[Zope-dev] PDF-specific Bug in the ZServer implementation??? Or just strange behavoiur of IE?
Martijn Pieters
mj@zope.com
Mon, 7 Jan 2002 16:12:01 -0500
--KsUBxXnnTURmGdap
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On Mon, Jan 07, 2002 at 09:56:40PM +0100, Joachim Werner wrote:
> What is the best approach to upgrading to the new code? Replacing the
> ZServer code by the CVS one?
The code only applies to OFS/Image.py (only File and Image objects support
HTTP Range) and ZPublisher/HTTPRangeSupport.py. I've attached the versions
for a Zope 2.4.x installation, just drop them in the correct places in your
current Zope setup.
--
Martijn Pieters
| Software Engineer mailto:mj@zope.com
| Zope Corporation http://www.zope.com/
| Creators of Zope http://www.zope.org/
---------------------------------------------
--KsUBxXnnTURmGdap
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Content-Disposition: attachment; filename="Image.py"
##############################################################################
#
# Zope Public License (ZPL) Version 1.0
# -------------------------------------
#
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# modification, are permitted provided that the following conditions are
# met:
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# 1. Redistributions in source code must retain the above copyright
# notice, this list of conditions, and the following disclaimer.
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# 2. Redistributions in binary form must reproduce the above copyright
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# in any manner possible. Zope includes a "Powered by Zope"
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# (http://www.zope.org/)."
#
# In the event that the product being advertised includes an
# intact Zope distribution (with copyright and license included)
# then this clause is waived.
#
# 5. Names associated with Zope or Digital Creations must not be used to
# endorse or promote products derived from this software without
# prior written permission from Digital Creations.
#
# 6. Modified redistributions of any form whatsoever must retain
# the following acknowledgment:
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# labeled as unofficial distributions. Modifications which do not
# carry the name Zope may be packaged in any form, as long as they
# conform to all of the clauses above.
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# Disclaimer
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# THIS SOFTWARE IS PROVIDED BY DIGITAL CREATIONS ``AS IS'' AND ANY
# EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL DIGITAL CREATIONS OR ITS
# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
# OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
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# This software consists of contributions made by Digital Creations and
# many individuals on behalf of Digital Creations. Specific
# attributions are listed in the accompanying credits file.
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##############################################################################
"""Image object"""
__version__='$Revision: 1.130.4.2 $'[11:-2]
import Globals, string, struct
from OFS.content_types import guess_content_type
from Globals import DTMLFile
from PropertyManager import PropertyManager
from AccessControl.Role import RoleManager
from webdav.common import rfc1123_date
from webdav.Lockable import ResourceLockedError
from webdav.WriteLockInterface import WriteLockInterface
from SimpleItem import Item_w__name__
from cStringIO import StringIO
from Globals import Persistent
from Acquisition import Implicit
from DateTime import DateTime
from Cache import Cacheable
from mimetools import choose_boundary
from ZPublisher import HTTPRangeSupport
StringType=type('')
manage_addFileForm=DTMLFile('dtml/imageAdd', globals(),Kind='File',kind='file')
def manage_addFile(self,id,file='',title='',precondition='', content_type='',
REQUEST=None):
"""Add a new File object.
Creates a new File object 'id' with the contents of 'file'"""
id=str(id)
title=str(title)
content_type=str(content_type)
precondition=str(precondition)
id, title = cookId(id, title, file)
self=self.this()
# First, we create the file without data:
self._setObject(id, File(id,title,'',content_type, precondition))
# Now we "upload" the data. By doing this in two steps, we
# can use a database trick to make the upload more efficient.
self._getOb(id).manage_upload(file)
if content_type:
self._getOb(id).content_type=content_type
if REQUEST is not None:
REQUEST['RESPONSE'].redirect(self.absolute_url()+'/manage_main')
class File(Persistent, Implicit, PropertyManager,
RoleManager, Item_w__name__, Cacheable):
"""A File object is a content object for arbitrary files."""
