debian-quixote3/quixote/util.py

383 lines
13 KiB
Python

"""quixote.util
Contains various useful functions and classes:
xmlrpc(request, func) : Processes the body of an XML-RPC request, and calls
'func' with the method name and parameters.
StaticFile : Wraps a file from a filesystem as a
Quixote resource.
StaticDirectory : Wraps a directory containing static files as
a Quixote directory.
StaticFile and StaticDirectory were contributed by Hamish Lawson.
See doc/static-files.txt for examples of their use.
"""
import sys
import os
import time
import binascii
import mimetypes
import urllib
import xmlrpclib
from rfc822 import formatdate
import quixote
from quixote import errors
from quixote.directory import Directory
from quixote.html import htmltext, TemplateIO
from quixote.http_response import Stream
def _encode_base64(s):
s = binascii.b2a_base64(s).strip('=\n')
s = s.replace('+', '-').replace('/', '_') # URL safe
return s
if hasattr(os, 'urandom'):
# available in Python 2.4 and also works on win32
def randbytes(bytes):
"""Return bytes of random data as a text string."""
return _encode_base64(os.urandom(bytes))
elif os.path.exists('/dev/urandom'):
# /dev/urandom is just as good as /dev/random for cookies (assuming
# SHA-1 is secure) and it never blocks.
def randbytes(bytes):
"""Return bytes of random data as a text string."""
return _encode_base64(open("/dev/urandom").read(bytes))
else:
# this is much less secure than the above function
import sha
import warnings
class _PRNG:
def __init__(self):
self.state = sha.new(str(time.time() + time.clock()))
self.count = 0
def _get_bytes(self):
self.state.update('%s %d' % (time.time() + time.clock(),
self.count))
self.count += 1
return self.state.digest()
def randbytes(self, bytes):
"""Return bytes of random data as a text string."""
warnings.warn('insecure randbytes(), os.urandom() missing')
s = ""
while len(s) < bytes:
s += self._get_bytes()
return _encode_base64(s[:bytes])
randbytes = _PRNG().randbytes
def import_object(name):
i = name.rfind('.')
if i != -1:
module_name = name[:i]
object_name = name[i+1:]
__import__(module_name)
return getattr(sys.modules[module_name], object_name)
else:
__import__(name)
return sys.modules[name]
def xmlrpc(request, func):
"""xmlrpc(request:Request, func:callable) : string
Processes the body of an XML-RPC request, and calls 'func' with
two arguments, a string containing the method name and a tuple of
parameters.
"""
# Get contents of POST body
if request.get_method() != 'POST':
request.response.set_status(405, "Only the POST method is accepted")
return "XML-RPC handlers only accept the POST method."
length = int(request.environ['CONTENT_LENGTH'])
data = request.stdin.read(length)
# Parse arguments
params, method = xmlrpclib.loads(data)
try:
result = func(method, params)
except xmlrpclib.Fault, exc:
result = exc
except:
# report exception back to client
result = xmlrpclib.dumps(
xmlrpclib.Fault(1, "%s:%s" % (sys.exc_type, sys.exc_value))
)
else:
result = (result,)
result = xmlrpclib.dumps(result, methodresponse=1)
request.response.set_content_type('text/xml')
return result
class FileStream(Stream):
CHUNK_SIZE = 20000
def __init__(self, fp, size=None):
self.fp = fp
self.length = size
def __iter__(self):
return self
def next(self):
chunk = self.fp.read(self.CHUNK_SIZE)
if not chunk:
raise StopIteration
return chunk
class StaticFile:
"""
Wrapper for a static file on the filesystem.
"""
def __init__(self, path, follow_symlinks=False,
mime_type=None, encoding=None, cache_time=None):
"""StaticFile(path:string, follow_symlinks:bool)
Initialize instance with the absolute path to the file. If
'follow_symlinks' is true, symbolic links will be followed.
'mime_type' specifies the MIME type, and 'encoding' the
encoding; if omitted, the MIME type will be guessed,
defaulting to text/plain.
Optional cache_time parameter indicates the number of
seconds a response is considered to be valid, and will
be used to set the Expires header in the response when
quixote gets to that part. If the value is None then
the Expires header will not be set.
"""
# Check that the supplied path is absolute and (if a symbolic link) may
# be followed
self.path = path
if not os.path.isabs(path):
raise ValueError("Path %r is not absolute" % path)
# Decide the Content-Type of the file
guess_mime, guess_enc = mimetypes.guess_type(os.path.basename(path),
strict=False)
self.mime_type = mime_type or guess_mime or 'text/plain'
self.encoding = encoding or guess_enc or None
self.cache_time = cache_time
self.follow_symlinks = follow_symlinks
def __call__(self):
if not self.follow_symlinks and os.path.islink(self.path):
raise errors.TraversalError(private_msg="Path %r is a symlink" % self.path)
request = quixote.get_request()
response = quixote.get_response()
if self.cache_time is None:
response.set_expires(None) # don't set the Expires header
else:
# explicitly allow client to cache page by setting the Expires
# header, this is even more efficient than the using
# Last-Modified/If-Modified-Since since the browser does not need
# to contact the server
response.set_expires(seconds=self.cache_time)
try:
stat = os.stat(self.path)
except OSError:
raise errors.TraversalError
last_modified = formatdate(stat.st_mtime, usegmt=True)
if last_modified == request.get_header('If-Modified-Since'):
# handle exact match of If-Modified-Since header
response.set_status(304)
return ''
# Set the Content-Type for the response and return the file's contents.
response.set_content_type(self.mime_type)
if self.encoding:
response.set_header("Content-Encoding", self.encoding)
response.set_header('Last-Modified', last_modified)
return FileStream(open(self.path, 'rb'), stat.st_size)
class StaticDirectory(Directory):
"""
Wrap a filesystem directory containing static files as a Quixote directory.
