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Fix: LargeResponseHandler was wrongly caching ETag value

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ETag values returned with download responses were cached internally within
the LargeResponseHandler class, with the file's path as key. That let to
problems once the content changed and hence the ETag value actually
becoming invalid. Since the path however stayed the same, the same ETag
value for the modified file was assumed and a 304 Not Modified response
was generated.

This patch changes the behaviour of LargeResponseHandler to use
the last modified date of the file as the ETag value and alternatively allowing
an etag generator function to be provided as constructor parameter as well
to use for calculating (or disabling) the ETag header dependant on the
situation.
This commit is contained in:
Gina Häußge 2015-10-06 18:19:53 +02:00
parent 45c92cb1f4
commit 637adc3095
1 changed files with 13 additions and 1 deletions
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14
src/octoprint/server/util/tornado.py
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@ -776,13 +776,19 @@ class LargeResponseHandler(tornado.web.StaticFileHandler):
with the requested path as parameter. Should raise a ``tornado.web.HTTPError`` (e.g. an 404) if the requested
path does not pass validation in which case the request will not be further processed.
Defaults to ``None`` and hence no path validation being performed.
etag_generator (function): Callback to call for generating the value of the ETag response header. Will be
called with the response handler as parameter. May return ``None`` to prevent the ETag response header
from being set. If not provided the last modified time of the file in question will be used as returned
by ``get_content_version``.
"""
def initialize(self, path, default_filename=None, as_attachment=False, access_validation=None, path_validation=None):
def initialize(self, path, default_filename=None, as_attachment=False,
access_validation=None, path_validation=None, etag_generator=None):
tornado.web.StaticFileHandler.initialize(self, os.path.abspath(path), default_filename)
self._as_attachment = as_attachment
self._access_validation = access_validation
self._path_validation = path_validation
self._etag_generator = etag_generator
def get(self, path, include_body=True):
if self._access_validation is not None:
@ -796,6 +802,12 @@ class LargeResponseHandler(tornado.web.StaticFileHandler):
if self._as_attachment:
self.set_header("Content-Disposition", "attachment")
def compute_etag(self):
if self._etag_generator is not None:
return self._etag_generator(self)
else:
return self.get_content_version(self.absolute_path)
@classmethod
def get_content_version(cls, abspath):
import os