request.go

package alexa

import "strings"

// RequestType represents confirmvarious Request Types
type RequestType int

const (
	// RequestTypeUndefined means incoming value incorrect or not supported
	RequestTypeUndefined RequestType = iota
	// RequestTypeLaunch is constant `LaunchRequest`
	RequestTypeLaunch
	// RequestTypeIntent is constant `IntentRequest`
	RequestTypeIntent
	// RequestTypeSessionEnded is constant `SessionEndedRequest`
	RequestTypeSessionEnded
	// RequestTypeCanFulfillIntent is constant `CanFulfillIntentRequest`
	RequestTypeCanFulfillIntent
)

// requestTypeStrings for use outside this module
var requestTypeStrings = [...]string{
	"Undefined", // Placeholder - should never be this
	"LaunchRequest",
	"IntentRequest",
	"SessionEndedRequest",
	"CanFulfillIntentRequest",
}

// Request is an Alexa skill request
// see https://developer.amazon.com/docs/custom-skills/request-and-response-json-reference.html#request-format
type Request struct {
	Version string  `json:"version"`
	Session Session `json:"session"`
	Context Context `json:"context"`
	Body    struct {
		Type        RequestType `json:"type"`
		RequestID   string      `json:"requestId"`
		Timestamp   string      `json:"timestamp"`
		Locale      string      `json:"locale"`
		Intent      Intent      `json:"intent,omitempty"`
		Reason      string      `json:"reason,omitempty"`
		DialogState string      `json:"dialogState,omitempty"`
	} `json:"request"`
}

// MarshalJSON Function to handle JSON parsing out
func (r RequestType) MarshalJSON() ([]byte, error) {
	j := string(`"` + requestTypeStrings[r] + `"`)
	return []byte(j), nil
}

// UnmarshalJSON Function to handle JSON parsing out
func (r *RequestType) UnmarshalJSON(data []byte) error {
	rt := RequestTypeUndefined
	// Convert to string whilst removing quotes
	x := string(data)[1 : len(data)-1]
	// Find the type in the range of values
	for i, s := range requestTypeStrings {
		if strings.ToLower(s) == strings.ToLower(x) {
			rt = RequestType(i)
		}
	}
	*r = rt
	return nil
}