__implements__ = (WriteLockInterface, HTTPRangeSupport.HTTPRangeInterface)
meta_type='File'
precondition=''
size=None
manage_editForm =DTMLFile('dtml/fileEdit',globals(),
Kind='File',kind='file')
manage_editForm._setName('manage_editForm')
manage=manage_main=manage_editForm
manage_uploadForm=manage_editForm
manage_options=(
(
{'label':'Edit', 'action':'manage_main',
'help':('OFSP','File_Edit.stx')},
{'label':'View', 'action':'',
'help':('OFSP','File_View.stx')},
)
+ PropertyManager.manage_options
+ RoleManager.manage_options
+ Item_w__name__.manage_options
+ Cacheable.manage_options
)
__ac_permissions__=(
('View management screens',
('manage', 'manage_main',)),
('Change Images and Files',
('manage_edit','manage_upload','PUT')),
('View',
('index_html', 'view_image_or_file', 'get_size',
'getContentType', '')),
('FTP access',
('manage_FTPstat','manage_FTPget','manage_FTPlist')),
('Delete objects',
('DELETE',)),
)
_properties=({'id':'title', 'type': 'string'},
{'id':'content_type', 'type':'string'},
)
def __init__(self, id, title, file, content_type='', precondition=''):
self.__name__=id
self.title=title
self.precondition=precondition
data, size = self._read_data(file)
content_type=self._get_content_type(file, data, id, content_type)
self.update_data(data, content_type, size)
def id(self):
return self.__name__
def index_html(self, REQUEST, RESPONSE):
"""
The default view of the contents of a File or Image.
Returns the contents of the file or image. Also, sets the
Content-Type HTTP header to the objects content type.
"""
# HTTP If-Modified-Since header handling.
header=REQUEST.get_header('If-Modified-Since', None)
if header is not None:
header=string.split(header, ';')[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).
# This happens to be what RFC2616 tells us to do in the face of an
# invalid date.
try: mod_since=long(DateTime(header).timeTime())
except: mod_since=None
if mod_since is not None:
if self._p_mtime:
last_mod = long(self._p_mtime)
else:
last_mod = long(0)
if last_mod > 0 and last_mod <= mod_since:
# Set header values since apache caching will return Content-Length
# of 0 in response if size is not set here
RESPONSE.setHeader('Last-Modified', rfc1123_date(self._p_mtime))
RESPONSE.setHeader('Content-Type', self.content_type)
RESPONSE.setHeader('Content-Length', self.size)
RESPONSE.setHeader('Accept-Ranges', 'bytes')
RESPONSE.setStatus(304)
return ''
if self.precondition and hasattr(self,self.precondition):
# Grab whatever precondition was defined and then
# execute it. The precondition will raise an exception
# if something violates its terms.
c=getattr(self,self.precondition)
if hasattr(c,'isDocTemp') and c.isDocTemp:
c(REQUEST['PARENTS'][1],REQUEST)
else:
c()
# HTTP Range header handling
range = REQUEST.get_header('Range', None)
request_range = REQUEST.get_header('Request-Range', None)
if request_range is not None:
# Netscape 2 through 4 and MSIE 3 implement a draft version
# Later on, we need to serve a different mime-type as well.
range = request_range
if_range = REQUEST.get_header('If-Range', None)
if range is not None:
ranges = HTTPRangeSupport.parseRange(range)
if if_range is not None:
# Only send ranges if the data isn't modified, otherwise send
# the whole object. Support both ETags and Last-Modified dates!
if len(if_range) > 1 and if_range[:2] == 'ts':
# ETag:
if if_range != self.http__etag():
# Modified, so send a normal response. We delete
# the ranges, which causes us to skip to the 200
# response.
ranges = None
else:
# Date
date = string.split(if_range, ';')[0]
try: mod_since=long(DateTime(date).timeTime())
except: mod_since=None
if mod_since is not None:
if self._p_mtime:
last_mod = long(self._p_mtime)
else:
last_mod = long(0)
if last_mod > mod_since:
# Modified, so send a normal response. We delete
# the ranges, which causes us to skip to the 200
# response.
ranges = None
if ranges:
