContainerView(parameters);
+                }
+                else {
+                    return new ContainerView(parameters);
+                }
+            },
+
             render: function(options) {
                 var self = this,
                     xblockView = this.xblockView,
@@ -106,7 +128,8 @@ define(["jquery", "underscore", "gettext", "js/views/pages/base_page", "js/views
 
                         // Re-enable Backbone events for any updated DOM elements
                         self.delegateEvents();
-                    }
+                    },
+                    block_added: options && options.block_added
                 });
             },
 
@@ -144,7 +167,7 @@ define(["jquery", "underscore", "gettext", "js/views/pages/base_page", "js/views
 
                 modal.edit(xblockElement, this.model, {
                     refresh: function() {
-                        self.refreshXBlock(xblockElement);
+                        self.refreshXBlock(xblockElement, false);
                     }
                 });
             },
@@ -226,7 +249,7 @@ define(["jquery", "underscore", "gettext", "js/views/pages/base_page", "js/views
 
                 // Inform the runtime that the child has been deleted in case
                 // other views are listening to deletion events.
-                xblockView.notifyRuntime('deleted-child', parent.data('locator'));
+                xblockView.acknowledgeXBlockDeletion(parent.data('locator'));
 
                 // Update publish and last modified information from the server.
                 this.model.fetch();
@@ -235,7 +258,7 @@ define(["jquery", "underscore", "gettext", "js/views/pages/base_page", "js/views
             onNewXBlock: function(xblockElement, scrollOffset, data) {
                 ViewUtils.setScrollOffset(xblockElement, scrollOffset);
                 xblockElement.data('locator', data.locator);
-                return this.refreshXBlock(xblockElement);
+                return this.refreshXBlock(xblockElement, true);
             },
 
             /**
@@ -243,17 +266,18 @@ define(["jquery", "underscore", "gettext", "js/views/pages/base_page", "js/views
              * reorderable container then the element will be refreshed inline. If not, then the
              * parent container will be refreshed instead.
              * @param element An element representing the xblock to be refreshed.
+             * @param block_added Flag to indicate that new block has been just added.
              */
-            refreshXBlock: function(element) {
+            refreshXBlock: function(element, block_added) {
                 var xblockElement = this.findXBlockElement(element),
                     parentElement = xblockElement.parent(),
                     rootLocator = this.xblockView.model.id;
                 if (xblockElement.length === 0 || xblockElement.data('locator') === rootLocator) {
-                    this.render({refresh: true});
+                    this.render({refresh: true, block_added: block_added});
                 } else if (parentElement.hasClass('reorderable-container')) {
                     this.refreshChildXBlock(xblockElement);
                 } else {
-                    this.refreshXBlock(this.findXBlockElement(parentElement));
+                    this.refreshXBlock(this.findXBlockElement(parentElement), block_added);
                 }
             },
 

cms/static/js/views/paging_footer.js

@@ -38,6 +38,12 @@ define(["underscore", "js/views/baseview"], function(_, BaseView) {
                 currentPage = collection.currentPage + 1,
                 pageInput = this.$("#page-number-input"),
                 pageNumber = parseInt(pageInput.val(), 10);
+            if (pageNumber > collection.totalPages) {
+                pageNumber = false;
+            }
+            if (pageNumber <= 0) {
+                pageNumber = false;
+            }
             if (pageNumber && pageNumber !== currentPage) {
                 view.setPage(pageNumber - 1);
             }

