Prevent path or view_name being longer than 190 characters

MySQL index restrictions prevent us from having path or view_name be longer than 190 characters (see jazzband#38), but there is no logic in the Request object to enforce this limit when saving, so long URLs cause a 500 error.

Closes jazzband#179.

project/tests/test_config_long_urls.py

@@ -0,0 +1,27 @@
+from django.test import TestCase
+from mock import Mock
+from silk.model_factory import RequestModelFactory
+
+
+class TestLongRequestUrl(TestCase):
+
+    def test_no_long_url(self):
+        url = '1234567890' * 19  # 190-character URL
+        mock_request = Mock()
+        mock_request.META = {'CONTENT_TYPE': 'text/plain'}
+        mock_request.GET = {}
+        mock_request.path = url
+        mock_request.method = 'get'
+        request_model = RequestModelFactory(mock_request).construct_request_model()
+        self.assertEqual(request_model.path, url)
+
+    def test_long_url(self):
+        url = '1234567890' * 200  # 2000-character URL
+        mock_request = Mock()
+        mock_request.META = {'CONTENT_TYPE': 'text/plain'}
+        mock_request.GET = {}
+        mock_request.method = 'get'
+        mock_request.path = url
+        request_model = RequestModelFactory(mock_request).construct_request_model()
+        self.assertEqual(request_model.path, '%s...%s' % (url[:94], url[1907:]))
+        self.assertEqual(len(request_model.path), 190)

silk/models.py

@@ -73,6 +73,11 @@ class Request(models.Model):
     pyprofile = TextField(blank=True, default='')
     prof_file = FileField(max_length=300, blank=True, storage=silk_storage)
 
+    # Useful method to create shortened copies of strings without losing start and end context
+    # Used to ensure path and view_name don't exceed 190 characters
+    def _shorten(self, string):
+        return '%s...%s' % (string[:94], string[len(string) - 93:])
+
     @property
     def total_meta_time(self):
         return (self.meta_time or 0) + (self.meta_time_spent_queries or 0)
@@ -163,6 +168,13 @@ def save(self, *args, **kwargs):
             interval = self.end_time - self.start_time
             self.time_taken = interval.total_seconds() * 1000
 
+        # We can't save if either path or view_name exceed 190 characters
+        if self.path and len(self.path) > 190:
+            self.path = self._shorten(self.path)
+
+        if self.view_name and len(self.view_name) > 190:
+            self.view_name = self._shorten(self.view_name)
+
         super(Request, self).save(*args, **kwargs)
         Request.garbage_collect(force=False)