Merge pull request #65 from praw-dev/abstract_classes

Abstract classes

.coveragerc

@@ -0,0 +1,5 @@
+[report]
+exclude_lines =
+    @abstract
+    if TYPE_CHECKING:
+    pragma: no cover

asyncprawcore/auth.py

@@ -1,6 +1,7 @@
 """Provides Authentication and Authorization classes."""
 import inspect
 import time
+from abc import ABC, abstractmethod
 from typing import (
     TYPE_CHECKING,
     Awaitable,
@@ -21,11 +22,11 @@
 from .codes import codes
 from .exceptions import InvalidInvocation, OAuthException, ResponseException
 
-if TYPE_CHECKING:  # pragma: no cover
+if TYPE_CHECKING:
     from asyncprawcore.requestor import Requestor
 
 
-class BaseAuthenticator(object):
+class BaseAuthenticator(ABC):
     """Provide the base authenticator object that stores OAuth2 credentials."""
 
     def __init__(
@@ -46,6 +47,10 @@ def __init__(
         self.client_id = client_id
         self.redirect_uri = redirect_uri
 
+    @abstractmethod
+    def _auth(self):
+        pass
+
     async def _post(
         self, url: str, success_status: int = codes["ok"], **data
     ) -> ClientResponse:
@@ -164,7 +169,7 @@ def _auth(self) -> BasicAuth:
         return BasicAuth(self.client_id, "")
 
 
-class BaseAuthorizer(object):
+class BaseAuthorizer(ABC):
     """Superclass for OAuth2 authorization tokens and scopes."""
 
     AUTHENTICATOR_CLASS: Union[Tuple, Type] = BaseAuthenticator

asyncprawcore/exceptions.py

@@ -3,7 +3,7 @@
 from typing import TYPE_CHECKING, Any, Dict, List, Optional, Tuple, Union
 from urllib.parse import urlparse
 
-if TYPE_CHECKING:  # pragma: no cover
+if TYPE_CHECKING:
     from aiohttp import ClientResponse
 
 

asyncprawcore/rate_limit.py

@@ -4,7 +4,7 @@
 import time
 from typing import TYPE_CHECKING, Any, Awaitable, Callable, Dict, Mapping, Optional
 
-if TYPE_CHECKING:  # pragma: no cover
+if TYPE_CHECKING:
     from aiohttp import ClientResponse
 
 log = logging.getLogger(__package__)

asyncprawcore/requestor.py

@@ -7,7 +7,7 @@
 from .const import TIMEOUT, __version__
 from .exceptions import InvalidInvocation, RequestException
 
-if TYPE_CHECKING:  # pragma: no cover
+if TYPE_CHECKING:
     from asyncio import AbstractEventLoop
 
     from .sessions import Session

asyncprawcore/sessions.py

@@ -2,6 +2,7 @@
 import asyncio
 import logging
 import random
+from abc import ABC, abstractmethod
 from copy import deepcopy
 from typing import TYPE_CHECKING, Any, Dict, List, Optional, Tuple, Union
 from urllib.parse import urljoin
@@ -29,7 +30,7 @@
 from .rate_limit import RateLimiter
 from .util import authorization_error_class
 
-if TYPE_CHECKING:  # pragma: no cover
+if TYPE_CHECKING:
     from io import BufferedReader
 
     from aiofiles.threadpool.binary import AsyncBufferedReader
@@ -41,7 +42,7 @@
 log = logging.getLogger(__package__)
 
 
-class RetryStrategy(object):
+class RetryStrategy(ABC):
     """An abstract class for scheduling request retries.
 
     The strategy controls both the number and frequency of retry attempts.
@@ -50,6 +51,10 @@ class RetryStrategy(object):
 
     """
 
+    @abstractmethod
+    def _sleep_seconds(self) -> Optional[float]:
+        pass
+
     async def sleep(self) -> None:
         """Sleep until we are ready to attempt the request."""
         sleep_seconds = self._sleep_seconds()
@@ -114,7 +119,9 @@ class Session(object):
         codes["service_unavailable"]: ServerError,
         codes["too_many_requests"]: TooManyRequests,
         codes["unauthorized"]: authorization_error_class,
-        codes["unavailable_for_legal_reasons"]: UnavailableForLegalReasons,
+        codes[
+            "unavailable_for_legal_reasons"
+        ]: UnavailableForLegalReasons,  # Cloudflare's status (not named in requests)
         520: ServerError,
         522: ServerError,
     }

asyncprawcore/util.py

@@ -1,14 +1,21 @@
 """Provide utility for the asyncprawcore package."""
+from typing import TYPE_CHECKING, Union
+
 from .exceptions import Forbidden, InsufficientScope, InvalidToken
 
+if TYPE_CHECKING:
+    from aiohttp import ClientResponse
+
 _auth_error_mapping = {
     403: Forbidden,
     "insufficient_scope": InsufficientScope,
     "invalid_token": InvalidToken,
 }
 
 
-def authorization_error_class(response):
+def authorization_error_class(
+    response: "ClientResponse",
+) -> Union[InvalidToken, Forbidden, InsufficientScope]:
     """Return an exception instance that maps to the OAuth Error.
 
     :param response: The HTTP response containing a www-authenticate error.