pull/1/head
gfxmonk 14 years ago
commit ad3d52ade4

1
.gitignore vendored

@ -0,0 +1 @@
*.pyc

@ -0,0 +1,10 @@
This code is under the Apache License 2.0. http://www.apache.org/licenses/LICENSE-2.0
This is a python port of a ruby port of arc90's readability project
http://lab.arc90.com/experiments/readability/
Given a html document, it pulls out the main body text and cleans it up.
Ruby port by starrhorne and iterationlabs
Python port by gfxmonk

@ -0,0 +1 @@
from readability import Document, main

@ -0,0 +1,320 @@
#!/usr/bin/env python
from BeautifulSoup import BeautifulSoup, NavigableString
import re
REGEXES = { 'unlikelyCandidatesRe': re.compile('combx|comment|disqus|foot|header|menu|meta|nav|rss|shoutbox|sidebar|sponsor',re.I),
'okMaybeItsACandidateRe': re.compile('and|article|body|column|main',re.I),
'positiveRe': re.compile('article|body|content|entry|hentry|page|pagination|post|text',re.I),
'negativeRe': re.compile('combx|comment|contact|foot|footer|footnote|link|media|meta|promo|related|scroll|shoutbox|sponsor|tags|widget',re.I),
'divToPElementsRe': re.compile('<(a|blockquote|dl|div|img|ol|p|pre|table|ul)',re.I),
'replaceBrsRe': re.compile('(<br[^>]*>[ \n\r\t]*){2,}',re.I),
'replaceFontsRe': re.compile('<(\/?)font[^>]*>',re.I),
'trimRe': re.compile('^\s+|\s+$/'),
'normalizeRe': re.compile('\s{2,}/'),
'killBreaksRe': re.compile('(<br\s*\/?>(\s|&nbsp;?)*){1,}/'),
'videoRe': re.compile('http:\/\/(www\.)?(youtube|vimeo)\.com', re.I),
}
from collections import defaultdict
def describe(node):
if not hasattr(node, 'name'):
return "[text]"
return "%s#%s.%s" % (
node.name, node.get('id', ''), node.get('class',''))
class Document:
TEXT_LENGTH_THRESHOLD = 25
RETRY_LENGTH = 250
def __init__(self, input, **options):
self.input = input
self.options = defaultdict(lambda: None)
for k, v in options.items():
self.options[k] = v
self.make_html()
def make_html(self):
self.html = BeautifulSoup(self.input)
def content(self, remove_unlikely_candidates = True):
def remove(tag): [i.extract() for i in self.html.findAll(tag)]
remove('script')
remove('style')
if remove_unlikely_candidates: self.remove_unlikely_candidates()
self.transform_misused_divs_into_paragraphs()
candidates = self.score_paragraphs(self.options.get('min_text_length', self.TEXT_LENGTH_THRESHOLD))
best_candidate = self.select_best_candidate(candidates)
article = self.get_article(candidates, best_candidate)
cleaned_article = self.sanitize(article, candidates)
if remove_unlikely_candidates and len(cleaned_article or '') < (self.options['retry_length'] or self.RETRY_LENGTH):
self.make_html()
return self.content(False)
else:
return cleaned_article
def get_article(self, candidates, best_candidate):
# Now that we have the top candidate, look through its siblings for content that might also be related.
# Things like preambles, content split by ads that we removed, etc.
sibling_score_threshold = max([10, best_candidate['content_score'] * 0.2])
output = BeautifulSoup("<div/>")
for sibling in best_candidate['elem'].parent.contents:
if isinstance(sibling, NavigableString): continue
append = False
if sibling is best_candidate['elem']:
append = True
sibling_key = HashableElement(sibling)
if sibling_key in candidates and candidates[sibling_key]['content_score'] >= sibling_score_threshold:
append = True
if sibling.name == "p":
link_density = self.get_link_density(sibling)
node_content = sibling.string or ""
node_length = len(node_content)
if node_length > 80 and link_density < 0.25:
append = True
elif node_length < 80 and link_density == 0 and re.search('\.( |$)', node_content):
append = True
if append:
output.append(sibling)
return output
def select_best_candidate(self, candidates):
sorted_candidates = sorted(candidates.values(), key=lambda x: x['content_score'], reverse=True)
self.debug("Top 5 canidates:")
for candidate in sorted_candidates[:5]:
elem = candidate['elem']
self.debug("Candidate %s with score %s" % (
describe(elem), candidate['content_score']))
best_candidate = sorted_candidates[0] if len(sorted_candidates) > 1 else { 'elem': self.html.find("body"), 'content_score': 0 }
elem = best_candidate['elem']
self.debug("Best candidate %s#%s.%s with score %s" % (
elem.name, elem.get('id',''), elem.get('class',''), best_candidate['content_score']))
return best_candidate
def get_link_density(self, elem):
link_length = len("".join([i.text or "" for i in elem.findAll("a")]))
text_length = len(elem.text or "")
return float(link_length) / max(text_length, 1)
def score_paragraphs(self, min_text_length):
candidates = {}
elems = self.html.findAll("p") + self.html.findAll("td")
for elem in elems:
parent_node = elem.parent
grand_parent_node = parent_node.parent
parent_key = HashableElement(parent_node)
grand_parent_key = HashableElement(grand_parent_node)
inner_text = elem.string
# If this paragraph is less than 25 characters, don't even count it.
if (not inner_text) or len(inner_text) < min_text_length:
continue
if parent_key not in candidates:
candidates[parent_key] = self.score_node(parent_node)
if grand_parent_node and grand_parent_key not in candidates:
candidates[grand_parent_key] = self.score_node(grand_parent_node)
content_score = 1
content_score += len(inner_text.split(','))
content_score += min([(len(inner_text) / 100), 3])
candidates[parent_key]['content_score'] += content_score
if grand_parent_node:
