##############################################################################
#
# Copyright (c) 2002 Zope Foundation and Contributors.
# All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.1 (ZPL). A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE.
#
##############################################################################
"""File-based browser resources.
"""
import os
import time
import re
from email.utils import formatdate, parsedate_tz, mktime_tz
from zope.contenttype import guess_content_type
from zope.interface import implementer, provider
from zope.component import adapter, queryMultiAdapter
from zope.publisher.browser import BrowserView
from zope.publisher.interfaces import NotFound
from zope.publisher.interfaces.browser import IBrowserRequest
from zope.publisher.interfaces.browser import IBrowserPublisher
from zope.browserresource.resource import Resource
from zope.browserresource.interfaces import IETag
from zope.browserresource.interfaces import IFileResource
from zope.browserresource.interfaces import IResourceFactory
from zope.browserresource.interfaces import IResourceFactoryFactory
ETAG_RX = re.compile(r'[*]|(?:W/)?"(?:[^"\\]|[\\].)*"')
[docs]def etag_matches(etag, tags):
"""Check if the entity tag matches any of the given tags.
>>> etag_matches('"xyzzy"', ['"abc"', '"xyzzy"', 'W/"woof"'])
True
>>> etag_matches('"woof"', ['"abc"', 'W/"woof"'])
False
>>> etag_matches('"xyzzy"', ['*'])
True
Note that you pass quoted etags in both arguments!
"""
for tag in tags:
if tag == etag or tag == '*':
return True
return False
[docs]def quote_etag(etag):
r"""Quote an etag value
>>> quote_etag("foo")
'"foo"'
Special characters are escaped
>>> quote_etag('"')
'"\\""'
>>> quote_etag('\\')
'"\\\\"'
"""
return '"%s"' % etag.replace('\\', '\\\\').replace('"', '\\"')
[docs]class File(object):
"""
An object representing a file on the filesystem.
These are created by `FileResourceFactory` for use with
`FileResource`.
"""
def __init__(self, path, name):
self.path = path
self.__name__ = name
with open(path, 'rb') as f:
self.data = f.read()
self.content_type = guess_content_type(path, self.data)[0]
self.lmt = float(os.path.getmtime(path)) or time.time()
self.lmh = formatdate(self.lmt, usegmt=True)
[docs]@implementer(IFileResource, IBrowserPublisher)
class FileResource(BrowserView, Resource):
"""
Default implementation of `.IFileResource`.
This class also implements
:class:`zope.publisher.interfaces.browser.IBrowserPublisher`.
"""
cacheTimeout = 86400
[docs] def publishTraverse(self, request, name):
'''File resources can't be traversed further, so raise NotFound if
someone tries to traverse it.
>>> factory = FileResourceFactory(testFilePath, nullChecker, 'test.txt')
>>> request = TestRequest()
>>> resource = factory(request)
>>> resource.publishTraverse(request, '_testData')
Traceback (most recent call last):
...
NotFound: Object: None, name: '_testData'
'''
raise NotFound(None, name)
[docs] def browserDefault(self, request):
'''Return a callable for processing browser requests.
>>> factory = FileResourceFactory(testFilePath, nullChecker, 'test.txt')
>>> request = TestRequest(REQUEST_METHOD='GET')
>>> resource = factory(request)
>>> view, next = resource.browserDefault(request)
>>> with open(testFilePath, 'rb') as f:
... view() == f.read()
True
>>> next == ()
True
>>> request = TestRequest(REQUEST_METHOD='HEAD')
>>> resource = factory(request)
>>> view, next = resource.browserDefault(request)
>>> view() == b''
True
>>> next == ()
True
'''
return getattr(self, request.method), ()
[docs] def chooseContext(self):
"""
Choose the appropriate context.
This method can be overriden in subclasses, that need to choose
appropriate file, based on current request or other condition,
like, for example, i18n files.
