Module: MTProto::Markdown

Defined in:
lib/mtproto/markdown.rb

Overview

Telegram-MarkdownV2-style formatting: text markup <-> (plain text, entities).

text, entities = MTProto::Markdown.parse("*bold* and _italic_ and ||spoiler||")
markup         = MTProto::Markdown.render(text, entities)

Entity offsets/lengths are in UTF-16 code units (Telegram's unit), so the parser counts astral characters (emoji) as 2. Supported markup:

*bold*  _italic_  __underline__  ~strikethrough~  ||spoiler||
`inline code`   ```lang\npre block```
[label](http://url)              -> text_url
[label](tg://user?id=123)        -> mention (text-mention)
![emoji](tg://emoji?id=123)      -> custom emoji
>quoted line(s)                  -> blockquote
\x escapes any markup character x.

Malformed markup (an unclosed entity, a broken link) raises ParseError, matching Telegram's own "can't parse entities" rejection rather than sending garbage.

Known limitations (vs full Telegram MarkdownV2): expandable/collapsed blockquotes are not produced; adjacent italic/underline runs (the _/__ adjacency, e.g. ___x___) are rejected as ambiguous; link labels are literal text (no nested formatting inside [...]); auto-detected entities (url/mention/hashtag/email/…) are left to Telegram's server-side detection and not emitted by parse.

Defined Under Namespace

Classes: ParseError, Parser, Renderer

Constant Summary collapse

Entity = 
MTProto::TL::MessageEntity

Class Method Summary collapse

Class Method Details

.parse(source) ⇒ Object 



36
37
38
 
# File 'lib/mtproto/markdown.rb', line 36

def parse(source)
  Parser.new(utf8(source)).parse
end

.render(text, entities) ⇒ Object 



40
41
42
 
# File 'lib/mtproto/markdown.rb', line 40

def render(text, entities)
  Renderer.new(utf8(text), entities).render
end

.utf16_size(char) ⇒ Object 



44
45
46
 
# File 'lib/mtproto/markdown.rb', line 44

def utf16_size(char)
  char.ord > 0xFFFF ? 2 : 1
end

.utf8(str) ⇒ Object

Treat input as UTF-8 text and reject invalid bytes with a clear error rather than letting a low-level ArgumentError/Encoding error escape from deep inside.

Raises:



50
51
52
53
54
55
56
 
# File 'lib/mtproto/markdown.rb', line 50

def utf8(str)
  s = str.to_s
  s = s.dup.force_encoding(Encoding::UTF_8) unless s.encoding == Encoding::UTF_8
  raise ParseError, 'input is not valid UTF-8' unless s.valid_encoding?

  s
end