Mercurial > repos > shellac > guppy_basecaller

comparison env/lib/python3.7/site-packages/lxml/html/soupparser.py @ 5:9b1c78e6ba9c draft default tip

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
"planemo upload commit 6c0a8142489327ece472c84e558c47da711a9142"
author shellac
date Mon, 01 Jun 2020 08:59:25 -0400
parents 79f47841a781
children
comparison
equal deleted inserted replaced
4:79f47841a781 5:9b1c78e6ba9c
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)