Make markdown parser use only Telegram's MessageEntity's

This commit is contained in:
Lonami Exo 2017-11-10 11:01:02 +01:00
parent cad1e883a6
commit 7d75eebdab
2 changed files with 24 additions and 58 deletions

View File

@ -4,29 +4,17 @@ for use within the library, which attempts to handle emojies correctly,
since they seem to count as two characters and it's a bit strange.
"""
import re
from enum import Enum
from ..tl.types import (
MessageEntityBold, MessageEntityItalic, MessageEntityCode,
MessageEntityPre, MessageEntityTextUrl
)
class Mode(Enum):
"""Different modes supported by Telegram's Markdown"""
NONE = 0
BOLD = 1
ITALIC = 2
CODE = 3
PRE = 4
URL = 5
DEFAULT_DELIMITERS = {
'**': Mode.BOLD,
'__': Mode.ITALIC,
'`': Mode.CODE,
'```': Mode.PRE
'**': MessageEntityBold,
'__': MessageEntityItalic,
'`': MessageEntityCode,
'```': MessageEntityPre
}
# Regex used to match utf-16le encoded r'\[(.+?)\]\((.+?)\)',
@ -37,8 +25,8 @@ DEFAULT_URL_RE = re.compile(b'\\[\0(.+?)\\]\0\\(\0(.+?)\\)\0')
def parse(message, delimiters=None, url_re=None):
"""
Parses the given message and returns the stripped message and a list
of tuples containing (start, end, mode) using the specified delimiters
dictionary (or default if None).
of MessageEntity* using the specified delimiters dictionary (or default
if None). The dictionary should be a mapping {delimiter: entity class}.
The url_re(gex) must contain two matching groups: the text to be
clickable and the URL itself, and be utf-16le encoded.
@ -59,14 +47,14 @@ def parse(message, delimiters=None, url_re=None):
# Cannot use a for loop because we need to skip some indices
i = 0
result = []
current = Mode.NONE
current = None
# Work on byte level with the utf-16le encoding to get the offsets right.
# The offset will just be half the index we're at.
message = message.encode('utf-16le')
while i < len(message):
url_match = None
if url_re and current == Mode.NONE:
if url_re and current is None:
# If we're not inside a previous match since Telegram doesn't allow
# nested message entities, try matching the URL from the i'th pos.
url_match = url_re.match(message, pos=i)
@ -78,10 +66,9 @@ def parse(message, delimiters=None, url_re=None):
message[url_match.end():]
))
result.append((
i // 2,
(i + len(url_match.group(1))) // 2,
(Mode.URL, url_match.group(2).decode('utf-16le'))
result.append(MessageEntityTextUrl(
offset=i // 2, length=len(url_match.group(1)) // 2,
url=url_match.group(2).decode('utf-16le')
))
# We matched the delimiter which is now gone, and we'll add
# +2 before next iteration which will make us skip a character.
@ -93,7 +80,7 @@ def parse(message, delimiters=None, url_re=None):
# Slice the string at the current i'th position to see if
# it matches the current delimiter d.
if message[i:i + len(d)] == d:
if current != Mode.NONE and current != m:
if current is not None and not isinstance(current, m):
# We were inside another delimiter/mode, ignore this.
continue
@ -105,46 +92,25 @@ def parse(message, delimiters=None, url_re=None):
# Get rid of the delimiter by slicing it away
message = message[:i] + message[i + len(d):]
if current == Mode.NONE:
result.append(i // 2)
current = m
if current is None:
if m == MessageEntityPre:
# Special case, also has 'lang'
current = MessageEntityPre(i // 2, None, '')
else:
current = m(i // 2, None)
# No need to i -= 2 here because it's been already
# checked that next character won't be a delimiter.
else:
result[-1] = (result[-1], i // 2, current)
current = Mode.NONE
current.length = (i // 2) - current.offset
result.append(current)
current = None
i -= 2 # Delimiter matched and gone, go back 1 char
break
# Next iteration, utf-16 encoded characters need 2 bytes.
i += 2
if result and not isinstance(result[-1], tuple):
# We may have found some a delimiter but not its ending pair. If
# that's the case we want to get rid of it before returning.
# We may have found some a delimiter but not its ending pair.
# TODO Should probably insert such delimiter back in the string.
result.pop()
return message.decode('utf-16le'), result
def parse_tg(message, delimiters=None):
"""Similar to parse(), but returns a list of MessageEntity's"""
message, tuples = parse(message, delimiters=delimiters)
result = []
for start, end, mode in tuples:
extra = None
if isinstance(mode, tuple):
mode, extra = mode
if mode == Mode.BOLD:
result.append(MessageEntityBold(start, end - start))
elif mode == Mode.ITALIC:
result.append(MessageEntityItalic(start, end - start))
elif mode == Mode.CODE:
result.append(MessageEntityCode(start, end - start))
elif mode == Mode.PRE:
result.append(MessageEntityPre(start, end - start, ''))
elif mode == Mode.URL:
result.append(MessageEntityTextUrl(start, end - start, extra))
return message, result

View File

@ -388,7 +388,7 @@ class TelegramClient(TelegramBareClient):
if parse_mode:
parse_mode = parse_mode.lower()
if parse_mode in {'md', 'markdown'}:
message, msg_entities = markdown.parse_tg(message)
message, msg_entities = markdown.parse(message)
else:
raise ValueError('Unknown parsing mode', parse_mode)
else: