recipes: improved support for queries containing quotes

Use shlex.split() to split the query string so that quotes can be used
to delimit strings containing spaces to be matched as a whole. This
worked with the previous code, but it did not support single quotes -
these caused an error in Django's filter code and thus an internal
server error (as did querying for ""). Add some additional checks for
single quotes as it is still possible to get them past shlex.split()
e.g. with something like "'hello'" (with quotes).

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>

layerindex/views.py

@@ -524,15 +524,27 @@ class RecipeSearchView(ListView):
         return qs, filtered
 
     def get_queryset(self):
+        import shlex
         _check_url_branch(self.kwargs)
         query_string = self.request.GET.get('q', '')
         init_qs = Recipe.objects.filter(layerbranch__branch__name=self.kwargs['branch'])
 
-        # Support slightly crude search on inherits field
+        try:
-        query_items = query_string.split()
+            # Note: we drop quotes here, they will be added back later
+            query_items = shlex.split(query_string)
+        except ValueError:
+            messages.add_message(self.request, messages.ERROR, 'Invalid query string')
+            return Recipe.objects.none()
+        # Check for single quotes which will cause the filter to blow up (e.g. searching for "'hello'" with all quotes)
+        for item in query_items:
+            if '\'' in item:
+                messages.add_message(self.request, messages.ERROR, 'Invalid query string')
+                return Recipe.objects.none()
+
         inherits = []
         query_terms = []
         for item in query_items:
+            # Support slightly crude search on inherits field
             if item.startswith('inherits:'):
                 inherits.append(item.split(':')[1])
 
@@ -565,6 +577,8 @@ layer name is expected to follow the \"layer:\" prefix without any spaces.')
                                             'No layer \"%s\" was found.'
                                             % query_layername)
             else:
+                if ' ' in item:
+                    item = '"%s"' % item
                 query_terms.append(item)
         if inherits:
             # FIXME This is a bit ugly, perhaps we should consider having this as a one-many relationship instead