Beautiful源碼：

"""Beautiful Soup Elixir and Tonic "The Screen-Scraper's Friend" http://www.crummy.com/software/BeautifulSoup/Beautiful Soup uses a pluggable XML or HTML parser to parse a (possibly invalid) document into a tree representation. Beautiful Soup provides methods and Pythonic idioms that make it easy to navigate, search, and modify the parse tree.Beautiful Soup works with Python 2.7 and up. It works better if lxml and/or html5lib is installed.For more than you ever wanted to know about Beautiful Soup, see the documentation: http://www.crummy.com/software/BeautifulSoup/bs4/doc/"""# Use of this source code is governed by a BSD-style license that can be # found in the LICENSE file.__author__ = "Leonard Richardson (leonardr@segfault.org)" __version__ = "4.6.3" __copyright__ = "Copyright (c) 2004-2018 Leonard Richardson" __license__ = "MIT"__all__ = ['BeautifulSoup']import os import re import sys import traceback import warningsfrom .builder import builder_registry, ParserRejectedMarkup from .dammit import UnicodeDammit from .element import (CData,Comment,DEFAULT_OUTPUT_ENCODING,Declaration,Doctype,NavigableString,PageElement,ProcessingInstruction,ResultSet,SoupStrainer,Tag,)# The very first thing we do is give a useful error if someone is # running this code under Python 3 without converting it. 'You are trying to run the Python 2 version of Beautiful Soup under Python 3. This will not work.'!='You need to convert the code, either by installing it (`python setup.py install`) or by running 2to3 (`2to3 -w bs4`).'class BeautifulSoup(Tag):"""This class defines the basic interface called by the tree builders.These methods will be called by the parser:reset()feed(markup)The tree builder may call these methods from its feed() implementation:handle_starttag(name, attrs) # See note about return valuehandle_endtag(name)handle_data(data) # Appends to the current data nodeendData(containerClass=NavigableString) # Ends the current data nodeNo matter how complicated the underlying parser is, you should beable to build a tree using 'start tag' events, 'end tag' events,'data' events, and "done with data" events.If you encounter an empty-element tag (aka a self-closing tag,like HTML's <br> tag), call handle_starttag and thenhandle_endtag."""ROOT_TAG_NAME = '[document]'# If the end-user gives no indication which tree builder they# want, look for one with these features.DEFAULT_BUILDER_FEATURES = ['html', 'fast']ASCII_SPACES = '\x20\x0a\x09\x0c\x0d'NO_PARSER_SPECIFIED_WARNING = "No parser was explicitly specified, so I'm using the best available %(markup_type)s parser for this system (\"%(parser)s\"). This usually isn't a problem, but if you run this code on another system, or in a different virtual environment, it may use a different parser and behave differently.\n\nThe code that caused this warning is on line %(line_number)s of the file %(filename)s. To get rid of this warning, pass the additional argument 'features=\"%(parser)s\"' to the BeautifulSoup constructor.\n"def __init__(self, markup="", features=None, builder=None,parse_only=None, from_encoding=None, exclude_encodings=None,**kwargs):"""Constructor.:param markup: A string or a file-like object representingmarkup to be parsed.:param features: Desirable features of the parser to be used. Thismay be the name of a specific parser ("lxml", "lxml-xml","html.parser", or "html5lib") or it may be the type of markupto be used ("html", "html5", "xml"). It's recommended that youname a specific parser, so that Beautiful Soup gives you thesame results across platforms and virtual environments.:param builder: A specific TreeBuilder to use instead of looking oneup based on `features`. You shouldn't need to use this.:param parse_only: A SoupStrainer. Only parts of the documentmatching the SoupStrainer will be considered. This is usefulwhen parsing part of a document that would otherwise be toolarge to fit into memory.:param from_encoding: A string indicating the encoding of thedocument to be parsed. Pass this in if Beautiful Soup isguessing wrongly about the document's encoding.:param exclude_encodings: A list of strings indicatingencodings known to be wrong. Pass this in if you don't knowthe document's encoding but you know Beautiful Soup's guess iswrong.:param kwargs: For backwards compatibility purposes, theconstructor accepts certain keyword arguments used inBeautiful Soup 3. None of these arguments do anything inBeautiful Soup 4 and there's no need to actually pass keywordarguments into the constructor."""if 'convertEntities' in kwargs:warnings.warn("BS4 does not respect the convertEntities argument to the ""BeautifulSoup constructor. Entities are always converted ""to Unicode characters.")if 'markupMassage' in kwargs:del kwargs['markupMassage']warnings.warn("BS4 does not respect the markupMassage argument to the ""BeautifulSoup constructor. The tree builder is responsible ""for any necessary markup massage.")if 'smartQuotesTo' in kwargs:del kwargs['smartQuotesTo']warnings.warn("BS4 does not respect the smartQuotesTo argument to the ""BeautifulSoup constructor. Smart quotes are always converted ""to Unicode characters.")if 'selfClosingTags' in kwargs:del kwargs['selfClosingTags']warnings.warn("BS4 does not respect the selfClosingTags argument to the ""BeautifulSoup constructor. The tree builder is responsible ""for understanding self-closing tags.")if 'isHTML' in kwargs:del kwargs['isHTML']warnings.warn("BS4 does not respect the isHTML argument to the ""BeautifulSoup constructor. Suggest you use ""features='lxml' for HTML and features='lxml-xml' for ""XML.")def deprecated_argument(old_name, new_name):if old_name in kwargs:warnings.warn('The "%s" argument to the BeautifulSoup constructor ''has been renamed to "%s."' % (old_name, new_name))value = kwargs[old_name]del kwargs[old_name]return valuereturn Noneparse_only = parse_only or deprecated_argument("parseOnlyThese", "parse_only")from_encoding = from_encoding or deprecated_argument("fromEncoding", "from_encoding")if from_encoding and isinstance(markup, str):warnings.warn("You provided Unicode markup but also provided a value for from_encoding. Your from_encoding will be ignored.")from_encoding = Noneif len(kwargs) > 0:arg = list(kwargs.keys()).pop()raise TypeError("__init__() got an unexpected keyword argument '%s'" % arg)if builder is None:original_features = featuresif isinstance(features, str):features = [features]if features is None or len(features) == 0:features = self.DEFAULT_BUILDER_FEATURESbuilder_class = builder_registry.lookup(*features)if builder_class is None:raise FeatureNotFound("Couldn't find a tree builder with the features you ""requested: %s. Do you need to install a parser library?"% ",".join(features))builder = builder_class()if not (original_features == builder.NAME ororiginal_features in builder.ALTERNATE_NAMES):if builder.is_xml:markup_type = "XML"else:markup_type = "HTML"# This code adapted from warnings.py so that we get the same line# of code as our warnings.warn() call gets, even if the answer is wrong# (as it may be in a multithreading situation).caller = Nonetry:caller = sys._getframe(1)except ValueError:passif caller:globals = caller.f_globalsline_number = caller.f_linenoelse:globals = sys.__dict__line_number= 1 filename = globals.get('__file__')if filename:fnl = filename.lower()if fnl.endswith((".pyc", ".pyo")):filename = filename[:-1]if filename:# If there is no filename at all, the user is most likely in a REPL,# and the warning is not necessary.values = dict(filename=filename,line_number=line_number,parser=builder.NAME,markup_type=markup_type)warnings.warn(self.NO_PARSER_SPECIFIED_WARNING % values, stacklevel=2)self.builder = builderself.is_xml = builder.is_xmlself.known_xml = self.is_xmlself.builder.soup = selfself.parse_only = parse_onlyif hasattr(markup, 'read'): # It's a file-type object.markup = markup.read()elif len(markup) <= 256 and ((isinstance(markup, bytes) and not b'<' in markup)or (isinstance(markup, str) and not '<' in markup)):# Print out warnings for a couple beginner problems# involving passing non-markup to Beautiful Soup.