# -*- coding: utf-8 -*-
#
# Copyright (C) 2006-2008 Edgewall Software
# All rights reserved.
#
# This software is licensed as described in the file COPYING, which
# you should have received as part of this distribution. The terms
# are also available at http://genshi.edgewall.org/wiki/License.
#
# This software consists of voluntary contributions made by many
# individuals. For the exact contribution history, see the revision
# history and logs, available at http://genshi.edgewall.org/log/.
"""Markup templating engine."""
from itertools import chain
from genshi.core import Attrs, Markup, Namespace, Stream, StreamEventKind
from genshi.core import START, END, START_NS, END_NS, TEXT, PI, COMMENT
from genshi.input import XMLParser
from genshi.template.base import BadDirectiveError, Template, \
TemplateSyntaxError, _apply_directives, \
EXEC, INCLUDE, SUB
from genshi.template.eval import Suite
from genshi.template.interpolation import interpolate
from genshi.template.directives import *
from genshi.template.text import NewTextTemplate
__all__ = ['MarkupTemplate']
__docformat__ = 'restructuredtext en'
class MarkupTemplate(Template):
"""Implementation of the template language for XML-based templates.
>>> tmpl = MarkupTemplate('''''')
>>> print tmpl.generate(items=[1, 2, 3])
"""
DIRECTIVE_NAMESPACE = Namespace('http://genshi.edgewall.org/')
XINCLUDE_NAMESPACE = Namespace('http://www.w3.org/2001/XInclude')
directives = [('def', DefDirective),
('match', MatchDirective),
('when', WhenDirective),
('otherwise', OtherwiseDirective),
('for', ForDirective),
('if', IfDirective),
('choose', ChooseDirective),
('with', WithDirective),
('replace', ReplaceDirective),
('content', ContentDirective),
('attrs', AttrsDirective),
('strip', StripDirective)]
serializer = 'xml'
_number_conv = Markup
def _init_filters(self):
Template._init_filters(self)
# Make sure the include filter comes after the match filter
if self.loader:
self.filters.remove(self._include)
self.filters += [self._match]
if self.loader:
self.filters.append(self._include)
def _parse(self, source, encoding):
streams = [[]] # stacked lists of events of the "compiled" template
dirmap = {} # temporary mapping of directives to elements
ns_prefix = {}
depth = 0
fallbacks = []
includes = []
if not isinstance(source, Stream):
source = XMLParser(source, filename=self.filename,
encoding=encoding)
for kind, data, pos in source:
stream = streams[-1]
if kind is START_NS:
# Strip out the namespace declaration for template directives
prefix, uri = data
ns_prefix[prefix] = uri
if uri not in (self.DIRECTIVE_NAMESPACE,
self.XINCLUDE_NAMESPACE):
stream.append((kind, data, pos))
elif kind is END_NS:
uri = ns_prefix.pop(data, None)
if uri and uri not in (self.DIRECTIVE_NAMESPACE,
self.XINCLUDE_NAMESPACE):
stream.append((kind, data, pos))
elif kind is START:
# Record any directive attributes in start tags
tag, attrs = data
directives = []
strip = False
if tag in self.DIRECTIVE_NAMESPACE:
cls = self._dir_by_name.get(tag.localname)
if cls is None:
raise BadDirectiveError(tag.localname, self.filepath,
pos[1])
args = dict([(name.localname, value) for name, value
in attrs if not name.namespace])
directives.append((cls, args, ns_prefix.copy(), pos))
strip = True
new_attrs = []
for name, value in attrs:
if name in self.DIRECTIVE_NAMESPACE:
cls = self._dir_by_name.get(name.localname)
if cls is None:
raise BadDirectiveError(name.localname,
self.filepath, pos[1])
directives.append((cls, value, ns_prefix.copy(), pos))
else:
if value:
value = list(interpolate(value, self.filepath,
pos[1], pos[2],
lookup=self.lookup))
if len(value) == 1 and value[0][0] is TEXT:
value = value[0][1]
else:
value = [(TEXT, u'', pos)]
new_attrs.append((name, value))
new_attrs = Attrs(new_attrs)
if directives:
index = self._dir_order.index
directives.sort(lambda a, b: cmp(index(a[0]), index(b[0])))
dirmap[(depth, tag)] = (directives, len(stream), strip)
if tag in self.XINCLUDE_NAMESPACE:
if tag.localname == 'include':
include_href = new_attrs.get('href')
if not include_href:
raise TemplateSyntaxError('Include misses required '
'attribute "href"',
self.filepath, *pos[1:])
includes.append((include_href, new_attrs.get('parse')))
streams.append([])
elif tag.localname == 'fallback':
streams.append([])
