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comparison env/lib/python3.7/site-packages/lxml/html/soupparser.py @ 0:26e78fe6e8c4 draft

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"planemo upload commit c699937486c35866861690329de38ec1a5d9f783"
author shellac
date Sat, 02 May 2020 07:14:21 -0400
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1 """External interface to the BeautifulSoup HTML parser.
2 """
3
4 __all__ = ["fromstring", "parse", "convert_tree"]
5
6 import re
7 from lxml import etree, html
8
9 try:
10 from bs4 import (
11 BeautifulSoup, Tag, Comment, ProcessingInstruction, NavigableString,
12 Declaration, Doctype)
13 _DECLARATION_OR_DOCTYPE = (Declaration, Doctype)
14 except ImportError:
15 from BeautifulSoup import (
16 BeautifulSoup, Tag, Comment, ProcessingInstruction, NavigableString,
17 Declaration)
18 _DECLARATION_OR_DOCTYPE = Declaration
19
20
21 def fromstring(data, beautifulsoup=None, makeelement=None, **bsargs):
22 """Parse a string of HTML data into an Element tree using the
23 BeautifulSoup parser.
24
25 Returns the root ``<html>`` Element of the tree.
26
27 You can pass a different BeautifulSoup parser through the
28 `beautifulsoup` keyword, and a diffent Element factory function
29 through the `makeelement` keyword. By default, the standard
30 ``BeautifulSoup`` class and the default factory of `lxml.html` are
31 used.
32 """
33 return _parse(data, beautifulsoup, makeelement, **bsargs)
34
35
36 def parse(file, beautifulsoup=None, makeelement=None, **bsargs):
37 """Parse a file into an ElemenTree using the BeautifulSoup parser.
38
39 You can pass a different BeautifulSoup parser through the
40 `beautifulsoup` keyword, and a diffent Element factory function
41 through the `makeelement` keyword. By default, the standard
42 ``BeautifulSoup`` class and the default factory of `lxml.html` are
43 used.
44 """
45 if not hasattr(file, 'read'):
46 file = open(file)
47 root = _parse(file, beautifulsoup, makeelement, **bsargs)
48 return etree.ElementTree(root)
49
50
51 def convert_tree(beautiful_soup_tree, makeelement=None):
52 """Convert a BeautifulSoup tree to a list of Element trees.
53
54 Returns a list instead of a single root Element to support
55 HTML-like soup with more than one root element.
56
57 You can pass a different Element factory through the `makeelement`
58 keyword.
59 """
60 root = _convert_tree(beautiful_soup_tree, makeelement)
61 children = root.getchildren()
62 for child in children:
63 root.remove(child)
64 return children
65
66
67 # helpers
68
69 def _parse(source, beautifulsoup, makeelement, **bsargs):
70 if beautifulsoup is None:
71 beautifulsoup = BeautifulSoup
72 if hasattr(beautifulsoup, "HTML_ENTITIES"): # bs3
73 if 'convertEntities' not in bsargs:
74 bsargs['convertEntities'] = 'html'
75 if hasattr(beautifulsoup, "DEFAULT_BUILDER_FEATURES"): # bs4
76 if 'features' not in bsargs:
77 bsargs['features'] = 'html.parser' # use Python html parser
78 tree = beautifulsoup(source, **bsargs)
79 root = _convert_tree(tree, makeelement)
80 # from ET: wrap the document in a html root element, if necessary
81 if len(root) == 1 and root[0].tag == "html":
82 return root[0]
83 root.tag = "html"
84 return root
85
86
87 _parse_doctype_declaration = re.compile(
88 r'(?:\s|[<!])*DOCTYPE\s*HTML'
89 r'(?:\s+PUBLIC)?(?:\s+(\'[^\']*\'|"[^"]*"))?'
90 r'(?:\s+(\'[^\']*\'|"[^"]*"))?',
91 re.IGNORECASE).match
92
93
94 class _PseudoTag:
95 # Minimal imitation of BeautifulSoup.Tag
96 def __init__(self, contents):
97 self.name = 'html'
98 self.attrs = []
99 self.contents = contents
100
101 def __iter__(self):
102 return self.contents.__iter__()
103
104
105 def _convert_tree(beautiful_soup_tree, makeelement):
106 if makeelement is None:
107 makeelement = html.html_parser.makeelement
108
109 # Split the tree into three parts:
110 # i) everything before the root element: document type
111 # declaration, comments, processing instructions, whitespace
112 # ii) the root(s),
113 # iii) everything after the root: comments, processing
114 # instructions, whitespace
115 first_element_idx = last_element_idx = None
116 html_root = declaration = None
117 for i, e in enumerate(beautiful_soup_tree):
118 if isinstance(e, Tag):
119 if first_element_idx is None:
120 first_element_idx = i
121 last_element_idx = i
122 if html_root is None and e.name and e.name.lower() == 'html':
123 html_root = e
124 elif declaration is None and isinstance(e, _DECLARATION_OR_DOCTYPE):
125 declaration = e
126
127 # For a nice, well-formatted document, the variable roots below is
128 # a list consisting of a single <html> element. However, the document
129 # may be a soup like '<meta><head><title>Hello</head><body>Hi
130 # all<\p>'. In this example roots is a list containing meta, head
131 # and body elements.
