Switch over to using the inputtype ajax handler for chemical input.

common/lib/capa/capa/inputtypes.py

@@ -45,8 +45,10 @@ import re
 import shlex  # for splitting quoted strings
 import sys
 import os
+import pyparsing
 
 from registry import TagRegistry
+from capa.chem import chemcalc
 
 log = logging.getLogger('mitx.' + __name__)
 
@@ -752,6 +754,45 @@ class ChemicalEquationInput(InputTypeBase):
         """
         return {'previewer': '/static/js/capa/chemical_equation_preview.js', }
 
+    def handle_ajax(self, dispatch, get):
+        '''
+        Since we only have one ajax handler for this input, check to see if it
+        matches the corresponding dispatch and send it through if it does
+        '''
+        if dispatch == 'preview_chemcalc':
+            return self.preview_chemcalc(get)
+        return {}
+
+    def preview_chemcalc(self, get):
+        """
+        Render an html preview of a chemical formula or equation.  get should
+        contain a key 'formula' and value 'some formula string'.
+
+        Returns a json dictionary:
+        {
+           'preview' : 'the-preview-html' or ''
+           'error' : 'the-error' or ''
+        }
+        """
+
+        result = {'preview': '',
+                  'error': ''}
+        formula = get['formula']
+        if formula is None:
+            result['error'] = "No formula specified."
+            return result
+
+        try:
+            result['preview'] = chemcalc.render_to_html(formula)
+        except pyparsing.ParseException as p:
+            result['error'] = "Couldn't parse formula: {0}".format(p)
+        except Exception:
+            # this is unexpected, so log
+            log.warning("Error while previewing chemical formula", exc_info=True)
+            result['error'] = "Error while rendering preview"
+
+        return result
+
 registry.register(ChemicalEquationInput)
 
 #-----------------------------------------------------------------------------

common/lib/capa/capa/templates/chemicalequationinput.html

@@ -11,7 +11,7 @@
     <div class="incorrect" id="status_${id}">
     % endif
 
-  <input type="text" name="input_${id}" id="input_${id}" value="${value|h}"
+    <input type="text" name="input_${id}" id="input_${id}" data-input-id="${id}" value="${value|h}"
    % if size:
    size="${size}"
    % endif

common/static/js/capa/chemical_equation_preview.js

@@ -11,9 +11,12 @@
         }
 
         prev_id = "#" + this.id + "_preview";
-        preview_div = $(prev_id)
+        preview_div = $(prev_id);
 
-        $.get("/preview/chemcalc/", {"formula" : this.value}, create_handler(preview_div));
+        url = $(this).parents('.problems-wrapper').data('url');
+        input_id = $(this).data('input-id')
+
+        Problem.inputAjax(url, input_id, 'preview_chemcalc', {"formula" : this.value}, create_handler(preview_div));
     }
 
     inputs = $('.chemicalequationinput input');

lms/djangoapps/courseware/module_render.py

@@ -16,7 +16,6 @@ from django.views.decorators.csrf import csrf_exempt
 from requests.auth import HTTPBasicAuth
 
 from capa.xqueue_interface import XQueueInterface
-from capa.chem import chemcalc
 from courseware.access import has_access
 from mitxmako.shortcuts import render_to_string
 from models import StudentModule, StudentModuleCache
@@ -559,42 +558,6 @@ def modx_dispatch(request, dispatch, location, course_id):
     return HttpResponse(ajax_return)
 
 
-def preview_chemcalc(request):
-    """
-    Render an html preview of a chemical formula or equation.  The fact that
-    this is here is a bit of hack.  See the note in lms/urls.py about why it's
-    here. (Victor is to blame.)
-
-    request should be a GET, with a key 'formula' and value 'some formula string'.
-
-    Returns a json dictionary:
-    {
-       'preview' : 'the-preview-html' or ''
-       'error' : 'the-error' or ''
-    }
-    """
-    if request.method != "GET":
-        raise Http404
-
-    result = {'preview': '',
-              'error': ''}
-    formula = request.GET.get('formula')
-    if formula is None:
-        result['error'] = "No formula specified."
-
-        return HttpResponse(json.dumps(result))
-
-    try:
-        result['preview'] = chemcalc.render_to_html(formula)
-    except pyparsing.ParseException as p:
-        result['error'] = "Couldn't parse formula: {0}".format(p)
-    except Exception:
-        # this is unexpected, so log
-        log.warning("Error while previewing chemical formula", exc_info=True)
-        result['error'] = "Error while rendering preview"
-
-    return HttpResponse(json.dumps(result))
-
 
 def get_score_bucket(grade, max_grade):
     """

lms/urls.py

@@ -224,14 +224,6 @@ if settings.COURSEWARE_ENABLED:
             'courseware.module_render.modx_dispatch',
             name='modx_dispatch'),
 
-        # TODO (vshnayder): This is a hack.  It creates a direct connection from
-        # the LMS to capa functionality, and really wants to go through the
-        # input types system so that previews can be context-specific.
-        # Unfortunately, we don't have time to think through the right way to do
-        # that (and implement it), and it's not a terrible thing to provide a
-        # generic chemical-equation rendering service.
-        url(r'^preview/chemcalc', 'courseware.module_render.preview_chemcalc',
-            name='preview_chemcalc'),
 
         # Software Licenses