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# Copyright (c) 2022 Tulir Asokan
#
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
from __future__ import annotations
from typing import Any, Callable, Generic, Type, TypeVar
import re
from ...types import EventID, MatrixURI, RoomAlias, RoomID, UserID
from .formatted_string import EntityType, FormattedString
from .html_reader import HTMLNode, read_html
from .markdown_string import MarkdownString
class RecursionContext:
preserve_whitespace: bool
ul_depth: int
_inited: bool
def __init__(self, preserve_whitespace: bool = False, ul_depth: int = 0) -> None:
self.preserve_whitespace = preserve_whitespace
self.ul_depth = ul_depth
self._inited = True
def __setattr__(self, key: str, value: Any) -> None:
if getattr(self, "_inited", False) is True:
raise TypeError("'RecursionContext' object is immutable")
super(RecursionContext, self).__setattr__(key, value)
def enter_list(self) -> RecursionContext:
return RecursionContext(
preserve_whitespace=self.preserve_whitespace, ul_depth=self.ul_depth + 1
)
def enter_code_block(self) -> RecursionContext:
return RecursionContext(preserve_whitespace=True, ul_depth=self.ul_depth)
T = TypeVar("T", bound=FormattedString)
spaces = re.compile(r"\s+")
space = " "
class MatrixParser(Generic[T]):
block_tags: tuple[str, ...] = (
"p",
"pre",
"blockquote",
"ol",
"ul",
"li",
"h1",
"h2",
"h3",
"h4",
"h5",
"h6",
"div",
"hr",
"table",
)
list_bullets: tuple[str, ...] = ("●", "○", "■", "‣")
e: Type[EntityType] = EntityType
fs: Type[T] = MarkdownString
read_html: Callable[[str], HTMLNode] = staticmethod(read_html)
ignore_less_relevant_links: bool = True
exclude_plaintext_attrib: str = "data-mautrix-exclude-plaintext"
def list_bullet(self, depth: int) -> str:
return self.list_bullets[(depth - 1) % len(self.list_bullets)] + " "
async def list_to_fstring(self, node: HTMLNode, ctx: RecursionContext) -> T:
ordered: bool = node.tag == "ol"
tagged_children: list[tuple[T, str]] = await self.node_to_tagged_fstrings(node, ctx)
counter: int = 1
indent_length: int = 0
if ordered:
try:
counter = int(node.attrib.get("start", "1"))
except ValueError:
counter = 1
longest_index = counter - 1 + len(tagged_children)
indent_length = len(str(longest_index))
indent: str = (indent_length + 2) * " "
children: list[T] = []
for child, tag in tagged_children:
if tag != "li":
continue
if ordered:
prefix = f"{counter}. "
counter += 1
else:
prefix = self.list_bullet(ctx.ul_depth)
child = child.prepend(prefix)
parts = child.split("\n")
parts = parts[:1] + [part.prepend(indent) for part in parts[1:]]
child = self.fs.join(parts, "\n")
children.append(child)
return self.fs.join(children, "\n")
async def blockquote_to_fstring(self, node: HTMLNode, ctx: RecursionContext) -> T:
msg = await self.tag_aware_parse_node(node, ctx)
return msg.format(self.e.BLOCKQUOTE)
async def hr_to_fstring(self, node: HTMLNode, ctx: RecursionContext) -> T:
return self.fs("---")
async def header_to_fstring(self, node: HTMLNode, ctx: RecursionContext) -> T:
children = await self.node_to_fstrings(node, ctx)
length = int(node.tag[1])
return self.fs.join(children, "").format(self.e.HEADER, size=length)
async def basic_format_to_fstring(self, node: HTMLNode, ctx: RecursionContext) -> T:
msg = await self.tag_aware_parse_node(node, ctx)
if self.exclude_plaintext_attrib in node.attrib:
return msg
if node.tag in ("b", "strong"):
msg = msg.format(self.e.BOLD)
elif node.tag in ("i", "em"):
msg = msg.format(self.e.ITALIC)
elif node.tag in ("s", "strike", "del"):
msg = msg.format(self.e.STRIKETHROUGH)
elif node.tag in ("u", "ins"):
msg = msg.format(self.e.UNDERLINE)
return msg
async def link_to_fstring(self, node: HTMLNode, ctx: RecursionContext) -> T:
msg = await self.tag_aware_parse_node(node, ctx)
href = node.attrib.get("href", "")
if not href:
return msg
if href.startswith("mailto:"):
return self.fs(href[len("mailto:") :]).format(self.e.EMAIL)
matrix_uri = MatrixURI.try_parse(href)
if matrix_uri:
if matrix_uri.user_id:
new_msg = await self.user_pill_to_fstring(msg, matrix_uri.user_id)
elif matrix_uri.event_id:
new_msg = await self.event_link_to_fstring(
msg, matrix_uri.room_id or matrix_uri.room_alias, matrix_uri.event_id
)
elif matrix_uri.room_alias:
new_msg = await self.room_pill_to_fstring(msg, matrix_uri.room_alias)
elif matrix_uri.room_id:
new_msg = await self.room_id_link_to_fstring(msg, matrix_uri.room_id)
else:
new_msg = None
if new_msg:
