Mercurial > genshi > mirror
annotate markup/filters.py @ 17:74cc70129d04 trunk
Refactoring to address #6: all match templates are now processed by a single filter, which means that match templates added by included templates are properly applied. A side effect of this refactoring is that `Context` objects may not be reused across multiple template processing runs.
Also, output filters are now applied in the `Stream.serialize()` method instead of by the `Template.generate()` method, which just makes more sense.
| author | cmlenz |
|---|---|
| date | Sun, 18 Jun 2006 22:33:33 +0000 |
| parents | b3edbde541c4 |
| children | 5420cfe42d36 |
| rev | line source |
|---|---|
| 1 | 1 # -*- coding: utf-8 -*- |
| 2 # | |
| 3 # Copyright (C) 2006 Christopher Lenz | |
| 4 # All rights reserved. | |
| 5 # | |
| 6 # This software is licensed as described in the file COPYING, which | |
| 7 # you should have received as part of this distribution. The terms | |
| 8 # are also available at http://trac.edgewall.com/license.html. | |
| 9 # | |
| 10 # This software consists of voluntary contributions made by many | |
| 11 # individuals. For the exact contribution history, see the revision | |
| 12 # history and logs, available at http://projects.edgewall.com/trac/. | |
| 13 | |
| 14 """Implementation of a number of stream filters.""" | |
| 15 | |
| 16 try: | |
| 17 frozenset | |
| 18 except NameError: | |
| 19 from sets import ImmutableSet as frozenset | |
| 20 import re | |
| 21 | |
| 22 from markup.core import Attributes, Markup, Stream | |
| 23 from markup.path import Path | |
| 24 | |
|
17
74cc70129d04
Refactoring to address #6: all match templates are now processed by a single filter, which means that match templates added by included templates are properly applied. A side effect of this refactoring is that `Context` objects may not be reused across multiple template processing runs.
cmlenz
parents:
15
diff
changeset
|
25 __all__ = ['IncludeFilter', 'WhitespaceFilter', 'HTMLSanitizer'] |
| 1 | 26 |
| 27 | |
| 28 class IncludeFilter(object): | |
| 29 """Template filter providing (very) basic XInclude support | |
| 30 (see http://www.w3.org/TR/xinclude/) in templates. | |
| 31 """ | |
| 32 | |
| 33 _NAMESPACE = 'http://www.w3.org/2001/XInclude' | |
| 34 | |
|
17
74cc70129d04
Refactoring to address #6: all match templates are now processed by a single filter, which means that match templates added by included templates are properly applied. A side effect of this refactoring is that `Context` objects may not be reused across multiple template processing runs.
cmlenz
parents:
15
diff
changeset
|
35 def __init__(self, loader): |
| 1 | 36 """Initialize the filter. |
| 37 | |
| 38 @param loader: the `TemplateLoader` to use for resolving references to | |
| 39 external template files | |
| 40 """ | |
| 41 self.loader = loader | |
| 42 | |
|
12
97423376736e
Make the XInclude filter track namespace context, to enable it to omit `END_NS` events for the XInclude namespace.
cmlenz
parents:
10
diff
changeset
|
43 def __call__(self, stream, ctxt=None, ns_prefixes=None): |
| 1 | 44 """Filter the stream, processing any XInclude directives it may |
| 45 contain. | |
| 46 | |
| 47 @param ctxt: the template context | |
| 48 @param stream: the markup event stream to filter | |
| 49 """ | |
|
12
97423376736e
Make the XInclude filter track namespace context, to enable it to omit `END_NS` events for the XInclude namespace.
cmlenz
parents:
10
diff
changeset
|
50 from markup.template import Template, TemplateError, TemplateNotFound |
| 1 | 51 |
|
12
97423376736e
Make the XInclude filter track namespace context, to enable it to omit `END_NS` events for the XInclude namespace.
cmlenz
parents:
10
diff
changeset
|
52 if ns_prefixes is None: |
|
97423376736e
Make the XInclude filter track namespace context, to enable it to omit `END_NS` events for the XInclude namespace.
cmlenz
parents:
10
diff
changeset
|
53 ns_prefixes = [] |
| 1 | 54 in_fallback = False |
| 55 include_href, fallback_stream = None, None | |
| 56 indent = 0 | |
| 57 | |
| 58 for kind, data, pos in stream: | |
| 59 | |
| 60 if kind is Stream.START and data[0].namespace == self._NAMESPACE \ | |
| 61 and not in_fallback: | |
| 62 tag, attrib = data | |
| 63 if tag.localname == 'include': | |
| 64 include_href = attrib.get('href') | |
| 65 indent = pos[1] | |
| 66 elif tag.localname == 'fallback': | |
| 67 in_fallback = True | |
| 68 fallback_stream = [] | |
| 69 | |
| 70 elif kind is Stream.END and data.namespace == self._NAMESPACE: | |
| 71 if data.localname == 'include': | |
| 72 try: | |
| 73 if not include_href: | |
| 74 raise TemplateError('Include misses required ' | |
| 75 'attribute "href"') | |
| 76 template = self.loader.load(include_href) | |
|
17
74cc70129d04
Refactoring to address #6: all match templates are now processed by a single filter, which means that match templates added by included templates are properly applied. A side effect of this refactoring is that `Context` objects may not be reused across multiple template processing runs.
cmlenz
parents:
15
diff
changeset
|
77 for event in template.generate(ctxt): |
|
74cc70129d04
Refactoring to address #6: all match templates are now processed by a single filter, which means that match templates added by included templates are properly applied. A side effect of this refactoring is that `Context` objects may not be reused across multiple template processing runs.
cmlenz
parents:
15
diff
changeset
|
78 yield event |
|
13
f9001cd6785b
Match directives should now also be applied when included indirectly.
cmlenz
parents:
12
diff
changeset
|
79 |
| 1 | 80 except TemplateNotFound: |
| 81 if fallback_stream is None: | |
| 82 raise | |
| 83 for event in fallback_stream: | |
| 84 yield event | |
| 85 | |
| 86 include_href = None | |
| 87 fallback_stream = None | |
| 88 indent = 0 | |
|
17
74cc70129d04
Refactoring to address #6: all match templates are now processed by a single filter, which means that match templates added by included templates are properly applied. A side effect of this refactoring is that `Context` objects may not be reused across multiple template processing runs.
cmlenz
parents:
15
diff
changeset
|
89 |
| 1 | 90 elif data.localname == 'fallback': |
| 91 in_fallback = False | |
| 92 | |
| 93 elif in_fallback: | |
| 94 fallback_stream.append((kind, data, pos)) | |
| 95 | |
| 96 elif kind is Stream.START_NS and data[1] == self._NAMESPACE: | |
|
12
97423376736e
Make the XInclude filter track namespace context, to enable it to omit `END_NS` events for the XInclude namespace.
cmlenz
parents:
10
diff
changeset
|
97 ns_prefixes.append(data[0]) |
|
97423376736e
Make the XInclude filter track namespace context, to enable it to omit `END_NS` events for the XInclude namespace.
cmlenz
parents:
10
diff
changeset
|
98 |
|
97423376736e
Make the XInclude filter track namespace context, to enable it to omit `END_NS` events for the XInclude namespace.
cmlenz
parents:
10
diff
changeset
|
99 elif kind is Stream.END_NS and data in ns_prefixes: |
|
97423376736e
Make the XInclude filter track namespace context, to enable it to omit `END_NS` events for the XInclude namespace.
cmlenz
parents:
10
diff
changeset
|
100 ns_prefixes.pop() |
| 1 | 101 |
| 102 else: | |
| 103 yield kind, data, pos | |
| 104 | |
| 105 | |
| 106 class WhitespaceFilter(object): | |
| 107 """A filter that removes extraneous white space from the stream. | |
| 108 | |
| 109 Todo: | |
| 110 * Support for xml:space | |
| 111 """ | |
| 112 | |
| 113 _TRAILING_SPACE = re.compile('[ \t]+(?=\n)') | |
| 114 _LINE_COLLAPSE = re.compile('\n{2,}') | |
| 115 | |
| 116 def __call__(self, stream, ctxt=None): | |
| 117 textbuf = [] | |
| 118 prev_kind = None | |
| 119 for kind, data, pos in stream: | |
| 120 if kind is Stream.TEXT: | |
| 121 textbuf.append(data) | |
| 122 elif prev_kind is Stream.TEXT: | |
|
17
74cc70129d04
Refactoring to address #6: all match templates are now processed by a single filter, which means that match templates added by included templates are properly applied. A side effect of this refactoring is that `Context` objects may not be reused across multiple template processing runs.
cmlenz
parents:
15
diff
changeset
|
123 text = Markup('').join(textbuf) |
| 1 | 124 text = self._TRAILING_SPACE.sub('', text) |
| 125 text = self._LINE_COLLAPSE.sub('\n', text) | |
|
17
74cc70129d04
Refactoring to address #6: all match templates are now processed by a single filter, which means that match templates added by included templates are properly applied. A side effect of this refactoring is that `Context` objects may not be reused across multiple template processing runs.
cmlenz
parents:
15
diff
changeset
|
126 yield Stream.TEXT, Markup(text), pos |
| 1 | 127 del textbuf[:] |
| 128 prev_kind = kind | |
| 129 if kind is not Stream.TEXT: | |
| 130 yield kind, data, pos | |
| 131 | |
| 132 if textbuf: | |
| 133 text = self._LINE_COLLAPSE.sub('\n', ''.join(textbuf)) | |
|
17
74cc70129d04
Refactoring to address #6: all match templates are now processed by a single filter, which means that match templates added by included templates are properly applied. A side effect of this refactoring is that `Context` objects may not be reused across multiple template processing runs.