# Search for satisfiable ranges.
satisfiable = 0
for start, end in ranges:
if start < self.size:
satisfiable = 1
break
if not satisfiable:
RESPONSE.setHeader('Content-Range',
'bytes */%d' % self.size)
RESPONSE.setHeader('Accept-Ranges', 'bytes')
RESPONSE.setHeader('Last-Modified',
rfc1123_date(self._p_mtime))
RESPONSE.setHeader('Content-Type', self.content_type)
RESPONSE.setHeader('Content-Length', self.size)
RESPONSE.setStatus(416)
return ''
# Can we optimize?
ranges = HTTPRangeSupport.optimizeRanges(ranges, self.size)
if len(ranges) == 1:
# Easy case, set extra header and return partial set.
start, end = ranges[0]
size = end - start
RESPONSE.setHeader('Last-Modified',
rfc1123_date(self._p_mtime))
RESPONSE.setHeader('Content-Type', self.content_type)
RESPONSE.setHeader('Content-Length', size)
RESPONSE.setHeader('Accept-Ranges', 'bytes')
RESPONSE.setHeader('Content-Range',
'bytes %d-%d/%d' % (start, end - 1, self.size))
RESPONSE.setStatus(206) # Partial content
data = self.data
if type(data) is StringType:
return data[start:end]
# Linked Pdata objects. Urgh.
pos = 0
while data is not None:
l = len(data.data)
pos = pos + l
if pos > start:
# We are within the range
lstart = l - (pos - start)
if lstart < 0: lstart = 0
# find the endpoint
if end <= pos:
lend = l - (pos - end)
# Send and end transmission
RESPONSE.write(data[lstart:lend])
break
# Not yet at the end, transmit what we have.
RESPONSE.write(data[lstart:])
data = data.next
return ''
else:
# When we get here, ranges have been optimized, so they are
# in order, non-overlapping, and start and end values are
# positive integers.
boundary = choose_boundary()
# Calculate the content length
size = (8 + len(boundary) + # End marker length
len(ranges) * ( # Constant lenght per set
49 + len(boundary) + len(self.content_type) +
len('%d' % self.size)))
for start, end in ranges:
# Variable length per set
size = (size + len('%d%d' % (start, end - 1)) +
end - start)
# Some clients implement an earlier draft of the spec, they
# will only accept x-byteranges.
draftprefix = (request_range is not None) and 'x-' or ''
RESPONSE.setHeader('Content-Length', size)
RESPONSE.setHeader('Accept-Ranges', 'bytes')
RESPONSE.setHeader('Last-Modified',
rfc1123_date(self._p_mtime))
RESPONSE.setHeader('Content-Type',
'multipart/%sbyteranges; boundary=%s' % (
draftprefix, boundary))
RESPONSE.setStatus(206) # Partial content
pos = 0
data = self.data
for start, end in ranges:
RESPONSE.write('\r\n--%s\r\n' % boundary)
RESPONSE.write('Content-Type: %s\r\n' %
self.content_type)
RESPONSE.write(
'Content-Range: bytes %d-%d/%d\r\n\r\n' % (
start, end - 1, self.size))
if type(data) is StringType:
RESPONSE.write(data[start:end])
else:
# Yippee. Linked Pdata objects.
while data is not None:
l = len(data.data)
pos = pos + l
if pos > start:
# We are within the range
lstart = l - (pos - start)
if lstart < 0: lstart = 0
# find the endpoint
if end <= pos:
lend = l - (pos - end)
# Send and loop to next range
RESPONSE.write(data[lstart:lend])
# Back up the position marker, it will
# be incremented again for the next
# part.
pos = pos - l
break
# Not yet at the end, transmit what we have.
RESPONSE.write(data[lstart:])
data = data.next
RESPONSE.write('\r\n--%s--\r\n' % boundary)
return ''
RESPONSE.setHeader('Last-Modified', rfc1123_date(self._p_mtime))
RESPONSE.setHeader('Content-Type', self.content_type)
RESPONSE.setHeader('Content-Length', self.size)
RESPONSE.setHeader('Accept-Ranges', 'bytes')
# Don't cache the data itself, but provide an opportunity
# for a cache manager to set response headers.
self.ZCacheable_set(None)
data=self.data
if type(data) is type(''): return data
while data is not None:
RESPONSE.write(data.data)
data=data.next
return ''
def view_image_or_file(self, URL1):
"""
The default view of the contents of the File or Image.
