hub: return error 404 for non-existent logs

Otherwise, the response would yield an empty file and 200 status code.

Resolves: #49

kobo/hub/views.py

@@ -19,7 +19,7 @@
     from django.urls import reverse
 else:
     from django.core.urlresolvers import reverse
-from django.http import HttpResponse, StreamingHttpResponse, HttpResponseForbidden
+from django.http import HttpResponse, HttpResponseNotFound, StreamingHttpResponse, HttpResponseForbidden
 from django.shortcuts import render, get_object_or_404
 from django.template import RequestContext
 from django.views.generic import RedirectView
@@ -111,13 +111,8 @@ def get_context_data(self, **kwargs):
         return context
 
 
-def _stream_file(file_path, offset=0):
+def _stream_file(f, offset=0):
     """Generator that returns 1M file chunks."""
-    try:
-        f = open(file_path, "rb")
-    except IOError:
-        return
-
     f.seek(offset)
     while 1:
         data = f.read(1024 ** 2)
@@ -149,8 +144,13 @@ def _streamed_log_response(task, log_name, offset, as_attachment):
     except OSError:
         content_len = 0
 
+    try:
+        f = open(file_path, "rb")
+    except OSError:
+        return HttpResponseNotFound('Cannot find file ' + log_name)
+
     # use _stream_file() instead of passing file object in order to improve performance
-    response = StreamingHttpResponse(_stream_file(file_path, offset), content_type=mimetype)
+    response = StreamingHttpResponse(_stream_file(f, offset), content_type=mimetype)
     response["Content-Length"] = content_len
 
     if as_attachment:

tests/test_view_log.py

@@ -134,6 +134,20 @@ def setUp(self):
         # for more accurate memory_profiler tests
         gc.collect()
 
+    def test_view_log_404(self):
+        """Fetching of non-existent logs should yield error 404"""
+        response = self.get_log('missing.htm')
+        self.assertEqual(response.content, b'Cannot find file missing.htm')
+        self.assertEqual(response.status_code, 404)
+
+        response = self.get_log('missing.html')
+        self.assertEqual(response.content, b'Cannot find file missing.html')
+        self.assertEqual(response.status_code, 404)
+
+        response = self.get_log('missing.tar.gz', data={'format': 'raw'})
+        self.assertEqual(response.content, b'Cannot find file missing.tar.gz')
+        self.assertEqual(response.status_code, 404)
+
     def test_view_zipped_small_raw(self):
         """Fetching a small compressed log with raw format should yield
         the gzip-compressed content."""