Function format_sse_event

fastapi/sse.py:159–227

Build SSE wire-format bytes from **pre-serialized** data. The result always ends with `\n\n` (the event terminator).

(
    *,
    data_str: Annotated[
        str | None,
        Doc(
            """
            Pre-serialized data string to use as the `data:` field.
            """
        ),
    ] = None,
    event: Annotated[
        str | None,
        Doc(
            """
            Optional event type name (`event:` field).
            """
        ),
    ] = None,
    id: Annotated[
        str | None,
        Doc(
            """
            Optional event ID (`id:` field).
            """
        ),
    ] = None,
    retry: Annotated[
        int | None,
        Doc(
            """
            Optional reconnection time in milliseconds (`retry:` field).
            """
        ),
    ] = None,
    comment: Annotated[
        str | None,
        Doc(
            """
            Optional comment line(s) (`:` prefix).
            """
        ),
    ] = None,
)

def format_sse_event(
    *,
    data_str: Annotated[
        str | None,
        Doc(
            """
            Pre-serialized data string to use as the `data:` field.
            """
        ),
    ] = None,
    event: Annotated[
        str | None,
        Doc(
            """
            Optional event type name (`event:` field).
            """
        ),
    ] = None,
    id: Annotated[
        str | None,
        Doc(
            """
            Optional event ID (`id:` field).
            """
        ),
    ] = None,
    retry: Annotated[
        int | None,
        Doc(
            """
            Optional reconnection time in milliseconds (`retry:` field).
            """
        ),
    ] = None,
    comment: Annotated[
        str | None,
        Doc(
            """
            Optional comment line(s) (`:` prefix).
            """
        ),
    ] = None,
) -> bytes:
    """Build SSE wire-format bytes from **pre-serialized** data.

    The result always ends with `\n\n` (the event terminator).
    """
    lines: list[str] = []

    if comment is not None:
        for line in comment.splitlines():
            lines.append(f": {line}")

    if event is not None:
        lines.append(f"event: {event}")

    if data_str is not None:
        for line in data_str.splitlines():