The formatter module provides formatter classes that can be used together with
the htmllib
module.
This module provides two class families, formatters and writers. Formatters convert a stream of tags and data strings from the HTML parser into an event stream suitable for an output device, and writers render that event stream on an output device. Example 5-13 demonstrates.
In most cases, you can use the
AbstractFormatter class to do the formatting.
It calls methods on the writer object, representing different kinds of
formatting events. The AbstractWriter class
simply prints a message for each method call.
Example 5-13. Using the formatter Module to Convert HTML to an Event Stream
File: formatter-example-1.py
import formatter
import htmllib
w = formatter.AbstractWriter()
f = formatter.AbstractFormatter(w)
file = open("samples/sample.htm")
p = htmllib.HTMLParser(f)
p.feed(file.read())
p.close()
file.close()
send_paragraph(1)
new_font(('h1', 0, 1, 0))
send_flowing_data('A Chapter.')
send_line_break()
send_paragraph(1)
new_font(None)
send_flowing_data('Some text. Some more text. Some')
send_flowing_data(' ')
new_font((None, 1, None, None))
send_flowing_data('emphasized')
new_font(None)
send_flowing_data(' text. A')
send_flowing_data(' link')
send_flowing_data('[1]')
send_flowing_data('.'
In addition to the AbstractWriter class, the
formatter module provides a
NullWriter class, which ignores all events
passed to it, and a DumbWriter class that
converts the event stream to a plain text document, as shown in Example 5-14.
Example 5-14. Using the formatter Module to Convert HTML to Plain Text
File: formatter-example-2.py
import formatter
import htmllib
w = formatter.DumbWriter() # plain text
f = formatter.AbstractFormatter(w)
file = open("samples/sample.htm")
# print html body as plain text
p = htmllib.HTMLParser(f)
p.feed(file.read())
p.close()
file.close()
# print links
print
print
i = 1
for link in p.anchorlist:
print i, "=>", link
i = i + 1
A Chapter.
Some text. Some more text. Some emphasized text. A link[1].
1 => http://www.python.org
Example 5-15 provides a custom Writer,
which in this case is subclassed from the
DumbWriter class. This version keeps track
of the current font style and tweaks the output somewhat depending
on the font.
Example 5-15. Using the formatter Module with a Custom Writer
File: formatter-example-3.py
import formatter
import htmllib, string
class Writer(formatter.DumbWriter):
def _ _init_ _(self):
formatter.DumbWriter._ _init_ _(self)
self.tag = ""
self.bold = self.italic = 0
self.fonts = []
def new_font(self, font):
if font is None:
font = self.fonts.pop()
self.tag, self.bold, self.italic = font
else:
self.fonts.append((self.tag, self.bold, self.italic))
tag, bold, italic, typewriter = font
if tag is not None:
self.tag = tag
if bold is not None:
self.bold = bold
if italic is not None:
self.italic = italic
def send_flowing_data(self, data):
if not data:
return
atbreak = self.atbreak or data[0] in string.whitespace
for word in string.split(data):
if atbreak:
self.file.write(" ")
if self.tag in ("h1", "h2", "h3"):
word = string.upper(word)
if self.bold:
word = "*" + word + "*"
if self.italic:
word = "_" + word + "_"
self.file.write(word)
atbreak = 1
self.atbreak = data[-1] in string.whitespace
w = Writer()
f = formatter.AbstractFormatter(w)
file = open("samples/sample.htm")
# print html body as plain text
p = htmllib.HTMLParser(f)
p.feed(file.read())
p.close()
_A_ _CHAPTER._
Some text. Some more text. Some *emphasized* text. A link[1].