mock.browser — in-page shim state

State the in-page JS shim consumes inside the browser's JavaScript runtime. These are not HTTP responses — they configure what the page sees from MusicKit JS's browser integrations.

Configuration surface

BrowserBehavior dataclass

BrowserBehavior(authorize_response: AuthorizeResponseSetter = None, eme_flavor: EmeFlavorSetter = None)

State that lives inside the page; the browser-side shim consumes it.

Configures the in-page shim's runtime behavior, not HTTP responses. Fields default to None; reading an unset value raises ValueError.

Attributes:

Name	Type	Description
authorize_response	AuthorizeResponseSetter	Response the shim returns from the authorize flow MusicKit JS opens on sign-in. Accepts either a static response variant or a zero-argument callable returning one (the callable is re-evaluated on each authorize attempt, so a fresh value can be returned per popup).
eme_flavor	EmeFlavorSetter	DRM key system the shim reports as supported when MusicKit JS probes Encrypted Media Extensions. Use one of the three key-system identifier strings.

Authorize popup

AuthorizeResponse module-attribute

AuthorizeResponse = AuthorizeSuccess | AuthorizeDecline | AuthorizeClose | AuthorizeSwitchUserId | AuthorizeUnavailable

AuthorizeSuccess dataclass

AuthorizeSuccess(user_token: str, cid: str, restricted: int | None = None)

User accepted the authorize prompt; carries the issued user token.

Attributes:

Name	Type	Description
user_token	str	Apple Music user token MusicKit JS stores and sends as the music-user-token header on subsequent requests.
cid	str	The cid Apple's authorize service issues alongside the token.
restricted	int | None	Integer the shim forwards as the restricted argument of MusicKit JS's authorize callback. Leave unset to forward 0.

AuthorizeDecline dataclass

AuthorizeDecline()

User declined the authorize prompt.

AuthorizeClose dataclass

AuthorizeClose()

User closed the authorize prompt without choosing.

AuthorizeSwitchUserId dataclass

AuthorizeSwitchUserId()

User switched Apple ID mid-flow; MusicKit JS retries authorization.

AuthorizeUnavailable dataclass

AuthorizeUnavailable()

Authorize flow is not available (e.g. service unavailable).

EME key system

KeySystem module-attribute

KeySystem = Literal['com.apple.fps', 'com.microsoft.playready', 'com.widevine.alpha']