# -*- coding: utf-8 -*-
"""
Various utilities for pyRdfa.
Most of the utilities are straightforward.
@organization: U{World Wide Web Consortium<http://www.w3.org>}
@author: U{Ivan Herman<a href="http://www.w3.org/People/Ivan/">}
@license: This software is available for use under the
U{W3C® SOFTWARE NOTICE AND LICENSE<href="http://www.w3.org/Consortium/Legal/2002/copyright-software-20021231">}
"""
"""
$Id: utils.py,v 1.9 2012/11/16 17:51:53 ivan Exp $
$Date: 2012/11/16 17:51:53 $
"""
import os, os.path, sys, imp, datetime
# Python 3 vs. 2 switch
if sys.version_info[0] >= 3 :
from urllib.request import Request, urlopen
from urllib.parse import urljoin, quote
from http.server import BaseHTTPRequestHandler
from urllib.error import HTTPError as urllib_HTTPError
else :
from urllib2 import Request, urlopen
from urllib2 import HTTPError as urllib_HTTPError
from urlparse import urljoin
from urllib import quote
from BaseHTTPServer import BaseHTTPRequestHandler
from .extras.httpheader import content_type, parse_http_datetime
import rdflib
if rdflib.__version__ >= "3.0.0" :
from rdflib import RDF as ns_rdf
else :
from rdflib.RDF import RDFNS as ns_rdf
from .host import HostLanguage, preferred_suffixes
#########################################################################################################
# Handling URIs
[docs]class URIOpener :
"""A wrapper around the urllib2 method to open a resource. Beyond accessing the data itself, the class
sets a number of instance variable that might be relevant for processing.
The class also adds an accept header to the outgoing request, namely
text/html and application/xhtml+xml (unless set explicitly by the caller).
If the content type is set by the server, the relevant HTTP response field is used. Otherwise,
common suffixes are used (see L{host.preferred_suffixes}) to set the content type (this is really of importance
for C{file:///} URI-s). If none of these works, the content type is empty.
Interpretation of the content type for the return is done by Deron Meranda's U{httpheader module<http://deron.meranda.us/>}.
@ivar data: the real data, ie, a file-like object
@ivar headers: the return headers as sent back by the server
@ivar content_type: the content type of the resource or the empty string, if the content type cannot be determined
@ivar location: the real location of the data (ie, after possible redirection and content negotiation)
@ivar last_modified_date: sets the last modified date if set in the header, None otherwise
@ivar expiration_date: sets the expiration date if set in the header, I{current UTC plus one day} otherwise (this is used for caching purposes, hence this artificial setting)
"""
CONTENT_LOCATION = 'Content-Location'
CONTENT_TYPE = 'Content-Type'
LAST_MODIFIED = 'Last-Modified'
EXPIRES = 'Expires'
[docs] def __init__(self, name, additional_headers = {}) :
"""
@param name: URL to be opened
@keyword additional_headers: additional HTTP request headers to be added to the call
"""
try :
# Note the removal of the fragment ID. This is necessary, per the HTTP spec
req = Request(url=name.split('#')[0])
for key in additional_headers :
req.add_header(key, additional_headers[key])
if 'Accept' not in additional_headers :
req.add_header('Accept', 'text/html, application/xhtml+xml')
self.data = urlopen(req)
self.headers = self.data.info()
if URIOpener.CONTENT_TYPE in self.headers :
# The call below will remove the possible media type parameters, like charset settings
ct = content_type(self.headers[URIOpener.CONTENT_TYPE])
self.content_type = ct.media_type
if 'charset' in ct.parmdict :
self.charset = ct.parmdict['charset']
else :
self.charset = None
# print
else :
# check if the suffix can be used for the content type; this may be important
# for file:// type URI or if the server is not properly set up to return the right
# mime type
self.charset = None
self.content_type = ""
for suffix in preferred_suffixes.keys() :
if name.endswith(suffix) :
self.content_type = preferred_suffixes[suffix]
break
if URIOpener.CONTENT_LOCATION in self.headers :
self.location = urljoin(self.data.geturl(),self.headers[URIOpener.CONTENT_LOCATION])
else :
self.location = name
self.expiration_date = datetime.datetime.utcnow() + datetime.timedelta(days=1)
if URIOpener.EXPIRES in self.headers :
try :
# Thanks to Deron Meranda for the HTTP date conversion method...
self.expiration_date = parse_http_datetime(self.headers[URIOpener.EXPIRES])
except :
# The Expires date format was wrong, sorry, forget it...
pass
self.last_modified_date = None
if URIOpener.LAST_MODIFIED in self.headers :
try :