"""
raise 'Redirect', URL1
# private
update_data__roles__=()
def update_data(self, data, content_type=None, size=None):
if content_type is not None: self.content_type=content_type
if size is None: size=len(data)
self.size=size
self.data=data
self.ZCacheable_invalidate()
self.http__refreshEtag()
def manage_edit(self, title, content_type, precondition='', REQUEST=None):
"""
Changes the title and content type attributes of the File or Image.
"""
if self.wl_isLocked():
raise ResourceLockedError, "File is locked via WebDAV"
self.title=str(title)
self.content_type=str(content_type)
if precondition: self.precondition=str(precondition)
elif self.precondition: del self.precondition
self.ZCacheable_invalidate()
if REQUEST:
message="Saved changes."
return self.manage_main(self,REQUEST,manage_tabs_message=message)
def manage_upload(self,file='',REQUEST=None):
"""
Replaces the current contents of the File or Image object with file.
The file or images contents are replaced with the contents of 'file'.
"""
if self.wl_isLocked():
raise ResourceLockedError, "File is locked via WebDAV"
data, size = self._read_data(file)
content_type=self._get_content_type(file, data, self.__name__,
'application/octet-stream')
self.update_data(data, content_type, size)
if REQUEST:
message="Saved changes."
return self.manage_main(self,REQUEST,manage_tabs_message=message)
def _get_content_type(self, file, body, id, content_type=None):
headers=getattr(file, 'headers', None)
if headers and headers.has_key('content-type'):
content_type=headers['content-type']
else:
if type(body) is not type(''): body=body.data
content_type, enc=guess_content_type(
getattr(file, 'filename',id), body, content_type)
return content_type
def _read_data(self, file):
n=1 << 16
if type(file) is StringType:
size=len(file)
if size < n: return file, size
return Pdata(file), size
if hasattr(file, '__class__') and file.__class__ is Pdata:
size=len(file)
return file, size
seek=file.seek
read=file.read
seek(0,2)
size=end=file.tell()
if size <= 2*n:
seek(0)
if size < n: return read(size), size
return Pdata(read(size)), size
# Make sure we have an _p_jar, even if we are a new object, by
# doing a sub-transaction commit.
get_transaction().commit(1)
jar=self._p_jar
if jar is None:
# Ugh
seek(0)
return Pdata(read(size)), size
# Now we're going to build a linked list from back
# to front to minimize the number of database updates
# and to allow us to get things out of memory as soon as
# possible.
next=None
while end > 0:
pos=end-n
if pos < n: pos=0 # we always want at least n bytes
seek(pos)
data=Pdata(read(end-pos))
# Woooop Woooop Woooop! This is a trick.
# We stuff the data directly into our jar to reduce the
# number of updates necessary.
data._p_jar=jar
# This is needed and has side benefit of getting
# the thing registered:
data.next=next
# Now make it get saved in a sub-transaction!
get_transaction().commit(1)
# Now make it a ghost to free the memory. We
# don't need it anymore!
data._p_changed=None
next=data
end=pos
return next, size
def PUT(self, REQUEST, RESPONSE):
"""Handle HTTP PUT requests"""
self.dav__init(REQUEST, RESPONSE)
self.dav__simpleifhandler(REQUEST, RESPONSE, refresh=1)
type=REQUEST.get_header('content-type', None)
file=REQUEST['BODYFILE']
data, size = self._read_data(file)
content_type=self._get_content_type(file, data, self.__name__,
type or self.content_type)
self.update_data(data, content_type, size)
RESPONSE.setStatus(204)
return RESPONSE
def get_size(self):
"""Get the size of a file or image.
Returns the size of the file or image.
"""
size=self.size
if size is None: size=len(self.data)
return size
# deprecated; use get_size!
getSize=get_size
def getContentType(self):
"""Get the content type of a file or image.
Returns the content type (MIME type) of a file or image.
"""
return self.content_type
def __str__(self): return str(self.data)
def __len__(self): return 1
manage_FTPget=index_html
manage_addImageForm=DTMLFile('dtml/imageAdd',globals(),
Kind='Image',kind='image')
def manage_addImage(self, id, file, title='', precondition='', content_type='',
REQUEST=None):
"""
Add a new Image object.
Creates a new Image object 'id' with the contents of 'file'.