# Beautiful Soup will still parse the input as markup,# just in case that's what the user really wants.if (isinstance(markup, str)and not os.path.supports_unicode_filenames):possible_filename = markup.encode("utf8")else:possible_filename = markupis_file = Falsetry:is_file = os.path.exists(possible_filename)except Exception as e:# This is almost certainly a problem involving# characters not valid in filenames on this# system. Just let it go.passif is_file:if isinstance(markup, str):markup = markup.encode("utf8")warnings.warn('"%s" looks like a filename, not markup. You should'' probably open this file and pass the filehandle into'' Beautiful Soup.' % markup)self._check_markup_is_url(markup)for (self.markup, self.original_encoding, self.declared_html_encoding,self.contains_replacement_characters) in (self.builder.prepare_markup(markup, from_encoding, exclude_encodings=exclude_encodings)):self.reset()try:self._feed()breakexcept ParserRejectedMarkup:pass# Clear out the markup and remove the builder's circular# reference to this object.self.markup = Noneself.builder.soup = Nonedef __copy__(self):copy = type(self)(self.encode('utf-8'), builder=self.builder, from_encoding='utf-8')# Although we encoded the tree to UTF-8, that may not have# been the encoding of the original markup. Set the copy's# .original_encoding to reflect the original object's# .original_encoding.copy.original_encoding = self.original_encodingreturn copydef __getstate__(self):# Frequently a tree builder can't be pickled.d = dict(self.__dict__)if 'builder' in d and not self.builder.picklable:d['builder'] = Nonereturn d@staticmethoddef _check_markup_is_url(markup):""" Check if markup looks like it's actually a url and raise a warning if so. Markup can be unicode or str (py2) / bytes (py3)."""if isinstance(markup, bytes):space = b' 'cant_start_with = (b"http:", b"https:")elif isinstance(markup, str):space = ' 'cant_start_with = ("http:", "https:")else:returnif any(markup.startswith(prefix) for prefix in cant_start_with):if not space in markup:if isinstance(markup, bytes):decoded_markup = markup.decode('utf-8', 'replace')else:decoded_markup = markupwarnings.warn('"%s" looks like a URL. Beautiful Soup is not an'' HTTP client. You should probably use an HTTP client like'' requests to get the document behind the URL, and feed'' that document to Beautiful Soup.' % decoded_markup)def _feed(self):# Convert the document to Unicode. self.builder.reset()self.builder.feed(self.markup)# Close out any unfinished strings and close all the open tags. self.endData()while self.currentTag.name != self.ROOT_TAG_NAME:self.popTag()def reset(self):Tag.__init__(self, self, self.builder, self.ROOT_TAG_NAME)self.hidden = 1self.builder.reset()self.current_data = []self.currentTag = Noneself.tagStack = []self.preserve_whitespace_tag_stack = []self.pushTag(self)def new_tag(self, name, namespace=None, nsprefix=None, attrs={}, **kwattrs):"""Create a new tag associated with this soup."""kwattrs.update(attrs)return Tag(None, self.builder, name, namespace, nsprefix, kwattrs)def new_string(self, s, subclass=NavigableString):"""Create a new NavigableString associated with this soup."""return subclass(s)def insert_before(self, successor):raise NotImplementedError("BeautifulSoup objects don't support insert_before().")def insert_after(self, successor):raise NotImplementedError("BeautifulSoup objects don't support insert_after().")def popTag(self):tag = self.tagStack.pop()if self.preserve_whitespace_tag_stack and tag == self.preserve_whitespace_tag_stack[-1]:self.preserve_whitespace_tag_stack.pop()#print "Pop", tag.nameif self.tagStack:self.currentTag = self.tagStack[-1]return self.currentTagdef pushTag(self, tag):#print "Push", tag.nameif self.currentTag:self.currentTag.contents.append(tag)self.tagStack.append(tag)self.currentTag = self.tagStack[-1]if tag.name in self.builder.preserve_whitespace_tags:self.preserve_whitespace_tag_stack.append(tag)def endData(self, containerClass=NavigableString):if self.current_data:current_data = ''.join(self.current_data)# If whitespace is not preserved, and this string contains# nothing but ASCII spaces, replace it with a single space# or newline.if not self.preserve_whitespace_tag_stack:strippable = Truefor i in current_data:if i not in self.ASCII_SPACES:strippable = Falsebreakif strippable:if '\n' in current_data:current_data = '\n'else:current_data = ' '# Reset the data collector.self.current_data = []# Should we add this string to the tree at all?if self.parse_only and len(self.tagStack) <= 1 and \(not self.parse_only.text or \not self.parse_only.search(current_data)):returno = containerClass(current_data)self.object_was_parsed(o)def object_was_parsed(self, o, parent=None, most_recent_element=None):"""Add an object to the parse tree."""parent = parent or self.currentTagprevious_element = most_recent_element or self._most_recent_elementnext_element = previous_sibling = next_sibling = Noneif isinstance(o, Tag):next_element = o.next_elementnext_sibling = o.next_siblingprevious_sibling = o.previous_siblingif not previous_element:previous_element = o.previous_elemento.setup(parent, previous_element, next_element, previous_sibling, next_sibling)self._most_recent_element = oparent.contents.append(o)if parent.next_sibling:# This node is being inserted into an element that has# already been parsed. Deal with any dangling references.index = len(parent.contents)-1while index >= 0:if parent.contents[index] is o:breakindex -= 1else:raise ValueError("Error building tree: supposedly %r was inserted ""into %r after the fact, but I don't see it!" % (o, parent))if index == 0:previous_element = parentprevious_sibling = Noneelse:previous_element = previous_sibling = parent.contents[index-1]if index == len(parent.contents)-1:next_element = parent.next_siblingnext_sibling = Noneelse:next_element = next_sibling = parent.contents[index+1]o.previous_element = previous_elementif previous_element:previous_element.next_element = oo.next_element = next_elementif next_element:next_element.previous_element = oo.next_sibling = next_siblingif next_sibling:next_sibling.previous_sibling = oo.previous_sibling = previous_siblingif previous_sibling:previous_sibling.next_sibling = odef _popToTag(self, name, nsprefix=None, inclusivePop=True):"""Pops the tag stack up to and including the most recentinstance of the given tag. If inclusivePop is false, pops the tagstack up to but *not* including the most recent instqance ofthe given tag."""#print "Popping to %s" % nameif name == self.ROOT_TAG_NAME:# The BeautifulSoup object itself can never be popped.returnmost_recently_popped = Nonestack_size = len(self.tagStack)for i in range(stack_size - 1, 0, -1):t = self.tagStack[i]if (name == t.name and nsprefix == t.prefix):if inclusivePop:most_recently_popped = self.popTag()breakmost_recently_popped = self.popTag()return most_recently_poppeddef handle_starttag(self, name, namespace, nsprefix, attrs):"""Push a start tag on to the stack.If this method returns None, the tag was rejected by theSoupStrainer. You should proceed as if the tag had not occurredin the document. For instance, if this was a self-closing tag,don't call handle_endtag."""# print "Start tag %s: %s" % (name, attrs) self.endData()if (self.parse_only and len(self.tagStack) <= 1and (self.parse_only.textor not self.parse_only.search_tag(name, attrs))):return Nonetag = Tag(self, self.builder, name, namespace, nsprefix, attrs,self.currentTag, self._most_recent_element)if tag is None:return tagif self._most_recent_element:self._most_recent_element.next_element = tagself._most_recent_element = tagself.pushTag(tag)return tagdef handle_endtag(self, name, nsprefix=None):#print "End tag: " + name self.endData()self._popToTag(name, nsprefix)def handle_data(self, data):self.current_data.append(data)def decode(self, pretty_print=False,eventual_encoding=DEFAULT_OUTPUT_ENCODING,formatter="minimal"):"""Returns a string or Unicode representation of this document.To get Unicode, pass None for encoding."""if self.is_xml:# Print the XML declarationencoding_part = ''if eventual_encoding != None:encoding_part = ' encoding="%s"' % eventual_encodingprefix = '<?xml version="1.0"%s?>\n' % encoding_partelse:prefix = ''if not pretty_print:indent_level = Noneelse:indent_level = 0return prefix + super(BeautifulSoup, self).decode(indent_level, eventual_encoding, formatter)# Alias to make it easier to type import: 'from bs4 import _soup' _s = BeautifulSoup _soup = BeautifulSoupclass BeautifulStoneSoup(BeautifulSoup):"""Deprecated interface to an XML parser."""def __init__(self, *args, **kwargs):kwargs['features'] = 'xml'warnings.warn('The BeautifulStoneSoup class is deprecated. Instead of using ''it, pass features="xml" into the BeautifulSoup constructor.')super(BeautifulStoneSoup, self).__init__(*args, **kwargs)class StopParsing(Exception):passclass FeatureNotFound(ValueError):pass#By default, act as an HTML pretty-printer. if __name__ == '__main__':import syssoup = BeautifulSoup(sys.stdin)print(soup.prettify())

find_all（）源碼：

