mirror of https://github.com/zulip/zulip.git
211 lines
8.7 KiB
Python
211 lines
8.7 KiB
Python
from functools import wraps
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from typing import Callable, Dict, Set, Tuple, Union
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from django.http import HttpRequest, HttpResponse
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from django.urls import path
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from django.urls.resolvers import URLPattern
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from django.utils.cache import add_never_cache_headers
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from django.views.decorators.csrf import csrf_exempt, csrf_protect
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from typing_extensions import Concatenate, ParamSpec
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from zerver.decorator import (
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authenticated_json_view,
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authenticated_rest_api_view,
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authenticated_uploads_api_view,
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process_as_post,
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public_json_view,
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)
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from zerver.lib.exceptions import MissingAuthenticationError
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from zerver.lib.request import RequestNotes
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from zerver.lib.response import json_method_not_allowed
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ParamT = ParamSpec("ParamT")
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METHODS = ("GET", "HEAD", "POST", "PUT", "DELETE", "PATCH")
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def default_never_cache_responses(
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view_func: Callable[Concatenate[HttpRequest, ParamT], HttpResponse]
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) -> Callable[Concatenate[HttpRequest, ParamT], HttpResponse]:
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"""Patched version of the standard Django never_cache_responses
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decorator that adds headers to a response so that it will never be
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cached, unless the view code has already set a Cache-Control
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header.
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"""
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@wraps(view_func)
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def _wrapped_view_func(
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request: HttpRequest, /, *args: ParamT.args, **kwargs: ParamT.kwargs
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) -> HttpResponse:
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response = view_func(request, *args, **kwargs)
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if response.has_header("Cache-Control"):
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return response
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add_never_cache_headers(response)
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return response
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return _wrapped_view_func
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def get_target_view_function_or_response(
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request: HttpRequest, rest_dispatch_kwargs: Dict[str, object]
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) -> Union[Tuple[Callable[..., HttpResponse], Set[str]], HttpResponse]:
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"""Helper for REST API request dispatch. The rest_dispatch_kwargs
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parameter is expected to be a dictionary mapping HTTP methods to
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a mix of view functions and (view_function, {view_flags}) tuples.
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* Returns an error HttpResponse for unsupported HTTP methods.
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* Otherwise, returns a tuple containing the view function
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corresponding to the request's HTTP method, as well as the
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appropriate set of view flags.
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HACK: Mutates the passed rest_dispatch_kwargs, removing the HTTP
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method details but leaving any other parameters for the caller to
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pass directly to the view function. We should see if we can remove
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this feature; it's not clear it's actually used.
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"""
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supported_methods: Dict[str, object] = {}
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request_notes = RequestNotes.get_notes(request)
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if request_notes.saved_response is not None:
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# For completing long-polled Tornado requests, we skip the
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# view function logic and just return the response.
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return request_notes.saved_response
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# The list() duplicates rest_dispatch_kwargs, since this loop
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# mutates the original.
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for arg in list(rest_dispatch_kwargs):
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if arg in METHODS:
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supported_methods[arg] = rest_dispatch_kwargs[arg]
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del rest_dispatch_kwargs[arg]
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if "GET" in supported_methods:
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supported_methods.setdefault("HEAD", supported_methods["GET"])
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if request.method == "OPTIONS":
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response = HttpResponse(status=204) # No content
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response["Allow"] = ", ".join(sorted(supported_methods.keys()))
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return response
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# Override requested method if magic method=??? parameter exists
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method_to_use = request.method
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if request.POST and "method" in request.POST:
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method_to_use = request.POST["method"]
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if method_to_use in supported_methods:
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entry = supported_methods[method_to_use]
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if isinstance(entry, tuple):
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handler, view_flags = entry
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assert callable(handler)
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assert isinstance(view_flags, set)
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return handler, view_flags
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assert callable(entry)
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return entry, set()
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return json_method_not_allowed(list(supported_methods.keys()))
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@default_never_cache_responses
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@csrf_exempt
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def rest_dispatch(request: HttpRequest, /, **kwargs: object) -> HttpResponse:
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"""Dispatch to a REST API endpoint.