# Thanks to Deron Meranda for the HTTP date conversion method...
self.last_modified_date = parse_http_datetime(self.headers[URIOpener.LAST_MODIFIED])
except :
# The last modified date format was wrong, sorry, forget it...
pass
except urllib_HTTPError :
e = sys.exc_info()[1]
from . import HTTPError
msg = BaseHTTPRequestHandler.responses[e.code]
raise HTTPError('%s' % msg[1], e.code)
except Exception :
e = sys.exc_info()[1]
from . import RDFaError
raise RDFaError('%s' % e)
#########################################################################################################
# 'safe' characters for the URI quoting, ie, characters that can safely stay as they are. Other
# special characters are converted to their %.. equivalents for namespace prefixes
_unquotedChars = ':/\?=#~'
_warnChars = [' ','\n','\r','\t']
[docs]def quote_URI(uri, options = None) :
"""
'quote' a URI, ie, exchange special characters for their '%..' equivalents. Some of the characters
may stay as they are (listed in L{_unquotedChars}. If one of the characters listed in L{_warnChars}
is also in the uri, an extra warning is also generated.
@param uri: URI
@param options:
@type options: L{Options<pyRdfa.Options>}
"""
from . import err_unusual_char_in_URI
suri = uri.strip()
for c in _warnChars :
if suri.find(c) != -1 :
if options != None :
options.add_warning(err_unusual_char_in_URI % suri)
break
return quote(suri, _unquotedChars)
#########################################################################################################
[docs]def create_file_name(uri) :
"""
Create a suitable file name from an (absolute) URI. Used, eg, for the generation of a file name for a cached vocabulary file.
"""
suri = uri.strip()
final_uri = quote(suri,_unquotedChars)
# Remove some potentially dangereous characters
return final_uri.replace(' ','_').replace('%','_').replace('-','_').replace('+','_').replace('/','_').replace('?','_').replace(':','_').replace('=','_').replace('#','_')
#########################################################################################################
[docs]def has_one_of_attributes(node,*args) :
"""
Check whether one of the listed attributes is present on a (DOM) node.
@param node: DOM element node
@param args: possible attribute names
@return: True or False
@rtype: Boolean
"""
if len(args) == 0 :
return None
if isinstance(args[0], tuple) or isinstance(args[0], list) :
rargs = args[0]
else :
rargs = args
return True in [ node.hasAttribute(attr) for attr in rargs ]
#########################################################################################################
[docs]def traverse_tree(node, func) :
"""Traverse the whole element tree, and perform the function C{func} on all the elements.
@param node: DOM element node
@param func: function to be called on the node. Input parameter is a DOM Element Node. If the function returns a boolean True, the recursion is stopped.
"""
if func(node) :
return
for n in node.childNodes :
if n.nodeType == node.ELEMENT_NODE :
traverse_tree(n, func)
#########################################################################################################
[docs]def return_XML(state, inode, base = True, xmlns = True) :
"""
Get (recursively) the XML Literal content of a DOM Element Node. (Most of the processing is done
via a C{node.toxml} call of the xml minidom implementation.)
@param inode: DOM Node
@param state: L{pyRdfa.state.ExecutionContext}
@param base: whether the base element should be added to the output
@type base: Boolean
@param xmlns: whether the namespace declarations should be repeated in the generated node
@type xmlns: Boolean
@return: string
"""
node = inode.cloneNode(True)
# Decorate the element with namespaces.lang values and, optionally, base
if base :
node.setAttribute("xml:base",state.base)
if xmlns :
for prefix in state.term_or_curie.xmlns :
if not node.hasAttribute("xmlns:%s" % prefix) :
node.setAttribute("xmlns:%s" % prefix,"%s" % state.term_or_curie.xmlns[prefix])
# Set the default namespace, if not done (and is available)
if not node.getAttribute("xmlns") and state.defaultNS != None :
node.setAttribute("xmlns", state.defaultNS)
# Get the lang, if necessary
if state.lang :
if state.options.host_language in [ HostLanguage.xhtml, HostLanguage.xhtml5, HostLanguage.html5 ] :
if not node.getAttribute("lang") :
node.setAttribute("lang", state.lang)
else :
if not node.getAttribute("xml:lang") :
node.setAttribute("xml:lang", state.lang)
if sys.version_info[0] >= 3 :
return node.toxml()
else :
q = node.toxml(encoding='utf-8')
return unicode(q, encoding='utf-8')
#########################################################################################################
[docs]def dump(node) :
"""
This is just for debug purposes: it prints the essential content of the node in the tree starting at node.
@param node: DOM node
"""
print( node.toprettyxml(indent="", newl="") )