# Use of this source code is governed by a BSD-style license that can be # found in the LICENSE file. __license__ = "MIT"try:from collections.abc import Callable # Python 3.6 except ImportError as e:from collections import Callable import re import shlex import sys import warnings from bs4.dammit import EntitySubstitutionDEFAULT_OUTPUT_ENCODING = "utf-8" PY3K = (sys.version_info[0] > 2)whitespace_re = re.compile(r"\s+")def _alias(attr):"""Alias one attribute name to another for backward compatibility"""@propertydef alias(self):return getattr(self, attr)@alias.setterdef alias(self):return setattr(self, attr)return aliasclass NamespacedAttribute(str):def __new__(cls, prefix, name, namespace=None):if name is None:obj = str.__new__(cls, prefix)elif prefix is None:# Not really namespaced.obj = str.__new__(cls, name)else:obj = str.__new__(cls, prefix + ":" + name)obj.prefix = prefixobj.name = nameobj.namespace = namespacereturn objclass AttributeValueWithCharsetSubstitution(str):"""A stand-in object for a character encoding specified in HTML."""class CharsetMetaAttributeValue(AttributeValueWithCharsetSubstitution):"""A generic stand-in for the value of a meta tag's 'charset' attribute.When Beautiful Soup parses the markup '<meta charset="utf8">', thevalue of the 'charset' attribute will be one of these objects."""def __new__(cls, original_value):obj = str.__new__(cls, original_value)obj.original_value = original_valuereturn objdef encode(self, encoding):return encodingclass ContentMetaAttributeValue(AttributeValueWithCharsetSubstitution):"""A generic stand-in for the value of a meta tag's 'content' attribute.When Beautiful Soup parses the markup:<meta http-equiv="content-type" content="text/html; charset=utf8">The value of the 'content' attribute will be one of these objects."""CHARSET_RE = re.compile(r"((^|;)\s*charset=)([^;]*)", re.M)def __new__(cls, original_value):match = cls.CHARSET_RE.search(original_value)if match is None:# No substitution necessary.return str.__new__(str, original_value)obj = str.__new__(cls, original_value)obj.original_value = original_valuereturn objdef encode(self, encoding):def rewrite(match):return match.group(1) + encodingreturn self.CHARSET_RE.sub(rewrite, self.original_value)class HTMLAwareEntitySubstitution(EntitySubstitution):"""Entity substitution rules that are aware of some HTML quirks.Specifically, the contents of <script> and <style> tags should notundergo entity substitution.Incoming NavigableString objects are checked to see if they're thedirect children of a <script> or <style> tag."""cdata_containing_tags = set(["script", "style"])preformatted_tags = set(["pre"])preserve_whitespace_tags = set(['pre', 'textarea'])@classmethoddef _substitute_if_appropriate(cls, ns, f):if (isinstance(ns, NavigableString)and ns.parent is not Noneand ns.parent.name in cls.cdata_containing_tags):# Do nothing.return ns# Substitute.return f(ns)@classmethoddef substitute_html(cls, ns):return cls._substitute_if_appropriate(ns, EntitySubstitution.substitute_html)@classmethoddef substitute_xml(cls, ns):return cls._substitute_if_appropriate(ns, EntitySubstitution.substitute_xml)class Formatter(object):"""Contains information about how to format a parse tree."""# By default, represent void elements as <tag/> rather than <tag>void_element_close_prefix = '/'def substitute_entities(self, *args, **kwargs):"""Transform certain characters into named entities."""raise NotImplementedError()class HTMLFormatter(Formatter):"""The default HTML formatter."""def substitute(self, *args, **kwargs):return HTMLAwareEntitySubstitution.substitute_html(*args, **kwargs)class MinimalHTMLFormatter(Formatter):"""A minimal HTML formatter."""def substitute(self, *args, **kwargs):return HTMLAwareEntitySubstitution.substitute_xml(*args, **kwargs)class HTML5Formatter(HTMLFormatter):"""An HTML formatter that omits the slash in a void tag."""void_element_close_prefix = Noneclass XMLFormatter(Formatter):"""Substitute only the essential XML entities."""def substitute(self, *args, **kwargs):return EntitySubstitution.substitute_xml(*args, **kwargs)class HTMLXMLFormatter(Formatter):"""Format XML using HTML rules."""def substitute(self, *args, **kwargs):return HTMLAwareEntitySubstitution.substitute_html(*args, **kwargs)class PageElement(object):"""Contains the navigational information for some part of the page(either a tag or a piece of text)"""# There are five possible values for the "formatter" argument passed in# to methods like encode() and prettify():# # "html" - All Unicode characters with corresponding HTML entities# are converted to those entities on output.# "html5" - The same as "html", but empty void tags are represented as# <tag> rather than <tag/># "minimal" - Bare ampersands and angle brackets are converted to# XML entities: &amp; &lt; &gt;# None - The null formatter. Unicode characters are never# converted to entities. This is not recommended, but it's# faster than "minimal".# A callable function - it will be called on every string that needs to undergo entity substitution.# A Formatter instance - Formatter.substitute(string) will be called on every string that# needs to undergo entity substitution.# # In an HTML document, the default "html", "html5", and "minimal"# functions will leave the contents of <script> and <style> tags# alone. For an XML document, all tags will be given the same# treatment. HTML_FORMATTERS = {"html" : HTMLFormatter(),"html5" : HTML5Formatter(),"minimal" : MinimalHTMLFormatter(),None : None}XML_FORMATTERS = {"html" : HTMLXMLFormatter(),"minimal" : XMLFormatter(),None : None}def format_string(self, s, formatter='minimal'):"""Format the given string using the given formatter."""if isinstance(formatter, str):formatter = self._formatter_for_name(formatter)if formatter is None:output = selse:if callable(formatter):# Backwards compatibility -- you used to pass in a formatting method.output = formatter(s)else:output = formatter.substitute(s)return output@propertydef _is_xml(self):"""Is this element part of an XML tree or an HTML tree?This is used when mapping a formatter name ("minimal") to anappropriate function (one that performs entity-substitution onthe contents of <script> and <style> tags, or not). It can beinefficient, but it should be called very rarely."""if self.known_xml is not None:# Most of the time we will have determined this when the# document is parsed.return self.known_xml# Otherwise, it's likely that this element was created by# direct invocation of the constructor from within the user's# Python code.if self.parent is None:# This is the top-level object. It should have .known_xml set# from tree creation. If not, take a guess--BS is usually# used on HTML markup.return getattr(self, 'is_xml', False)return self.parent._is_xmldef _formatter_for_name(self, name):"Look up a formatter function based on its name and the tree."if self._is_xml:return self.XML_FORMATTERS.get(name, XMLFormatter())else:return self.HTML_FORMATTERS.get(name, HTMLFormatter())def setup(self, parent=None, previous_element=None, next_element=None,previous_sibling=None, next_sibling=None):"""Sets up the initial relations between this element andother elements."""self.parent = parentself.previous_element = previous_elementif previous_element is not None:self.previous_element.next_element = selfself.next_element = next_elementif self.next_element:self.next_element.previous_element = selfself.next_sibling = next_siblingif self.next_sibling:self.next_sibling.previous_sibling = selfif (not previous_siblingand self.parent is not None and self.parent.contents):previous_sibling = self.parent.contents[-1]self.previous_sibling = previous_siblingif previous_sibling:self.previous_sibling.next_sibling = selfnextSibling = _alias("next_sibling") # BS3previousSibling = _alias("previous_sibling") # BS3def replace_with(self, replace_with):if not self.parent:raise ValueError("Cannot replace one element with another when the""element to be replaced is not part of a tree.")if replace_with is self:returnif replace_with is self.parent:raise ValueError("Cannot replace a Tag with its parent.")old_parent = self.parentmy_index = self.parent.index(self)self.extract()old_parent.insert(my_index, replace_with)return selfreplaceWith = replace_with # BS3def unwrap(self):my_parent = self.parentif not self.parent:raise ValueError("Cannot replace an element with its contents when that""element is not part of a tree.")my_index = self.parent.index(self)self.extract()for child in reversed(self.contents[:]):my_parent.insert(my_index, child)return selfreplace_with_children = unwrapreplaceWithChildren = unwrap # BS3def wrap(self, wrap_inside):me = self.replace_with(wrap_inside)wrap_inside.append(me)return wrap_insidedef extract(self):"""Destructively rips this element out of the tree."""if self.parent is not None:del self.parent.contents[self.parent.index(self)]#Find the two elements that would be next to each other if#this element (and any children) hadn't been parsed. Connect#the two.last_child = self._last_descendant()next_element = last_child.next_elementif (self.previous_element is not None andself.previous_element is not next_element):self.previous_element.next_element = next_elementif next_element is not None and next_element is not self.previous_element:next_element.previous_element = self.previous_elementself.previous_element = Nonelast_child.next_element = Noneself.parent = Noneif (self.previous_sibling is not Noneand self.previous_sibling is not self.next_sibling):self.previous_sibling.next_sibling = self.next_siblingif (self.next_sibling is not Noneand self.next_sibling is not self.previous_sibling):self.next_sibling.previous_sibling = self.previous_siblingself.previous_sibling = self.next_sibling = Nonereturn selfdef _last_descendant(self, is_initialized=True, accept_self=True):"Finds the last element beneath this object to be parsed."if is_initialized and self.next_sibling:last_child = self.next_sibling.previous_elementelse:last_child = selfwhile isinstance(last_child, Tag) and last_child.contents:last_child = last_child.contents[-1]if not accept_self and last_child is self:last_child = Nonereturn last_child# BS3: Not part of the API!