"""
id=str(id)
title=str(title)
content_type=str(content_type)
precondition=str(precondition)
id, title = cookId(id, title, file)
self=self.this()
# First, we create the image without data:
self._setObject(id, Image(id,title,'',content_type, precondition))
# Now we "upload" the data. By doing this in two steps, we
# can use a database trick to make the upload more efficient.
self._getOb(id).manage_upload(file)
if content_type:
self._getOb(id).content_type=content_type
if REQUEST is not None:
try: url=self.DestinationURL()
except: url=REQUEST['URL1']
REQUEST.RESPONSE.redirect('%s/manage_main' % url)
return id
def getImageInfo(data):
data = str(data)
size = len(data)
height = -1
width = -1
content_type = ''
# handle GIFs
if (size >= 10) and data[:6] in ('GIF87a', 'GIF89a'):
# Check to see if content_type is correct
content_type = 'image/gif'
w, h = struct.unpack("<HH", data[6:10])
width = int(w)
height = int(h)
# See PNG v1.2 spec (http://www.cdrom.com/pub/png/spec/)
# Bytes 0-7 are below, 4-byte chunk length, then 'IHDR'
# and finally the 4-byte width, height
elif ((size >= 24) and (data[:8] == '\211PNG\r\n\032\n')
and (data[12:16] == 'IHDR')):
content_type = 'image/png'
w, h = struct.unpack(">LL", data[16:24])
width = int(w)
height = int(h)
# Maybe this is for an older PNG version.
elif (size >= 16) and (data[:8] == '\211PNG\r\n\032\n'):
# Check to see if we have the right content type
content_type = 'image/png'
w, h = struct.unpack(">LL", data[8:16])
width = int(w)
height = int(h)
# handle JPEGs
elif (size >= 2) and (data[:2] == '\377\330'):
content_type = 'image/jpeg'
jpeg = StringIO(data)
jpeg.read(2)
b = jpeg.read(1)
try:
while (b and ord(b) != 0xDA):
while (ord(b) != 0xFF): b = jpeg.read(1)
while (ord(b) == 0xFF): b = jpeg.read(1)
if (ord(b) >= 0xC0 and ord(b) <= 0xC3):
jpeg.read(3)
h, w = struct.unpack(">HH", jpeg.read(4))
break
else:
jpeg.read(int(struct.unpack(">H", jpeg.read(2))[0])-2)
b = jpeg.read(1)
width = int(w)
height = int(h)
except: pass
return content_type, width, height
class Image(File):
"""Image objects can be GIF, PNG or JPEG and have the same methods
as File objects. Images also have a string representation that
renders an HTML 'IMG' tag.
"""
__implements__ = (WriteLockInterface,)
meta_type='Image'
height=''
width=''
__ac_permissions__=(
('View management screens',
('manage', 'manage_main',)),
('Change Images and Files',
('manage_edit','manage_upload','PUT')),
('View',
('index_html', 'tag', 'view_image_or_file', 'get_size',
'getContentType', '')),
('FTP access',
('manage_FTPstat','manage_FTPget','manage_FTPlist')),
('Delete objects',
('DELETE',)),
)
_properties=({'id':'title', 'type': 'string'},
{'id':'content_type', 'type':'string'},
{'id':'height', 'type':'string'},
{'id':'width', 'type':'string'},
)
manage_options=(
({'label':'Edit', 'action':'manage_main',
'help':('OFSP','Image_Edit.stx')},
{'label':'View', 'action':'view_image_or_file',
'help':('OFSP','Image_View.stx')},)
+ PropertyManager.manage_options
+ RoleManager.manage_options
+ Item_w__name__.manage_options
+ Cacheable.manage_options
)
manage_editForm =DTMLFile('dtml/imageEdit',globals(),
Kind='Image',kind='image')
view_image_or_file =DTMLFile('dtml/imageView',globals())
manage_editForm._setName('manage_editForm')
manage=manage_main=manage_editForm
manage_uploadForm=manage_editForm
# private
update_data__roles__=()
def update_data(self, data, content_type=None, size=None):
if size is None: size=len(data)
self.size=size
self.data=data
ct, width, height = getImageInfo(data)
if ct:
content_type = ct
if width >= 0 and height >= 0:
self.width = width
self.height = height
# Now we should have the correct content type, or still None
if content_type is not None: self.content_type = content_type
self.ZCacheable_invalidate()
def __str__(self):
return self.tag()
def tag(self, height=None, width=None, alt=None,
scale=0, xscale=0, yscale=0, css_class=None, **args):
"""
Generate an HTML IMG tag for this image, with customization.
