Query Fetcher

Outbound port for asynchronously fetching query results.

QueryFetcher provides an application-layer abstraction for retrieving data
by dispatching query messages through a MessageBus. It supports CQRS-style
architectures where queries are processed independently of commands.

Responsibilities:
- Forward queries to the message bus.
- Return the result of the query execution.

Non-Responsibilities:
- Define caching or projection logic.
- Guarantee consistency between read and write models.

query_fetcher

Outbound port for asynchronously fetching query results.

QueryFetcher provides an application-layer abstraction for retrieving data
by dispatching query messages through a MessageBus. It supports CQRS-style
architectures where queries are processed independently of commands.

Responsibilities

• Forward queries to the message bus.
• Return the result of the query execution.

Non-Responsibilities

• Define caching or projection logic.
• Guarantee consistency between read and write models.

QueryFetcher

Bases: OutboundPort[Query, QueryFetcherResult]

Outbound port for dispatching query messages.

The QueryFetcher abstracts query execution through a MessageBus. It does
not apply any interpretation to the returned data; shaping is the query
handler’s responsibility.

Source code in src/forging_blocks/application/ports/outbound/query_fetcher.py

class QueryFetcher(OutboundPort[Query, QueryFetcherResult]):
    """Outbound port for dispatching query messages.

    The QueryFetcher abstracts query execution through a MessageBus. It does
    not apply any interpretation to the returned data; shaping is the query
    handler’s responsibility.
    """

    def __init__(self, message_bus: MessageBus[Query, QueryFetcherResult]) -> None:
        self._message_bus = message_bus

    async def fetch(self, query: Query) -> QueryFetcherResult:
        """Fetch the result of a query.

        Args:
            query: The query instance.

        Returns:
            Any result returned by the underlying query handler.

        Notes:
            - Asynchronous execution.
            - Data shape is determined by the handler responsible for the query.
        """
        return await self._message_bus.dispatch(query)

fetch(query: Query) -> QueryFetcherResult async

Fetch the result of a query.

Parameters:

Name	Type	Description	Default
query	Query	The query instance.	required

Returns:

Type	Description
QueryFetcherResult	Any result returned by the underlying query handler.

Notes

• Asynchronous execution.
• Data shape is determined by the handler responsible for the query.

Source code in src/forging_blocks/application/ports/outbound/query_fetcher.py

async def fetch(self, query: Query) -> QueryFetcherResult:
    """Fetch the result of a query.

    Args:
        query: The query instance.

    Returns:
        Any result returned by the underlying query handler.

    Notes:
        - Asynchronous execution.
        - Data shape is determined by the handler responsible for the query.
    """
    return await self._message_bus.dispatch(query)