LastModified should be in UTC

tests/handlers/test_base_handler.py

@@ -13,6 +13,8 @@
 import shutil
 from os.path import abspath, join, dirname
 import os
+from datetime import datetime, timedelta
+import pytz
 
 import tornado.web
 from preggy import expect
@@ -370,6 +372,60 @@ def test_can_get_image_without_etags(self):
         expect(response.code).to_equal(200)
         expect(response.headers).not_to_include('Etag')
 
+class ImageOperationsWithLastModifiedTestCase(BaseImagingTestCase):
+    def get_context(self):
+        cfg = Config(SECURITY_KEY='ACME-SEC')
+        cfg.LOADER = "thumbor.loaders.file_loader"
+        cfg.FILE_LOADER_ROOT_PATH = self.loader_path
+
+        cfg.RESULT_STORAGE = 'thumbor.result_storages.file_storage'
+        cfg.RESULT_STORAGE_EXPIRATION_SECONDS = 60
+        cfg.RESULT_STORAGE_FILE_STORAGE_ROOT_PATH = self.root_path
+
+        cfg.SEND_IF_MODIFIED_LAST_MODIFIED_HEADERS = True
+
+        importer = Importer(cfg)
+        importer.import_modules()
+        server = ServerParameters(8889, 'localhost', 'thumbor.conf', None, 'info', None)
+        server.security_key = 'ACME-SEC'
+        return Context(server, cfg, importer)
+
+    @property
+    def result_storage(self):
+        return self.context.modules.result_storage
+
+    def write_image(self):
+        expected_path = self.result_storage.normalize_path('_wIUeSaeHw8dricKG2MGhqu5thk=/smart/image.jpg')
+
+        if not os.path.exists(dirname(expected_path)):
+            os.makedirs(dirname(expected_path))
+
+        if not os.path.exists(expected_path):
+            with open(expected_path, 'w') as img:
+                img.write(default_image())
+
+    def test_can_get_304_with_last_modified(self):
+        self.write_image()
+        response = self.fetch('/_wIUeSaeHw8dricKG2MGhqu5thk=/smart/image.jpg', headers={
+            "Accept": 'image/webp,*/*;q=0.8',
+            "If-Modified-Since": (datetime.utcnow() + timedelta(seconds=1))
+                              .replace(tzinfo=pytz.utc).strftime("%a, %d %b %Y %H:%M:%S GMT"), # NOW +1 sec UTC
+        })
+
+        expect(response.code).to_equal(304)
+        expect(response.headers).to_include('Last-Modified')
+
+    def test_can_get_image_with_last_modified(self):
+        self.write_image()
+        response = self.fetch('/_wIUeSaeHw8dricKG2MGhqu5thk=/smart/image.jpg', headers={
+            "Accept": 'image/webp,*/*;q=0.8',
+            "If-Modified-Since": (datetime.utcnow() - timedelta(days=365))
+                              .replace(tzinfo=pytz.utc).strftime("%a, %d %b %Y %H:%M:%S GMT"), # Last Year
+        })
+
+        expect(response.code).to_equal(200)
+        expect(response.headers).to_include('Last-Modified')
+
 
 class ImageOperationsWithGifVTestCase(BaseImagingTestCase):
     def get_context(self):

thumbor/handlers/__init__.py

@@ -11,6 +11,7 @@
 import sys
 import functools
 import datetime
+import pytz
 import traceback
 
 import tornado.web
@@ -263,22 +264,32 @@ def _load_results(self, context):
     @gen.coroutine
     def _process_result_from_storage(self, result):
         if self.context.config.SEND_IF_MODIFIED_LAST_MODIFIED_HEADERS:
+            logger.debug('Sending last modified headers')
             # Handle If-Modified-Since & Last-Modified header
             try:
                 if isinstance(result, ResultStorageResult):
                     result_last_modified = result.last_modified
+                    logger.debug('Got last modified from result object')
                 else:
                     result_last_modified = yield gen.maybe_future(self.context.modules.result_storage.last_updated())
+                    logger.debug('Getting last modified from result storage')
+
+                logger.debug('Last-Modified date is: {lm}'.format(lm=result_last_modified))
 
                 if result_last_modified:
                     if 'If-Modified-Since' in self.request.headers:
-                        date_modified_since = datetime.datetime.strptime(self.request.headers['If-Modified-Since'], HTTP_DATE_FMT)
+                        logger.debug('Asking for last-modified (if-modified header set to: {im})'.format(im=self.request.headers['If-Modified-Since']))
+                        date_modified_since = datetime.datetime.strptime(self.request.headers['If-Modified-Since'], HTTP_DATE_FMT).replace(tzinfo=pytz.utc)
 
                         if result_last_modified <= date_modified_since:
+                            logger.debug('if modified is later than last modified, returning 304')
                             self.set_status(304)
                             self.finish()
                             return
 
+                        logger.debug('if modified is sooner than last modified, returning 200')
+
+                    logger.debug('Setting last-modified header')
                     self.set_header('Last-Modified', result_last_modified.strftime(HTTP_DATE_FMT))
             except NotImplementedError:
                 logger.warn('last_updated method is not supported by your result storage service, hence If-Modified-Since & '

thumbor/result_storages/file_storage.py

@@ -11,6 +11,7 @@
 from datetime import datetime
 from uuid import uuid4
 from shutil import move
+import pytz
 
 from os.path import exists, dirname, join, getmtime, abspath
 
@@ -64,7 +65,7 @@ def get(self, callback):
             result = ResultStorageResult(
                 buffer=buffer,
                 metadata={
-                    'LastModified':  datetime.fromtimestamp(getmtime(file_abspath)),
+                    'LastModified':  datetime.fromtimestamp(getmtime(file_abspath)).replace(tzinfo=pytz.utc),
                     'ContentLength': len(buffer),
                     'ContentType':   BaseEngine.get_mimetype(buffer)
                 }
@@ -111,4 +112,4 @@ def last_updated(self):
             logger.debug("[RESULT_STORAGE] image not found at %s" % file_abspath)
             return True
 
-        return datetime.fromtimestamp(getmtime(file_abspath))
+        return datetime.fromtimestamp(getmtime(file_abspath)).replace(tzinfo=pytz.utc)