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- from bs4.dammit import EntitySubstitution
- class Formatter(EntitySubstitution):
- """Describes a strategy to use when outputting a parse tree to a string.
- Some parts of this strategy come from the distinction between
- HTML4, HTML5, and XML. Others are configurable by the user.
- Formatters are passed in as the `formatter` argument to methods
- like `PageElement.encode`. Most people won't need to think about
- formatters, and most people who need to think about them can pass
- in one of these predefined strings as `formatter` rather than
- making a new Formatter object:
- For HTML documents:
- * 'html' - HTML entity substitution for generic HTML documents. (default)
- * 'html5' - HTML entity substitution for HTML5 documents, as
- well as some optimizations in the way tags are rendered.
- * 'minimal' - Only make the substitutions necessary to guarantee
- valid HTML.
- * None - Do not perform any substitution. This will be faster
- but may result in invalid markup.
- For XML documents:
- * 'html' - Entity substitution for XHTML documents.
- * 'minimal' - Only make the substitutions necessary to guarantee
- valid XML. (default)
- * None - Do not perform any substitution. This will be faster
- but may result in invalid markup.
- """
- # Registries of XML and HTML formatters.
- XML_FORMATTERS = {}
- HTML_FORMATTERS = {}
- HTML = 'html'
- XML = 'xml'
- HTML_DEFAULTS = dict(
- cdata_containing_tags=set(["script", "style"]),
- )
- def _default(self, language, value, kwarg):
- if value is not None:
- return value
- if language == self.XML:
- return set()
- return self.HTML_DEFAULTS[kwarg]
- def __init__(
- self, language=None, entity_substitution=None,
- void_element_close_prefix='/', cdata_containing_tags=None,
- empty_attributes_are_booleans=False, indent=1,
- ):
- """Constructor.
- :param language: This should be Formatter.XML if you are formatting
- XML markup and Formatter.HTML if you are formatting HTML markup.
- :param entity_substitution: A function to call to replace special
- characters with XML/HTML entities. For examples, see
- bs4.dammit.EntitySubstitution.substitute_html and substitute_xml.
- :param void_element_close_prefix: By default, void elements
- are represented as <tag/> (XML rules) rather than <tag>
- (HTML rules). To get <tag>, pass in the empty string.
- :param cdata_containing_tags: The list of tags that are defined
- as containing CDATA in this dialect. For example, in HTML,
- <script> and <style> tags are defined as containing CDATA,
- and their contents should not be formatted.
- :param blank_attributes_are_booleans: Render attributes whose value
- is the empty string as HTML-style boolean attributes.
- (Attributes whose value is None are always rendered this way.)
- :param indent: If indent is a non-negative integer or string,
- then the contents of elements will be indented
- appropriately when pretty-printing. An indent level of 0,
- negative, or "" will only insert newlines. Using a
- positive integer indent indents that many spaces per
- level. If indent is a string (such as "\t"), that string
- is used to indent each level. The default behavior to
- indent one space per level.
- """
- self.language = language
- self.entity_substitution = entity_substitution
- self.void_element_close_prefix = void_element_close_prefix
- self.cdata_containing_tags = self._default(
- language, cdata_containing_tags, 'cdata_containing_tags'
- )
- self.empty_attributes_are_booleans=empty_attributes_are_booleans
- if indent is None:
- indent = 0
- if isinstance(indent, int):
- if indent < 0:
- indent = 0
- indent = ' ' * indent
- elif isinstance(indent, str):
- indent = indent
- else:
- indent = ' '
- self.indent = indent
-
- def substitute(self, ns):
- """Process a string that needs to undergo entity substitution.
- This may be a string encountered in an attribute value or as
- text.
- :param ns: A string.
- :return: A string with certain characters replaced by named
- or numeric entities.
- """
- if not self.entity_substitution:
- return ns
- from .element import NavigableString
- if (isinstance(ns, NavigableString)
- and ns.parent is not None
- and ns.parent.name in self.cdata_containing_tags):
- # Do nothing.
- return ns
- # Substitute.
- return self.entity_substitution(ns)
- def attribute_value(self, value):
- """Process the value of an attribute.
- :param ns: A string.
- :return: A string with certain characters replaced by named
- or numeric entities.
- """
- return self.substitute(value)
-
- def attributes(self, tag):
- """Reorder a tag's attributes however you want.
-
- By default, attributes are sorted alphabetically. This makes
- behavior consistent between Python 2 and Python 3, and preserves
- backwards compatibility with older versions of Beautiful Soup.
- If `empty_boolean_attributes` is True, then attributes whose
- values are set to the empty string will be treated as boolean
- attributes.
- """
- if tag.attrs is None:
- return []
- return sorted(
- (k, (None if self.empty_attributes_are_booleans and v == '' else v))
- for k, v in list(tag.attrs.items())
- )
-
- class HTMLFormatter(Formatter):
- """A generic Formatter for HTML."""
- REGISTRY = {}
- def __init__(self, *args, **kwargs):
- return super(HTMLFormatter, self).__init__(self.HTML, *args, **kwargs)
-
- class XMLFormatter(Formatter):
- """A generic Formatter for XML."""
- REGISTRY = {}
- def __init__(self, *args, **kwargs):
- return super(XMLFormatter, self).__init__(self.XML, *args, **kwargs)
- # Set up aliases for the default formatters.
- HTMLFormatter.REGISTRY['html'] = HTMLFormatter(
- entity_substitution=EntitySubstitution.substitute_html
- )
- HTMLFormatter.REGISTRY["html5"] = HTMLFormatter(
- entity_substitution=EntitySubstitution.substitute_html,
- void_element_close_prefix=None,
- empty_attributes_are_booleans=True,
- )
- HTMLFormatter.REGISTRY["minimal"] = HTMLFormatter(
- entity_substitution=EntitySubstitution.substitute_xml
- )
- HTMLFormatter.REGISTRY[None] = HTMLFormatter(
- entity_substitution=None
- )
- XMLFormatter.REGISTRY["html"] = XMLFormatter(
- entity_substitution=EntitySubstitution.substitute_html
- )
- XMLFormatter.REGISTRY["minimal"] = XMLFormatter(
- entity_substitution=EntitySubstitution.substitute_xml
- )
- XMLFormatter.REGISTRY[None] = Formatter(
- Formatter(Formatter.XML, entity_substitution=None)
- )
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