api: Fix UnicodeEncodeError when parsing and rendering results

This is an attempt to prevent encoding errors when posting results or
when rendering them in the API and built-in interface.

Setting UNICODE_JSON [1] to false allows the callback to post results'
content and allows the API browsing interface to render the result.

The built-in UI had a similar problem but isn't fixed by the
UNICODE_JSON because we are using a Response object so use
"surrogateescape" instead.

Related: https://github.com/ansible-community/ara/issues/48

[1]: https://www.django-rest-framework.org/api-guide/settings/#unicode_json

Change-Id: I48bcef440a1ee9c8574fdd24d5c05ef0f13ca666

ara/server/settings.py

@@ -230,6 +230,7 @@ REST_FRAMEWORK = {
     "DEFAULT_AUTHENTICATION_CLASSES": ("rest_framework.authentication.BasicAuthentication",),
     "DEFAULT_PERMISSION_CLASSES": ("ara.api.auth.APIAccessPermission",),
     "TEST_REQUEST_DEFAULT_FORMAT": "json",
+    "UNICODE_JSON": False,
 }
 
 ARA_SETTINGS = os.getenv("ARA_SETTINGS", DEFAULT_SETTINGS)

ara/ui/views.py

@@ -1,3 +1,5 @@
+import codecs
+
 from rest_framework import generics
 from rest_framework.renderers import TemplateHTMLRenderer
 from rest_framework.response import Response
@@ -90,6 +92,8 @@ class Result(generics.RetrieveAPIView):
     template_name = "result.html"
 
     def get(self, request, *args, **kwargs):
+        # Results can contain a wide array of non-ascii or binary characters, escape them
+        codecs.register_error("strict", codecs.lookup_error("surrogateescape"))
         result = self.get_object()
         serializer = serializers.DetailedResultSerializer(result)
         return Response({"result": serializer.data})

tests/integration/smoke.yaml

@@ -65,6 +65,6 @@
         - untag
         - verytag
 
-    - name: Echo a binary string
+    - name: Echo the <20>abc binary string
       command: echo -e '\x80abc'
       changed_when: false