pyarrow.flight.ClientMiddleware

class pyarrow.flight.ClientMiddleware

Bases: _Weakrefable

Client-side middleware for a call, instantiated per RPC.

Methods here should be fast and must be infallible: they should not raise exceptions or stall indefinitely.

__init__(*args, **kwargs)

Methods

__init__(*args, **kwargs)
call_completed(self, exception)	A callback when the call finishes.
received_headers(self, headers)	A callback when headers are received.
sending_headers(self)	A callback before headers are sent.

call_completed(self, exception)

A callback when the call finishes.

The default implementation does nothing.

Parameters:

exceptionArrowException

If the call errored, this is the equivalent exception. Will be None if the call succeeded.

received_headers(self, headers)

A callback when headers are received.

The default implementation does nothing.

Parameters:

headersdict

A dictionary of headers from the server. Keys are strings and values are lists of strings (for text headers) or bytes (for binary headers).

sending_headers(self)

A callback before headers are sent.

Returns:

headersdict

A dictionary of header values to add to the request, or None if no headers are to be added. The dictionary should have string keys and string or list-of-string values.

Bytes values are allowed, but the underlying transport may not support them or may restrict them. For gRPC, binary values are only allowed on headers ending in “-bin”.

Header names must be lowercase ASCII.

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pyarrow.flight.ClientMiddlewareFactory

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