sync_bridge - Pounce

asgi.sync_bridge

Sync ASGI bridge — run ASGI apps from a synchronous context.

For simple request-response (no streaming receive, no streaming send), collects the response in memory and returns it as a SyncResponse.

If the app sends more_body=True (streaming) or the scope type is websocket, raises NeedsAsyncError so the caller can hand off to the async pool.

Classes

NeedsAsyncError 0 ▼

Raised when the ASGI app requires async (streaming, WebSocket). The SyncWorker catches this and ha…

Bases: Exception

Raised when the ASGI app requires async (streaming, WebSocket).

The SyncWorker catches this and hands off the connection to the AsyncPool for multiplexed I/O handling.

SyncResponse 4 ▼

Complete HTTP response from a sync ASGI invocation.

Attributes

Name	Type	Description
`status`	`int`	HTTP status code.
`headers`	`list[tuple[bytes, bytes]]`	Response headers as list of (name, value) byte pairs.
`body`	`bytes`	Full response body bytes.
`needs_async`	`bool`	True if the app indicated streaming (more_body=True).

Functions

call_asgi_sync 4 SyncResponse ▼

Run an ASGI app from a sync context. For simple request-response (no streaming…

def call_asgi_sync(app: ASGIApp, scope: dict[str, Any], body: bytes, *, runner: asyncio.Runner | None = None) -> SyncResponse

Run an ASGI app from a sync context.

For simple request-response (no streaming receive, no streaming send), this collects the response in memory and returns it as a SyncResponse.

If the app sends more_body=True (streaming), sets needs_async=True on the response so the caller can hand off. The response may be partial (headers + first body chunk).

Raises NeedsAsyncError immediately for WebSocket scopes (caller must hand off before invoking the app).

Parameters

Name	Type	Description
`app`	`ASGIApp`	The ASGI application.
`scope`	`dict[str, Any]`	ASGI scope dict.
`body`	`bytes`	Full request body (for non-streaming requests).
`runner`	`asyncio.Runner \| None`	Reusable asyncio.Runner owned by the calling worker thread. Avoids creating/destroying an event loop per request. When None, a temporary Runner is created (slow fallback). Default:`None`

Returns

SyncResponse