Repository: grpc/grpc-go
File: internal/transport/transport.go (Go)

Code before:
	// Host specifies the peer's host.
	Host string

	// Method specifies the operation to perform.
	Method string

	// SendCompress specifies the compression algorithm applied on
	// outbound message.
	SendCompress string

	// Creds specifies credentials.PerRPCCredentials for a call.
	Creds credentials.PerRPCCredentials

	// ContentSubtype specifies the content-subtype for a request. For example, a
	// content-subtype of "proto" will result in a content-type of
	// "application/grpc+proto". The value of ContentSubtype must be all
	// lowercase, otherwise the behavior is undefined. See
	// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests
	// for more details.
	ContentSubtype string

	PreviousAttempts int // value of grpc-previous-rpc-attempts header to set

	DoneFunc func() // called when the stream is finished

	// Authority is used to override the `:authority` header.
	Authority string
}

// ClientTransport is the common interface for all gRPC client-side transport
// implementations.
type ClientTransport interface {
	// Close tears down this transport. Once it returns, the transport
	// should not be accessed any more. The caller must make sure this
	// is called only once.
	Close(err error)

	// GracefulClose starts to tear down the transport: the transport will stop
	// accepting new RPCs and NewStream will return error. Once all streams are
	// finished, the transport will close.
	//
	// It does not block.
	GracefulClose()

	// NewStream creates a Stream for an RPC.
	NewStream(ctx context.Context, callHdr *CallHdr) (*ClientStream, error)

	// Error returns a channel that is closed when some I/O error
	// happens. Typically the caller should have a goroutine to monitor
	// this in order to take action (e.g., close the current transport
	// and create a new one) in error case. It should not return nil

Review comment (security):
I understand this is an internal package, but I feel it makes sense to mention here that if this value is populated, it will be preferred over the `Host` field to be used as the value for the `:authority` header.

Code after:
	// Host specifies the peer's host.
	Host string

	// Method specifies the operation to perform.
	Method string

	// SendCompress specifies the compression algorithm applied on
	// outbound message.
	SendCompress string

	// Creds specifies credentials.PerRPCCredentials for a call.
	Creds credentials.PerRPCCredentials

	// ContentSubtype specifies the content-subtype for a request. For example, a
	// content-subtype of "proto" will result in a content-type of
	// "application/grpc+proto". The value of ContentSubtype must be all
	// lowercase, otherwise the behavior is undefined. See
	// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests
	// for more details.
	ContentSubtype string

	PreviousAttempts int // value of grpc-previous-rpc-attempts header to set

	DoneFunc func() // called when the stream is finished

	// Authority is used to explicitly override the `:authority` header. If set,
	// this value takes precedence over the Host field and will be used as the
	// value for the `:authority` header.
	Authority string
}

// ClientTransport is the common interface for all gRPC client-side transport
// implementations.
type ClientTransport interface {
	// Close tears down this transport. Once it returns, the transport
	// should not be accessed any more. The caller must make sure this
	// is called only once.
	Close(err error)

	// GracefulClose starts to tear down the transport: the transport will stop
	// accepting new RPCs and NewStream will return error. Once all streams are
	// finished, the transport will close.
	//
	// It does not block.
	GracefulClose()

	// NewStream creates a Stream for an RPC.
	NewStream(ctx context.Context, callHdr *CallHdr) (*ClientStream, error)

	// Error returns a channel that is closed when some I/O error
	// happens. Typically the caller should have a goroutine to monitor