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Diffstat (limited to 'genshi/template/markup.py')
| -rw-r--r-- | genshi/template/markup.py | 397 |
1 files changed, 397 insertions, 0 deletions
diff --git a/genshi/template/markup.py b/genshi/template/markup.py new file mode 100644 index 0000000..0e31632 --- /dev/null +++ b/genshi/template/markup.py @@ -0,0 +1,397 @@ +# -*- coding: utf-8 -*- +# +# Copyright (C) 2006-2010 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('''<ul xmlns:py="http://genshi.edgewall.org/"> + ... <li py:for="item in items">${item}</li> + ... </ul>''') + >>> print(tmpl.generate(items=[1, 2, 3])) + <ul> + <li>1</li><li>2</li><li>3</li> + </ul> + """ + + DIRECTIVE_NAMESPACE = 'http://genshi.edgewall.org/' + XINCLUDE_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__(self, source, filepath=None, filename=None, loader=None, + encoding=None, lookup='strict', allow_exec=True): + Template.__init__(self, source, filepath=filepath, filename=filename, + loader=loader, encoding=encoding, lookup=lookup, + allow_exec=allow_exec) + self.add_directives(self.DIRECTIVE_NAMESPACE, self) + + def _init_filters(self): + Template._init_filters(self) + # Make sure the include filter comes after the match filter + self.filters.remove(self._include) + self.filters += [self._match, self._include] + + def _parse(self, source, encoding): + if not isinstance(source, Stream): + source = XMLParser(source, filename=self.filename, + encoding=encoding) + stream = [] + + for kind, data, pos in source: + + if 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 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 COMMENT: + if not data.lstrip().startswith('!'): + stream.append((kind, data, pos)) + + else: + stream.append((kind, data, pos)) + + return stream + + def _extract_directives(self, stream, namespace, factory): + depth = 0 + dirmap = {} # temporary mapping of directives to elements + new_stream = [] + ns_prefix = {} # namespace prefixes in use + + for kind, data, pos in stream: + + if kind is START: + tag, attrs = data + directives = [] + strip = False + + if tag.namespace == namespace: + cls = factory.get_directive(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((factory.get_directive_index(cls), cls, + args, ns_prefix.copy(), pos)) + strip = True + + new_attrs = [] + for name, value in attrs: + if name.namespace == namespace: + cls = factory.get_directive(name.localname) + if cls is None: + raise BadDirectiveError(name.localname, + self.filepath, pos[1]) + if type(value) is list and len(value) == 1: + value = value[0][1] + directives.append((factory.get_directive_index(cls), + cls, value, ns_prefix.copy(), pos)) + else: + new_attrs.append((name, value)) + new_attrs = Attrs(new_attrs) + + if directives: + directives.sort() + dirmap[(depth, tag)] = (directives, len(new_stream), + strip) + + new_stream.append((kind, (tag, new_attrs), pos)) + depth += 1 + + elif kind is END: + depth -= 1 + new_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, offset, strip = dirmap.pop((depth, data)) + substream = new_stream[offset:] + if strip: + substream = substream[1:-1] + new_stream[offset:] = [ + (SUB, (directives, substream), pos) + ] + + elif kind is SUB: + directives, substream = data + substream = self._extract_directives(substream, namespace, + factory) + + if len(substream) == 1 and substream[0][0] is SUB: + added_directives, substream = substream[0][1] + directives += added_directives + + new_stream.append((kind, (directives, substream), pos)) + + elif kind is START_NS: + # Strip out the namespace declaration for template + # directives + prefix, uri = data + ns_prefix[prefix] = uri + if uri != namespace: + new_stream.append((kind, data, pos)) + + elif kind is END_NS: + uri = ns_prefix.pop(data, None) + if uri and uri != namespace: + new_stream.append((kind, data, pos)) + + else: + new_stream.append((kind, data, pos)) + + return new_stream + + def _extract_includes(self, stream): + streams = [[]] # stacked lists of events of the "compiled" template + prefixes = {} + fallbacks = [] + includes = [] + xinclude_ns = Namespace(self.XINCLUDE_NAMESPACE) + + for kind, data, pos in stream: + stream = streams[-1] + + if kind is START: + # Record any directive attributes in start tags + tag, attrs = data + if tag in xinclude_ns: + if tag.localname == 'include': + include_href = attrs.get('href') + if not include_href: + raise TemplateSyntaxError('Include misses required ' + 'attribute "href"', + self.filepath, *pos[1:]) + includes.append((include_href, attrs.get('parse'))) + streams.append([]) + elif tag.localname == 'fallback': + streams.append([]) + fallbacks.append(streams[-1]) + else: + stream.append((kind, (tag, attrs), pos)) + + elif kind is END: + if fallbacks and data == xinclude_ns['fallback']: + assert streams.pop() is fallbacks[-1] + elif data == xinclude_ns['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 + }.get(parse) or self.__class__ + 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)) + + elif kind is START_NS and data[1] == xinclude_ns: + # Strip out the XInclude namespace + prefixes[data[0]] = data[1] + + elif kind is END_NS and data in prefixes: + prefixes.pop(data) + + else: + stream.append((kind, data, pos)) + + assert len(streams) == 1 + return streams[0] + + def _interpolate_attrs(self, stream): + for kind, data, pos in stream: + + if kind is START: + # Record any directive attributes in start tags + tag, attrs = data + new_attrs = [] + for name, value in attrs: + 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] + new_attrs.append((name, value)) + data = tag, Attrs(new_attrs) + + yield kind, data, pos + + def _prepare(self, stream): + return Template._prepare(self, + self._extract_includes(self._interpolate_attrs(stream)) + ) + + def add_directives(self, namespace, factory): + """Register a custom `DirectiveFactory` for a given namespace. + + :param namespace: the namespace URI + :type namespace: `basestring` + :param factory: the directive factory to register + :type factory: `DirectiveFactory` + :since: version 0.6 + """ + assert not self._prepared, 'Too late for adding directives, ' \ + 'template already prepared' + self._stream = self._extract_directives(self._stream, namespace, + factory) + + 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, append=tail.append): + depth = 1 + next = stream.next + while 1: + event = next() + if event[0] is START: + depth += 1 + elif event[0] is END: + depth -= 1 + if depth > 0: + yield event + else: + append(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, start=start, + end=pre_end, **vars) + content = self._include(chain([event], inner, tail), ctxt) + if 'not_buffered' not in hints: + content = list(content) + content = Stream(content) + + # Make the select() function available in the body of the + # match template + selected = [False] + def select(path): + selected[0] = True + return 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._flatten(template, 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[idx + 1:]]: + test(tail[0], namespaces, ctxt, updateonly=True) + + break + + else: # no matches + yield event |