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bibformat_xslt_engine.py
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bibformat_xslt_engine.py
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# -*- coding: utf-8 -*-
##
## $Id$
##
## This file is part of CDS Invenio.
## Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008 CERN.
##
## CDS Invenio is free software; you can redistribute it and/or
## modify it under the terms of the GNU General Public License as
## published by the Free Software Foundation; either version 2 of the
## License, or (at your option) any later version.
##
## CDS Invenio is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
## General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with CDS Invenio; if not, write to the Free Software Foundation, Inc.,
## 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
"""
bibformat_xslt_engine - Wrapper for an XSLT engine.
Some functions are registered in order to be used in XSL code:
- creation_date(recID)
- modification_date(recID)
Dependencies: Need one of the following XSLT processors:
- libxml2 & libxslt
- 4suite
Used by: bibformat_engine.py
"""
__revision__ = "$Id$"
import sys
import os
from invenio.config import \
CFG_SITE_URL
from invenio.bibformat_config import \
CFG_BIBFORMAT_TEMPLATES_PATH
from invenio.bibformat_dblayer import \
get_creation_date, \
get_modification_date
# The namespace used for BibFormat function
CFG_BIBFORMAT_FUNCTION_NS = "http://cdsweb.cern.ch/bibformat/fn"
# Import one XSLT processor
#
# processor_type:
# -1 : No processor found
# 0 : libxslt
# 1 : 4suite
processor_type = -1
try:
# libxml2 & libxslt
processor_type = 0
import libxml2
import libxslt
except ImportError:
pass
if processor_type == -1:
try:
# 4suite
processor_type = 1
from Ft.Xml.Xslt import Processor
from Ft.Xml import InputSource
from xml.dom import Node
except ImportError:
pass
if processor_type == -1:
# No XSLT processor found
sys.stderr.write('No XSLT processor could be found.\n' \
'No output produced.\n')
sys.exit(1)
##################################################################
# Support for 'creation_date' and 'modification_date' functions #
def get_creation_date_libxslt(ctx, recID):
"""
libxslt extension function:
Bridge between BibFormat and XSL stylesheets.
Returns record creation date.
Can be used in that way in XSL stylesheet
(provided xmlns:fn="http://cdsweb.cern.ch/bibformat/fn" has been declared):
<xsl:value-of select="fn:creation_date(445)"/> where 445 is a recID
if recID is string, value is converted to int
if recID is Node, first child node (text node) is taken as value
"""
try:
if isinstance(recID, str):
recID_int = int(recID)
elif isinstance(recID, int):
recID_int = recID
else:
recID_int = libxml2.xmlNode(_obj=recID[0]).children.content
return get_creation_date(recID_int)
except Exception, err:
sys.stderr.write("Error during formatting function evaluation: " + \
str(err) + \
'\n')
return ''
def get_creation_date_4suite(ctx, recID):
"""
4suite extension function:
Bridge between BibFormat and XSL stylesheets.
Returns record creation date.
Can be used in that way in XSL stylesheet
(provided xmlns:fn="http://cdsweb.cern.ch/bibformat/fn" has been declared):
<xsl:value-of select="fn:creation_date(445)"/>
if value is int, value is converted to string
if value is Node, first child node (text node) is taken as value
"""
try:
if len(recID) > 0 and isinstance(recID[0], Node):
recID_int = recID[0].firstChild.nodeValue
if recID_int is None:
return ''
else:
recID_int = int(recID_int)
return get_creation_date(recID_int)
except Exception, err:
sys.stderr.write("Error during formatting function evaluation: " + \
str(err) + \
'\n')
return ''
def get_modification_date_libxslt(ctx, recID):
"""
libxslt extension function:
Bridge between BibFormat and XSL stylesheets.
Returns record modification date.
Can be used in that way in XSL stylesheet
(provided xmlns:fn="http://cdsweb.cern.ch/bibformat/fn" has been declared):
<xsl:value-of select="fn:creation_date(445)"/> where 445 is a recID
if recID is string, value is converted to int
if recID is Node, first child node (text node) is taken as value
"""
try:
if isinstance(recID, str):
recID_int = int(recID)
elif isinstance(recID, int):
recID_int = recID
else:
recID_int = libxml2.xmlNode(_obj=recID[0]).children.content
return get_modification_date(recID_int)
except Exception, err:
sys.stderr.write("Error during formatting function evaluation: " + \
str(err) + \
'\n')
return ''
def get_modification_date_4suite(ctx, recID):
"""
4suite extension function:
Bridge between BibFormat and XSL stylesheets.
Returns record modification date.
Can be used in that way in XSL stylesheet
(provided xmlns:fn="http://cdsweb.cern.ch/bibformat/fn" has been declared):
<xsl:value-of select="fn:modification_date(445)"/>
if value is int, value is converted to string
if value is Node, first child node (text node) is taken as value
"""
try:
if len(recID) > 0 and isinstance(recID[0], Node):
recID_int = recID[0].firstChild.nodeValue
if recID_int is None:
return ''
else:
recID_int = int(recID_int)
return get_modification_date(recID_int)
except Exception, err:
sys.stderr.write("Error during formatting function evaluation: " + \
str(err) + \
'\n')
return ''
def eval_bibformat_libxslt(ctx, recID, template_code):
"""
libxslt extension function:
Bridge between BibFormat and XSL stylesheets.
