Implemented simple cache control for files and thumbnails.

Send the Last-Modified header, and react accordingly when receiving an
If-Modified-Since header.

1 files changed, 25 insertions, 17 deletions

diff --git a/fbin.py b/fbin.py
index 2689f47..0a5f578 100755
--- a/fbin.py
+++ b/fbin.py
@@ -5,6 +5,7 @@ import settings, db, os, random, datetime, shutil, mimetypes, cgi, tempfile, has
 from PIL import Image
 
 base62_alphabet = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
+rfc1123_format = '%a, %d %b %Y %H:%M:%S +0000'
 
 if not os.path.isdir(settings.file_directory):
 	os.mkdir(settings.file_directory)
@@ -55,17 +56,6 @@ class Application(object):
 
 		return user
 
-	def get_file_path(self, hash):
-		session = db.Session()
-		try:
-			file = session.query(db.File).filter(db.File.hash == hash).one()
-		except db.NoResultFound:
-			return None
-		finally:
-			session.close()
-
-		return os.path.join(settings.file_directory, hash + os.path.splitext(file.filename)[1])
-
 	def add_file(self, path, filename, file_hash, user = None):
 		hash = ''.join(random.choice(base62_alphabet) for x in xrange(5))
 		new_path = os.path.join(settings.file_directory, hash + os.path.splitext(filename)[1])
@@ -122,18 +112,31 @@ class Application(object):
 		finally:
 			session.close()
 
+	def not_modified(self, environ, date):
+		if not 'HTTP_IF_MODIFIED_SINCE' in environ:
+			return False
+		mod_since_date = datetime.datetime.strptime(environ['HTTP_IF_MODIFIED_SINCE'], rfc1123_format)
+		return date == mod_since_date
+
 	def file(self, environ, start_response, path):
 		hash = path[1]
 		if '.' in hash:
 			hash = hash.split('.')[0]
-		filename = self.get_file_path(hash)
+		file = self.get_file_by_file_hash(hash)
+		filename = file.get_path()
 		if filename == None:
 			start_response('404 Not Found', [('Content-Type', 'text/html')])
 			return ['<h1>Not Found</h1><p>The file you requested does not exist.</p>']
 
-		mime = mimetypes.guess_type(filename, strict = False)[0] or 'application/octet-stream'
+		# strip microseconds
+		if self.not_modified(environ, file.date - datetime.timedelta(microseconds = file.date.microsecond)):
+			start_response('304 Not Modified', [('Last-Modified', file.date.strftime(rfc1123_format))])
+			return []
 
-		start_response('200 OK', [('Content-Type', mime), ('Content-Length', str(os.path.getsize(filename)))])
+		mime = mimetypes.guess_type(file.filename, strict = False)[0] or 'application/octet-stream'
+
+		start_response('200 OK', [('Content-Type', mime), ('Content-Length', str(os.path.getsize(filename))),
+			('Last-Modified', file.date.strftime(rfc1123_format))])
 		return open(filename, 'rb')
 
 	def upload(self, environ, start_response, path):
@@ -308,12 +311,17 @@ class Application(object):
 		hash = path[1]
 		thumbfile = os.path.join(settings.thumb_directory, hash + '.jpg')
 		if not os.access(thumbfile, os.F_OK):
-			filename = self.get_file_path(hash)
-			im = Image.open(filename)
+			file = self.get_file_by_file_hash(hash)
+			im = Image.open(file.get_path())
 			im.thumbnail(settings.thumb_size, Image.ANTIALIAS)
 			im.save(thumbfile)
 
-		start_response('200 OK', [('Content-Type', 'image/jpeg')])
+		date = datetime.datetime.utcfromtimestamp(os.path.getmtime(thumbfile))
+		if self.not_modified(environ, date):
+			start_response('304 Not Modified', [('Last-Modified', date.strftime(rfc1123_format))])
+			return []
+
+		start_response('200 OK', [('Content-Type', 'image/jpeg'), ('Last-Modified', date.strftime(rfc1123_format))])
 		return open(thumbfile, 'rb')
 
 	f = file