_lastRecursiveChild = _last_descendantdef insert(self, position, new_child):if new_child is None:raise ValueError("Cannot insert None into a tag.")if new_child is self:raise ValueError("Cannot insert a tag into itself.")if (isinstance(new_child, str)and not isinstance(new_child, NavigableString)):new_child = NavigableString(new_child)from bs4 import BeautifulSoupif isinstance(new_child, BeautifulSoup):# We don't want to end up with a situation where one BeautifulSoup# object contains another. Insert the children one at a time.for subchild in list(new_child.contents):self.insert(position, subchild)position += 1returnposition = min(position, len(self.contents))if hasattr(new_child, 'parent') and new_child.parent is not None:# We're 'inserting' an element that's already one# of this object's children.if new_child.parent is self:current_index = self.index(new_child)if current_index < position:# We're moving this element further down the list# of this object's children. That means that when# we extract this element, our target index will# jump down one.position -= 1new_child.extract()new_child.parent = selfprevious_child = Noneif position == 0:new_child.previous_sibling = Nonenew_child.previous_element = selfelse:previous_child = self.contents[position - 1]new_child.previous_sibling = previous_childnew_child.previous_sibling.next_sibling = new_childnew_child.previous_element = previous_child._last_descendant(False)if new_child.previous_element is not None:new_child.previous_element.next_element = new_childnew_childs_last_element = new_child._last_descendant(False)if position >= len(self.contents):new_child.next_sibling = Noneparent = selfparents_next_sibling = Nonewhile parents_next_sibling is None and parent is not None:parents_next_sibling = parent.next_siblingparent = parent.parentif parents_next_sibling is not None:# We found the element that comes next in the document.breakif parents_next_sibling is not None:new_childs_last_element.next_element = parents_next_siblingelse:# The last element of this tag is the last element in# the document.new_childs_last_element.next_element = Noneelse:next_child = self.contents[position]new_child.next_sibling = next_childif new_child.next_sibling is not None:new_child.next_sibling.previous_sibling = new_childnew_childs_last_element.next_element = next_childif new_childs_last_element.next_element is not None:new_childs_last_element.next_element.previous_element = new_childs_last_elementself.contents.insert(position, new_child)def append(self, tag):"""Appends the given tag to the contents of this tag."""self.insert(len(self.contents), tag)def insert_before(self, predecessor):"""Makes the given element the immediate predecessor of this one.The two elements will have the same parent, and the given elementwill be immediately before this one."""if self is predecessor:raise ValueError("Can't insert an element before itself.")parent = self.parentif parent is None:raise ValueError("Element has no parent, so 'before' has no meaning.")# Extract first so that the index won't be screwed up if they# are siblings.if isinstance(predecessor, PageElement):predecessor.extract()index = parent.index(self)parent.insert(index, predecessor)def insert_after(self, successor):"""Makes the given element the immediate successor of this one.The two elements will have the same parent, and the given elementwill be immediately after this one."""if self is successor:raise ValueError("Can't insert an element after itself.")parent = self.parentif parent is None:raise ValueError("Element has no parent, so 'after' has no meaning.")# Extract first so that the index won't be screwed up if they# are siblings.if isinstance(successor, PageElement):successor.extract()index = parent.index(self)parent.insert(index+1, successor)def find_next(self, name=None, attrs={}, text=None, **kwargs):"""Returns the first item that matches the given criteria andappears after this Tag in the document."""return self._find_one(self.find_all_next, name, attrs, text, **kwargs)findNext = find_next # BS3def find_all_next(self, name=None, attrs={}, text=None, limit=None,**kwargs):"""Returns all items that match the given criteria and appearafter this Tag in the document."""return self._find_all(name, attrs, text, limit, self.next_elements,**kwargs)findAllNext = find_all_next # BS3def find_next_sibling(self, name=None, attrs={}, text=None, **kwargs):"""Returns the closest sibling to this Tag that matches thegiven criteria and appears after this Tag in the document."""return self._find_one(self.find_next_siblings, name, attrs, text,**kwargs)findNextSibling = find_next_sibling # BS3def find_next_siblings(self, name=None, attrs={}, text=None, limit=None,**kwargs):"""Returns the siblings of this Tag that match the givencriteria and appear after this Tag in the document."""return self._find_all(name, attrs, text, limit,self.next_siblings, **kwargs)findNextSiblings = find_next_siblings # BS3fetchNextSiblings = find_next_siblings # BS2def find_previous(self, name=None, attrs={}, text=None, **kwargs):"""Returns the first item that matches the given criteria andappears before this Tag in the document."""return self._find_one(self.find_all_previous, name, attrs, text, **kwargs)findPrevious = find_previous # BS3def find_all_previous(self, name=None, attrs={}, text=None, limit=None,**kwargs):"""Returns all items that match the given criteria and appearbefore this Tag in the document."""return self._find_all(name, attrs, text, limit, self.previous_elements,**kwargs)findAllPrevious = find_all_previous # BS3fetchPrevious = find_all_previous # BS2def find_previous_sibling(self, name=None, attrs={}, text=None, **kwargs):"""Returns the closest sibling to this Tag that matches thegiven criteria and appears before this Tag in the document."""return self._find_one(self.find_previous_siblings, name, attrs, text,**kwargs)findPreviousSibling = find_previous_sibling # BS3def find_previous_siblings(self, name=None, attrs={}, text=None,limit=None, **kwargs):"""Returns the siblings of this Tag that match the givencriteria and appear before this Tag in the document."""return self._find_all(name, attrs, text, limit,self.previous_siblings, **kwargs)findPreviousSiblings = find_previous_siblings # BS3fetchPreviousSiblings = find_previous_siblings # BS2def find_parent(self, name=None, attrs={}, **kwargs):"""Returns the closest parent of this Tag that matches the givencriteria."""