cmds-api-revamp-draft.go

type ResponseEmitter interface {
	// closes http conn or channel
	io.Closer

	// Set/Return the response Error
	SetError(err error, code ErrorType)

	// Gets Stdout and Stderr, for writing to console without using SetOutput
	Stdout() io.Writer
	Stderr() io.Writer

	// send value
	// if value is io.Reader there needs to be a marshaller that copies that to the connection
	Emit(value interface{}) error
}

type HTTPResponseEmitter interface {
	ReponseEmitter

	SetLength(i uint64) error
  Flush()
}

// implements HTTPResponseEmitter
type httpResponseEmitter struct {
	// ...
}

type writerResponseEmitter struct {
 // ...
}

// implements ResponseEmitter
type chanResponseEmitter struct {
	// ...
}

/* NewResponse:

	Currently cmds.NewResponse only takes a request as parameter.

	From now on it also takes the destination. This can be an http.ResponseWriter,
	an io.Writer or a channel:

	func NewHTTPResponseEmitter(req Request, http.ResponseWriter) ResponseEmitter
	func NewWriterResponseEmitter(req Request, io.Writer) ResponseEmitter
	func NewChanResponseEmitter(req Request, chan<- interface{}) ResponseEmitter

	Note that different concrete implementations will be used. If transport-specific
	features are needed, you can type-assert to an interface that provides that.
	At the moment the only transport with special features is HTTP.

	There are not many uses of NewResponse so this is not really a problem:

		github.com/ipfs/go-ipfs/commands/response.go:245:6: github.com/ipfs/go-ipfs/commands.NewResponse is called from these 3 sites:
		github.com/ipfs/go-ipfs/commands/command.go:90:20: 	static function call from (*github.com/ipfs/go-ipfs/commands.Command).Call
		github.com/ipfs/go-ipfs/commands/response_test.go:21:20: 	static function call from github.com/ipfs/go-ipfs/commands.TestMarshalling
		github.com/ipfs/go-ipfs/commands/http/client.go:157:25: 	static function call from github.com/ipfs/go-ipfs/commands/http.getResponse
*/

/* cmd.Call:

	Currently the first thing it does is to call NewResponse. We pull that out:

	`cmd.Call(req, respwr)`

	cmd.Call is only called in a few places so its not a lot of work:
		github.com/ipfs/go-ipfs/commands/command.go:89:19: (*github.com/ipfs/go-ipfs/commands.Command).Call is called from these 10 sites:
		github.com/ipfs/go-ipfs/cmd/ipfs/main.go:349:18: 	static method call from github.com/ipfs/go-ipfs/cmd/ipfs.callCommand
		github.com/ipfs/go-ipfs/commands/http/handler.go:186:20: 	static method call from (github.com/ipfs/go-ipfs/commands/http.internalHandler).ServeHTTP
		github.com/ipfs/go-ipfs/commands/command_test.go:22:17: 	static method call from github.com/ipfs/go-ipfs/commands.TestOptionValidation
		github.com/ipfs/go-ipfs/commands/command_test.go:29:16: 	static method call from github.com/ipfs/go-ipfs/commands.TestOptionValidation
		github.com/ipfs/go-ipfs/commands/command_test.go:37:16: 	static method call from github.com/ipfs/go-ipfs/commands.TestOptionValidation
		github.com/ipfs/go-ipfs/commands/command_test.go:45:16: 	static method call from github.com/ipfs/go-ipfs/commands.TestOptionValidation
		github.com/ipfs/go-ipfs/commands/command_test.go:52:16: 	static method call from github.com/ipfs/go-ipfs/commands.TestOptionValidation
		github.com/ipfs/go-ipfs/commands/command_test.go:59:16: 	static method call from github.com/ipfs/go-ipfs/commands.TestOptionValidation
		github.com/ipfs/go-ipfs/commands/command_test.go:66:16: 	static method call from github.com/ipfs/go-ipfs/commands.TestOptionValidation
		github.com/ipfs/go-ipfs/commands/command_test.go:73:16: 	static method call from github.com/ipfs/go-ipfs/commands.TestOptionValidation
*/