Arguments to self.tag() can be any valid attributes of an IMG tag.
'src' will always be an absolute pathname, to prevent redundant
downloading of images. Defaults are applied intelligently for
'height', 'width', and 'alt'. If specified, the 'scale', 'xscale',
and 'yscale' keyword arguments will be used to automatically adjust
the output height and width values of the image tag.
Since 'class' is a Python reserved word, it cannot be passed in
directly in keyword arguments which is a problem if you are
trying to use 'tag()' to include a CSS class. The tag() method
will accept a 'css_class' argument that will be converted to
'class' in the output tag to work around this.
"""
if height is None: height=self.height
if width is None: width=self.width
# Auto-scaling support
xdelta = xscale or scale
ydelta = yscale or scale
if xdelta and width:
width = str(int(round(int(width) * xdelta)))
if ydelta and height:
height = str(int(round(int(height) * ydelta)))
result='<img src="%s"' % (self.absolute_url())
if alt is None:
alt=getattr(self, 'title', '')
result = '%s alt="%s"' % (result, alt)
if height:
result = '%s height="%s"' % (result, height)
if width:
result = '%s width="%s"' % (result, width)
if not 'border' in map(string.lower, args.keys()):
result = '%s border="0"' % result
if css_class is not None:
result = '%s class="%s"' % (result, css_class)
for key in args.keys():
value = args.get(key)
result = '%s %s="%s"' % (result, key, value)
return '%s />' % result
def cookId(id, title, file):
if not id and hasattr(file,'filename'):
filename=file.filename
title=title or filename
id=filename[max(string.rfind(filename, '/'),
string.rfind(filename, '\\'),
string.rfind(filename, ':'),
)+1:]
return id, title
class Pdata(Persistent, Implicit):
# Wrapper for possibly large data
next=None
def __init__(self, data):
self.data=data
def __getslice__(self, i, j):
return self.data[i:j]
def __len__(self):
data = str(self)
return len(data)
def __str__(self):
next=self.next
if next is None: return self.data
r=[self.data]
while next is not None:
self=next
r.append(self.data)
next=self.next
return string.join(r,'')
--KsUBxXnnTURmGdap
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment; filename="HTTPRangeSupport.py"
##############################################################################
#
# Zope Public License (ZPL) Version 1.0
# -------------------------------------
#
# Copyright (c) Digital Creations. All rights reserved.
#
# This license has been certified as Open Source(tm).
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# 1. Redistributions in source code must retain the above copyright
# notice, this list of conditions, and the following disclaimer.
#
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions, and the following disclaimer in