candidates[grand_parent_key]['content_score'] += content_score / 2.0
# Scale the final candidates score based on link density. Good content should have a
# relatively small link density (5% or less) and be mostly unaffected by this operation.
for elem, candidate in candidates.items():
candidate['content_score'] = candidate['content_score'] * (1 - self.get_link_density(elem))
return candidates
def class_weight(self, e):
weight = 0
if e.get('class', None):
if REGEXES['negativeRe'].search(e['class']):
weight -= 25
if REGEXES['positiveRe'].search(e['class']):
weight += 25
if e.get('id', None):
if REGEXES['negativeRe'].search(e['id']):
weight -= 25
if REGEXES['positiveRe'].search(e['id']):
weight += 25
return weight
def score_node(self, elem):
content_score = self.class_weight(elem)
name = elem.name.lower()
if name == "div":
content_score += 5
elif name == "blockquote":
content_score += 3
elif name == "form":
content_score -= 3
elif name == "th":
content_score -= 5
return { 'content_score': content_score, 'elem': elem }
def debug(self, str):
if self.options['debug']:
print(str)
def remove_unlikely_candidates(self):
for elem in self.html.findAll():
s = "%s%s" % (elem.get('class', ''), elem.get('id'))
if REGEXES['unlikelyCandidatesRe'].search(s) and (not REGEXES['okMaybeItsACandidateRe'].search(s)) and elem.name != 'body':
self.debug("Removing unlikely candidate - %s" % (s,))
elem.extract()
def transform_misused_divs_into_paragraphs(self):
for elem in self.html.findAll():
if elem.name.lower() == "div":
# transform <div>s that do not contain other block elements into <p>s
if REGEXES['divToPElementsRe'].search(''.join(map(str, elem.contents))):
self.debug("Altering div(#%s.%s) to p" % (elem.get('id', ''), elem.get('class', '')))
elem.name = "p"
def tags(self, node, *tag_names):
for tag_name in tag_names:
for e in node.findAll(tag_name):
yield e
def sanitize(self, node, candidates):
for header in self.tags(node, "h1", "h2", "h3", "h4", "h5", "h6"):
if self.class_weight(header) < 0 or self.get_link_density(header) > 0.33: header.extract()
for elem in self.tags(node, "form", "object", "iframe", "embed"):
elem.extract()
# remove empty <p> tags
for elem in node.findAll("p"):
if not (elem.string or elem.contents):
elem.extract()
# Conditionally clean <table>s, <ul>s, and <div>s
for el in self.tags(node, "table", "ul", "div"):
weight = self.class_weight(el)
el_key = HashableElement(el)
if el_key in candidates:
content_score = candidates[el_key]['content_score']
else:
content_score = 0
name = el.name
if weight + content_score < 0:
el.extract()
self.debug("Conditionally cleaned %s with weight %s and content score %s because score + content score was less than zero." %
(describe(el), weight, content_score))
elif len((el.text or "").split(",")) < 10:
counts = {}
for kind in ['p', 'img', 'li', 'a', 'embed', 'input']:
counts[kind] = len(el.findAll(kind))
counts["li"] -= 100
content_length = len(el.text or "") # Count the text length excluding any surrounding whitespace
link_density = self.get_link_density(el)
to_remove = False
reason = ""
if counts["img"] > counts["p"]:
reason = "too many images"
to_remove = True
elif counts["li"] > counts["p"] and name != "ul" and name != "ol":
reason = "more <li>s than <p>s"
to_remove = True
elif counts["input"] > (counts["p"] / 3):
reason = "less than 3x <p>s than <input>s"
to_remove = True
elif content_length < (self.options.get('min_text_length', self.TEXT_LENGTH_THRESHOLD)) and (counts["img"] == 0 or counts["img"] > 2):
reason = "too short a content length without a single image"
to_remove = True
elif weight < 25 and link_density > 0.2:
reason = "too many links for its weight (#{weight})"
to_remove = True
elif weight >= 25 and link_density > 0.5:
reason = "too many links for its weight (#{weight})"
to_remove = True
elif (counts["embed"] == 1 and content_length < 75) or counts["embed"] > 1:
reason = "<embed>s with too short a content length, or too many <embed>s"
to_remove = True
if to_remove:
self.debug("Conditionally cleaned %s#%s.%s with weight %s and content score %s because it has %s." %
(el.name, el.get('id',''), el.get('class', ''), weight, content_score, reason))
el.extract()
for el in ([node] + node.findAll()):
if not (self.options['attributes']):
el.attrMap = {}
return str(node)
class HashableElement():
def __init__(self, node):
self.node = node
self._path = None
def _get_path(self):
if self._path is None:
reverse_path = []
node = self.node
while node:
node_id = (node.name, tuple(node.attrs), node.string)
reverse_path.append(node_id)
node = node.parent
self._path = tuple(reverse_path)
return self._path
path = property(_get_path)
def __hash__(self):
return hash(self.path)
def __eq__(self, other):
return self.path == other.path
def __getattr__(self, name):
return getattr(self.node, name)
def main():
import sys
from optparse import OptionParser
parser = OptionParser(usage="%prog: [options] [file]")
parser.add_option('-v', '--verbose', action='store_true')
parser.add_option('-u', '--url', help="use URL instead of a local file")
(options, args) = parser.parse_args()
if not (len(args) == 1 or options.url):
parser.print_help()
sys.exit(1)
file = None
if options.url:
import urllib
file = urllib.urlopen(options.url)
else:
file = open(args[0])
try:
print Document(file.read(), debug=options.verbose).content()
finally:
file.close()
if __name__ == '__main__':
main()
Loading…
Cancel
Save