# NOTE: We can't use _find_one because findParents takes a different# set of arguments.r = Nonel = self.find_parents(name, attrs, 1, **kwargs)if l:r = l[0]return rfindParent = find_parent # BS3def find_parents(self, name=None, attrs={}, limit=None, **kwargs):"""Returns the parents of this Tag that match the givencriteria."""return self._find_all(name, attrs, None, limit, self.parents,**kwargs)findParents = find_parents # BS3fetchParents = find_parents # BS2 @propertydef next(self):return self.next_element@propertydef previous(self):return self.previous_element#These methods do the real heavy lifting.def _find_one(self, method, name, attrs, text, **kwargs):r = Nonel = method(name, attrs, text, 1, **kwargs)if l:r = l[0]return rdef _find_all(self, name, attrs, text, limit, generator, **kwargs):"Iterates over a generator looking for things that match."if text is None and 'string' in kwargs:text = kwargs['string']del kwargs['string']if isinstance(name, SoupStrainer):strainer = nameelse:strainer = SoupStrainer(name, attrs, text, **kwargs)if text is None and not limit and not attrs and not kwargs:if name is True or name is None:# Optimization to find all tags.result = (element for element in generatorif isinstance(element, Tag))return ResultSet(strainer, result)elif isinstance(name, str):# Optimization to find all tags with a given name.if name.count(':') == 1:# This is a name with a prefix. If this is a namespace-aware document,# we need to match the local name against tag.name. If not,# we need to match the fully-qualified name against tag.name.prefix, local_name = name.split(':', 1)else:prefix = Nonelocal_name = nameresult = (element for element in generatorif isinstance(element, Tag)and (element.name == name) or (element.name == local_nameand (prefix is None or element.prefix == prefix)))return ResultSet(strainer, result)results = ResultSet(strainer)while True:try:i = next(generator)except StopIteration:breakif i:found = strainer.search(i)if found:results.append(found)if limit and len(results) >= limit:breakreturn results#These generators can be used to navigate starting from both#NavigableStrings and Tags. @propertydef next_elements(self):i = self.next_elementwhile i is not None:yield ii = i.next_element@propertydef next_siblings(self):i = self.next_siblingwhile i is not None:yield ii = i.next_sibling@propertydef previous_elements(self):i = self.previous_elementwhile i is not None:yield ii = i.previous_element@propertydef previous_siblings(self):i = self.previous_siblingwhile i is not None:yield ii = i.previous_sibling@propertydef parents(self):i = self.parentwhile i is not None:yield ii = i.parent# Methods for supporting CSS selectors. tag_name_re = re.compile('^[a-zA-Z0-9][-.a-zA-Z0-9:_]*$')# /^([a-zA-Z0-9][-.a-zA-Z0-9:_]*)\[(\w+)([=~\|\^\$\*]?)=?"?([^\]"]*)"?\]$/# \---------------------------/ \---/\-------------/ \-------/# | | | |# | | | The value# | | ~,|,^,$,* or =# | Attribute# Tagattribselect_re = re.compile(r'^(?P<tag>[a-zA-Z0-9][-.a-zA-Z0-9:_]*)?\[(?P<attribute>[\w-]+)(?P<operator>[=~\|\^\$\*]?)' +r'=?"?(?P<value>[^\]"]*)"?\]$')def _attr_value_as_string(self, value, default=None):"""Force an attribute value into a string representation.A multi-valued attribute will be converted into aspace-separated stirng."""value = self.get(value, default)if isinstance(value, list) or isinstance(value, tuple):value =" ".join(value)return valuedef _tag_name_matches_and(self, function, tag_name):if not tag_name:return functionelse:def _match(tag):return tag.name == tag_name and function(tag)return _matchdef _attribute_checker(self, operator, attribute, value=''):"""Create a function that performs a CSS selector operation.Takes an operator, attribute and optional value. Returns afunction that will return True for elements that match thatcombination."""if operator == '=':# string representation of `attribute` is equal to `value`return lambda el: el._attr_value_as_string(attribute) == valueelif operator == '~':# space-separated list representation of `attribute`# contains `value`def _includes_value(element):attribute_value = element.get(attribute, [])if not isinstance(attribute_value, list):attribute_value = attribute_value.split()return value in attribute_valuereturn _includes_valueelif operator == '^':# string representation of `attribute` starts with `value`return lambda el: el._attr_value_as_string(attribute, '').startswith(value)elif operator == '$':# string representation of `attribute` ends with `value`return lambda el: el._attr_value_as_string(attribute, '').endswith(value)elif operator == '*':# string representation of `attribute` contains `value`return lambda el: value in el._attr_value_as_string(attribute, '')elif operator == '|':# string representation of `attribute` is either exactly# `value` or starts with `value` and then a dash.def _is_or_starts_with_dash(element):attribute_value = element._attr_value_as_string(attribute, '')return (attribute_value == value or attribute_value.startswith(value + '-'))return _is_or_starts_with_dashelse:return lambda el: el.has_attr(attribute)# Old non-property versions of the generators, for backwards# compatibility with BS3.def nextGenerator(self):return self.next_elementsdef nextSiblingGenerator(self):return self.next_siblingsdef previousGenerator(self):return self.previous_elementsdef previousSiblingGenerator(self):return self.previous_siblingsdef parentGenerator(self):return self.parentsclass NavigableString(str, PageElement):PREFIX = ''SUFFIX = ''# We can't tell just by looking at a string whether it's contained# in an XML document or an HTML document. known_xml = Nonedef __new__(cls, value):"""Create a new NavigableString.When unpickling a NavigableString, this method is called withthe string in DEFAULT_OUTPUT_ENCODING. That encoding needs to bepassed in to the superclass's __new__ or the superclass won't knowhow to handle non-ASCII characters."""if isinstance(value, str):u = str.__new__(cls, value)else:u = str.__new__(cls, value, DEFAULT_OUTPUT_ENCODING)u.setup()return udef __copy__(self):"""A copy of a NavigableString has the same contents and classas the original, but it is not connected to the parse tree."""return type(self)(self)def __getnewargs__(self):return (str(self),)def __getattr__(self, attr):"""text.string gives you text. This is for backwardscompatibility for Navigable*String, but for CData* it lets youget the string without the CData wrapper."""if attr == 'string':return selfelse:raise AttributeError("'%s' object has no attribute '%s'" % (self.__class__.__name__, attr))def output_ready(self, formatter="minimal"):output = self.format_string(self, formatter)return self.PREFIX + output + self.SUFFIX@propertydef name(self):return None@name.setterdef name(self, name):raise AttributeError("A NavigableString cannot be given a name.")class PreformattedString(NavigableString):"""A NavigableString not subject to the normal formatting rules.The string will be passed into the formatter (to trigger side effects),but the return value will be ignored."""def output_ready(self, formatter="minimal"):"""CData strings are passed into the formatter.But the return value is ignored."""self.format_string(self, formatter)return self.PREFIX + self + self.SUFFIXclass CData(PreformattedString):PREFIX = '<![CDATA['SUFFIX = ']]>'class ProcessingInstruction(PreformattedString):"""A SGML processing instruction."""PREFIX = '<?'SUFFIX = '>'class XMLProcessingInstruction(ProcessingInstruction):"""An XML processing instruction."""PREFIX = '<?'SUFFIX = '?>'class Comment(PreformattedString):PREFIX = '<!--'SUFFIX = '-->'class Declaration(PreformattedString):PREFIX = '<?'SUFFIX = '?>'class Doctype(PreformattedString):@classmethoddef for_name_and_ids(cls, name, pub_id, system_id):value = name or ''if pub_id is not None:value += ' PUBLIC "%s"' % pub_idif system_id is not None:value += ' "%s"' % system_idelif system_id is not None:value += ' SYSTEM "%s"' % system_idreturn Doctype(value)PREFIX = '<!DOCTYPE 'SUFFIX = '>\n'class Tag(PageElement):"""Represents a found HTML tag with its attributes and contents."""def __init__(self, parser=None, builder=None, name=None, namespace=None,prefix=None, attrs=None, parent=None, previous=None,is_xml=None):"Basic constructor."if parser is None:self.parser_class = Noneelse:# We don't actually store the parser object: that lets extracted# chunks be garbage-collected.self.parser_class = parser.__class__if name is None:raise ValueError("No value provided for new tag's name.")self.name = nameself.namespace = namespaceself.prefix = prefixif builder is not None:preserve_whitespace_tags = builder.preserve_whitespace_tagselse:if is_xml:preserve_whitespace_tags = []else:preserve_whitespace_tags = HTMLAwareEntitySubstitution.preserve_whitespace_tagsself.preserve_whitespace_tags = preserve_whitespace_tagsif attrs is None:attrs = {}elif attrs:if builder is not None and builder.cdata_list_attributes:attrs = builder._replace_cdata_list_attribute_values(self.name, attrs)else:attrs = dict(attrs)else:attrs = dict(attrs)# If possible, determine ahead of time whether this tag is an# XML tag.if builder:self.known_xml = builder.is_xmlelse:self.known_xml = is_xmlself.attrs = attrsself.contents = []self.setup(parent, previous)self.hidden = False# Set up any substitutions, such as the charset in a META tag.if builder is not None:builder.set_up_substitutions(self)self.can_be_empty_element = builder.can_be_empty_element(name)else:self.can_be_empty_element = FalseparserClass = _alias("parser_class") # BS3def __copy__(self):"""A copy of a Tag is a new Tag, unconnected to the parse tree.Its contents are a copy of the old Tag's contents."""clone = type(self)(None, self.builder, self.name, self.namespace,self.prefix, self.attrs, is_xml=self._is_xml)for attr in ('can_be_empty_element', 'hidden'):setattr(clone, attr, getattr(self, attr))for child in self.contents:clone.append(child.