fallbacks.append(streams[-1])
else:
stream.append((kind, (tag, new_attrs), pos))
depth += 1
elif kind is END:
depth -= 1
if fallbacks and data == self.XINCLUDE_NAMESPACE['fallback']:
assert streams.pop() is fallbacks[-1]
elif data == self.XINCLUDE_NAMESPACE['include']:
fallback = None
if len(fallbacks) == len(includes):
fallback = fallbacks.pop()
streams.pop() # discard anything between the include tags
# and the fallback element
stream = streams[-1]
href, parse = includes.pop()
try:
cls = {
'xml': MarkupTemplate,
'text': NewTextTemplate
}[parse or 'xml']
except KeyError:
raise TemplateSyntaxError('Invalid value for "parse" '
'attribute of include',
self.filepath, *pos[1:])
stream.append((INCLUDE, (href, cls, fallback), pos))
else:
stream.append((kind, data, pos))
# If there have have directive attributes with the corresponding
# start tag, move the events inbetween into a "subprogram"
if (depth, data) in dirmap:
directives, start_offset, strip = dirmap.pop((depth, data))
substream = stream[start_offset:]
if strip:
substream = substream[1:-1]
stream[start_offset:] = [(SUB, (directives, substream),
pos)]
elif kind is PI and data[0] == 'python':
if not self.allow_exec:
raise TemplateSyntaxError('Python code blocks not allowed',
self.filepath, *pos[1:])
try:
suite = Suite(data[1], self.filepath, pos[1],
lookup=self.lookup)
except SyntaxError, err:
raise TemplateSyntaxError(err, self.filepath,
pos[1] + (err.lineno or 1) - 1,
pos[2] + (err.offset or 0))
stream.append((EXEC, suite, pos))
elif kind is TEXT:
for kind, data, pos in interpolate(data, self.filepath, pos[1],
pos[2], lookup=self.lookup):
stream.append((kind, data, pos))
elif kind is COMMENT:
if not data.lstrip().startswith('!'):
stream.append((kind, data, pos))
else:
stream.append((kind, data, pos))
assert len(streams) == 1
return streams[0]
def _match(self, stream, ctxt, start=0, end=None, **vars):
"""Internal stream filter that applies any defined match templates
to the stream.
"""
match_templates = ctxt._match_templates
tail = []
def _strip(stream):
depth = 1
while 1:
event = stream.next()
if event[0] is START:
depth += 1
elif event[0] is END:
depth -= 1
if depth > 0:
yield event
else:
tail[:] = [event]
break
for event in stream:
# We (currently) only care about start and end events for matching
# We might care about namespace events in the future, though
if not match_templates or (event[0] is not START and
event[0] is not END):
yield event
continue
for idx, (test, path, template, hints, namespaces, directives) \
in enumerate(match_templates):
if idx < start or end is not None and idx >= end:
continue
if test(event, namespaces, ctxt) is True:
if 'match_once' in hints:
del match_templates[idx]
idx -= 1
# Let the remaining match templates know about the event so
# they get a chance to update their internal state
for test in [mt[0] for mt in match_templates[idx + 1:]]:
test(event, namespaces, ctxt, updateonly=True)
# Consume and store all events until an end event
# corresponding to this start event is encountered
pre_end = idx + 1
if 'match_once' not in hints and 'not_recursive' in hints:
pre_end -= 1
inner = _strip(stream)
if pre_end > 0:
inner = self._match(inner, ctxt, end=pre_end)
content = self._include(chain([event], inner, tail), ctxt)
if 'not_buffered' not in hints:
content = list(content)
# Make the select() function available in the body of the
# match template
selected = [False]
def select(path):
selected[0] = True
return Stream(content).select(path, namespaces, ctxt)
vars = dict(select=select)
# Recursively process the output
template = _apply_directives(template, directives, ctxt,
**vars)
for event in self._match(
self._exec(
self._eval(
self._flatten(template, ctxt, **vars),
ctxt, **vars),
ctxt, **vars),
ctxt, start=idx + 1, **vars):
yield event
# If the match template did not actually call select to
# consume the matched stream, the original events need to
# be consumed here or they'll get appended to the output
if not selected[0]:
for event in content:
pass
# Let the remaining match templates know about the last
# event in the matched content, so they can update their
# internal state accordingly
for test in [mt[0] for mt in match_templates]:
test(tail[0], namespaces, ctxt, updateonly=True)
break
else: # no matches
yield event