mirror of
https://github.com/yogeshojha/rengine.git
synced 2026-09-19 00:07:44 +02:00
107 lines
4.3 KiB
Python
107 lines
4.3 KiB
Python
from difflib import SequenceMatcher
|
|
import re
|
|
|
|
from thirdparty import chardet
|
|
|
|
|
|
class DynamicContentParser:
|
|
def __init__(self, requester, path, firstPage, secondPage, comparisons=2):
|
|
self.DYNAMICITY_MARK_LENGTH = 32
|
|
self.UPPER_RATIO_BOUND = 0.98
|
|
self.requester = requester
|
|
self.keyCallback = path
|
|
self.comparisons = comparisons
|
|
self.dynamicMarks = []
|
|
self.seqMatcher = SequenceMatcher()
|
|
self.generateDynamicMarks(firstPage, secondPage)
|
|
|
|
def generateDynamicMarks(self, firstPage, secondPage):
|
|
if any(page is None for page in (firstPage, secondPage)):
|
|
# No content
|
|
return
|
|
|
|
self.seqMatcher.set_seq1(firstPage)
|
|
self.seqMatcher.set_seq2(secondPage)
|
|
ratio = self.seqMatcher.quick_ratio()
|
|
# In case of an intolerable difference turn on dynamicity removal engine
|
|
if ratio <= self.UPPER_RATIO_BOUND:
|
|
self.dynamicMarks += self.findDynamicContent(firstPage, secondPage)
|
|
for i in range(self.comparisons):
|
|
response = self.requester.request(self.keyCallback)
|
|
secondPage = response.body
|
|
self.dynamicMarks += self.findDynamicContent(firstPage, secondPage)
|
|
self.cleanPage = self.removeDynamicContent(firstPage, self.dynamicMarks)
|
|
self.seqMatcher.set_seq1(self.cleanPage)
|
|
self.seqMatcher.set_seq2(self.removeDynamicContent(secondPage, self.dynamicMarks))
|
|
ratio = self.seqMatcher.quick_ratio()
|
|
else:
|
|
self.cleanPage = firstPage
|
|
self.comparisonRatio = ratio
|
|
|
|
def compareTo(self, page):
|
|
seqMatcher = SequenceMatcher()
|
|
seqMatcher.set_seq1(self.cleanPage)
|
|
seqMatcher.set_seq2(self.removeDynamicContent(page, self.dynamicMarks))
|
|
ratio = seqMatcher.quick_ratio()
|
|
return ratio
|
|
|
|
def findDynamicContent(self, firstPage, secondPage):
|
|
dynamicMarks = []
|
|
|
|
blocks = list(SequenceMatcher(None, firstPage, secondPage).get_matching_blocks())
|
|
|
|
# Removing too small matching blocks
|
|
for block in blocks[:]:
|
|
(_, _, length) = block
|
|
|
|
if length <= self.DYNAMICITY_MARK_LENGTH:
|
|
blocks.remove(block)
|
|
|
|
# Making of dynamic markings based on prefix/suffix principle
|
|
if len(blocks) > 0:
|
|
blocks.insert(0, None)
|
|
blocks.append(None)
|
|
|
|
for i in range(len(blocks) - 1):
|
|
prefix = firstPage[blocks[i][0]:blocks[i][0] + blocks[i][2]] if blocks[i] else None
|
|
suffix = firstPage[blocks[i + 1][0]:blocks[i + 1][0] + blocks[i + 1][2]] if blocks[i + 1] else None
|
|
|
|
if prefix is None and blocks[i + 1][0] == 0:
|
|
continue
|
|
|
|
if suffix is None and (blocks[i][0] + blocks[i][2] >= len(firstPage)):
|
|
continue
|
|
|
|
dynamicMarks.append((re.escape(prefix[int(-self.DYNAMICITY_MARK_LENGTH / 2):]) if prefix else None,
|
|
re.escape(suffix[:int(self.DYNAMICITY_MARK_LENGTH / 2)]) if suffix else None))
|
|
|
|
return dynamicMarks
|
|
|
|
def removeDynamicContent(self, page, dynamicMarks):
|
|
"""
|
|
Removing dynamic content from supplied page basing removal on
|
|
precalculated dynamic markings
|
|
"""
|
|
if page and len(dynamicMarks) > 0:
|
|
encoding = chardet.detect(page)['encoding']
|
|
page = page.decode(encoding, errors='replace')
|
|
for item in dynamicMarks:
|
|
prefix, suffix = item
|
|
if prefix is not None:
|
|
prefix = prefix.decode(encoding, errors='replace')
|
|
if suffix is not None:
|
|
suffix = suffix.decode(encoding, errors='replace')
|
|
|
|
if prefix is None and suffix is None:
|
|
continue
|
|
elif prefix is None:
|
|
page = re.sub(r'(?s)^.+{0}'.format(re.escape(suffix)), suffix.replace('\\', r'\\'), page)
|
|
elif suffix is None:
|
|
page = re.sub(r'(?s){0}.+$'.format(re.escape(prefix)), prefix.replace('\\', r'\\'), page)
|
|
else:
|
|
page = re.sub(r'(?s){0}.+{1}'.format(re.escape(prefix), re.escape(suffix)), "{0}{1}".format(prefix.replace('\\', r'\\'), suffix.replace('\\', r'\\')), page)
|
|
|
|
page = page.encode()
|
|
|
|
return page
|