cms/static/sass/elements/_pagination.scss

+// studio - elements - pagination
+// ==========================
+
+%pagination {
+  @include clearfix;
+  display: inline-block;
+  width: flex-grid(3, 12);
+
+  &.pagination-compact {
+    @include text-align(right);
+  }
+
+  &.pagination-full {
+    display: block;
+    width: flex-grid(4, 12);
+    margin: $baseline auto;
+  }
+
+  .nav-item {
+    position: relative;
+    display: inline-block;
+  }
+
+  .nav-link {
+    @include transition(all $tmg-f2 ease-in-out 0s);
+    display: block;
+    padding: ($baseline/4) ($baseline*0.75);
+
+    &.previous {
+      margin-right: ($baseline/2);
+    }
+
+    &.next {
+      margin-left: ($baseline/2);
+    }
+
+    &:hover {
+      background-color: $blue;
+      border-radius: 3px;
+      color: $white;
+    }
+
+    &.is-disabled {
+      background-color: transparent;
+      color: $gray-l2;
+      pointer-events: none;
+    }
+  }
+
+  .nav-label {
+    @extend .sr;
+  }
+
+  .pagination-form,
+  .current-page,
+  .page-divider,
+  .total-pages {
+    display: inline-block;
+  }
+
+  .current-page,
+  .page-number-input,
+  .total-pages {
+    @extend %t-copy-base;
+    @extend %t-strong;
+    width: ($baseline*2.5);
+    margin: 0 ($baseline*0.75);
+    padding: ($baseline/4);
+    text-align: center;
+    color: $gray;
+  }
+
+  .current-page {
+    @extend %ui-depth1;
+    position: absolute;
+    @include left(-($baseline/4));
+  }
+
+  .page-divider {
+    @extend %t-title4;
+    @extend %t-regular;
+    vertical-align: middle;
+    color: $gray-l2;
+  }
+
+  .pagination-form {
+    @extend %ui-depth2;
+    position: relative;
+
+    .page-number-label,
+    .submit-pagination-form {
+      @extend .sr;
+    }
+
+    .page-number-input {
+      @include transition(all $tmg-f2 ease-in-out 0s);
+      border: 1px solid transparent;
+      border-bottom: 1px dotted $gray-l2;
+      border-radius: 0;
+      box-shadow: none;
+      background: none;
+
+      &:hover {
+        background-color: $white;
+        opacity: 0.6;
+      }
+
+      &:focus {
+        // borrowing the base input focus styles to match overall app
+        @include linear-gradient($paleYellow, tint($paleYellow, 90%));
+        opacity: 1.0;
+        box-shadow: 0 0 3px $shadow-d1 inset;
+        background-color: $white;
+        border: 1px solid transparent;
+        border-radius: 3px;
+      }
+    }
+  }
+}
\ No newline at end of file

cms/static/sass/elements/_uploaded-assets.scss

@@ -28,120 +28,7 @@
     }
 
     .pagination {
-      @include clearfix;
-      display: inline-block;
-      width: flex-grid(3, 12);
-
-      &.pagination-compact {
-        @include text-align(right);
-      }
-
-      &.pagination-full {
-        display: block;
-        width: flex-grid(4, 12);
-        margin: $baseline auto;
-      }
-
-      .nav-item {
-        position: relative;
-        display: inline-block;
-      }
-
-      .nav-link {
-        @include transition(all $tmg-f2 ease-in-out 0s);
-        display: block;
-        padding: ($baseline/4) ($baseline*0.75);
-
-        &.previous {
-          margin-right: ($baseline/2);
-        }
-
-        &.next {
-          margin-left: ($baseline/2);
-        }
-
-        &:hover {
-          background-color: $blue;
-          border-radius: 3px;
-          color: $white;
-        }
-
-        &.is-disabled {
-          background-color: transparent;
-          color: $gray-l2;
-          pointer-events: none;
-        }
-      }
-
-      .nav-label {
-        @extend .sr;
-      }
-
-      .pagination-form,
-      .current-page,
-      .page-divider,
-      .total-pages {
-        display: inline-block;
-      }
-
-      .current-page,
-      .page-number-input,
-      .total-pages {
-        @extend %t-copy-base;
-        @extend %t-strong;
-        width: ($baseline*2.5);
-        margin: 0 ($baseline*0.75);
-        padding: ($baseline/4);
-        text-align: center;
-        color: $gray;
-      }
-
-      .current-page {
-        @extend %ui-depth1;
-        position: absolute;
-        @include left(-($baseline/4));
-      }
-
-      .page-divider {
-        @extend %t-title4;
-        @extend %t-regular;
-        vertical-align: middle;
-        color: $gray-l2;
-      }
-
-      .pagination-form {
-        @extend %ui-depth2;
-        position: relative;
-
-        .page-number-label,
-        .submit-pagination-form {
-          @extend .sr;
-        }
-
-        .page-number-input {
-          @include transition(all $tmg-f2 ease-in-out 0s);
-          border: 1px solid transparent;
-          border-bottom: 1px dotted $gray-l2;
-          border-radius: 0;
-          box-shadow: none;
-          background: none;
-
-          &:hover {
-            background-color: $white;
-            opacity: 0.6;
-          }
-
-          &:focus {
-            // borrowing the base input focus styles to match overall app
-            @include linear-gradient($paleYellow, tint($paleYellow, 90%));
-            opacity: 1.0;
-            box-shadow: 0 0 3px $shadow-d1 inset;
-            background-color: $white;
-            border: 1px solid transparent;
-            border-radius: 3px;
-          }
-        }
-      }
+      @extend %pagination;
     }
 
