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xslt.py
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xslt.py
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# -*- coding: utf-8 -*-
##
## This file is part of Invenio.
## Copyright (C) 2007, 2008, 2009, 2010, 2011, 2014 CERN.
##
## 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.
##
## 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 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)
Used by: bibformat_engine.py
"""
from __future__ import print_function
import os
import sys
from lxml import etree
from invenio.modules.formatter.config import CFG_BIBFORMAT_TEMPLATES_PATH
from invenio.modules.formatter.api import (get_creation_date,
get_modification_date)
CFG_BIBFORMAT_FUNCTION_NS = "http://cdsweb.cern.ch/bibformat/fn"
"""The namespace used for BibFormat function."""
def _get_creation_date(ctx, recID, fmt="%Y-%m-%dT%H:%M:%SZ"):
"""
Bridge between BibFormat and XSL stylesheets.
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
:param ctx: context as passed by lxml
:param recID: record ID
:param fmt: format of the returned date
:return: creation date of X{recID}
:rtype: str
"""
try:
if isinstance(recID, str):
recID_int = int(recID)
elif isinstance(recID, (int, long)):
recID_int = recID
elif isinstance(recID, list):
recID = recID[0]
if isinstance(recID, str):
recID_int = int(recID)
else:
recID_int = int(recID.text)
else:
recID_int = int(recID.text)
if isinstance(fmt, str):
fmt_str = fmt
elif isinstance(fmt, list):
fmt = fmt[0]
if isinstance(fmt, str):
fmt_str = fmt
else:
fmt_str = fmt.text
else:
fmt_str = fmt.text
return get_creation_date(recID_int, fmt_str)
except Exception as err:
print("Error during formatting function evaluation: {0}".format(err),
file=sys.stderr)
return ''
def _get_modification_date(ctx, recID, fmt="%Y-%m-%dT%H:%M:%SZ"):
"""
Bridge between BibFormat and XSL stylesheets.
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)"/>`` 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
:param ctx: context as passed by lxml
:param recID: record ID
:param fmt: format of the returned date
:return: modification date of X{recID}
:rtype: str
"""
try:
if isinstance(recID, str):
recID_int = int(recID)
elif isinstance(recID, (int, long)):
recID_int = recID
elif isinstance(recID, list):
recID = recID[0]
if isinstance(recID, str):
recID_int = int(recID)
else:
recID_int = int(recID.text)
else:
recID_int = int(recID.text)
if isinstance(fmt, str):
fmt_str = fmt
elif isinstance(fmt, list):
fmt = fmt[0]
if isinstance(fmt, str):
fmt_str = fmt
else:
fmt_str = fmt.text
else:
fmt_str = fmt.text
return get_modification_date(recID_int, fmt_str)
except Exception as err:
print("Error during formatting function evaluation: {0}".format(err),
file=sys.stderr)
return ''
def _eval_bibformat(ctx, recID, template_code):
"""
Bridge between BibFormat and XSL stylesheets.
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;'
:param ctx: context as passed by lxml
:param recID: record ID
:param template_code: the code calling a BFE_ as it would be used in
format template
:return: the evaluated call to a format template (usually a call to a
format element)
:rtype: str
"""
from invenio.modules.formatter.engine import format_with_format_template, \
BibFormatObject
try:
if isinstance(recID, str):
recID_int = int(recID)
elif isinstance(recID, (int, long)):
recID_int = recID
elif isinstance(recID, list):
recID = recID[0]
if isinstance(recID, str):
recID_int = int(recID)
else:
recID_int = int(recID.text)
else:
recID_int = int(recID.text)
bfo = BibFormatObject(recID_int)
out = format_with_format_template(None, bfo,
verbose=0,
format_template_code=template_code)
return out[0]
except Exception as err:
print("Error during formatting function evaluation: {0}".format(err),
file=sys.stderr)
return ''
def format(xmltext, template_filename=None, template_source=None):
"""
Process 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.
"""
# 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:
print('{0} does not exist'.format(template_filename),
file=sys.stderr)
return None
except IOError:
print('{0} could not be read.'.format(template_filename),
file=sys.stderr)
return None
else:
print('No templates were given.', file=sys.stderr)
return None
# Some massaging of the input to avoid the default namespace issue
# in XPath. More elegant solution might be found though.
xmltext = xmltext.replace('xmlns="http://www.loc.gov/MARC21/slim"', '')
# For older MARCXML records stored in bibfmt with empty indicators
xmltext = xmltext.replace('ind1=""', 'ind1=" "')
xmltext = xmltext.replace('ind2=""', 'ind2=" "')
result = ""
try:
xml = etree.XML(xmltext)
except etree.XMLSyntaxError as e:
error = 'The XML code given is invalid. [%s]' % (e,)
print(error, file=sys.stderr)
return result
except:
error = 'Failed to process the XML code.'
print(error, file=sys.stderr)
return result
try:
xsl = etree.XML(template)
except etree.XMLSyntaxError as e:
error = 'The XSL code given is invalid. [%s]' % (e,)
print(error, file=sys.stderr)
return result
except:
error = 'Failed to process the XSL code.'
print(error, file=sys.stderr)
return result
try:
fns = etree.FunctionNamespace(CFG_BIBFORMAT_FUNCTION_NS)
fns["creation_date"] = _get_creation_date
fns["modification_date"] = _get_modification_date
fns["eval_bibformat"] = _eval_bibformat
except etree.NamespaceRegistryError as e:
error = 'Failed registering the XPath extension function. [%s]' % e
print(error, file=sys.stderr)
return result
try:
xslt = etree.XSLT(xsl)
except etree.XSLTParseError as e:
error = 'The XSL code given is invalid. [%s]' % e
print(error, file=sys.stderr)
return result
except:
error = 'Failed to process the XSL code.'
print(error, file=sys.stderr)
return result
try:
temporary_result = xslt(xml)
except:
error = 'Failed to perform the XSL transformation.'
print(error, file=sys.stderr)
return result
result = str(temporary_result)
# Housekeeping
del temporary_result
del xslt
del xsl
del xml
return result

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