mirror of https://github.com/zulip/zulip.git
131 lines
4.3 KiB
Python
131 lines
4.3 KiB
Python
from __future__ import absolute_import
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from typing import Callable, List, Tuple, Text
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from django.conf import settings
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from diff_match_patch import diff_match_patch
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import platform
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import logging
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# TODO: handle changes in link hrefs
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def highlight_with_class(klass, text):
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# type: (Text, Text) -> Text
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return '<span class="%s">%s</span>' % (klass, text)
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def highlight_inserted(text):
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# type: (Text) -> Text
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return highlight_with_class('highlight_text_inserted', text)
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def highlight_deleted(text):
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# type: (Text) -> Text
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return highlight_with_class('highlight_text_deleted', text)
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def highlight_replaced(text):
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# type: (Text) -> Text
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return highlight_with_class('highlight_text_replaced', text)
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def chunkize(text, in_tag):
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# type: (Text, bool) -> Tuple[List[Tuple[Text, Text]], bool]
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start = 0
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idx = 0
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chunks = [] # type: List[Tuple[Text, Text]]
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for c in text:
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if c == '<':
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in_tag = True
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if start != idx:
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chunks.append(('text', text[start:idx]))
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start = idx
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elif c == '>':
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in_tag = False
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if start != idx + 1:
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chunks.append(('tag', text[start:idx + 1]))
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start = idx + 1
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idx += 1
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if start != idx:
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chunks.append(('tag' if in_tag else 'text', text[start:idx]))
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return chunks, in_tag
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def highlight_chunks(chunks, highlight_func):
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# type: (List[Tuple[Text, Text]], Callable[[Text], Text]) -> Text
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retval = u''
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for type, text in chunks:
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if type == 'text':
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retval += highlight_func(text)
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else:
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retval += text
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return retval
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def verify_html(html):
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# type: (Text) -> bool
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# TODO: Actually parse the resulting HTML to ensure we don't
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# create mal-formed markup. This is unfortunately hard because
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# we both want pretty strict parsing and we want to parse html5
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# fragments. For now, we do a basic sanity check.
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in_tag = False
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for c in html:
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if c == '<':
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if in_tag:
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return False
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in_tag = True
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elif c == '>':
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if not in_tag:
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return False
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in_tag = False
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if in_tag:
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return False
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return True
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def highlight_html_differences(s1, s2):
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# type: (Text, Text) -> Text
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differ = diff_match_patch()
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ops = differ.diff_main(s1, s2)
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differ.diff_cleanupSemantic(ops)
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retval = u''
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in_tag = False
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idx = 0
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while idx < len(ops):
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op, text = ops[idx]
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next_op = None
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if idx != len(ops) - 1:
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next_op, next_text = ops[idx + 1]
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if op == diff_match_patch.DIFF_DELETE and next_op == diff_match_patch.DIFF_INSERT:
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# Replace operation
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chunks, in_tag = chunkize(next_text, in_tag)
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retval += highlight_chunks(chunks, highlight_replaced)
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idx += 1
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elif op == diff_match_patch.DIFF_INSERT and next_op == diff_match_patch.DIFF_DELETE:
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# Replace operation
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# I have no idea whether diff_match_patch generates inserts followed
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# by deletes, but it doesn't hurt to handle them
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chunks, in_tag = chunkize(text, in_tag)
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retval += highlight_chunks(chunks, highlight_replaced)
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idx += 1
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elif op == diff_match_patch.DIFF_DELETE:
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retval += highlight_deleted(' ')
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elif op == diff_match_patch.DIFF_INSERT:
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chunks, in_tag = chunkize(text, in_tag)
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retval += highlight_chunks(chunks, highlight_inserted)
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elif op == diff_match_patch.DIFF_EQUAL:
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chunks, in_tag = chunkize(text, in_tag)
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retval += text
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idx += 1
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if not verify_html(retval):
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from zerver.lib.actions import internal_send_message
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from zerver.models import get_user_profile_by_email
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# We probably want more information here
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logging.getLogger('').error('HTML diff produced mal-formed HTML')
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if settings.ERROR_BOT is not None:
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subject = "HTML diff failure on %s" % (platform.node(),)
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realm = get_user_profile_by_email(settings.ERROR_BOT).realm
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internal_send_message(realm, settings.ERROR_BOT, "stream",
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"errors", subject, "HTML diff produced malformed HTML")
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return s2
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return retval
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