types: Better types for API fields.

Signed-off-by: Zixuan James Li <359101898@qq.com>

zerver/lib/types.py

@@ -221,6 +221,49 @@ class NeverSubscribedStreamDict(TypedDict):
     subscribers: NotRequired[List[int]]
 
 
+class APIStreamDict(TypedDict):
+    """Stream information provided to Zulip clients as a dictionary via API.
+    It should contain all the fields specified in `zerver.models.Stream.API_FIELDS`
+    with few exceptions and possible additional fields.
+    """
+
+    date_created: int
+    description: str
+    first_message_id: Optional[int]
+    history_public_to_subscribers: bool
+    invite_only: bool
+    is_web_public: bool
+    message_retention_days: Optional[int]
+    name: str
+    rendered_description: str
+    stream_id: int  # `stream_id`` represents `id` of the `Stream` object in `API_FIELDS`
+    stream_post_policy: int
+    # Computed fields not specified in `Stream.API_FIELDS`
+    is_announcement_only: bool
+    is_default: NotRequired[bool]
+
+
+class APISubscriptionDict(APIStreamDict):
+    """Similar to StreamClientDict, it should contain all the fields specified in
+    `zerver.models.Subscription.API_FIELDS` and several additional fields.
+    """
+
+    audible_notifications: Optional[bool]
+    color: str
+    desktop_notifications: Optional[bool]
+    email_notifications: Optional[bool]
+    is_muted: bool
+    pin_to_top: bool
+    push_notifications: Optional[bool]
+    role: int
+    wildcard_mentions_notify: Optional[bool]
+    # Computed fields not specified in `Subscription.API_FIELDS`
+    email_address: str
+    in_home_view: bool
+    stream_weekly_traffic: Optional[int]
+    subscribers: List[int]
+
+
 @dataclass
 class SubscriptionInfo:
     subscriptions: List[SubscriptionStreamDict]