ugrpc::server::MiddlewareBase Class Reference

#include <userver/ugrpc/server/middlewares/base.hpp>

Detailed Description

Base class for server gRPC middleware.

Examples

samples/grpc_middleware_service/src/middlewares/server/auth.hpp, and samples/grpc_middleware_service/src/middlewares/server/meta_filter.hpp.

Definition at line 91 of file base.hpp.

Inheritance diagram for ugrpc::server::MiddlewareBase:

Public Member Functions
	MiddlewareBase (const MiddlewareBase &)=delete
MiddlewareBase &	operator= (const MiddlewareBase &)=delete
MiddlewareBase &	operator= (MiddlewareBase &&)=delete
virtual void	OnCallStart (MiddlewareCallContext &context) const
	This hook is invoked once per Call (RPC), after the message metadata is received, but before the handler function is called.
virtual void	PostRecvMessage (MiddlewareCallContext &context, google::protobuf::Message &request) const
	The function is invoked after each received message.
virtual void	PreSendMessage (MiddlewareCallContext &context, google::protobuf::Message &response) const
	The function is invoked before each sended message.
virtual void	PreSendStatus (MiddlewareCallContext &context, grpc::Status &status) const
	The function is invoked before sending the final status of the call.
virtual void	OnCallFinish (MiddlewareCallContext &context, const std::optional< grpc::Status > &status) const
	This hook is invoked once per Call (RPC), after the handler function has finished execution and the final status is determined.

Member Function Documentation

OnCallFinish()

virtual void ugrpc::server::MiddlewareBase::OnCallFinish ( MiddlewareCallContext &  context, const std::optional< grpc::Status > &  status  ) const

virtual

This hook is invoked once per Call (RPC), after the handler function has finished execution and the final status is determined.

OnCallFinish is called exactly once per Call (RPC), regardless of whether the call succeeded or failed. It's the final middleware hook in the call chain. This is useful for cleanup operations, logging, or metrics collection that should happen after the RPC is completely processed.

Parameters

context	The middleware call context containing call information
status	The final status of the call, if available

OnCallStart()

virtual void ugrpc::server::MiddlewareBase::OnCallStart ( MiddlewareCallContext &  context ) const

virtual

This hook is invoked once per Call (RPC), after the message metadata is received, but before the handler function is called.

If all OnCallStart succeeded => OnCallFinish will invoked after a success method call.

Reimplemented in ugrpc::server::middlewares::baggage::Middleware, and ugrpc::server::middlewares::deadline_propagation::Middleware.

PostRecvMessage()

virtual void ugrpc::server::MiddlewareBase::PostRecvMessage ( MiddlewareCallContext &  context, google::protobuf::Message &  request  ) const

virtual

The function is invoked after each received message.

PostRecvMessage is called:

• unary: exactly once per Call (RPC)
• stream: 0, 1 or more times

Reimplemented in grpc_protovalidate::server::Middleware.

PreSendMessage()

virtual void ugrpc::server::MiddlewareBase::PreSendMessage ( MiddlewareCallContext &  context, google::protobuf::Message &  response  ) const

virtual

The function is invoked before each sended message.

PreSendMessage is called:

• unary: 0 or 1 per Call (RPC), depending on whether the RPC returns a response or a failed status
• stream: once per response message, that is, 0, 1, more times per Call (RPC).

PreSendStatus()

virtual void ugrpc::server::MiddlewareBase::PreSendStatus ( MiddlewareCallContext &  context, grpc::Status &  status  ) const

virtual

The function is invoked before sending the final status of the call.

PreSendStatus is called exactly once per Call (RPC), right before sending the final gRPC status to the client. This allows middlewares to inspect and potentially modify the status that will be sent to the client.

Reimplemented in ugrpc::server::middlewares::deadline_propagation::Middleware.

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The documentation for this class was generated from the following file:

• userver/ugrpc/server/middlewares/base.hpp