     .assets-table {

cms/static/sass/elements/_xblocks.scss

@@ -103,6 +103,37 @@
     }
   }
 
+  .container-paging-header {
+    .meta-wrap {
+      margin: $baseline $baseline/2;
+    }
+    .meta {
+      @extend %t-copy-sub2;
+      display: inline-block;
+      vertical-align: top;
+      width: flex-grid(9, 12);
+      color: $gray-l1;
+
+      .count-current-shown,
+      .count-total,
+      .sort-order {
+        @extend %t-strong;
+      }
+    }
+
+    .pagination {
+      @extend %pagination;
+    }
+  }
+
+  .container-paging-footer {
+    .pagination {
+      @extend %pagination;
+    }
+  }
+
+
+
   // ====================
 
   //UI: default internal xblock content styles

cms/static/sass/style-app-extend1-rtl.scss

@@ -40,6 +40,7 @@
 // +Base - Elements
 // ==================== 
 @import 'elements/typography';
+@import 'elements/pagination'; // pagination
 @import 'elements/icons'; // references to icons used
 @import 'elements/controls'; // buttons, link styles, sliders, etc.
 @import 'elements/xblocks'; //  studio rendering chrome for xblocks

cms/static/sass/style-app-extend1.scss

@@ -40,6 +40,7 @@
 // +Base - Elements
 // ==================== 
 @import 'elements/typography';
+@import 'elements/pagination'; // pagination
 @import 'elements/icons'; // references to icons used
 @import 'elements/controls'; // buttons, link styles, sliders, etc.
 @import 'elements/xblocks'; //  studio rendering chrome for xblocks

cms/templates/container.html

@@ -31,7 +31,10 @@ from django.utils.translation import ugettext as _
     require(["js/factories/container"], function(ContainerFactory) {
         ContainerFactory(
             ${component_templates | n}, ${json.dumps(xblock_info) | n},
-            "${action}", ${json.dumps(is_unit_page)}
+            "${action}",
+            {
+                isUnitPage: ${json.dumps(is_unit_page)}
+            }
         );
     });
 </%block>

cms/templates/library.html

@@ -22,8 +22,12 @@ from django.utils.translation import ugettext as _
 <%block name="requirejs">
     require(["js/factories/library"], function(LibraryFactory) {
         LibraryFactory(
-            ${component_templates | n},
-            ${json.dumps(xblock_info) | n}
+            ${component_templates | n}, ${json.dumps(xblock_info) | n},
+            {
+                isUnitPage: false,
+                enable_paging: true,
+                page_size: 10
+            }
         );
     });
 </%block>

common/lib/xmodule/xmodule/library_root_xblock.py

@@ -3,10 +3,10 @@
 """
 import logging
 
-from .studio_editable import StudioEditableModule
 from xblock.core import XBlock
 from xblock.fields import Scope, String, List
 from xblock.fragment import Fragment
+from xmodule.studio_editable import StudioEditableModule
 
 log = logging.getLogger(__name__)
 