cmlenz
parents:
15
diff
changeset
|
134 yield Stream.TEXT, Markup(text), pos |
| 1 | 135 |
| 136 | |
| 137 class HTMLSanitizer(object): | |
| 138 """A filter that removes potentially dangerous HTML tags and attributes | |
| 139 from the stream. | |
| 140 """ | |
| 141 | |
| 142 _SAFE_TAGS = frozenset(['a', 'abbr', 'acronym', 'address', 'area', 'b', | |
| 143 'big', 'blockquote', 'br', 'button', 'caption', 'center', 'cite', | |
| 144 'code', 'col', 'colgroup', 'dd', 'del', 'dfn', 'dir', 'div', 'dl', 'dt', | |
| 145 'em', 'fieldset', 'font', 'form', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6', | |
| 146 'hr', 'i', 'img', 'input', 'ins', 'kbd', 'label', 'legend', 'li', 'map', | |
| 147 'menu', 'ol', 'optgroup', 'option', 'p', 'pre', 'q', 's', 'samp', | |
| 148 'select', 'small', 'span', 'strike', 'strong', 'sub', 'sup', 'table', | |
| 149 'tbody', 'td', 'textarea', 'tfoot', 'th', 'thead', 'tr', 'tt', 'u', | |
| 150 'ul', 'var']) | |
| 151 | |
| 152 _SAFE_ATTRS = frozenset(['abbr', 'accept', 'accept-charset', 'accesskey', | |
| 15 | 153 'action', 'align', 'alt', 'axis', 'bgcolor', 'border', 'cellpadding', |
| 1 | 154 'cellspacing', 'char', 'charoff', 'charset', 'checked', 'cite', 'class', |
| 155 'clear', 'cols', 'colspan', 'color', 'compact', 'coords', 'datetime', | |
| 156 'dir', 'disabled', 'enctype', 'for', 'frame', 'headers', 'height', | |
| 157 'href', 'hreflang', 'hspace', 'id', 'ismap', 'label', 'lang', | |
| 158 'longdesc', 'maxlength', 'media', 'method', 'multiple', 'name', | |
| 159 'nohref', 'noshade', 'nowrap', 'prompt', 'readonly', 'rel', 'rev', | |
| 160 'rows', 'rowspan', 'rules', 'scope', 'selected', 'shape', 'size', | |
| 161 'span', 'src', 'start', 'style', 'summary', 'tabindex', 'target', | |
| 162 'title', 'type', 'usemap', 'valign', 'value', 'vspace', 'width']) | |
| 163 _URI_ATTRS = frozenset(['action', 'background', 'dynsrc', 'href', 'lowsrc', | |
| 164 'src']) | |
| 165 _SAFE_SCHEMES = frozenset(['file', 'ftp', 'http', 'https', 'mailto', None]) | |
| 166 | |
| 167 def __call__(self, stream, ctxt=None): | |
| 168 waiting_for = None | |
| 169 | |
| 170 for kind, data, pos in stream: | |
| 171 if kind is Stream.START: | |
| 172 if waiting_for: | |
| 173 continue | |
| 174 tag, attrib = data | |
| 175 if tag not in self._SAFE_TAGS: | |
| 176 waiting_for = tag | |
| 177 continue | |
| 178 | |
| 179 new_attrib = [] | |
| 180 for attr, value in attrib: | |
| 181 if attr not in self._SAFE_ATTRS: | |
| 182 continue | |
| 183 elif attr in self._URI_ATTRS: | |
| 184 # Don't allow URI schemes such as "javascript:" | |
| 185 if self._get_scheme(value) not in self._SAFE_SCHEMES: | |
| 186 continue | |
| 187 elif attr == 'style': | |
| 188 # Remove dangerous CSS declarations from inline styles | |
| 189 decls = [] | |
| 190 for decl in filter(None, value.split(';')): | |
| 191 is_evil = False | |
| 192 if 'expression' in decl: | |
| 193 is_evil = True | |
| 194 for m in re.finditer(r'url\s*\(([^)]+)', decl): | |
| 195 if self._get_scheme(m.group(1)) not in self._SAFE_SCHEMES: | |
| 196 is_evil = True | |
| 197 break | |
| 198 if not is_evil: | |
| 199 decls.append(decl.strip()) | |
| 200 if not decls: | |
| 201 continue | |
| 202 value = '; '.join(decls) | |
| 203 new_attrib.append((attr, value)) | |
| 204 | |
| 205 yield kind, (tag, new_attrib), pos | |
| 206 | |
| 207 elif kind is Stream.END: | |
| 208 tag = data | |
| 209 if waiting_for: | |
| 210 if waiting_for == tag: | |
| 211 waiting_for = None | |
| 212 else: | |
| 213 yield kind, data, pos | |
| 214 | |
| 215 else: | |
| 216 if not waiting_for: | |
| 217 yield kind, data, pos | |
| 218 | |
| 219 def _get_scheme(self, text): | |
| 220 if ':' not in text: | |
| 221 return None | |
| 222 chars = [char for char in text.split(':', 1)[0] if char.isalnum()] | |
| 223 return ''.join(chars).lower() |