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Updated scoring algorithm to match readability.js v1.7.1

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pull/1/head
Yuri Baburov 13 years ago
parent 96f476181c
commit f55f16baa1
2 changed files with 187 additions and 137 deletions
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2
readability/cleaners.py
Unescape Escape View File

@ -2,7 +2,7 @@
import re
from lxml.html.clean import Cleaner
bad_attrs = ['width', 'height', 'style', '[-a-z]*color', 'background[-a-z]*']
bad_attrs = ['width', 'height', 'style', '[-a-z]*color', 'background[-a-z]*', 'on*']
single_quoted = "'[^']+'"
double_quoted = '"[^"]+"'
non_space = '[^ "\'>]+'

322
readability/readability.py
Unescape Escape View File

@ -1,8 +1,9 @@
#!/usr/bin/env python
from collections import defaultdict
from cleaners import html_cleaner, clean_attributes
from collections import defaultdict
from htmls import build_doc, get_body, get_title, shorten_title
from lxml.etree import tostring, tounicode
from lxml.html import fragment_fromstring, document_fromstring
import logging
import re
import sys
@ -10,10 +11,10 @@ import sys
logging.basicConfig(level=logging.INFO)
REGEXES = {
'unlikelyCandidatesRe': re.compile('share|bookmark|adwrapper|ad_wrapper|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('caption|article|body|content|entry|hentry|page|pagination|post|text',re.I),
'negativeRe': re.compile('adwrapper|ad_wrapper|share|bookmark|nav|combx|comment|contact|foot|footer|footnote|link|media|meta|promo|related|scroll|shoutbox|sponsor|tags|widget',re.I),
'unlikelyCandidatesRe': re.compile('combx|comment|community|disqus|extra|foot|header|menu|remark|rss|shoutbox|sidebar|sponsor|ad-break|agegate|pagination|pager|popup|tweet|twitter',re.I),
'okMaybeItsACandidateRe': re.compile('and|article|body|column|main|shadow',re.I),
'positiveRe': re.compile('article|body|content|entry|hentry|main|page|pagination|post|text|blog|story',re.I),
'negativeRe': re.compile('combx|comment|com-|contact|foot|footer|footnote|masthead|media|meta|outbrain|promo|related|scroll|shoutbox|sidebar|sponsor|shopping|tags|tool|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),
@ -21,21 +22,21 @@ REGEXES = {
#'normalizeRe': re.compile('\s{2,}/'),
#'killBreaksRe': re.compile('(<br\s*\/?>(\s|&nbsp;?)*){1,}/'),
#'videoRe': re.compile('http:\/\/(www\.)?(youtube|vimeo)\.com', re.I),
#skipFootnoteLink: /^\s*(\[?[a-z0-9]{1,2}\]?|^|edit|citation needed)\s*$/i,
}
def describe(node):
def describe(node, depth=1):
if not hasattr(node, 'tag'):
return "[text]"
return "%s#%s.%s" % (
node.tag, node.get('id', ''), node.get('class',''))
def log_candidates(candidates, print_format=""):
for candidate, value in candidates.items():
logging.info( "%s\t%s\t%s\t%s" %(id(candidate), describe(candidate), value['content_score'], describe(value['elem'])))
#def _text(node):
# return " ".join(node.findall(text=True))
return "[%s]" % type(node)
name = node.tag
if node.get('id', ''): name += '#'+node.get('id')
if node.get('class', ''):
name += '.' + node.get('class').replace(' ','.')
if name[:4] in ['div#', 'div.']:
name = name[3:]
if depth and node.getparent() is not None:
return name+' - '+describe(node.getparent(), depth-1)
return name
def to_int(x):
if not x: return None
@ -46,6 +47,14 @@ def to_int(x):
return int(x[:-2]) * 12
return int(x)
def clean(text):
text = re.sub('\s*\n\s*', '\n', text)
text = re.sub('[ \t]{2,}', ' ', text)
return text.strip()
def text_length(i):
return len(clean(i.text_content() or ""))
class Unparseable(ValueError):
pass
@ -92,12 +101,12 @@ class Document:
for i in self.tags(self.html, 'script', 'style'):
i.drop_tree()
for i in self.tags(self.html, 'body'):
i.set('id', 'readabilityBody')
if ruthless:
self.remove_unlikely_candidates()
self.transform_misused_divs_into_paragraphs()
candidates = self.score_paragraphs(self.options.get('min_text_length', self.TEXT_LENGTH_THRESHOLD))
#log_candidates(candidates)
candidates = self.score_paragraphs()
best_candidate = self.select_best_candidate(candidates)
if best_candidate:
@ -130,11 +139,12 @@ class Document:
# Things like preambles, content split by ads that we removed, etc.
sibling_score_threshold = max([10, best_candidate['content_score'] * 0.2])
output = self._parse("<div/>")
for sibling in best_candidate['elem'].getparent().getchildren():
output = document_fromstring('<div/>')
best_elem = best_candidate['elem']
for sibling in best_elem.getparent().getchildren():
#if isinstance(sibling, NavigableString): continue#in lxml there no concept of simple text
append = False
if sibling is best_candidate['elem']:
if sibling is best_elem:
append = True
sibling_key = sibling #HashableElement(sibling)
if sibling_key in candidates and candidates[sibling_key]['content_score'] >= sibling_score_threshold:
@ -152,65 +162,78 @@ class Document:
if append:
output.append(sibling)
if output is not None: output.append(best_candidate['elem'])
#if output is not None:
# output.append(best_elem)
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 candidates:")
for candidate in sorted_candidates[:5]:
elem = candidate['elem']
self.debug("Candidate %s with score %s" % (describe(elem), candidate['content_score']))
self.debug("Top 5 : %6.3f %s" % (candidate['content_score'], describe(elem)))
if len(sorted_candidates) == 0:
return None
best_candidate = sorted_candidates[0]
#self.debug("Best candidate %s with score %s" % (describe(best_candidate['elem']), 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_content())
return float(link_length) / max(text_length, 1)
def score_paragraphs(self, min_text_length):
def get_link_density(self, elem):
link_length = 0
for i in elem.findall(".//a"):
link_length += text_length(i)
#if len(elem.findall(".//div") or elem.findall(".//p")):
# link_length = link_length
total_length = text_length(elem)
return float(link_length) / max(total_length, 1)
def score_paragraphs(self, ):
MIN_LEN = self.options.get('min_text_length', self.TEXT_LENGTH_THRESHOLD)
candidates = {}
self.debug(str([describe(node) for node in self.tags(self.html, "div")]))
elems = self.tags(self.html, "div", "p", "td", 'li', "a")
#self.debug(str([describe(node) for node in self.tags(self.html, "div")]))
for elem in elems:
ordered = []
for elem in self.tags(self.html, "p", "pre", "td"):
parent_node = elem.getparent()
if parent_node is None:
continue
grand_parent_node = parent_node.getparent()
elem_key = elem#HashableElement(elem)
parent_key = parent_node#HashableElement(parent_node)
grand_parent_key = grand_parent_node#HashableElement(grand_parent_node)
inner_text = elem.text_content()
inner_text = clean(elem.text_content() or "")
inner_text_len = len(inner_text)
# If this paragraph is less than 25 characters, don't even count it.
if (not inner_text) or len(inner_text) < min_text_length:
if inner_text_len < MIN_LEN:
continue
if parent_key not in candidates:
candidates[parent_key] = self.score_node(parent_node)
if grand_parent_node is not None and grand_parent_key not in candidates:
candidates[grand_parent_key] = self.score_node(grand_parent_node)
if parent_node not in candidates:
candidates[parent_node] = self.score_node(parent_node)
ordered.append(parent_node)
if grand_parent_node is not None and grand_parent_node not in candidates:
candidates[grand_parent_node] = self.score_node(grand_parent_node)
ordered.append(grand_parent_node)
content_score = 1
content_score += len(inner_text.split(','))
content_score += min([(len(inner_text) / 100), 3])
if elem not in candidates:
candidates[elem_key] = self.score_node(elem)
candidates[elem_key]['content_score'] += content_score
candidates[parent_key]['content_score'] += content_score
content_score += min((inner_text_len / 100), 3)
#if elem not in candidates:
# candidates[elem] = self.score_node(elem)
#WTF? candidates[elem]['content_score'] += content_score
candidates[parent_node]['content_score'] += content_score
if grand_parent_node is not None:
candidates[grand_parent_key]['content_score'] += content_score / 2.0
candidates[grand_parent_node]['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'] *= (1 - self.get_link_density(elem))
#self.debug("candidate %s scored %s" % (describe(elem), candidate['content_score']))
for elem in ordered:
candidate = candidates[elem]
ld = self.get_link_density(elem)
score = candidate['content_score']
self.debug("Candid: %6.3f %s link density %.3f -> %6.3f" % (score, describe(elem), ld, score*(1-ld)))
candidate['content_score'] *= (1 - ld)
return candidates
@ -237,43 +260,68 @@ class Document:
name = elem.tag.lower()
if name == "div":
content_score += 5
elif name == "blockquote":
elif name in ["pre", "td", "blockquote"]:
content_score += 3
elif name == "form":
elif name in ["address", "ol", "ul", "dl", "dd", "dt", "li", "form"]:
content_score -= 3
elif name == "th":
elif name in ["h1", "h2", "h3", "h4", "h5", "h6", "th"]:
content_score -= 5
return { 'content_score': content_score, 'elem': elem }
return {
'content_score': content_score,
'elem': elem
}
def debug(self, *a):
#if self.options['debug']:
logging.debug(*a)
def remove_unlikely_candidates(self):
for elem in self.html.iter():
s = "%s%s" % (elem.get('class', ''), elem.get('id', ''))
self.debug(s)
s = "%s %s" % (elem.get('class', ''), elem.get('id', ''))
#self.debug(s)
if REGEXES['unlikelyCandidatesRe'].search(s) and (not REGEXES['okMaybeItsACandidateRe'].search(s)) and elem.tag != 'body':
self.debug("Removing unlikely candidate - %s" % (s,))
self.debug("Removing unlikely candidate - %s" % describe(elem))
elem.drop_tree()
def transform_misused_divs_into_paragraphs(self):
for elem in self.html.iter():
if not isinstance(elem.tag, basestring):
raise Exception("You have to strip html comments!")
