import json import logging import urllib from http.client import HTTPResponse from ssl import SSLContext from typing import Dict, Union, Sequence, Optional, List, Any from urllib.error import HTTPError from urllib.request import Request, urlopen, OpenerDirector, ProxyHandler, HTTPSHandler from slack_sdk.errors import SlackRequestError from slack_sdk.models.attachments import Attachment from slack_sdk.models.blocks import Block from .internal_utils import ( _build_body, _build_request_headers, _debug_log_response, get_user_agent, ) from .webhook_response import WebhookResponse from slack_sdk.http_retry import default_retry_handlers from slack_sdk.http_retry.handler import RetryHandler from slack_sdk.http_retry.request import HttpRequest as RetryHttpRequest from slack_sdk.http_retry.response import HttpResponse as RetryHttpResponse from slack_sdk.http_retry.state import RetryState from ..proxy_env_variable_loader import load_http_proxy_from_env class WebhookClient: url: str timeout: int ssl: Optional[SSLContext] proxy: Optional[str] default_headers: Dict[str, str] logger: logging.Logger retry_handlers: List[RetryHandler] def __init__( self, url: str, timeout: int = 30, ssl: Optional[SSLContext] = None, proxy: Optional[str] = None, default_headers: Optional[Dict[str, str]] = None, user_agent_prefix: Optional[str] = None, user_agent_suffix: Optional[str] = None, logger: Optional[logging.Logger] = None, retry_handlers: Optional[List[RetryHandler]] = None, ): """API client for Incoming Webhooks and `response_url` https://docs.slack.dev/messaging/sending-messages-using-incoming-webhooks/ Args: url: Complete URL to send data (e.g., `https://hooks.slack.com/XXX`) timeout: Request timeout (in seconds) ssl: `ssl.SSLContext` to use for requests proxy: Proxy URL (e.g., `localhost:9000`, `http://localhost:9000`) default_headers: Request headers to add to all requests user_agent_prefix: Prefix for User-Agent header value user_agent_suffix: Suffix for User-Agent header value logger: Custom logger retry_handlers: Retry handlers """ self.url = url self.timeout = timeout self.ssl = ssl self.proxy = proxy self.default_headers = default_headers if default_headers else {} self.default_headers["User-Agent"] = get_user_agent(user_agent_prefix, user_agent_suffix) self.logger = logger if logger is not None else logging.getLogger(__name__) self.retry_handlers = retry_handlers if retry_handlers is not None else default_retry_handlers() if self.proxy is None or len(self.proxy.strip()) == 0: env_variable = load_http_proxy_from_env(self.logger) if env_variable is not None: self.proxy = env_variable def send( self, *, text: Optional[str] = None, attachments: Optional[Sequence[Union[Dict[str, Any], Attachment]]] = None, blocks: Optional[Sequence[Union[Dict[str, Any], Block]]] = None, response_type: Optional[str] = None, replace_original: Optional[bool] = None, delete_original: Optional[bool] = None, unfurl_links: Optional[bool] = None, unfurl_media: Optional[bool] = None, metadata: Optional[Dict[str, Any]] = None, headers: Optional[Dict[str, str]] = None, ) -> WebhookResponse: """Performs a Slack API request and returns the result. Args: text: The text message (even when having blocks, setting this as well is recommended as it works as fallback) attachments: A collection of attachments blocks: A collection of Block Kit UI components response_type: The type of message (either 'in_channel' or 'ephemeral') replace_original: True if you use this option for response_url requests delete_original: True if you use this option for response_url requests unfurl_links: Option to indicate whether text url should unfurl unfurl_media: Option to indicate whether media url should unfurl metadata: Metadata attached to the message headers: Request headers to append only for this request Returns: Webhook response """ return self.send_dict( # It's fine to have None value elements here # because _build_body() filters them out when constructing the actual body data body={ "text": text, "attachments": attachments, "blocks": blocks, "response_type": response_type, "replace_original": replace_original, "delete_original": delete_original, "unfurl_links": unfurl_links, "unfurl_media": unfurl_media, "metadata": metadata, }, headers=headers, ) def send_dict(self, body: Dict[str, Any], headers: Optional[Dict[str, str]] = None) -> WebhookResponse: """Performs a Slack API request and returns the result. Args: body: JSON data structure (it's still a dict at this point), if you give this