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userfield.py

#!/usr/bin/python
# -*- coding: utf-8 -*-
# Copyright (C) 2006-2007 Søren Roug, European Environment Agency
#
# This is free software.  You may redistribute it under the terms
# of the Apache license and the GNU General Public License Version
# 2 or at your option any later version.
#
# This program 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 this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
#
# Contributor(s): Michael Howitz, gocept gmbh & co. kg
#

"""Class to show and manipulate user fields in odf documents."""

import sys
import time
import zipfile

import xml.sax
import xml.sax.handler
import xml.sax.saxutils

from odf.namespaces import OFFICENS, TEXTNS

try:
    from cStringIO import StringIO
except ImportError:
    from StringIO import StringIO


OUTENCODING = "utf-8"


# OpenDocument v.1.0 section 6.7.1
VALUE_TYPES = {
    'float': (OFFICENS, u'value'),
    'percentage': (OFFICENS, u'value'),
    'currency': (OFFICENS, u'value'),
    'date': (OFFICENS, u'date-value'),
    'time': (OFFICENS, u'time-value'),
    'boolean': (OFFICENS, u'boolean-value'),
    'string': (OFFICENS, u'string-value'),
    }


00054 class UserFields(object):
    """List, view and manipulate user fields."""

    # these attributes can be a filename or a file like object
    src_file = None
    dest_file = None

00061     def __init__(self, src=None, dest=None):
        """Constructor

        src ... source document name, file like object or None for stdin
        dest ... destination document name, file like object or None for stdout
   
        """
        self.src_file = src
        self.dest_file = dest

00071     def list_fields(self):
        """List (extract) all known user-fields.
        
        Returns list of user-field names.
        
        """
        return [x[0] for x in self.list_fields_and_values()]

00079     def list_fields_and_values(self, field_names=None):
        """List (extract) user-fields with type and value.

        field_names ... list of field names to show or None for all.

        Returns list of tuples (<field name>, <field type>, <value>).

        """
        found_fields = []
        def _callback(field_name, value_type, value, attrs):
            if field_names is None or field_name in field_names:
                found_fields.append((field_name.encode(OUTENCODING),
                                     value_type.encode(OUTENCODING),
                                     value.encode(OUTENCODING)))
            return attrs
        
        self._content_handler(_callback)
        return found_fields

00098     def list_values(self, field_names):
        """Extract the contents of given field names from the file.

        field_names ... list of field names

        Returns list of field values.

        """
        return [x[2] for x in self.list_fields_and_values(field_names)]

00108     def get(self, field_name):
        """Extract the contents of this field from the file.

        Returns field value or None if field does not exist.

        """
        values = self.list_values([field_name])
        if not values:
            return None
        return values[0]

00119     def get_type_and_value(self, field_name):
        """Extract the type and contents of this field from the file.

        Returns tuple (<type>, <field-value>) or None if field does not exist.

        """
        fields = self.list_fields_and_values([field_name])
        if not fields:
            return None
        field_name, value_type, value = fields[0]
        return value_type, value

00131     def update(self, data):
        """Set the value of user fields. The field types will be the same.

        data ... dict, with field name as key, field value as value

        Returns None

        """
        def _callback(field_name, value_type, value, attrs):
            if field_name in data:
                valattr = VALUE_TYPES.get(value_type)
                attrs = dict(attrs.items())
                # Take advantage that startElementNS can take a normal
                # dict as attrs
                attrs[valattr] = data[field_name]
            return attrs
        self._content_handler(_callback, write_file=True)

00149     def _content_handler(self, callback_func, write_file=False):
        """Handle the content using the callback function and write result if
           necessary.

        callback_func ... function called for each field found in odf document
                          signature: field_name ... name of current field
                                     value_type ... type of current field
                                     value ... value of current field
                                     attrs ... tuple of attrs of current field
                          returns: tuple or dict of attrs
        write_file ... boolean telling wether write result to file

        """
        class DevNull(object):
            """IO-object which behaves like /dev/null."""
            def write(self, str):
                pass

        # get input
        if isinstance(self.src_file, basestring):
            # src_file is a filename, check if it is a zip-file
            if not zipfile.is_zipfile(self.src_file):
                raise TypeError("%s is no odt file." % self.src_file)
        elif self.src_file is None:
            # use stdin if no file given
            self.src_file = sys.stdin

        zin = zipfile.ZipFile(self.src_file, 'r')
        content_xml = zin.read('content.xml')

