[Alc-Alc]

Description

While checking #3207 I found this sentry issue.

• GET /api/v1/ returns a 500 to browsers.
  • Browsers send Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 when opening a page.
  • That header ranks application/xml above */*, so tastypie serializes the index as XML.
  • The index is keyed by resource names like pages/page, and / is not valid in an XML tag name, which fails.

Fix

• Give the v1 Api a JSON-only serializer for the index.
  • Resource endpoints keep their own serializer, so ?format=xml on them is unchanged (XML is in use there).
  • ?format=yaml on the index now returns JSON instead of YAML, this shouldn't affect anyone (no yaml requests).

Closes

• Fixes PYDOTORG-PROD-1JW (issue)

Before / After (DEBUG=False), traceback and body trimmed for brevity

curl -i http://localhost:8000/api/v1/ -H 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8'

Before (500 status code; server log has a 500 with a traceback)

HTTP/1.1 500 Internal Server Error
Content-Type: text/html; charset=utf-8

[error] request_failed [django_structlog.middlewares.request] code=500 request='GET /api/v1/' user_id=None
Traceback (most recent call last):
  ...
  File "<site-packages>/tastypie/api.py", line 164, in top_level
    serialized = self.serializer.serialize(available_resources, desired_format, options)
  ...
  File "<site-packages>/tastypie/serializers.py", line 346, in to_etree
    element = Element(name or 'object')
  ...
ValueError: Invalid tag name 'pages/page'
[error] "GET /api/v1/ HTTP/1.1" 500 13602 [django.server] status_code=500

After (200 status code; server log has only the 200 info line)

HTTP/1.1 200 OK
Content-Type: application/json

{"downloads/os": {"list_endpoint": "/api/v1/downloads/os/", "schema": "/api/v1/downloads/os/schema/"}, "downloads/release": {...}, "downloads/release_file": {...}, "pages/page": {...}}

[info] "GET /api/v1/ HTTP/1.1" 200 447 [django.server] status_code=200