doodle/pkg/scripting/pubsub.go

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package scripting
import (
"git.kirsle.net/apps/doodle/pkg/log"
"github.com/robertkrimen/otto"
)
// Message holds data being published from one script VM with information sent
// to the linked VMs.
type Message struct {
Name string
Args []interface{}
}
/*
RegisterPublishHooks adds the pub/sub hooks to a JavaScript VM.
This adds the global methods `Message.Subscribe(name, func)` and
`Message.Publish(name, args)` to the JavaScript VM's scope.
*/
func RegisterPublishHooks(vm *VM) {
// Goroutine to watch the VM's inbound channel and invoke Subscribe handlers
// for any matching messages received.
go func() {
for msg := range vm.Inbound {
log.Warn("vm: %s msg: %+v", vm.Name, msg)
if _, ok := vm.subscribe[msg.Name]; ok {
for _, callback := range vm.subscribe[msg.Name] {
callback.Call(otto.Value{}, msg.Args...)
}
}
}
}()
// Register the Message.Subscribe and Message.Publish functions.
vm.vm.Set("Message", map[string]interface{}{
"Subscribe": func(name string, callback otto.Value) {
if !callback.IsFunction() {
log.Error("SUBSCRIBE(%s): callback is not a function", name)
return
}
if _, ok := vm.subscribe[name]; !ok {
vm.subscribe[name] = []otto.Value{}
}
vm.subscribe[name] = append(vm.subscribe[name], callback)
},
"Publish": func(name string, v ...interface{}) {
log.Error("PUBLISH: %s %+v", name, v)
for _, channel := range vm.Outbound {
channel <- Message{
Name: name,
Args: v,
}
}
},
})
}