__copy__())return clone@propertydef is_empty_element(self):"""Is this tag an empty-element tag? (aka a self-closing tag)A tag that has contents is never an empty-element tag.A tag that has no contents may or may not be an empty-elementtag. It depends on the builder used to create the tag. If thebuilder has a designated list of empty-element tags, then onlya tag whose name shows up in that list is considered anempty-element tag.If the builder has no designated list of empty-element tags,then any tag with no contents is an empty-element tag."""return len(self.contents) == 0 and self.can_be_empty_elementisSelfClosing = is_empty_element # BS3 @propertydef string(self):"""Convenience property to get the single string within this tag.:Return: If this tag has a single string child, return valueis that string. If this tag has no children, or more than onechild, return value is None. If this tag has one child tag,return value is the 'string' attribute of the child tag,recursively."""if len(self.contents) != 1:return Nonechild = self.contents[0]if isinstance(child, NavigableString):return childreturn child.string@string.setterdef string(self, string):self.clear()self.append(string.__class__(string))def _all_strings(self, strip=False, types=(NavigableString, CData)):"""Yield all strings of certain classes, possibly stripping them.By default, yields only NavigableString and CData objects. Sono comments, processing instructions, etc."""for descendant in self.descendants:if ((types is None and not isinstance(descendant, NavigableString))or(types is not None and type(descendant) not in types)):continueif strip:descendant = descendant.strip()if len(descendant) == 0:continueyield descendantstrings = property(_all_strings)@propertydef stripped_strings(self):for string in self._all_strings(True):yield stringdef get_text(self, separator="", strip=False,types=(NavigableString, CData)):"""Get all child strings, concatenated using the given separator."""return separator.join([s for s in self._all_strings(strip, types=types)])getText = get_texttext = property(get_text)def decompose(self):"""Recursively destroys the contents of this tree."""self.extract()i = selfwhile i is not None:next = i.next_elementi.__dict__.clear()i.contents = []i = nextdef clear(self, decompose=False):"""Extract all children. If decompose is True, decompose instead."""if decompose:for element in self.contents[:]:if isinstance(element, Tag):element.decompose()else:element.extract()else:for element in self.contents[:]:element.extract()def index(self, element):"""Find the index of a child by identity, not value. Avoids issues withtag.contents.index(element) getting the index of equal elements."""for i, child in enumerate(self.contents):if child is element:return iraise ValueError("Tag.index: element not in tag")def get(self, key, default=None):"""Returns the value of the 'key' attribute for the tag, orthe value given for 'default' if it doesn't have thatattribute."""return self.attrs.get(key, default)def get_attribute_list(self, key, default=None):"""The same as get(), but always returns a list."""value = self.get(key, default)if not isinstance(value, list):value = [value]return valuedef has_attr(self, key):return key in self.attrsdef __hash__(self):return str(self).__hash__()def __getitem__(self, key):"""tag[key] returns the value of the 'key' attribute for the tag,and throws an exception if it's not there."""return self.attrs[key]def __iter__(self):"Iterating over a tag iterates over its contents."return iter(self.contents)def __len__(self):"The length of a tag is the length of its list of contents."return len(self.contents)def __contains__(self, x):return x in self.contentsdef __bool__(self):"A tag is non-None even if it has no contents."return Truedef __setitem__(self, key, value):"""Setting tag[key] sets the value of the 'key' attribute for thetag."""self.attrs[key] = valuedef __delitem__(self, key):"Deleting tag[key] deletes all 'key' attributes for the tag."self.attrs.pop(key, None)def __call__(self, *args, **kwargs):"""Calling a tag like a function is the same as calling itsfind_all() method. Eg. tag('a') returns a list of all the A tagsfound within this tag."""return self.find_all(*args, **kwargs)def __getattr__(self, tag):#print "Getattr %s.%s" % (self.__class__, tag)if len(tag) > 3 and tag.endswith('Tag'):# BS3: soup.aTag -> "soup.find("a")tag_name = tag[:-3]warnings.warn('.%(name)sTag is deprecated, use .find("%(name)s") instead. If you really were looking for a tag called %(name)sTag, use .find("%(name)sTag")' % dict(name=tag_name))return self.find(tag_name)# We special case contents to avoid recursion.elif not tag.startswith("__") and not tag == "contents":return self.find(tag)raise AttributeError("'%s' object has no attribute '%s'" % (self.__class__, tag))def __eq__(self, other):"""Returns true iff this tag has the same name, the same attributes,and the same contents (recursively) as the given tag."""if self is other:return Trueif (not hasattr(other, 'name') ornot hasattr(other, 'attrs') ornot hasattr(other, 'contents') orself.name != other.name orself.attrs != other.attrs orlen(self) != len(other)):return Falsefor i, my_child in enumerate(self.contents):if my_child != other.contents[i]:return Falsereturn Truedef __ne__(self, other):"""Returns true iff this tag is not identical to the other tag,as defined in __eq__."""return not self == otherdef __repr__(self, encoding="unicode-escape"):"""Renders this tag as a string."""if PY3K:# "The return value must be a string object", i.e. Unicodereturn self.decode()else:# "The return value must be a string object", i.e. a bytestring.# By convention, the return value of __repr__ should also be# an ASCII string.return self.encode(encoding)def __unicode__(self):return self.decode()def __str__(self):if PY3K:return self.decode()else:return self.encode()if PY3K:__str__ = __repr__ = __unicode__def encode(self, encoding=DEFAULT_OUTPUT_ENCODING,indent_level=None, formatter="minimal",errors="xmlcharrefreplace"):# Turn the data structure into Unicode, then encode the# Unicode.u = self.decode(indent_level, encoding, formatter)return u.encode(encoding, errors)def _should_pretty_print(self, indent_level):"""Should this tag be pretty-printed?"""return (indent_level is not Noneand self.name not in self.preserve_whitespace_tags)def decode(self, indent_level=None,eventual_encoding=DEFAULT_OUTPUT_ENCODING,formatter="minimal"):"""Returns a Unicode representation of this tag and its contents.:param eventual_encoding: The tag is destined to beencoded into this encoding. This method is _not_responsible for performing that encoding. This informationis passed in so that it can be substituted in if thedocument contains a <META> tag that mentions the document'sencoding."""# First off, turn a string formatter into a Formatter object. This# will stop the lookup from happening over and over again.if not isinstance(formatter, Formatter) and not callable(formatter):formatter = self._formatter_for_name(formatter)attrs = []if self.attrs:for key, val in sorted(self.attrs.items()):if val is None:decoded = keyelse:if isinstance(val, list) or isinstance(val, tuple):val = ' '.join(val)elif not isinstance(val, str):val = str(val)elif (isinstance(val, AttributeValueWithCharsetSubstitution)and eventual_encoding is not None):val = val.encode(eventual_encoding)text = self.format_string(val, formatter)decoded = (str(key) + '='+ EntitySubstitution.quoted_attribute_value(text))attrs.append(decoded)close = ''closeTag = ''prefix = ''if self.prefix:prefix = self.prefix + ":"if self.is_empty_element:close = ''if isinstance(formatter, Formatter):close = formatter.void_element_close_prefix or closeelse:closeTag = '</%s%s>' % (prefix, self.name)pretty_print = self._should_pretty_print(indent_level)space = ''indent_space = ''if indent_level is not None:indent_space = (' ' * (indent_level - 1))if pretty_print:space = indent_spaceindent_contents = indent_level + 1else:indent_contents = Nonecontents = self.decode_contents(indent_contents, eventual_encoding, formatter)if self.hidden:# This is the 'document root' object.s = contentselse:s = []attribute_string = ''if attrs:attribute_string = ' ' + ' '.join(attrs)if indent_level is not None:# Even if this particular tag is not pretty-printed,# we should indent up to the start of the tag. s.append(indent_space)s.append('<%s%s%s%s>' % (prefix, self.name, attribute_string, close))if pretty_print:s.append("\n")s.append(contents)if pretty_print and contents and contents[-1] != "\n":s.append("\n")if pretty_print and closeTag:s.append(space)s.append(closeTag)if indent_level is not None and closeTag and self.next_sibling:# Even if this particular tag is not pretty-printed,# we're now done with the tag, and we should add a# newline if appropriate.s.append("\n")s = ''.join(s)return sdef prettify(self, encoding=None, formatter="minimal"):if encoding is None:return self.decode(True, formatter=formatter)else:return self.encode(encoding, True, formatter=formatter)def decode_contents(self, indent_level=None,eventual_encoding=DEFAULT_OUTPUT_ENCODING,formatter="minimal"):"""Renders the contents of this tag as a Unicode string.:param indent_level: Each line of the rendering will beindented this many spaces.:param eventual_encoding: The tag is destined to beencoded into this encoding. This method is _not_responsible for performing that encoding. This informationis passed in so that it can be substituted in if thedocument contains a <META> tag that mentions the document'sencoding.:param formatter: The output formatter responsible for convertingentities to Unicode characters."""