return new_msg
# Custom attribute to tell the parser that the link isn't relevant and
# shouldn't be included in plaintext representation.
if self.ignore_less_relevant_links and self.exclude_plaintext_attrib in node.attrib:
return msg
return await self.url_to_fstring(msg, href)
async def url_to_fstring(self, msg: T, url: str) -> T | None:
return msg.format(self.e.URL, url=url)
async def user_pill_to_fstring(self, msg: T, user_id: UserID) -> T | None:
return msg.format(self.e.USER_MENTION, user_id=user_id)
async def room_pill_to_fstring(self, msg: T, room_alias: RoomAlias) -> T | None:
return None
async def room_id_link_to_fstring(self, msg: T, room_id: RoomID) -> T | None:
return None
async def event_link_to_fstring(
self, msg: T, room: RoomID | RoomAlias, event_id: EventID
) -> T | None:
return None
async def img_to_fstring(self, node: HTMLNode, ctx: RecursionContext) -> T:
return self.fs(node.attrib.get("alt") or node.attrib.get("title") or "")
async def custom_node_to_fstring(self, node: HTMLNode, ctx: RecursionContext) -> T | None:
return None
async def color_to_fstring(self, msg: T, color: str) -> T:
return msg.format(self.e.COLOR, color=color)
async def spoiler_to_fstring(self, msg: T, reason: str) -> T:
return msg.format(self.e.SPOILER, reason=reason)
async def node_to_fstring(self, node: HTMLNode, ctx: RecursionContext) -> T:
custom = await self.custom_node_to_fstring(node, ctx)
if custom:
return custom
elif node.tag == "mx-reply":
return self.fs("")
elif node.tag == "blockquote":
return await self.blockquote_to_fstring(node, ctx)
elif node.tag == "hr":
return await self.hr_to_fstring(node, ctx)
elif node.tag == "ol":
return await self.list_to_fstring(node, ctx)
elif node.tag == "ul":
return await self.list_to_fstring(node, ctx.enter_list())
elif node.tag in ("h1", "h2", "h3", "h4", "h5", "h6"):
return await self.header_to_fstring(node, ctx)
elif node.tag == "br":
return self.fs("\n")
elif node.tag in ("b", "strong", "i", "em", "s", "del", "u", "ins"):
return await self.basic_format_to_fstring(node, ctx)
elif node.tag == "a":
return await self.link_to_fstring(node, ctx)
elif node.tag == "img":
return await self.img_to_fstring(node, ctx)
elif node.tag == "p":
return (await self.tag_aware_parse_node(node, ctx)).append("\n")
elif node.tag in ("font", "span"):
msg = await self.tag_aware_parse_node(node, ctx)
try:
spoiler = node.attrib["data-mx-spoiler"]
except KeyError:
pass
else:
msg = await self.spoiler_to_fstring(msg, spoiler)
try:
color = node.attrib["color"]
except KeyError:
try:
color = node.attrib["data-mx-color"]
except KeyError:
color = None
if color:
msg = await self.color_to_fstring(msg, color)
return msg
elif node.tag == "pre":
lang = ""
try:
if node[0].tag == "code":
node = node[0]
lang = node.attrib["class"][len("language-") :]
except (IndexError, KeyError):
pass
return (await self.parse_node(node, ctx.enter_code_block())).format(
self.e.PREFORMATTED, language=lang
)
elif node.tag == "code":
return (await self.parse_node(node, ctx.enter_code_block())).format(self.e.INLINE_CODE)
return await self.tag_aware_parse_node(node, ctx)
async def text_to_fstring(
self, text: str, ctx: RecursionContext, strip_leading_whitespace: bool = False
) -> T:
if not ctx.preserve_whitespace:
text = spaces.sub(space, text.lstrip() if strip_leading_whitespace else text)
return self.fs(text)
async def node_to_tagged_fstrings(
self, node: HTMLNode, ctx: RecursionContext
) -> list[tuple[T, str]]:
output = []
if node.text:
output.append((await self.text_to_fstring(node.text, ctx), "text"))
for child in node:
output.append((await self.node_to_fstring(child, ctx), child.tag))
if child.tail:
# For text following a block tag, the leading whitespace is meaningless (there'll
# be a newline added later), but for other tags it can be interpreted as a space.
text = await self.text_to_fstring(
child.tail, ctx, strip_leading_whitespace=child.tag in self.block_tags
)
output.append((text, "text"))
return output
async def node_to_fstrings(self, node: HTMLNode, ctx: RecursionContext) -> list[T]:
return [msg for (msg, tag) in await self.node_to_tagged_fstrings(node, ctx)]
async def tag_aware_parse_node(self, node: HTMLNode, ctx: RecursionContext) -> T:
msgs = await self.node_to_tagged_fstrings(node, ctx)
output = self.fs()
prev_was_block = False
for msg, tag in msgs:
if tag in self.block_tags:
msg = msg.append("\n")
if not prev_was_block:
msg = msg.prepend("\n")
prev_was_block = True
output = output.append(msg)
return output.trim()
async def parse_node(self, node: HTMLNode, ctx: RecursionContext) -> T:
return self.fs.join(await self.node_to_fstrings(node, ctx))
async def parse(self, data: str) -> T:
msg = await self.node_to_fstring(
self.read_html(f"<body>{data}</body>"), RecursionContext()
)
return msg
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