zulip/zerver/webhooks/slack_incoming/view.py

245 lines
9.5 KiB
Python

# Webhooks for external integrations.
import re
from itertools import zip_longest
from typing import Literal, Optional, TypedDict, cast
from django.http import HttpRequest, HttpResponse
from django.utils.translation import gettext as _
from zerver.decorator import webhook_view
from zerver.lib.exceptions import JsonableError
from zerver.lib.request import REQ, RequestVariableMissingError, has_request_variables
from zerver.lib.response import json_success
from zerver.lib.types import Validator
from zerver.lib.validator import (
WildValue,
check_dict,
check_int,
check_list,
check_string,
check_string_in,
check_url,
to_wild_value,
)
from zerver.lib.webhooks.common import check_send_webhook_message
from zerver.models import UserProfile
@webhook_view("SlackIncoming")
@has_request_variables
def api_slack_incoming_webhook(
request: HttpRequest,
user_profile: UserProfile,
user_specified_topic: Optional[str] = REQ("topic", default=None),
) -> HttpResponse:
# Slack accepts webhook payloads as payload="encoded json" as
# application/x-www-form-urlencoded, as well as in the body as
# application/json.
if request.content_type == "application/json":
try:
val = request.body.decode(request.encoding or "utf-8")
except UnicodeDecodeError: # nocoverage
raise JsonableError(_("Malformed payload"))
else:
req_var = "payload"
if req_var in request.POST:
val = request.POST[req_var]
elif req_var in request.GET: # nocoverage
val = request.GET[req_var]
else:
raise RequestVariableMissingError(req_var)
payload = to_wild_value("payload", val)
if user_specified_topic is None and "channel" in payload:
channel = payload["channel"].tame(check_string)
user_specified_topic = re.sub("^[@#]", "", channel)
if user_specified_topic is None:
user_specified_topic = "(no topic)"
pieces = []
if "blocks" in payload and payload["blocks"]:
for block in payload["blocks"]:
pieces.append(render_block(block))
if "attachments" in payload and payload["attachments"]:
for attachment in payload["attachments"]:
pieces.append(render_attachment(attachment))
body = "\n\n".join(piece.strip() for piece in pieces if piece.strip() != "")
if body == "" and "text" in payload and payload["text"]:
if "icon_emoji" in payload and payload["icon_emoji"]:
body = payload["icon_emoji"].tame(check_string) + " "
body += payload["text"].tame(check_string)
body = body.strip()
if body != "":
body = replace_formatting(replace_links(body).strip())
check_send_webhook_message(request, user_profile, user_specified_topic, body)
return json_success(request)
def render_block(block: WildValue) -> str:
# https://api.slack.com/reference/block-kit/blocks
block_type = block["type"].tame(
check_string_in(["actions", "context", "divider", "header", "image", "input", "section"])
)
if block_type == "actions":
# Unhandled
return ""
elif block_type == "context" and block.get("elements"):
pieces = []
# Slack renders these pieces left-to-right, packed in as
# closely as possible. We just render them above each other,
# for simplicity.
for element in block["elements"]:
element_type = element["type"].tame(check_string_in(["image", "plain_text", "mrkdwn"]))
if element_type == "image":
pieces.append(render_block_element(element))
else:
pieces.append(element.tame(check_text_block())["text"])
return "\n\n".join(piece.strip() for piece in pieces if piece.strip() != "")
elif block_type == "divider":
return "----"
elif block_type == "header":
return "## " + block["text"].tame(check_text_block(plain_text_only=True))["text"]
elif block_type == "image":
image_url = block["image_url"].tame(check_url)
alt_text = block["alt_text"].tame(check_string)
if "title" in block:
alt_text = block["title"].tame(check_text_block(plain_text_only=True))["text"]
return f"[{alt_text}]({image_url})"
elif block_type == "input":
# Unhandled
pass
elif block_type == "section":
pieces = []
if "text" in block:
pieces.append(block["text"].tame(check_text_block())["text"])
if "accessory" in block:
pieces.append(render_block_element(block["accessory"]))
if "fields" in block:
fields = block["fields"].tame(check_list(check_text_block()))
if len(fields) == 1:
# Special-case a single field to display a bit more
# nicely, without extraneous borders and limitations
# on its contents.
pieces.append(fields[0]["text"])
else:
# It is not possible to have newlines in a table, nor
# escape the pipes that make it up; replace them with
# whitespace.
field_text = [f["text"].replace("\n", " ").replace("|", " ") for f in fields]
# Because Slack formats this as two columns, but not
# necessarily a table with a bold header, we emit a
# blank header row first.
table = "| | |\n|-|-|\n"
# Then take the fields two-at-a-time to make the table
iters = [iter(field_text)] * 2
for left, right in zip_longest(*iters, fillvalue=""):
table += f"| {left} | {right} |\n"
pieces.append(table)
return "\n\n".join(piece.strip() for piece in pieces if piece.strip() != "")
return ""
class TextField(TypedDict):
text: str
type: Literal["plain_text", "mrkdwn"]
def check_text_block(plain_text_only: bool = False) -> Validator[TextField]:
if plain_text_only:
type_validator = check_string_in(["plain_text"])
else:
type_validator = check_string_in(["plain_text", "mrkdwn"])
def f(var_name: str, val: object) -> TextField:
block = check_dict(
[
("type", type_validator),
("text", check_string),
],
)(var_name, val)
return cast(TextField, block)
return f
def render_block_element(element: WildValue) -> str:
# https://api.slack.com/reference/block-kit/block-elements
# Zulip doesn't support interactive elements, so we only render images here
element_type = element["type"].tame(check_string)
if element_type == "image":
image_url = element["image_url"].tame(check_url)
alt_text = element["alt_text"].tame(check_string)
return f"[{alt_text}]({image_url})"
else:
# Unsupported
return ""
def render_attachment(attachment: WildValue) -> str:
# https://api.slack.com/reference/messaging/attachments
# Slack recommends the usage of "blocks" even within attachments; the
# rest of the fields we handle here are legacy fields. These fields are
# optional and may contain null values.
pieces = []
if "title" in attachment and attachment["title"]:
title = attachment["title"].tame(check_string)
if "title_link" in attachment and attachment["title_link"]:
title_link = attachment["title_link"].tame(check_url)
pieces.append(f"## [{title}]({title_link})")
else:
pieces.append(f"## {title}")
if "pretext" in attachment and attachment["pretext"]:
pieces.append(attachment["pretext"].tame(check_string))
if "text" in attachment and attachment["text"]:
pieces.append(attachment["text"].tame(check_string))
if "fields" in attachment:
fields = []
for field in attachment["fields"]:
if "title" in field and "value" in field and field["title"] and field["value"]:
title = field["title"].tame(check_string)
value = field["value"].tame(check_string)
fields.append(f"*{title}*: {value}")
elif "title" in field and field["title"]:
title = field["title"].tame(check_string)
fields.append(f"*{title}*")
elif "value" in field and field["value"]:
value = field["value"].tame(check_string)
fields.append(f"{value}")
pieces.append("\n".join(fields))
if "blocks" in attachment and attachment["blocks"]:
for block in attachment["blocks"]:
pieces.append(render_block(block))
if "image_url" in attachment and attachment["image_url"]:
pieces.append("[]({})".format(attachment["image_url"].tame(check_url)))
if "footer" in attachment and attachment["footer"]:
pieces.append(attachment["footer"].tame(check_string))
if "ts" in attachment and attachment["ts"]:
time = attachment["ts"].tame(check_int)
pieces.append(f"<time:{time}>")
return "\n\n".join(piece.strip() for piece in pieces if piece.strip() != "")
def replace_links(text: str) -> str:
return re.sub(r"<(\w+?:\/\/.*?)\|(.*?)>", r"[\2](\1)", text)
def replace_formatting(text: str) -> str:
# Slack uses *text* for bold, whereas Zulip interprets that as italics
text = re.sub(r"([^\w]|^)\*(?!\s+)([^\*\n]+)(?<!\s)\*((?=[^\w])|$)", r"\1**\2**\3", text)
# Slack uses _text_ for emphasis, whereas Zulip interprets that as nothing
text = re.sub(r"([^\w]|^)[_](?!\s+)([^\_\n]+)(?<!\s)[_]((?=[^\w])|$)", r"\1*\2*\3", text)
return text