# First off, turn a string formatter into a Formatter object. This# will stop the lookup from happening over and over again.if not isinstance(formatter, Formatter) and not callable(formatter):formatter = self._formatter_for_name(formatter)pretty_print = (indent_level is not None)s = []for c in self:text = Noneif isinstance(c, NavigableString):text = c.output_ready(formatter)elif isinstance(c, Tag):s.append(c.decode(indent_level, eventual_encoding,formatter))if text and indent_level and not self.name == 'pre':text = text.strip()if text:if pretty_print and not self.name == 'pre':s.append(" " * (indent_level - 1))s.append(text)if pretty_print and not self.name == 'pre':s.append("\n")return ''.join(s)def encode_contents(self, indent_level=None, encoding=DEFAULT_OUTPUT_ENCODING,formatter="minimal"):"""Renders the contents of this tag as a bytestring.:param indent_level: Each line of the rendering will beindented this many spaces.:param eventual_encoding: The bytestring will be in this encoding.:param formatter: The output formatter responsible for convertingentities to Unicode characters."""contents = self.decode_contents(indent_level, encoding, formatter)return contents.encode(encoding)# Old method for BS3 compatibilitydef renderContents(self, encoding=DEFAULT_OUTPUT_ENCODING,prettyPrint=False, indentLevel=0):if not prettyPrint:indentLevel = Nonereturn self.encode_contents(indent_level=indentLevel, encoding=encoding)#Soup methodsdef find(self, name=None, attrs={}, recursive=True, text=None,**kwargs):"""Return only the first child of this Tag matching the givencriteria."""r = Nonel = self.find_all(name, attrs, recursive, text, 1, **kwargs)if l:r = l[0]return rfindChild = finddef find_all(self, name=None, attrs={}, recursive=True, text=None,limit=None, **kwargs):"""Extracts a list of Tag objects that match the givencriteria. You can specify the name of the Tag and anyattributes you want the Tag to have.The value of a key-value pair in the 'attrs' map can be astring, a list of strings, a regular expression object, or acallable that takes a string and returns whether or not thestring matches for some custom definition of 'matches'. Thesame is true of the tag name."""generator = self.descendantsif not recursive:generator = self.childrenreturn self._find_all(name, attrs, text, limit, generator, **kwargs)findAll = find_all # BS3findChildren = find_all # BS2#Generator methods @propertydef children(self):# return iter() to make the purpose of the method clearreturn iter(self.contents) # XXX This seems to be untested. @propertydef descendants(self):if not len(self.contents):returnstopNode = self._last_descendant().next_elementcurrent = self.contents[0]while current is not stopNode:yield currentcurrent = current.next_element# CSS selector code _selector_combinators = ['>', '+', '~']_select_debug = Falsequoted_colon = re.compile('"[^"]*:[^"]*"')def select_one(self, selector):"""Perform a CSS selection operation on the current element."""value = self.select(selector, limit=1)if value:return value[0]return Nonedef select(self, selector, _candidate_generator=None, limit=None):"""Perform a CSS selection operation on the current element."""# Handle grouping selectors if ',' exists, ie: p,aif ',' in selector:context = []selectors = [x.strip() for x in selector.split(",")]# If a selector is mentioned multiple times we don't want# to use it more than once.used_selectors = set()# We also don't want to select the same element more than once,# if it's matched by multiple selectors.selected_object_ids = set()for partial_selector in selectors:if partial_selector == '':raise ValueError('Invalid group selection syntax: %s' % selector)if partial_selector in used_selectors:continueused_selectors.add(partial_selector)candidates = self.select(partial_selector, limit=limit)for candidate in candidates:# This lets us distinguish between distinct tags that# represent the same markup.object_id = id(candidate)if object_id not in selected_object_ids:context.append(candidate)selected_object_ids.add(object_id)if limit and len(context) >= limit:breakreturn contexttokens = shlex.split(selector)current_context = [self]if tokens[-1] in self._selector_combinators:raise ValueError('Final combinator "%s" is missing an argument.' % tokens[-1])if self._select_debug:print('Running CSS selector "%s"' % selector)for index, token in enumerate(tokens):new_context = []new_context_ids = set([])if tokens[index-1] in self._selector_combinators:# This token was consumed by the previous combinator. Skip it.if self._select_debug:print(' Token was consumed by the previous combinator.')continueif self._select_debug:print(' Considering token "%s"' % token)recursive_candidate_generator = Nonetag_name = None# Each operation corresponds to a checker function, a rule# for determining whether a candidate matches the# selector. Candidates are generated by the active# iterator.checker = Nonem = self.attribselect_re.match(token)if m is not None:# Attribute selectortag_name, attribute, operator, value = m.groups()checker = self._attribute_checker(operator, attribute, value)elif '#' in token:# ID selectortag_name, tag_id = token.split('#', 1)def id_matches(tag):return tag.get('id', None) == tag_idchecker = id_matcheselif '.' in token:# Class selectortag_name, klass = token.split('.', 1)classes = set(klass.split('.'))def classes_match(candidate):return classes.issubset(candidate.get('class', []))checker = classes_matchelif ':' in token and not self.quoted_colon.search(token):# Pseudo-classtag_name, pseudo = token.split(':', 1)if tag_name == '':raise ValueError("A pseudo-class must be prefixed with a tag name.")pseudo_attributes = re.match(r'([a-zA-Z\d-]+)\(([a-zA-Z\d]+)\)', pseudo)found = []if pseudo_attributes is None:pseudo_type = pseudopseudo_value = Noneelse:pseudo_type, pseudo_value = pseudo_attributes.groups()if pseudo_type == 'nth-of-type':try:pseudo_value = int(pseudo_value)except:raise NotImplementedError('Only numeric values are currently supported for the nth-of-type pseudo-class.')if pseudo_value < 1:raise ValueError('nth-of-type pseudo-class value must be at least 1.')class Counter(object):def __init__(self, destination):self.count = 0self.destination = destinationdef nth_child_of_type(self, tag):self.count += 1if self.count == self.destination:return Trueelse:return Falsechecker = Counter(pseudo_value).nth_child_of_typeelse:raise NotImplementedError('Only the following pseudo-classes are implemented: nth-of-type.')elif token == '*':# Star selector -- matches everythingpasselif token == '>':# Run the next token as a CSS selector against the# direct children of each tag in the current context.recursive_candidate_generator = lambda tag: tag.childrenelif token == '~':# Run the next token as a CSS selector against the# siblings of each tag in the current context.recursive_candidate_generator = lambda tag: tag.next_siblingselif token == '+':# For each tag in the current context, run the next# token as a CSS selector against the tag's next# sibling that's a tag.def next_tag_sibling(tag):yield tag.find_next_sibling(True)recursive_candidate_generator = next_tag_siblingelif self.tag_name_re.match(token):# Just a tag name.tag_name = tokenelse:raise ValueError('Unsupported or invalid CSS selector: "%s"' % token)if recursive_candidate_generator:# This happens when the selector looks like "> foo".# # The generator calls select() recursively on every# member of the current context, passing in a different# candidate generator and a different selector.