# sync_bridge

URL: /pounce/api/asgi/sync_bridge/
Section: asgi
Description: 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.

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Module

#
`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.

2Classes1Function

## 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.

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 (/pounce/api/asgi/sync_bridge/#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 (/pounce/api/asgi/sync_bridge/#SyncResponse)`