Add function to pretty print HttpRequest

Make it easy to dump the contents of a view's HttpRequest to a logger.

Author: hmpf

python/nav/django/utils.py

@@ -18,6 +18,7 @@
 """Utility methods for django used in NAV"""
 
 from django.core.exceptions import FieldDoesNotExist
+from django.http import HttpRequest
 from django.urls import reverse
 from django.utils.http import urlencode
 
@@ -56,6 +57,39 @@ def get_verbose_name(model, lookup):
     raise FieldDoesNotExist
 
 
+def pformat_request(request: HttpRequest, function, *attributes) -> None:
+    """View ``request`` via `function``, one line per attribute
+
+    Use the ``attributes`` parameter to limit what attributes are inspected.
+
+    Also dumps the contents of the dicts ``request.environ``and
+    ``request.META``, one line per value, sorted per key.
+
+    The ``function`` must have an input signature compatible with
+    ``logging.Logger.debug()``.
+
+    Meant for debugging via logs.
+
+    Example usage::
+
+        pformat_request(request, logging.getLogger(__name__).debug)
+    """
+    DICT_ATTRIBUTES = ('META', 'environ')
+
+    existing_attributes = vars(request).keys()
+    if attributes:
+        attributes = set(existing_attributes).intersection(attributes)
+    else:
+        attributes = existing_attributes
+    for attribute in sorted(attributes):
+        value = getattr(request, attribute)
+        if attribute in DICT_ATTRIBUTES:
+            for key in sorted(value.keys()):
+                function('request.%s: %s: %s', attribute, key, value[key])
+        else:
+            function('request.%s: %s', attribute, value)
+
+
 #
 # Django version differentiated helper functions:
 #

tests/unittests/django/utils_test.py

@@ -1,5 +1,12 @@
 # -*- coding: utf-8 -*-
-from nav.django.utils import get_verbose_name, reverse_with_query
+import logging
+from unittest import TestCase
+
+from django.test import RequestFactory
+
+from nav.django.utils import get_verbose_name, pformat_request, reverse_with_query
+
+_logger = logging.getLogger(__name__)
 
 
 def test_verbose_name():
@@ -13,3 +20,29 @@ def test_verbose_name():
 def test_reverse_with_query_should_work_with_unicode():
     """Reveals issues with PY2/PY3 co-compatibility"""
     assert reverse_with_query("maintenance-new", roomid="bø-123")
+
+
+class TestPFormatRequest(TestCase):
+    def test_should_log_more_lines_than_there_are_attributes_in_request(
+        self,
+    ):
+        r = RequestFactory()
+        request = r.get('/')
+        num_request_attributes = len(vars(request))
+        with self.assertLogs(level=logging.DEBUG) as logs:
+            pformat_request(request, _logger.debug)
+            self.assertTrue(len(logs.records) > num_request_attributes)
+
+    def test_should_log_nothing_for_nonexistent_attribute(self):
+        r = RequestFactory()
+        request = r.get('/')
+        with self.assertRaises(AssertionError):
+            with self.assertLogs():
+                pformat_request(request, _logger.debug, 'doesnotexist-nanana')
+
+    def test_should_log_one_line_for_content_type(self):
+        r = RequestFactory()
+        request = r.get('/')
+        with self.assertLogs(level=logging.DEBUG) as logs:
+            pformat_request(request, _logger.debug, 'content_type')
+            self.assertEqual(len(logs.records), 1)