callbackgen generates callback pattern for your callback fields.

go install github.com/c9s/callbackgen@latest

callbackgen scans all the fields of the target struct, and generate methods for the fields that end with Callbacks. In the following example, methods of snapshotCallbacks and messageCallbacks will be generated in stream_callbacks.go.

//go:generate callbackgen -type Stream
type Stream struct {
	Name string
  
	snapshotCallbacks []func(ctx context.Context)

	messageCallbacks []TextMessageCallback
}

Run go generate <target path> and stream_callbacks.go will be created with the following context:

import (
	"context"
)

func (S *Stream) OnSnapshot(cb func(ctx context.Context)) {
	S.snapshotCallbacks = append(S.snapshotCallbacks, cb)
}

func (S *Stream) EmitSnapshot(ctx context.Context) {
	for _, cb := range S.snapshotCallbacks {
		cb(ctx)
	}
}

func (S *Stream) OnMessage(cb TextMessageCallback) {
	S.messageCallbacks = append(S.messageCallbacks, cb)
}

func (S *Stream) EmitMessage() {
	for _, cb := range S.messageCallbacks {
		cb()
	}
}

You could register the callback using On* methods, and trigger callbacks using Emit* methods.

• requestgen https://github.com/c9s/requestgen

MIT License