# the documentation and/or other materials provided with the
# distribution.
#
# 3. Digital Creations requests that attribution be given to Zope
# in any manner possible. Zope includes a "Powered by Zope"
# button that is installed by default. While it is not a license
# violation to remove this button, it is requested that the
# attribution remain. A significant investment has been put
# into Zope, and this effort will continue if the Zope community
# continues to grow. This is one way to assure that growth.
#
# 4. All advertising materials and documentation mentioning
# features derived from or use of this software must display
# the following acknowledgement:
#
# "This product includes software developed by Digital Creations
# for use in the Z Object Publishing Environment
# (http://www.zope.org/)."
#
# In the event that the product being advertised includes an
# intact Zope distribution (with copyright and license included)
# then this clause is waived.
#
# 5. Names associated with Zope or Digital Creations must not be used to
# endorse or promote products derived from this software without
# prior written permission from Digital Creations.
#
# 6. Modified redistributions of any form whatsoever must retain
# the following acknowledgment:
#
# "This product includes software developed by Digital Creations
# for use in the Z Object Publishing Environment
# (http://www.zope.org/)."
#
# Intact (re-)distributions of any official Zope release do not
# require an external acknowledgement.
#
# 7. Modifications are encouraged but must be packaged separately as
# patches to official Zope releases. Distributions that do not
# clearly separate the patches from the original work must be clearly
# labeled as unofficial distributions. Modifications which do not
# carry the name Zope may be packaged in any form, as long as they
# conform to all of the clauses above.
#
#
# Disclaimer
#
# THIS SOFTWARE IS PROVIDED BY DIGITAL CREATIONS ``AS IS'' AND ANY
# EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL DIGITAL CREATIONS OR ITS
# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
# OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#
#
# This software consists of contributions made by Digital Creations and
# many individuals on behalf of Digital Creations. Specific
# attributions are listed in the accompanying credits file.
#
##############################################################################
"""HTTP Range support utilities.
The RFC 2616 specification defines the 'Range' and 'If-Range' headers for
enabeling partial download of published resources. This module provides a
flag-interface and some support functions for implementing this functionality.
For an implementation example, see the File class in OFS/Image.py.
"""
__version__='$Revision'[11:-2]
import re, string, sys
import Interface
WHITESPACE = re.compile('\s*', re.MULTILINE)
def parseRange(header):
"""RFC 2616 (HTTP 1.1) Range header parsing.
Convert a range header to a list of slice indexes, returned as (start, end)
tuples. If no end was given, end is None. Note that the RFC specifies the
end offset to be inclusive, we return python convention indexes, where the
end is exclusive. Syntactically incorrect headers are to be ignored, so if
we encounter one we return None.
"""
ranges = []
add = ranges.append
# First, clean out *all* whitespace. This is slightly more tolerant
# than the spec asks for, but hey, it makes this function much easier.
header = WHITESPACE.sub('', header)
# A range header only can specify a byte range
try: spec, sets = string.split(header, '=')
except ValueError: return None
if spec != 'bytes':
return None
# The sets are delimited by commas.
sets = string.split(sets, ',')
# Filter out empty values, things like ',,' are allowed in the spec
sets = filter(None, sets)
# We need at least one set
if not sets:
return None
for set in sets:
try: start, end = string.split(set, '-')
except ValueError: return None
# Catch empty sets
if not start and not end:
return None
# Convert to integers or None (which will raise errors if
# non-integers were used (which is what we want)).
try:
if start == '': start = None
else: start = int(start)
if end == '': end = None
else: end = int(end)
except ValueError:
return None
# Special case: No start means the suffix format was used, which
# means the end value is actually a negative start value.
# Convert this by making it absolute.
# A -0 range is converted to sys.maxint, which will result in a
# Unsatisfiable response if no other ranges can by satisfied either.
if start is None:
start, end = -end, None
if not start:
start = sys.maxint
elif end is not None:
end = end + 1 # Make the end of the range exclusive
if end is not None and end <= start:
return None
# And store
add((start, end))
return ranges
def optimizeRanges(ranges, size):
"""Optimize Range sets, given those sets and the length of the resource.
Optimisation is done by first expanding relative start values and open
ends, then sorting and combining overlapping ranges. We also remove
unsatisfiable ranges (where the start lies beyond the size of the resource).
"""
expanded = []
add = expanded.append
for start, end in ranges:
if start < 0:
start = size + start
end = end or size
if end > size: end = size
# Only use satisfiable ranges
if start < size:
add((start, end))
ranges = expanded
ranges.sort()
ranges.reverse()
optimized = []
add = optimized.append
start, end = ranges.pop()
while ranges:
nextstart, nextend = ranges.pop()
# If the next range overlaps
if nextstart < end:
# If it falls within the current range, discard
if nextend <= end:
continue
# Overlap, adjust end
end = nextend
else:
add((start, end))
start, end = nextstart, nextend
# Add the remaining optimized range
add((start, end))
return optimized
class HTTPRangeInterface(Interface.Base):
"""Objects implementing this Interface support the HTTP Range header.
Objects implementing support for the HTTP Range header will return partial
content as specified in RFC 2616. Note that the'If-Range' header must
either be implemented correctly or result in a normal '200 OK' response at
all times.
This interface specifies no methods, as this functionality can either be
implemented in the index_html or __call__ methods of a published object.
"""
--KsUBxXnnTURmGdap--