api/service_instance.go
func serviceInstanceProxy(w http.ResponseWriter, r *http.Request, t auth.Token) (err error) {
	serviceName := r.URL.Query().Get(":service")
	instanceName := r.URL.Query().Get(":instance")
	serviceInstance, err := getServiceInstanceOrError(serviceName, instanceName)
	if err != nil {
		return err
	}
	allowed := permission.Check(t, permission.PermServiceInstanceUpdateProxy,
		contextsForServiceInstance(serviceInstance, serviceName)...,
	)
	if !allowed {
		return permission.ErrUnauthorized
	}
	path := r.URL.Query().Get("callback")
	var evt *event.Event
	if r.Method != http.MethodGet && r.Method != http.MethodHead {
		evt, err = event.New(&event.Opts{
			Target: serviceInstanceTarget(serviceName, instanceName),
			Kind:   permission.PermServiceInstanceUpdateProxy,
			Owner:  t,
			CustomData: append(event.FormToCustomData(InputFields(r)), map[string]interface{}{
				"name":  "method",
				"value": r.Method,
			}),
			Allowed: event.Allowed(permission.PermServiceInstanceReadEvents,
				contextsForServiceInstance(serviceInstance, serviceName)...),
		})
		if err != nil {
			return err
		}
		defer func() { evt.Done(err) }()
	}
	return service.ProxyInstance(serviceInstance, path, evt, requestIDHeader(r), w, r)
}
func serviceInstanceProxy(w http.ResponseWriter, r *http.Request, t auth.Token) (err error) {
	serviceName := r.URL.Query().Get(":service")
	instanceName := r.URL.Query().Get(":instance")
	serviceInstance, err := getServiceInstanceOrError(serviceName, instanceName)
	if err != nil {
		return err
	}
	allowed := permission.Check(t, permission.PermServiceInstanceUpdateProxy,
		contextsForServiceInstance(serviceInstance, serviceName)...,
	)
	if !allowed {
		return permission.ErrUnauthorized
	}
	path := r.URL.Query().Get("callback")
	var evt *event.Event
	if r.Method != http.MethodGet && r.Method != http.MethodHead {
		evt, err = event.New(&event.Opts{
			Target: serviceInstanceTarget(serviceName, instanceName),
			Kind:   permission.PermServiceInstanceUpdateProxy,
			Owner:  t,
			CustomData: append(event.FormToCustomData(InputFields(r)), map[string]interface{}{
				"name":  "method",
				"value": r.Method,
			}),
			Allowed: event.Allowed(permission.PermServiceInstanceReadEvents,
				contextsForServiceInstance(serviceInstance, serviceName)...),
		})
		if err != nil {
			return err
		}
		defer func() { evt.Done(err) }()
	}
	return service.ProxyInstance(serviceInstance, path, evt, requestIDHeader(r), w, r)
}
// title: service instance proxy
// path: /services/{service}/proxy/{instance}
// method: "*"
// responses:
//   401: Unauthorized
//   404: Instance not found