.. seealso:: `.I18nFileResource`
.. seealso:: `.II18nResourceDirective`
"""
return self.context
[docs] def GET(self):
'''Return a file data for downloading with GET requests
>>> factory = FileResourceFactory(testFilePath, nullChecker, 'test.txt')
>>> request = TestRequest()
>>> resource = factory(request)
>>> with open(testFilePath, 'rb') as f:
... resource.GET() == f.read()
True
>>> request.response.getHeader('Content-Type') == 'text/plain'
True
'''
file = self.chooseContext()
request = self.request
response = request.response
etag = self._makeETag(file)
setCacheControl(response, self.cacheTimeout)
can_return_304 = False
all_cache_checks_passed = True
# HTTP If-Modified-Since header handling. This is duplicated
# from OFS.Image.Image - it really should be consolidated
# somewhere...
header = request.getHeader('If-Modified-Since', None)
if header is not None:
can_return_304 = True
header = header.split(';')[0]
# Some proxies seem to send invalid date strings for this
# header. If the date string is not valid, we ignore it
# rather than raise an error to be generally consistent
# with common servers such as Apache (which can usually
# understand the screwy date string as a lucky side effect
# of the way they parse it).
try:
mod_since = int(mktime_tz(parsedate_tz(header)))
except (ValueError, TypeError):
mod_since = None
if getattr(file, 'lmt', None):
last_mod = int(file.lmt)
else:
last_mod = 0
if mod_since is None or last_mod <= 0 or last_mod > mod_since:
all_cache_checks_passed = False
# HTTP If-None-Match header handling
header = request.getHeader('If-None-Match', None)
if header is not None:
can_return_304 = True
tags = parse_etags(header)
if not etag or not etag_matches(quote_etag(etag), tags):
all_cache_checks_passed = False
# 304 responses MUST contain ETag, if one would've been sent with
# a 200 response
if etag:
response.setHeader('ETag', quote_etag(etag))
if can_return_304 and all_cache_checks_passed:
response.setStatus(304)
return b''
# 304 responses SHOULD NOT or MUST NOT include other entity headers,
# depending on whether the conditional GET used a strong or a weak
# validator. We only use strong validators, which makes it SHOULD
# NOT.
response.setHeader('Content-Type', file.content_type)
response.setHeader('Last-Modified', file.lmh)
return file.data
[docs] def HEAD(self):
'''Return proper headers and no content for HEAD requests
>>> factory = FileResourceFactory(testFilePath, nullChecker, 'test.txt')
>>> request = TestRequest()
>>> resource = factory(request)
>>> resource.HEAD() == b''
True
>>> request.response.getHeader('Content-Type') == 'text/plain'
True
'''
file = self.chooseContext()
etag = self._makeETag(file)
response = self.request.response
response.setHeader('Content-Type', file.content_type)
response.setHeader('Last-Modified', file.lmh)
if etag:
response.setHeader('ETag', etag)
setCacheControl(response, self.cacheTimeout)
return b''
def _makeETag(self, file_):
etag_adapter = queryMultiAdapter((self, self.request), IETag)
if etag_adapter is None:
return None
return etag_adapter(file_.lmt, file_.data)
# for unit tests
def _testData(self):
with open(self.context.path, 'rb') as f:
return f.read()
[docs]@adapter(IFileResource, IBrowserRequest)
@implementer(IETag)
class FileETag(object):
"""
Default implementation of `.IETag`
registered for `.IFileResource`
and :class:`zope.publisher.interfaces.browser.IBrowserRequest`.
"""
def __init__(self, context, request):
self.context = context
self.request = request
def __call__(self, mtime, content):
return '%s-%s' % (mtime, len(content))
def setCacheControl(response, secs=86400):
# Cache for one day by default
response.setHeader('Cache-Control', 'public,max-age=%s' % secs)
t = time.time() + secs
response.setHeader('Expires', formatdate(t, usegmt=True))
[docs]@implementer(IResourceFactory)
@provider(IResourceFactoryFactory)
class FileResourceFactory(object):
"""
Implementation of `.IResourceFactory` producing `FileResource`.
The class itself provides `.IResourceFactoryFactory`
"""
resourceClass = FileResource
def __init__(self, path, checker, name):
self.__file = File(path, name)
self.__checker = checker
self.__name = name
def __call__(self, request):
resource = self.resourceClass(self.__file, request)
resource.__Security_checker__ = self.__checker
resource.__name__ = self.__name
return resource