if elem.tag.lower() == "div":
# transform <div>s that do not contain other block elements into <p>s
if not REGEXES['divToPElementsRe'].search(unicode(''.join(map(tostring, list(elem))))):
self.debug("Altering div(#%s.%s) to p" % (elem.get('id', ''), elem.get('class', '')))
elem.tag = "p"
for elem in self.tags(self.html, 'div'):
# transform <div>s that do not contain other block elements into <p>s
if not REGEXES['divToPElementsRe'].search(unicode(''.join(map(tostring, list(elem))))):
#self.debug("Altering %s to p" % (describe(elem)))
elem.tag = "p"
#print "Fixed element "+describe(elem)
for elem in self.tags(self.html, 'div'):
if elem.text and elem.text.strip():
p = fragment_fromstring('<p/>')
p.text = elem.text
elem.text = None
elem.insert(0, p)
#print "Appended "+tounicode(p)+" to "+describe(elem)
for pos, child in reversed(list(enumerate(elem))):
if child.tail and child.tail.strip():
p = fragment_fromstring('<p/>')
p.text = child.tail
child.tail = None
elem.insert(pos + 1, p)
#print "Inserted "+tounicode(p)+" to "+describe(elem)
if child.tag == 'br':
#print 'Dropped <br> at '+describe(elem)
child.drop_tree()
def tags(self, node, *tag_names):
for tag_name in tag_names:
for e in node.findall('.//%s' %tag_name):
for e in node.findall('.//%s' % tag_name):
yield e
def reverse_tags(self, node, *tag_names):
for tag_name in tag_names:
for e in reversed(node.findall('.//%s' % tag_name)):
yield e
def sanitize(self, node, candidates):
MIN_LEN = self.options.get('min_text_length', self.TEXT_LENGTH_THRESHOLD)
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.drop_tree()
@ -282,47 +330,48 @@ class Document:
elem.drop_tree()
allowed = {}
# Conditionally clean <table>s, <ul>s, and <div>s
for el in self.tags(node, "table", "ul", "div"):
for el in self.reverse_tags(node, "table", "ul", "div"):
if el in allowed:
continue
weight = self.class_weight(el)
el_key = el #HashableElement(el)
if el_key in candidates:
content_score = candidates[el_key]['content_score']
if el in candidates:
content_score = candidates[el]['content_score']
#print '!',el, '-> %6.3f' % content_score
else:
content_score = 0
tag = el.tag
if weight + content_score < 0:
self.debug("Cleaned %s with score %6.3f and weight %-3s" %
(describe(el), content_score, weight, ))
el.drop_tree()
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_content().split(",")) < 10:
elif el.text_content().count(",") < 10:
counts = {}
for kind in ['p', 'img', 'li', 'a', 'embed', 'input']:
counts[kind] = len(el.findall('.//%s' %kind))
counts["li"] -= 100
content_length = len(el.text_content()) # Count the text length excluding any surrounding whitespace
content_length = text_length(el) # Count the text length excluding any surrounding whitespace
link_density = self.get_link_density(el)
parent_node = el.getparent()
if parent_node:
if parent_node is not None:
if parent_node in candidates:
content_score = candidates[parent_node]['content_score']
else:
content_score = 0
pweight = self.class_weight(parent_node) + content_score
pname = parent_node.tag
else:
pweight = 0
pname = "no parent"
#if parent_node is not None:
#pweight = self.class_weight(parent_node) + content_score
#pname = describe(parent_node)
#else:
#pweight = 0
#pname = "no parent"
to_remove = False
reason = ""
#if el.tag == 'div' and counts["img"] >= 1:
# continue
if counts["p"] and counts["img"] > counts["p"]:
reason = "too many images"
reason = "too many images (%s)" % counts["img"]
to_remove = True
elif counts["li"] > counts["p"] and tag != "ul" and tag != "ol":
reason = "more <li>s than <p>s"
@ -330,68 +379,69 @@ class Document:
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"
