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from bs4.dammit import EntitySubstitution |
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class Formatter(EntitySubstitution): |
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"""Describes a strategy to use when outputting a parse tree to a string. |
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Some parts of this strategy come from the distinction between |
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HTML4, HTML5, and XML. Others are configurable by the user. |
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Formatters are passed in as the `formatter` argument to methods |
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like `PageElement.encode`. Most people won't need to think about |
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formatters, and most people who need to think about them can pass |
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in one of these predefined strings as `formatter` rather than |
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making a new Formatter object: |
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For HTML documents: |
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* 'html' - HTML entity substitution for generic HTML documents. (default) |
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* 'html5' - HTML entity substitution for HTML5 documents, as |
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well as some optimizations in the way tags are rendered. |
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* 'minimal' - Only make the substitutions necessary to guarantee |
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valid HTML. |
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* None - Do not perform any substitution. This will be faster |
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but may result in invalid markup. |
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For XML documents: |
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* 'html' - Entity substitution for XHTML documents. |
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* 'minimal' - Only make the substitutions necessary to guarantee |
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valid XML. (default) |
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* None - Do not perform any substitution. This will be faster |
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but may result in invalid markup. |
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""" |
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XML_FORMATTERS = {} |
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HTML_FORMATTERS = {} |
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HTML = 'html' |
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XML = 'xml' |
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HTML_DEFAULTS = dict( |
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cdata_containing_tags=set(["script", "style"]), |
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) |
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def _default(self, language, value, kwarg): |
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if value is not None: |
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return value |
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if language == self.XML: |
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return set() |
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return self.HTML_DEFAULTS[kwarg] |
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def __init__( |
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self, language=None, entity_substitution=None, |
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void_element_close_prefix='/', cdata_containing_tags=None, |
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empty_attributes_are_booleans=False, indent=1, |
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): |
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r"""Constructor. |
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:param language: This should be Formatter.XML if you are formatting |
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XML markup and Formatter.HTML if you are formatting HTML markup. |
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:param entity_substitution: A function to call to replace special |
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characters with XML/HTML entities. For examples, see |
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bs4.dammit.EntitySubstitution.substitute_html and substitute_xml. |
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:param void_element_close_prefix: By default, void elements |
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are represented as <tag/> (XML rules) rather than <tag> |
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(HTML rules). To get <tag>, pass in the empty string. |
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:param cdata_containing_tags: The list of tags that are defined |
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as containing CDATA in this dialect. For example, in HTML, |
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<script> and <style> tags are defined as containing CDATA, |
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and their contents should not be formatted. |
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:param blank_attributes_are_booleans: Render attributes whose value |
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is the empty string as HTML-style boolean attributes. |
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(Attributes whose value is None are always rendered this way.) |
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:param indent: If indent is a non-negative integer or string, |
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then the contents of elements will be indented |
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appropriately when pretty-printing. An indent level of 0, |
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negative, or "" will only insert newlines. Using a |
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positive integer indent indents that many spaces per |
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level. If indent is a string (such as "\t"), that string |
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is used to indent each level. The default behavior is to |
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indent one space per level. |
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""" |
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self.language = language |
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self.entity_substitution = entity_substitution |
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self.void_element_close_prefix = void_element_close_prefix |
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self.cdata_containing_tags = self._default( |
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language, cdata_containing_tags, 'cdata_containing_tags' |
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) |
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self.empty_attributes_are_booleans=empty_attributes_are_booleans |
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if indent is None: |
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indent = 0 |
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if isinstance(indent, int): |
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if indent < 0: |
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indent = 0 |
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indent = ' ' * indent |
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elif isinstance(indent, str): |
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indent = indent |
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else: |
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indent = ' ' |
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self.indent = indent |
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def substitute(self, ns): |
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"""Process a string that needs to undergo entity substitution. |
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This may be a string encountered in an attribute value or as |
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text. |
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:param ns: A string. |
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:return: A string with certain characters replaced by named |
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or numeric entities. |
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""" |
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if not self.entity_substitution: |
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return ns |
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from .element import NavigableString |
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if (isinstance(ns, NavigableString) |
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and ns.parent is not None |
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and ns.parent.name in self.cdata_containing_tags): |
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return ns |
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return self.entity_substitution(ns) |
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def attribute_value(self, value): |
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"""Process the value of an attribute. |
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:param ns: A string. |
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:return: A string with certain characters replaced by named |
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or numeric entities. |
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""" |
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return self.substitute(value) |
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def attributes(self, tag): |
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"""Reorder a tag's attributes however you want. |
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By default, attributes are sorted alphabetically. This makes |
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behavior consistent between Python 2 and Python 3, and preserves |
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backwards compatibility with older versions of Beautiful Soup. |
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If `empty_boolean_attributes` is True, then attributes whose |
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values are set to the empty string will be treated as boolean |
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attributes. |
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""" |
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if tag.attrs is None: |
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return [] |
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return sorted( |
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(k, (None if self.empty_attributes_are_booleans and v == '' else v)) |
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for k, v in list(tag.attrs.items()) |
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) |
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class HTMLFormatter(Formatter): |
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"""A generic Formatter for HTML.""" |
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REGISTRY = {} |
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def __init__(self, *args, **kwargs): |
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super(HTMLFormatter, self).__init__(self.HTML, *args, **kwargs) |
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class XMLFormatter(Formatter): |
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"""A generic Formatter for XML.""" |
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REGISTRY = {} |
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def __init__(self, *args, **kwargs): |
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super(XMLFormatter, self).__init__(self.XML, *args, **kwargs) |
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HTMLFormatter.REGISTRY['html'] = HTMLFormatter( |
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entity_substitution=EntitySubstitution.substitute_html |
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) |
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HTMLFormatter.REGISTRY["html5"] = HTMLFormatter( |
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entity_substitution=EntitySubstitution.substitute_html, |
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void_element_close_prefix=None, |
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empty_attributes_are_booleans=True, |
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) |
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HTMLFormatter.REGISTRY["minimal"] = HTMLFormatter( |
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entity_substitution=EntitySubstitution.substitute_xml |
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) |
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HTMLFormatter.REGISTRY[None] = HTMLFormatter( |
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entity_substitution=None |
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) |
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XMLFormatter.REGISTRY["html"] = XMLFormatter( |
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entity_substitution=EntitySubstitution.substitute_html |
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) |
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XMLFormatter.REGISTRY["minimal"] = XMLFormatter( |
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entity_substitution=EntitySubstitution.substitute_xml |
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) |
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XMLFormatter.REGISTRY[None] = Formatter( |
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Formatter(Formatter.XML, entity_substitution=None) |
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) |
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