132 if first_element_idx is None:
133 pre_root = post_root = []
134 roots = beautiful_soup_tree.contents
135 else:
136 pre_root = beautiful_soup_tree.contents[:first_element_idx]
137 roots = beautiful_soup_tree.contents[first_element_idx:last_element_idx+1]
138 post_root = beautiful_soup_tree.contents[last_element_idx+1:]
139
140 # Reorganize so that there is one <html> root...
141 if html_root is not None:
142 # ... use existing one if possible, ...
143 i = roots.index(html_root)
144 html_root.contents = roots[:i] + html_root.contents + roots[i+1:]
145 else:
146 # ... otherwise create a new one.
147 html_root = _PseudoTag(roots)
148
149 convert_node = _init_node_converters(makeelement)
150
151 # Process pre_root
152 res_root = convert_node(html_root)
153 prev = res_root
154 for e in reversed(pre_root):
155 converted = convert_node(e)
156 if converted is not None:
157 prev.addprevious(converted)
158 prev = converted
159
160 # ditto for post_root
161 prev = res_root
162 for e in post_root:
163 converted = convert_node(e)
164 if converted is not None:
165 prev.addnext(converted)
166 prev = converted
167
168 if declaration is not None:
169 try:
170 # bs4 provides full Doctype string
171 doctype_string = declaration.output_ready()
172 except AttributeError:
173 doctype_string = declaration.string
174
175 match = _parse_doctype_declaration(doctype_string)
176 if not match:
177 # Something is wrong if we end up in here. Since soupparser should
178 # tolerate errors, do not raise Exception, just let it pass.
179 pass
180 else:
181 external_id, sys_uri = match.groups()
182 docinfo = res_root.getroottree().docinfo
183 # strip quotes and update DOCTYPE values (any of None, '', '...')
184 docinfo.public_id = external_id and external_id[1:-1]
185 docinfo.system_url = sys_uri and sys_uri[1:-1]
186
187 return res_root
188
189
190 def _init_node_converters(makeelement):
191 converters = {}
192 ordered_node_types = []
193
194 def converter(*types):
195 def add(handler):
196 for t in types:
197 converters[t] = handler
198 ordered_node_types.append(t)
199 return handler
200 return add
201
202 def find_best_converter(node):
203 for t in ordered_node_types:
204 if isinstance(node, t):
205 return converters[t]
206 return None
207
208 def convert_node(bs_node, parent=None):
209 # duplicated in convert_tag() below
210 try:
211 handler = converters[type(bs_node)]
212 except KeyError:
213 handler = converters[type(bs_node)] = find_best_converter(bs_node)
214 if handler is None:
215 return None
216 return handler(bs_node, parent)
217
218 def map_attrs(bs_attrs):
219 if isinstance(bs_attrs, dict): # bs4
220 attribs = {}
221 for k, v in bs_attrs.items():
222 if isinstance(v, list):
223 v = " ".join(v)
224 attribs[k] = unescape(v)
225 else:
226 attribs = dict((k, unescape(v)) for k, v in bs_attrs)
227 return attribs
228
229 def append_text(parent, text):
230 if len(parent) == 0:
231 parent.text = (parent.text or '') + text
232 else:
233 parent[-1].tail = (parent[-1].tail or '') + text
234
235 # converters are tried in order of their definition
236
237 @converter(Tag, _PseudoTag)
238 def convert_tag(bs_node, parent):
239 attrs = bs_node.attrs
240 if parent is not None:
241 attribs = map_attrs(attrs) if attrs else None
242 res = etree.SubElement(parent, bs_node.name, attrib=attribs)
243 else:
244 attribs = map_attrs(attrs) if attrs else {}
245 res = makeelement(bs_node.name, attrib=attribs)
246
247 for child in bs_node:
248 # avoid double recursion by inlining convert_node(), see above
249 try:
250 handler = converters[type(child)]
251 except KeyError:
252 pass
253 else:
254 if handler is not None:
255 handler(child, res)
256 continue
257 convert_node(child, res)
258 return res
259
260 @converter(Comment)
261 def convert_comment(bs_node, parent):
262 res = html.HtmlComment(bs_node)
263 if parent is not None:
264 parent.append(res)
265 return res
266
267 @converter(ProcessingInstruction)
268 def convert_pi(bs_node, parent):
269 if bs_node.endswith('?'):
270 # The PI is of XML style (<?as df?>) but BeautifulSoup
271 # interpreted it as being SGML style (<?as df>). Fix.
272 bs_node = bs_node[:-1]
273 res = etree.ProcessingInstruction(*bs_node.split(' ', 1))
274 if parent is not None:
275 parent.append(res)
276 return res
277
278 @converter(NavigableString)
279 def convert_text(bs_node, parent):
280 if parent is not None:
281 append_text(parent, unescape(bs_node))
282 return None
283
284 return convert_node
285
286
287 # copied from ET's ElementSoup
288
289 try:
290 from html.entities import name2codepoint # Python 3
291 except ImportError:
292 from htmlentitydefs import name2codepoint
293
294
295 handle_entities = re.compile(r"&(\w+);").sub
296
297
298 try:
299 unichr
300 except NameError:
301 # Python 3
302 unichr = chr
303
304
305 def unescape(string):
306 if not string:
307 return ''
308 # work around oddities in BeautifulSoup's entity handling
309 def unescape_entity(m):
310 try:
311 return unichr(name2codepoint[m.group(1)])
312 except KeyError:
313 return m.group(0) # use as is
314 return handle_entities(unescape_entity, string)