argument, body_params and files will be skipped headers: Request headers to append only for this request Returns: Webhook response """ return self._perform_http_request( body=_build_body(body), # type: ignore[arg-type] headers=_build_request_headers(self.default_headers, headers), ) def _perform_http_request(self, *, body: Dict[str, Any], headers: Dict[str, str]) -> WebhookResponse: raw_body = json.dumps(body) headers["Content-Type"] = "application/json;charset=utf-8" if self.logger.level <= logging.DEBUG: self.logger.debug(f"Sending a request - url: {self.url}, body: {raw_body}, headers: {headers}") url = self.url # NOTE: Intentionally ignore the `http_verb` here # Slack APIs accepts any API method requests with POST methods req = Request(method="POST", url=url, data=raw_body.encode("utf-8"), headers=headers) resp = None last_error = Exception("undefined internal error") retry_state = RetryState() counter_for_safety = 0 while counter_for_safety < 100: counter_for_safety += 1 # If this is a retry, the next try started here. We can reset the flag. retry_state.next_attempt_requested = False try: resp = self._perform_http_request_internal(url, req) # The resp is a 200 OK response return resp except HTTPError as e: # read the response body here charset = e.headers.get_content_charset() or "utf-8" response_body: str = e.read().decode(charset) # As adding new values to HTTPError#headers can be ignored, building a new dict object here response_headers = dict(e.headers.items()) resp = WebhookResponse( url=url, status_code=e.code, body=response_body, headers=response_headers, ) if e.code == 429: # for backward-compatibility with WebClient (v.2.5.0 or older) if "retry-after" not in resp.headers and "Retry-After" in resp.headers: resp.headers["retry-after"] = resp.headers["Retry-After"] if "Retry-After" not in resp.headers and "retry-after" in resp.headers: resp.headers["Retry-After"] = resp.headers["retry-after"] _debug_log_response(self.logger, resp) # Try to find a retry handler for this error retry_request = RetryHttpRequest.from_urllib_http_request(req) retry_response = RetryHttpResponse( status_code=e.code, headers={k: [v] for k, v in e.headers.items()}, data=response_body.encode("utf-8") if response_body is not None else None, ) for handler in self.retry_handlers: if handler.can_retry( state=retry_state, request=retry_request, response=retry_response, error=e, ): if self.logger.level <= logging.DEBUG: self.logger.info( f"A retry handler found: {type(handler).__name__} for {req.method} {req.full_url} - {e}" ) handler.prepare_for_next_attempt( state=retry_state, request=retry_request, response=retry_response, error=e, ) break if retry_state.next_attempt_requested is False: return resp except Exception as err: last_error = err self.logger.error(f"Failed to send a request to Slack API server: {err}") # Try to find a retry handler for this error retry_request = RetryHttpRequest.from_urllib_http_request(req) for handler in self.retry_handlers: if handler.can_retry( state=retry_state, request=retry_request, response=None, error=err, ): if self.logger.level <= logging.DEBUG: self.logger.info( f"A retry handler found: {type(handler).__name__} for {req.method} {req.full_url} - {err}" ) handler.prepare_for_next_attempt( state=retry_state, request=retry_request, response=None, error=err, ) self.logger.info(f"Going to retry the same request: {req.method} {req.full_url}") break if retry_state.next_attempt_requested is False: raise err if resp is not None: return resp raise last_error def _perform_http_request_internal(self, url: str, req: Request): opener: Optional[OpenerDirector] = None # for security (BAN-B310) if url.lower().startswith("http"): if self.proxy is not None: if isinstance(self.proxy, str): opener = urllib.request.build_opener( ProxyHandler({"http": self.proxy, "https": self.proxy}), HTTPSHandler(context=self.ssl), ) else: raise SlackRequestError(f"Invalid proxy detected: {self.proxy} must be a str value") else: raise SlackRequestError(f"Invalid URL detected: {url}") http_resp: Optional[HTTPResponse] = None if opener: http_resp = opener.open(req, timeout=self.timeout) else: http_resp = urlopen(req, context=self.ssl, timeout=self.timeout) charset: str = http_resp.headers.get_content_charset() or "utf-8" response_body: str = http_resp.read().decode(charset) resp = WebhookResponse( url=url, status_code=http_resp.status, body=response_body, headers=http_resp.headers, # type: ignore[arg-type] ) _debug_log_response(self.logger, resp) return resp