introduce ReactRenderer module and renderReact mako def

[FEDX-453]

[extreme wip] mako/react bridge code [FEDX-453]

more attempts

split out entry points into separate file

this works!

kill dynamic import

error handling

didn't need webpack_static

handle passing props

cleanup django-template-rendering defs

pytest monkeypatch fix

cleanup

add id arg to renderReact def

more cleanup

oops

quality xss fixes

unittest fix

kill HelloWorld

cms/templates/index.html

@@ -552,6 +552,7 @@ <h3 class="title title-3">${_('Need help?')}</h3>
 
   %endif
 </div>
+
 <%static:webpack entry="StudioIndex">
     var enableReruns = ${allow_course_reruns and rerun_creator_status and course_creator_status=='granted' | n, dump_js_escaped_json};
     new StudioCourseIndex(

common/djangoapps/pipeline_mako/templates/static_content.html

@@ -1,13 +1,15 @@
 <%page expression_filter="h"/>
 <%!
 import logging
+import json
 from django.contrib.staticfiles.storage import staticfiles_storage
 from pipeline_mako import compressed_css, compressed_js
 from django.utils.translation import get_language_bidi
 from mako.exceptions import TemplateLookupException
 from edxmako.shortcuts import marketing_link
 
-from openedx.core.djangolib.js_utils import js_escaped_string
+from openedx.core.djangolib.js_utils import js_escaped_string, dump_js_escaped_json
+from openedx.core.djangolib.markup import HTML
 from openedx.core.djangoapps.site_configuration.helpers import (
   page_title_breadcrumbs,
   get_value,
@@ -18,6 +20,7 @@
   is_request_in_themed_site,
 )
 from certificates.api import get_asset_url_by_slug
+from webpack_loader.templatetags.webpack_loader import render_bundle
 logger = logging.getLogger(__name__)
 %>
 
@@ -97,25 +100,15 @@
             -include it as the first script in this block
     </%doc>
     <%
-        from django.template import Template, Context
-        from webpack_loader.exceptions import WebpackLoaderBadStatsError
-        import json
-
         body = capture(caller.body)
         body_dict = json.loads(body)
         body_dict['lang'] = lang
-        return Template("""
-            <script type="text/javascript" id='studioContext'>
-                var studioContext = {% autoescape off %}{{ body }}{% endautoescape %};
-            </script>
-            <div id="root"></div>
-            {% load render_bundle from webpack_loader %}
-            {% render_bundle page %}
-        """).render(Context({
-            'body': json.dumps(body_dict),
-            'page': page
-        }))
     %>
+    <script type="text/javascript" id='courseContext'>
+      var studioContext = ${ body | n, decode.utf8};
+    </script>
+    <div id="root"></div>
+    ${HTML(render_bundle(page))}
 </%def>
 
 <%def name="webpack(entry)">
@@ -124,21 +117,41 @@
         Uses the Django template engine because our webpack loader only provides template tags for Jinja and Django.
     </%doc>
     <%
-        from django.template import Template, Context
-        from webpack_loader.exceptions import WebpackLoaderBadStatsError
-        return Template("""
-            {% load render_bundle from webpack_loader %}
-            {% render_bundle entry %}
-            {% if body %}
-              <script type="text/javascript">
-                  {% autoescape off %}{{ body }}{% endautoescape %}
-              </script>
-            {% endif %}
-        """).render(Context({
-            'entry': entry,
-            'body': capture(caller.body)
-        }))
+        body = capture(caller.body)
     %>
+    ${HTML(render_bundle(entry))}
+    % if body:
+      <script type="text/javascript">
+        ${body | n, decode.utf8}
+      </script>
+    % endif
+</%def>
+
+<%def name="renderReact(component, id, props={})">
+    <%doc>
+        Wrapper function to load a React component via webpack() and render
+        it onto the page, passing an optional context object via props.
+        component: (string) The component to render, as specified by the name
+        of its Webpack entry point.
+        id: (string) A unique id to apply to the component's container div.
+        props: (dict, optional) An object containing data to pass into the
+        component as props.
+    </%doc>
+
+    ${HTML(render_bundle(component))}
+    ${HTML(render_bundle('ReactRenderer'))}
+
+    <div id="${id}"></div>
+    <script type="text/javascript">
+      var c;
+      try { c = ${component | n, decode.utf8}; } catch (e) { c = null; }
+      new ReactRenderer({
+        component: c,
+        selector: '#${id | n, decode.utf8}',
+        componentName: '${component | n, js_escaped_string}',
+        props: ${props | n, dump_js_escaped_json}
+      });
+    </script>
 </%def>
 
