streaming_context

server.streaming_context

module

Capture and re-establish request-scoped state for deferred stream rendering.

Suspense, Stream, EventStream, and other streaming generators often run after middlewarefinallyblocks reset the request ContextVars (request_var,…

Capture and re-establish request-scoped state for deferred stream rendering.

Suspense, Stream, EventStream, and other streaming generators often run after middlewarefinallyblocks reset the request ContextVars (request_var, the auth user, CSRF token, and g). The handler resets these before the streaming/SSE body is drained, so accessing them inside a deferred render —get_request(), get_user() / current_user(), get_csrf_token(), or g — would raise LookupErroror return an AnonymousUserunless we capture them while they are still live and re-establish them for the drain.

This module is the single capture-then-re-establish path shared by all three streamed-render types. The carrier (_CapturedRequestContext) is internal — underscore-prefixed and not exported to the top-level public surface.

server.streaming_context

Name	Type	Default	Description
`type`		—
`qualified_name`		—
`element_type`		—
`description`		—
`source_file`		—
`line_number`		—
`is_autodoc`		—
`autodoc_element`		—
`_autodoc_template`		—
`_autodoc_url_path`		—
`_autodoc_page_type`		—
`title`		—
`doc_content_hash`		—

Symbols on this page

class _CapturedRequestContext

Snapshot of request-scoped state captured while ContextVars are live.

Carried ontoStreamingResponse/ SSEResponse so the drain (send_streaming_response forSuspense/Stream, …

function capture_streaming_render_context

Snapshot request/user/CSRF/g/nonce while middleware ContextVars are live.

request_context and csp_nonceare passed in by the caller (the negotiation site already holds the live request…

function attach_streaming_render_context

Stamp live request-scoped snapshots onto a streaming response when unset.

_CapturedRequestContext

class

Snapshot of request-scoped state captured while ContextVars are live.

Carried ontoStreamingResponse/ SSEResponse so the drain (send_streaming_response forSuspense/Stream, produce_events for EventStream) can re-establish identical request context. Internal — not public API.

Fields:

auth_user: The authenticated ``User`` (or ``AnonymousUser``), or ``None``
    when ``AuthMiddleware`` was not active.
csrf_token: The CSRF token string, or ``None``.
csrf_field_name: The CSRF form field name, or ``None``.
g_snapshot: A shallow copy of ``g``'s store, or ``None`` when ``g`` was
    never touched (the zero-``g`` hot path allocates nothing).
request_context: The current `Request`, or
    ``None``.
csp_nonce: The live CSP nonce, or ``None`` when CSP nonces are disabled.
runtime_context: A `copy_context`() snapshot taken while
    middleware and OTel spans are still live, re-attached when the SSE
    producer task starts so trace context survives the handler ``finally``.

capture_streaming_render_context

function

def capture_streaming_render_context(*, request_context: Request | None = None, csp_nonce: str | None = None) -> _CapturedRequestContext

Snapshot request/user/CSRF/g/nonce while middleware ContextVars are live.

request_context and csp_nonce are passed in by the caller (the negotiation site already holds the live request and nonce); the auth user, CSRF token, andgare read from their ContextVars here.

Parameters

Name	Type	Default	Description
`request_context`	`Request \| None`	`None`
`csp_nonce`	`str \| None`	`None`

attach_streaming_render_context

function

def attach_streaming_render_context(response: StreamingResponse) -> StreamingResponse

Stamp live request-scoped snapshots onto a streaming response when unset.

Parameters

Name	Type	Default	Description
`response`	`StreamingResponse`	—

View source · /home/runner/work/chirp/chirp/site/../src/chirp/server/streaming_context.py:1