Returns the evaluation of the given piece of format template
Can be used in that way in XSL stylesheet
(provided xmlns:fn="http://cdsweb.cern.ch/bibformat/fn" has been declared):
<xsl:value-of select="fn:eval_bibformat(marc:controlfield[@tag='001'],'&lt;BFE_SERVER_INFO var=&quot;recurl&quot;>')" />
if recID is string, value is converted to int
if recID is Node, first child node (text node) is taken as value
template_code is evaluated as a format template piece of code. '<'
and '"' need to be escaped with '&lt;' and '&quot;'
"""
from invenio.bibformat_engine import \
format_with_format_template, \
BibFormatObject
try:
if isinstance(recID, str):
recID_int = int(recID)
elif isinstance(recID, int):
recID_int = recID
else:
recID_int = libxml2.xmlNode(_obj=recID[0]).children.content
bfo = BibFormatObject(recID_int)
return format_with_format_template(None, bfo,
verbose=0,
format_template_code=template_code)[0]
except Exception, err:
sys.stderr.write("Error during formatting function evaluation: " + \
str(err) + \
'\n')
return ''
def eval_bibformat_4suite(ctx, recID, template_code):
"""
4suite extension function:
Bridge between BibFormat and XSL stylesheets.
Returns the evaluation of the given piece of format template
Can be used in that way in XSL stylesheet
(provided xmlns:fn="http://cdsweb.cern.ch/bibformat/fn" has been declared):
<xsl:value-of select="fn:eval_bibformat(marc:controlfield[@tag='001'],'&lt;BFE_SERVER_INFO var=&quot;recurl&quot;>')" />
if recID is string, value is converted to int
if recID is Node, first child node (text node) is taken as value
template_code is evaluated as a format template piece of code. '<'
and '"' need to be escaped with '&lt;' and '&quot;'
"""
from invenio.bibformat_engine import \
format_with_format_template, \
BibFormatObject
try:
if len(recID) > 0 and isinstance(recID[0], Node):
recID_int = recID[0].firstChild.nodeValue
if recID_int is None:
return ''
else:
recID_int = int(recID_int)
bfo = BibFormatObject(recID_int)
return format_with_format_template(None, bfo,
verbose=0,
format_template_code=template_code)[0]
except Exception, err:
sys.stderr.write("Error during formatting function evaluation: " + \
str(err) + \
'\n')
return ''
# End of date-related functions #
##################################################################
def format(xmltext, template_filename=None, template_source=None):
"""
Processes an XML text according to a template, and returns the result.
The template can be given either by name (or by path) or by source.
If source is given, name is ignored.
bibformat_xslt_engine will look for template_filename in standard directories
for templates. If not found, template_filename will be assumed to be a path to
a template. If none can be found, return None.
@param xmltext The string representation of the XML to process
@param template_filename The name of the template to use for the processing
@param template_source The configuration describing the processing.
@return the transformed XML text.
"""
if processor_type == -1:
# No XSLT processor found
sys.stderr.write('No XSLT processor could be found.')
sys.exit(1)
# Retrieve template and read it
if template_source:
template = template_source
elif template_filename:
try:
path_to_templates = (CFG_BIBFORMAT_TEMPLATES_PATH + os.sep +
template_filename)
if os.path.exists(path_to_templates):
template = file(path_to_templates).read()
elif os.path.exists(template_filename):
template = file(template_filename).read()
else:
sys.stderr.write(template_filename +' does not exist.')
return None
except IOError:
sys.stderr.write(template_filename +' could not be read.')
return None
else:
sys.stderr.write(template_filename +' was not given.')
return None
result = ""
if processor_type == 0:
# libxml2 & libxslt
# Register BibFormat functions for use in XSL
libxslt.registerExtModuleFunction("creation_date",
CFG_BIBFORMAT_FUNCTION_NS,
get_creation_date_libxslt)
libxslt.registerExtModuleFunction("modification_date",
CFG_BIBFORMAT_FUNCTION_NS,
get_modification_date_libxslt)
libxslt.registerExtModuleFunction("eval_bibformat",
CFG_BIBFORMAT_FUNCTION_NS,
eval_bibformat_libxslt)
# Load template and source
template_xml = libxml2.parseDoc(template)
processor = libxslt.parseStylesheetDoc(template_xml)
source = libxml2.parseDoc(xmltext)
# Transform
result_object = processor.applyStylesheet(source, None)
try:
result = processor.saveResultToString(result_object)
except SystemError :
# Catch an exception thrown when result is empty,
# due to a bug in libxslt
result = ''
# Deallocate
processor.freeStylesheet()
source.freeDoc()
result_object.freeDoc()
elif processor_type == 1:
# 4suite
# Init
processor = Processor.Processor()
# Register BibFormat functions for use in XSL
processor.registerExtensionFunction(CFG_BIBFORMAT_FUNCTION_NS,
"creation_date",
get_creation_date_4suite)
processor.registerExtensionFunction(CFG_BIBFORMAT_FUNCTION_NS,
"modification_date",
get_modification_date_4suite)
processor.registerExtensionFunction(CFG_BIBFORMAT_FUNCTION_NS,
"eval_bibformat",
eval_bibformat_4suite)
# Load template and source
transform = InputSource.DefaultFactory.fromString(template,
uri=CFG_SITE_URL)
source = InputSource.DefaultFactory.fromString(xmltext,
uri=CFG_SITE_URL)
processor.appendStylesheet(transform)
# Transform
result = processor.run(source)
else:
sys.stderr.write("No XSLT processor could be found")
return result
if __name__ == "__main__":
pass

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