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.