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Authentication is verified in the following ways:
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* for paths beginning with /api, HTTP basic auth
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* for paths beginning with /json (used by the web client), the session token
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Unauthenticated requests may use this endpoint only with the
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allow_anonymous_user_web view flag.
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This calls the function named in kwargs[request.method], if that request
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method is supported, and after wrapping that function to:
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* protect against CSRF (if the user is already authenticated through
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a Django session)
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* authenticate via an API key (otherwise)
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* coerce PUT/PATCH/DELETE into having POST-like semantics for
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retrieving variables
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Any keyword args that are *not* HTTP methods are passed through to the
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target function.
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Never make a urls.py pattern put user input into a variable called GET, POST,
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etc, as that is where we route HTTP verbs to target functions.
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"""
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result = get_target_view_function_or_response(request, kwargs)
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if isinstance(result, HttpResponse):
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return result
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target_function, view_flags = result
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request_notes = RequestNotes.get_notes(request)
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# Set request_notes.query for update_activity_user(), which is called
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# by some of the later wrappers.
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request_notes.query = target_function.__name__
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# We want to support authentication by both cookies (web client)
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# and API keys (API clients). In the former case, we want to
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# do a check to ensure that CSRF etc is honored, but in the latter
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# we can skip all of that.
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#
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# Security implications of this portion of the code are minimal,
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# as we should worst-case fail closed if we miscategorize a request.
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# for some special views (e.g. serving a file that has been
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# uploaded), we support using the same URL for web and API clients.
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if "override_api_url_scheme" in view_flags and "Authorization" in request.headers:
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# This request uses standard API based authentication.
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# For override_api_url_scheme views, we skip our normal
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# rate limiting, because there are good reasons clients
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# might need to (e.g.) request a large number of uploaded
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# files or avatars in quick succession.
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target_function = authenticated_rest_api_view(skip_rate_limiting=True)(target_function)
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elif "override_api_url_scheme" in view_flags and request.GET.get("api_key") is not None:
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# This request uses legacy API authentication. We
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# unfortunately need that in the React Native mobile apps,
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# because there's no way to set the Authorization header in
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# React Native. See last block for rate limiting notes.
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target_function = authenticated_uploads_api_view(skip_rate_limiting=True)(target_function)
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# /json views (web client) validate with a session token (cookie)
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elif not request.path.startswith("/api") and request.user.is_authenticated:
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# Authenticated via sessions framework, only CSRF check needed
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auth_kwargs = {}
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if "override_api_url_scheme" in view_flags:
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auth_kwargs["skip_rate_limiting"] = True
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target_function = csrf_protect(authenticated_json_view(target_function, **auth_kwargs))
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# most clients (mobile, bots, etc) use HTTP basic auth and REST calls, where instead of
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# username:password, we use email:apiKey
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elif request.path.startswith("/api") and "Authorization" in request.headers:
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# Wrap function with decorator to authenticate the user before
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# proceeding
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target_function = authenticated_rest_api_view(
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allow_webhook_access="allow_incoming_webhooks" in view_flags,
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)(target_function)
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elif (
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request.path.startswith(("/json", "/avatar", "/user_uploads", "/thumbnail"))
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and "allow_anonymous_user_web" in view_flags
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):
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# For endpoints that support anonymous web access, we do that.
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# TODO: Allow /api calls when this is stable enough.
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target_function = csrf_protect(public_json_view(target_function))
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else:
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# Otherwise, throw an authentication error; our middleware
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# will generate the appropriate HTTP response.
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raise MissingAuthenticationError()
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if request.method in ["DELETE", "PATCH", "PUT"]:
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# process_as_post needs to be the outer decorator, because
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# otherwise we might access and thus cache a value for
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# request.POST.
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target_function = process_as_post(target_function)
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return target_function(request, **kwargs)
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def rest_path(
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route: str,
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**handlers: Union[Callable[..., HttpResponse], Tuple[Callable[..., HttpResponse], Set[str]]],
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) -> URLPattern:
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return path(route, rest_dispatch, handlers)
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