htmllib — A parser for HTML documents
This module defines a class which can serve as a base for parsing text files
formatted in the HyperText Mark-up Language (HTML). The class is not directly
concerned with I/O — it must be provided with input in string form via a
method, and makes calls to methods of a “formatter” object in order to produce
HTMLParser class is designed to be used as a base class
for other classes in order to add functionality, and allows most of its methods
to be extended or overridden. In turn, this class is derived from and extends
SGMLParser class defined in module
HTMLParser implementation supports the HTML 2.0 language as described
in RFC 1866. Two implementations of formatter objects are provided in the
formatter module; refer to the documentation for that module for
information on the formatter interface.
The following is a summary of the interface defined by
The interface to feed data to an instance is through the
feed()method, which takes a string argument. This can be called with as little or as much text at a time as desired;
p.feed(a); p.feed(b)has the same effect as
p.feed(a+b). When the data contains complete HTML markup constructs, these are processed immediately; incomplete constructs are saved in a buffer. To force processing of all unprocessed data, call the
For example, to parse the entire contents of a file, use:
The interface to define semantics for HTML tags is very simple: derive a class and define methods called
do_tag(). The parser will call these at appropriate moments:
do_tag()is called when an opening tag of the form
<tag ...>is encountered;
end_tag()is called when a closing tag of the form
<tag>is encountered. If an opening tag requires a corresponding closing tag, like
</H1>, the class should define the
start_tag()method; if a tag requires no closing tag, like
<P>, the class should define the
The module defines a parser class and an exception:
This is the basic HTML parser class. It supports all entity names required by the XHTML 1.0 Recommendation (https://www.w3.org/TR/xhtml1). It also defines handlers for all HTML 2.0 and many HTML 3.0 and 3.2 elements.
Exception raised by the
HTMLParserclass when it encounters an error while parsing.
New in version 2.4.
- Interface definition for transforming an abstract flow of formatting events into specific output events on writer objects.
- Alternate HTML parser that offers a slightly lower-level view of the input, but is designed to work with XHTML, and does not implement some of the SGML syntax not used in “HTML as deployed” and which isn’t legal for XHTML.
- Definition of replacement text for XHTML 1.0 entities.
- Base class for
19.3.1. HTMLParser Objects
In addition to tag methods, the
HTMLParser class provides some
additional methods and instance variables for use within tag methods.
This is the formatter instance associated with the parser.
Boolean flag which should be true when whitespace should not be collapsed, or false when it should be. In general, this should only be true when character data is to be treated as “preformatted” text, as within a
<PRE>element. The default value is false. This affects the operation of
anchor_bgn(href, name, type)
This method is called at the start of an anchor region. The arguments correspond to the attributes of the
<A>tag with the same names. The default implementation maintains a list of hyperlinks (defined by the
<A>tags) within the document. The list of hyperlinks is available as the data attribute
This method is called at the end of an anchor region. The default implementation adds a textual footnote marker using an index into the list of hyperlinks created by
handle_image(source, alt[, ismap[, align[, width[, height]]]])
This method is called to handle images. The default implementation simply passes the alt value to the
htmlentitydefs — Definitions of HTML general entities
Source code: Lib/htmlentitydefs.py
This module defines three dictionaries,
entitydefs is used by the
htmllib module to
entitydefs attribute of the
HTMLParser class. The
definition provided here contains all the entities defined by XHTML 1.0 that
can be handled using simple textual substitution in the Latin-1 character set
A dictionary mapping XHTML 1.0 entity definitions to their replacement text in ISO Latin-1.
A dictionary that maps HTML entity names to the Unicode code points.
New in version 2.3.
A dictionary that maps Unicode code points to HTML entity names.
New in version 2.3.