        # prepare output
        if write_file:
            output_io = StringIO()
            if self.dest_file is None:
                # use stdout if no filename given
                self.dest_file = sys.stdout
            zout = zipfile.ZipFile(self.dest_file, 'w')
        else:
            output_io = DevNull()


        # parse input
        odfs = ODFContentParser(callback_func, output_io)
        parser = xml.sax.make_parser()
        parser.setFeature(xml.sax.handler.feature_namespaces, 1)
        parser.setContentHandler(odfs)
        parser.parse(StringIO(content_xml))

        # write output
        if write_file:
            # Loop through the input zipfile and copy the content to
            # the output until we get to the content.xml. Then
            # substitute.
            for zinfo in zin.infolist():
                if zinfo.filename == "content.xml":
                    # Write meta
                    zi = zipfile.ZipInfo("content.xml", time.localtime()[:6])
                    zi.compress_type = zipfile.ZIP_DEFLATED
                    zout.writestr(zi, odfs.content())
                else:
                    payload = zin.read(zinfo.filename)
                    zout.writestr(zinfo, payload)
            zout.close()
        zin.close()


class ODFContentParser(xml.sax.saxutils.XMLGenerator):

    def __init__(self, callback_func, out=None, encoding=OUTENCODING):
        """Constructor.

        callback_func ... function called for each field found in odf document
                          signature: field_name ... name of current field
                                     value_type ... type of current field
                                     value ... value of current field
                                     attrs ... tuple of attrs of current field
                          returns: tuple or dict of attrs
        out ... file like object for output
        encoding ... encoding for output

        """
        self._callback_func = callback_func
        xml.sax.saxutils.XMLGenerator.__init__(self, out, encoding)

    def startElementNS(self, name, qname, attrs):
        if name == (TEXTNS, u'user-field-decl'):
            field_name = attrs.get((TEXTNS, u'name'))
            value_type = attrs.get((OFFICENS, u'value-type'))
            if value_type == 'string':
                value = attrs.get((OFFICENS, u'string-value'))
            else:
                value = attrs.get((OFFICENS, u'value'))

            attrs = self._callback_func(field_name, value_type, value, attrs)

        self._startElementNS(name, qname, attrs)

    def _startElementNS(self, name, qname, attrs):
        # copy of xml.sax.saxutils.XMLGenerator.startElementNS
        # necessary because we have to provide our own writeattr
        # function which is called by this mehtod
        if name[0] is None:
            name = name[1]
        elif self._current_context[name[0]] is None:
            # default namespace
            name = name[1]
        else:
            name = self._current_context[name[0]] + ":" + name[1]
        self._out.write('<' + name)

        for k,v in self._undeclared_ns_maps:
            if k is None:
                self._out.write(' xmlns="%s"' % (v or ''))
            else:
                self._out.write(' xmlns:%s="%s"' % (k,v))
        self._undeclared_ns_maps = []

        for (name, value) in attrs.items():
            if name[0] is None:
                name = name[1]
            elif self._current_context[name[0]] is None:
                # default namespace
                #If an attribute has a nsuri but not a prefix, we must
                #create a prefix and add a nsdecl
                prefix = self.GENERATED_PREFIX % self._generated_prefix_ctr
                self._generated_prefix_ctr = self._generated_prefix_ctr + 1
                name = prefix + ':' + name[1]
                self._out.write(' xmlns:%s=%s' % (prefix, quoteattr(name[0])))
                self._current_context[name[0]] = prefix
            else:
                name = self._current_context[name[0]] + ":" + name[1]
            self._out.write(' %s=' % name)
            writeattr(self._out, value)
        self._out.write('>')

    def content(self):
        return self._out.getvalue()


ATTR_ENTITIES = {
    '\n': '&#x0a;' # convert newlines into entities inside attributes
    }


def writeattr(stream, text):
    # copied from xml.sax.saxutils.writeattr added support for an
    # additional entity mapping
    countdouble = text.count('"')
    entities = ATTR_ENTITIES.copy()
    if countdouble:
        countsingle = text.count("'")
        if countdouble <= countsingle:
            entities['"'] = "&quot;"
            quote = '"'
        else:
            entities["'"] =  "&apos;"
            quote = "'"
    else:
        quote = '"'
    stream.write(quote)
    xml.sax.saxutils.writetext(stream, text, entities)
    stream.write(quote)

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