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 output. The
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 the SGMLParser class defined in module
sgmllib. The 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
sgmllib.SGMLParser:
The module defines a single class:
- HTMLParser (formatter)
-
This is the basic HTML parser class. It supports all entity names
required by the HTML 2.0 specification (RFC 1866). It also defines
handlers for all HTML 2.0 and many HTML 3.0 and 3.2 elements.
In addition to tag methods, the HTMLParser class provides some
additional methods and instance variables for use within tag methods.
- formatter
-
This is the formatter instance associated with the parser.
- nofill
-
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 handle_data() and save_end().
- 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 href attribute) within the document. The list
of hyperlinks is available as the data attribute anchorlist.
- anchor_end ()
-
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 anchor_bgn().
- 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 handle_data()
method.
- save_bgn ()
-
Begins saving character data in a buffer instead of sending it to the
formatter object. Retrieve the stored data via save_end().
Use of the save_bgn() / save_end() pair may not be
nested.
- save_end ()
-
Ends buffering character data and returns all data saved since the
preceeding call to save_bgn(). If the nofill flag is
false, whitespace is collapsed to single spaces. A call to this
method without a preceeding call to save_bgn() will raise a
TypeError exception.