# # In the case of "> foo", the candidate generator is# one that yields a tag's direct children (">"), and# the selector is "foo".next_token = tokens[index+1]def recursive_select(tag):if self._select_debug:print(' Calling select("%s") recursively on %s %s' % (next_token, tag.name, tag.attrs))print('-' * 40)for i in tag.select(next_token, recursive_candidate_generator):if self._select_debug:print('(Recursive select picked up candidate %s %s)' % (i.name, i.attrs))yield iif self._select_debug:print('-' * 40)_use_candidate_generator = recursive_selectelif _candidate_generator is None:# By default, a tag's candidates are all of its# children. If tag_name is defined, only yield tags# with that name.if self._select_debug:if tag_name:check = "[any]"else:check = tag_nameprint(' Default candidate generator, tag name="%s"' % check)if self._select_debug:# This is redundant with later code, but it stops# a bunch of bogus tags from cluttering up the# debug log.def default_candidate_generator(tag):for child in tag.descendants:if not isinstance(child, Tag):continueif tag_name and not child.name == tag_name:continueyield child_use_candidate_generator = default_candidate_generatorelse:_use_candidate_generator = lambda tag: tag.descendantselse:_use_candidate_generator = _candidate_generatorcount = 0for tag in current_context:if self._select_debug:print(" Running candidate generator on %s %s" % (tag.name, repr(tag.attrs)))for candidate in _use_candidate_generator(tag):if not isinstance(candidate, Tag):continueif tag_name and candidate.name != tag_name:continueif checker is not None:try:result = checker(candidate)except StopIteration:# The checker has decided we should no longer# run the generator.breakif checker is None or result:if self._select_debug:print(" SUCCESS %s %s" % (candidate.name, repr(candidate.attrs)))if id(candidate) not in new_context_ids:# If a tag matches a selector more than once,# don't include it in the context more than once. new_context.append(candidate)new_context_ids.add(id(candidate))elif self._select_debug:print(" FAILURE %s %s" % (candidate.name, repr(candidate.attrs)))current_context = new_contextif limit and len(current_context) >= limit:current_context = current_context[:limit]if self._select_debug:print("Final verdict:")for i in current_context:print(" %s %s" % (i.name, i.attrs))return current_context# Old names for backwards compatibilitydef childGenerator(self):return self.childrendef recursiveChildGenerator(self):return self.descendantsdef has_key(self, key):"""This was kind of misleading because has_key() (attributes)was different from __in__ (contents). has_key() is gone inPython 3, anyway."""warnings.warn('has_key is deprecated. Use has_attr("%s") instead.' % (key))return self.has_attr(key)# Next, a couple classes to represent queries and their results. class SoupStrainer(object):"""Encapsulates a number of ways of matching a markup element (tag ortext)."""def __init__(self, name=None, attrs={}, text=None, **kwargs):self.name = self._normalize_search_value(name)if not isinstance(attrs, dict):# Treat a non-dict value for attrs as a search for the 'class'# attribute.kwargs['class'] = attrsattrs = Noneif 'class_' in kwargs:# Treat class_="foo" as a search for the 'class'# attribute, overriding any non-dict value for attrs.kwargs['class'] = kwargs['class_']del kwargs['class_']if kwargs:if attrs:attrs = attrs.copy()attrs.update(kwargs)else:attrs = kwargsnormalized_attrs = {}for key, value in list(attrs.items()):normalized_attrs[key] = self._normalize_search_value(value)self.attrs = normalized_attrsself.text = self._normalize_search_value(text)def _normalize_search_value(self, value):# Leave it alone if it's a Unicode string, a callable, a# regular expression, a boolean, or None.if (isinstance(value, str) or callable(value) or hasattr(value, 'match')or isinstance(value, bool) or value is None):return value# If it's a bytestring, convert it to Unicode, treating it as UTF-8.if isinstance(value, bytes):return value.decode("utf8")# If it's listlike, convert it into a list of strings.if hasattr(value, '__iter__'):new_value = []for v in value:if (hasattr(v, '__iter__') and not isinstance(v, bytes)and not isinstance(v, str)):# This is almost certainly the user's mistake. In the# interests of avoiding infinite loops, we'll let# it through as-is rather than doing a recursive call. new_value.append(v)else:new_value.append(self._normalize_search_value(v))return new_value# Otherwise, convert it into a Unicode string.# The unicode(str()) thing is so this will do the same thing on Python 2# and Python 3.return str(str(value))def __str__(self):if self.text:return self.textelse:return "%s|%s" % (self.name, self.attrs)def search_tag(self, markup_name=None, markup_attrs={}):found = Nonemarkup = Noneif isinstance(markup_name, Tag):markup = markup_namemarkup_attrs = markupcall_function_with_tag_data = (isinstance(self.name, Callable)and not isinstance(markup_name, Tag))if ((not self.name)or call_function_with_tag_dataor (markup and self._matches(markup, self.name))or (not markup and self._matches(markup_name, self.name))):if call_function_with_tag_data:match = self.name(markup_name, markup_attrs)else:match = Truemarkup_attr_map = Nonefor attr, match_against in list(self.attrs.items()):if not markup_attr_map:if hasattr(markup_attrs, 'get'):markup_attr_map = markup_attrselse:markup_attr_map = {}for k, v in markup_attrs:markup_attr_map[k] = vattr_value = markup_attr_map.get(attr)if not self._matches(attr_value, match_against):match = Falsebreakif match:if markup:found = markupelse:found = markup_nameif found and self.text and not self._matches(found.string, self.text):found = Nonereturn foundsearchTag = search_tagdef search(self, markup):# print 'looking for %s in %s' % (self, markup)found = None# If given a list of items, scan it for a text element that# matches.if hasattr(markup, '__iter__') and not isinstance(markup, (Tag, str)):for element in markup:if isinstance(element, NavigableString) \and self.search(element):found = elementbreak# If it's a Tag, make sure its name or attributes match.# Don't bother with Tags if we're searching for text.elif isinstance(markup, Tag):if not self.text or self.name or self.attrs:found = self.search_tag(markup)# If it's text, make sure the text matches.elif isinstance(markup, NavigableString) or \isinstance(markup, str):if not self.name and not self.attrs and self._matches(markup, self.text):found = markupelse:raise Exception("I don't know how to match against a %s" % markup.__class__)return founddef _matches(self, markup, match_against, already_tried=None):# print u"Matching %s against %s" % (markup, match_against)result = Falseif isinstance(markup, list) or isinstance(markup, tuple):# This should only happen when searching a multi-valued attribute# like 'class'.for item in markup:if self._matches(item, match_against):return True# We didn't match any particular value of the multivalue# attribute, but maybe we match the attribute value when# considered as a string.if self._matches(' '.join(markup), match_against):return Truereturn Falseif match_against is True:# True matches any non-None value.return markup is not Noneif isinstance(match_against, Callable):return match_against(markup)# Custom callables take the tag as an argument, but all# other ways of matching match the tag name as a string.original_markup = markupif isinstance(markup, Tag):markup = markup.name# Ensure that `markup` is either a Unicode string, or None.markup = self._normalize_search_value(markup)if markup is None:# None matches None, False, an empty string, an empty list, and so on.return not match_againstif (hasattr(match_against, '__iter__')and not isinstance(match_against, str)):# We're asked to match against an iterable of items.# The markup must be match at least one item in the# iterable. We'll try each one in turn.# # To avoid infinite recursion we need to keep track of# items we've already seen.if not already_tried:already_tried = set()for item in match_against:if item.__hash__:key = itemelse:key = id(item)if key in already_tried:continueelse:already_tried.add(key)if self._matches(original_markup, item, already_tried):return Trueelse:return False# Beyond this point we might need to run the test twice: once against# the tag's name and once against its prefixed name.match = Falseif not match and isinstance(match_against, str):# Exact string matchmatch = markup == match_againstif not match and hasattr(match_against, 'search'):# Regexp matchreturn match_against.search(markup)if (not matchand isinstance(original_markup, Tag)and original_markup.prefix):# Try the whole thing again with the prefixed tag name.return self._matches(original_markup.prefix + ':' + original_markup.name, match_against)return matchclass ResultSet(list):"""A ResultSet is just a list that keeps track of the SoupStrainerthat created it."""def __init__(self, source, result=()):super(ResultSet, self).__init__(result)self.source = sourcedef __getattr__(self, key):raise AttributeError("ResultSet object has no attribute '%s'. You're probably treating a list of items like a single item. Did you call find_all() when you meant to call find()?" % key) View Code

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轉(zhuǎn)載于:https://www.cnblogs.com/zhangsanfeng/p/10212067.html

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