@@ -42,29 +42,55 @@ class LibraryRoot(XBlock):
 
     def author_view(self, context):
         """
-        Renders the Studio preview view, which supports drag and drop.
+        Renders the Studio preview view.
         """
         fragment = Fragment()
+        self.render_children(context, fragment, can_reorder=False, can_add=True)
+        return fragment
+
+    def render_children(self, context, fragment, can_reorder=False, can_add=False):  # pylint: disable=unused-argument
+        """
+        Renders the children of the module with HTML appropriate for Studio. If can_reorder is True,
+        then the children will be rendered to support drag and drop.
+        """
         contents = []
 
-        for child_key in self.children:  # pylint: disable=E1101
-            context['reorderable_items'].add(child_key)
+        paging = context.get('paging', None)
+
+        children_count = len(self.children)  # pylint: disable=no-member
+        item_start, item_end = 0, children_count
+
+        # TODO sort children
+        if paging:
+            page_number = paging.get('page_number', 0)
+            raw_page_size = paging.get('page_size', None)
+            page_size = raw_page_size if raw_page_size is not None else children_count
+            item_start, item_end = page_size * page_number, page_size * (page_number + 1)
+
+        children_to_show = self.children[item_start:item_end]  # pylint: disable=no-member
+
+        for child_key in children_to_show:  # pylint: disable=E1101
             child = self.runtime.get_block(child_key)
-            rendered_child = self.runtime.render_child(child, StudioEditableModule.get_preview_view_name(child), context)
+            child_view_name = StudioEditableModule.get_preview_view_name(child)
+            rendered_child = self.runtime.render_child(child, child_view_name, context)
             fragment.add_frag_resources(rendered_child)
 
             contents.append({
-                'id': unicode(child_key),
-                'content': rendered_child.content,
+                'id': child.location.to_deprecated_string(),
+                'content': rendered_child.content
             })
 
-        fragment.add_content(self.runtime.render_template("studio_render_children_view.html", {
-            'items': contents,
-            'xblock_context': context,
-            'can_add': True,
-            'can_reorder': True,
-        }))
-        return fragment
+        fragment.add_content(
+            self.runtime.render_template("studio_render_paged_children_view.html", {
+                'items': contents,
+                'xblock_context': context,
+                'can_add': can_add,
+                'can_reorder': False,
+                'first_displayed': item_start,
+                'total_children': children_count,
+                'displayed_children': len(children_to_show)
+            })
+        )
 
     @property
     def display_org_with_default(self):

common/lib/xmodule/xmodule/video_module/video_handlers.py

@@ -155,7 +155,6 @@ class VideoStudentViewHandlers(object):
 
         if transcript_name:
             # Get the asset path for course
-            asset_path = None
             course = self.descriptor.runtime.modulestore.get_course(self.course_id)
             if course.static_asset_path:
                 asset_path = course.static_asset_path

lms/templates/studio_render_paged_children_view.html

+<%! from django.utils.translation import ugettext as _ %>
+
+<%namespace name='static' file='static_content.html'/>
+
+% for template_name in ["paging-header", "paging-footer"]:
+<script type="text/template" id="${template_name}-tpl">
+    <%static:include path="js/${template_name}.underscore" />
+</script>
+% endfor
+
+<div class="xblock-container-paging-parameters" data-start="${first_displayed}" data-displayed="${displayed_children}" data-total="${total_children}"></div>
+
+<div class="container-paging-header"></div>
+
+% for item in items:
+    ${item['content']}
+% endfor
+
+% if can_add:
+    <div class="add-xblock-component new-component-item adding"></div>
+% endif
+
+<div class="container-paging-footer"></div>