"""
_q_exports = ['']
FILE_CLASS = StaticFile
def __init__(self, path, use_cache=False, list_directory=False,
follow_symlinks=False, cache_time=None, file_class=None,
index_filenames=None):
"""(path:string, use_cache:bool, list_directory:bool,
follow_symlinks:bool, cache_time:int,
file_class=None, index_filenames:[string])
Initialize instance with the absolute path to the file.
If 'use_cache' is true, StaticFile instances will be cached in memory.
If 'list_directory' is true, users can request a directory listing.
If 'follow_symlinks' is true, symbolic links will be followed.
Optional parameter cache_time allows setting of Expires header in
response object (see note for StaticFile for more detail).
Optional parameter 'index_filenames' specifies a list of
filenames to be used as index files in the directory. First
file found searching left to right is returned.
"""
# Check that the supplied path is absolute
self.path = path
if not os.path.isabs(path):
raise ValueError("Path %r is not absolute" % path)
self.use_cache = use_cache
self.cache = {}
self.list_directory = list_directory
self.follow_symlinks = follow_symlinks
self.cache_time = cache_time
if file_class is not None:
self.file_class = file_class
else:
self.file_class = self.FILE_CLASS
self.index_filenames = index_filenames
def _q_index(self):
"""
If directory listings are allowed, generate a simple HTML
listing of the directory's contents with each item hyperlinked;
if the item is a subdirectory, place a '/' after it. If not allowed,
return a page to that effect.
"""
if self.index_filenames:
for name in self.index_filenames:
try:
obj = self._q_lookup(name)
except errors.TraversalError:
continue
if (not isinstance(obj, StaticDirectory)
and hasattr(obj, '__call__')):
return obj()
if self.list_directory:
title = 'Index of %s' % quixote.get_path()
r = TemplateIO(html=True)
template = htmltext('<a href="%s">%s</a>%s\n')
r += htmltext('<pre>')
r += template % ('..', '..', '')
files = os.listdir(self.path)
files.sort()
for filename in files:
filepath = os.path.join(self.path, filename)
marker = os.path.isdir(filepath) and "/" or ""
r += template % (urllib.quote(filename), filename, marker)
r += htmltext('</pre>')
body = r.getvalue()
else:
title = 'Directory listing denied'
body = htmltext('<p>This directory does not allow its contents '
'to be listed.</p>')
return errors.format_page(title, body)
def _q_lookup(self, name):
"""
Get a file from the filesystem directory and return the StaticFile
or StaticDirectory wrapper of it; use caching if that is in use.
"""
if name in ('.', '..'):
raise errors.TraversalError(private_msg="Attempt to use '.', '..'")
if name in self.cache:
# Get item from cache
item = self.cache[name]
else:
# Get item from filesystem; cache it if caching is in use.
item_filepath = os.path.join(self.path, name)
while os.path.islink(item_filepath):
if not self.follow_symlinks:
raise errors.TraversalError
else:
dest = os.readlink(item_filepath)
item_filepath = os.path.join(self.path, dest)
if os.path.isdir(item_filepath):
item = self.__class__(item_filepath, self.use_cache,
self.list_directory,
self.follow_symlinks, self.cache_time,
self.file_class, self.index_filenames)
elif os.path.isfile(item_filepath):
item = self.file_class(item_filepath, self.follow_symlinks,
cache_time=self.cache_time)
else:
raise errors.TraversalError
if self.use_cache:
self.cache[name] = item
return item
class Redirector:
"""
A simple class that can be used from inside _q_lookup() to redirect
requests.
"""
_q_exports = []
def __init__(self, location, permanent=False):
self.location = location
self.permanent = permanent
def _q_lookup(self, component):
return self
def __call__(self):
return quixote.redirect(self.location, self.permanent)
def dump_request(request=None):
if request is None:
request = quixote.get_request()
"""Dump an HTTPRequest object as HTML."""
row_fmt = htmltext('<tr><th>%s</th><td>%s</td></tr>')
r = TemplateIO(html=True)
r += htmltext('<h3>form</h3>'
'<table>')
for k, v in request.form.items():
r += row_fmt % (k, v)
r += htmltext('</table>'
'<h3>cookies</h3>'
'<table>')
for k, v in request.cookies.items():
r += row_fmt % (k, v)
r += htmltext('</table>'
'<h3>environ</h3>'
'<table>')
for k, v in request.environ.items():
r += row_fmt % (k, v)
r += htmltext('</table>')
return r.getvalue()
def get_directory_path():
"""() -> [object]
Return the list of traversed instances.
"""
path = []
frame = sys._getframe()
while frame:
if frame.f_code.co_name == '_q_traverse':
self = frame.f_locals.get('self', None)
if path[:1] != [self]:
path.insert(0, self)
frame = frame.f_back
return path