elif content_length < (MIN_LEN) and (counts["img"] == 0 or counts["img"] > 2):
reason = "too short content length %s without a single image" % content_length
to_remove = True
elif weight < 25 and link_density > 0.2:
reason = "too many links for its weight less than 25 (#{weight})"
reason = "too many links %.3f for its weight %s" % (link_density, weight)
to_remove = True
elif weight >= 25 and link_density > 0.5:
reason = "too many links for its weight (#{weight})"
reason = "too many links %.3f for its weight %s" % (link_density, 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"
reason = "<embed>s with too short content length, or too many <embed>s"
to_remove = True
if el.tag == 'div' and counts['img'] >= 1 and to_remove:
imgs = el.findall('.//img')
valid_img = False
self.debug(tounicode(el))
for img in imgs:
height = img.get('height')
width = img.get('width')
self.debug ("height %s width %s" %(repr(height), repr(width)))
if to_int(height) >= 100 or to_int(width) >= 100:
valid_img = True
self.debug("valid image" + tounicode(img))
break
if valid_img:
# if el.tag == 'div' and counts['img'] >= 1 and to_remove:
# imgs = el.findall('.//img')
# valid_img = False
# self.debug(tounicode(el))
# for img in imgs:
#
# height = img.get('height')
# text_length = img.get('text_length')
# self.debug ("height %s text_length %s" %(repr(height), repr(text_length)))
# if to_int(height) >= 100 or to_int(text_length) >= 100:
# valid_img = True
# self.debug("valid image" + tounicode(img))
# break
# if valid_img:
# to_remove = False
# self.debug("Allowing %s" %el.text_content())
# for desnode in self.tags(el, "table", "ul", "div"):
# allowed[desnode] = True
#find x non empty preceding and succeeding siblings
i, j = 0, 0
x = 1
siblings = []
for sib in el.itersiblings():
#self.debug(sib.text_content())
sib_content_length = text_length(sib)
if sib_content_length:
i =+ 1
siblings.append(sib_content_length)
if i == x:
break
for sib in el.itersiblings(preceding=True):
#self.debug(sib.text_content())
sib_content_length = text_length(sib)
if sib_content_length:
j =+ 1
siblings.append(sib_content_length)
if j == x:
break
#self.debug(str(siblings))
if siblings and sum(siblings) > 1000 :
to_remove = False
self.debug("Allowing %s" %el.text_content())
self.debug("Allowing %s" % describe(el))
for desnode in self.tags(el, "table", "ul", "div"):
allowed[desnode] = True
#find x non empty preceeding and succeeding siblings
"""
i, j = 0, 0
x = 1
siblings = []
for sib in el.itersiblings():
self.debug(sib.text_content())
sib_content_length = len(sib.text_content())
if sib_content_length:
i =+ 1
siblings.append(sib_content_length)
if i == x:
break
for sib in el.itersiblings(preceding=True):
self.debug(sib.text_content())
sib_content_length = len(sib.text_content())
if sib_content_length:
j =+ 1
siblings.append(sib_content_length)
if j == x:
break
self.debug(str(siblings))
if siblings and sum(siblings) > 1000 :
to_remove = False
self.debug("Allowing %s" %el.text_content())
for desnode in self.tags(el, "table", "ul", "div"):
allowed[desnode] = True
"""
if to_remove:
self.debug("Conditionally cleaned %s#%s.%s with weight %s and content score %s because it has %s." %
(el.tag, el.get('id',''), el.get('class', ''), weight, content_score, reason))
self.debug("pname %s pweight %s" %(pname, pweight))
self.debug("Cleaned %6.3f %s with weight %s cause it has %s." %
(content_score, describe(el), weight, reason))
#print tounicode(el)
#self.debug("pname %s pweight %.3f" %(pname, pweight))
el.drop_tree()
for el in ([node] + [n for n in node.iter()]):

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