 <%def name="require_module(module_name, class_name)">

common/static/js/src/ReactRenderer.jsx

@@ -0,0 +1,66 @@
+import React from 'react';
+import ReactDOM from 'react-dom';
+
+class ReactRendererException extends Error {
+  constructor(message) {
+    super(`ReactRendererException: ${message}`);
+    Error.captureStackTrace(this, ReactRendererException);
+  }
+}
+
+export class ReactRenderer {
+  constructor({ component, selector, componentName, props = {} }) {
+    Object.assign(this, {
+      component,
+      selector,
+      componentName,
+      props,
+    });
+    this.handleArgumentErrors();
+    this.targetElement = this.getTargetElement();
+    this.renderComponent();
+  }
+
+  handleArgumentErrors() {
+    if (this.component === null) {
+      throw new ReactRendererException(
+        `Component ${this.componentName} is not defined. Make sure you're ` +
+        `using a non-default export statement for the ${this.componentName} ` +
+        `class, that ${this.componentName} has an entry point defined ` +
+        'within the \'entry\' section of webpack.common.config.js, and that the ' +
+        'entry point is pointing at the correct file path.',
+      );
+    }
+    if (!(this.props instanceof Object && this.props.constructor === Object)) {
+      let propsType = typeof this.props;
+      if (Array.isArray(this.props)) {
+        propsType = 'array';
+      } else if (this.props === null) {
+        propsType = 'null';
+      }
+      throw new ReactRendererException(
+        `Invalid props passed to component ${this.componentName}. Expected ` +
+        `an object, but received a ${propsType}.`,
+      );
+    }
+  }
+
+  getTargetElement() {
+    const elementList = document.querySelectorAll(this.selector);
+    if (elementList.length !== 1) {
+      throw new ReactRendererException(
+        `Expected 1 element match for selector "${this.selector}" ` +
+        `but received ${elementList.length} matches.`,
+      );
+    } else {
+      return elementList[0];
+    }
+  }
+
+  renderComponent() {
+    ReactDOM.render(
+      React.createElement(this.component, this.props, null),
+      this.targetElement,
+    );
+  }
+}

conftest.py

@@ -1,10 +1,18 @@
 """
 Default unit test configuration and fixtures.
 """
-
 from __future__ import absolute_import, unicode_literals
+import pytest
 
 # Import hooks and fixture overrides from the cms package to
 # avoid duplicating the implementation
 
 from cms.conftest import _django_clear_site_cache, pytest_configure  # pylint: disable=unused-import
+
+
+@pytest.fixture(autouse=True)
+def no_webpack_loader(monkeypatch):
+    monkeypatch.setattr(
+        "webpack_loader.templatetags.webpack_loader.render_bundle",
+        lambda x: ''
+    )

webpack.common.config.js

@@ -35,7 +35,10 @@ module.exports = {
         Currency: './openedx/features/course_experience/static/course_experience/js/currency.js',
         Enrollment: './openedx/features/course_experience/static/course_experience/js/Enrollment.js',
         LatestUpdate: './openedx/features/course_experience/static/course_experience/js/LatestUpdate.js',
-        WelcomeMessage: './openedx/features/course_experience/static/course_experience/js/WelcomeMessage.js'
+        WelcomeMessage: './openedx/features/course_experience/static/course_experience/js/WelcomeMessage.js',
+
+        // Common
+        ReactRenderer: './common/static/js/src/ReactRenderer.jsx'
     },
 
     output: {