message.go

package xco

import (
	"encoding/xml"

	"github.com/pkg/errors"
)

// MessageType defines the constants for the types of messages within XEP-0114
type MessageType string

const (

	// CHAT defines the chat message type
	CHAT = MessageType("chat")

	// ERROR defines the error message type
	ERROR = MessageType("error")

	// GROUPCHAT defines the group chat message type
	GROUPCHAT = MessageType("groupchat")

	// HEADLINE defines the headline message type
	HEADLINE = MessageType("headline")

	// NORMAL defines the normal message type
	NORMAL = MessageType("normal")
)

// A Message is an incoming or outgoing Component message
type Message struct {
	Header
	Type MessageType `xml:"type,attr,omitempty"`

	Subject string `xml:"subject,omitempty"`
	Body    string `xml:"body,omitempty"`
	Error   *Error `xml:"error"`
	Thread  string `xml:"thread,omitempty"`
	Content string `xml:",innerxml"` // allow arbitrary content

	// XEP-0184 message delivery receipts
	ReceiptRequest *xml.Name   `xml:"urn:xmpp:receipts request,omitempty"`
	ReceiptAck     *ReceiptAck `xml:"urn:xmpp:receipts received,omitempty"`

	// XEP-0172 User nicknames
	Nick string `xml:"http://jabber.org/protocol/nick nick,omitempty"`

	XMLName xml.Name `xml:"message"`
}

// A MessageHandler handles an incoming message
type MessageHandler func(*Component, *Message) error

func noOpMessageHandler(c *Component, m *Message) error {
	return nil
}

// BodyResponseHandler builds a simple request-response style function which returns the body
// of the response message
func BodyResponseHandler(fn func(*Message) (string, error)) MessageHandler {
	return func(c *Component, m *Message) error {

		body, err := fn(m)
		if err != nil {
			return err
		}
		resp := m.Response()
		resp.Body = body
		return errors.Wrap(c.Send(resp), "Error sending message response")
	}
}

// Response returns a new message representing a response to this
// message.  The To and From attributes of the header are reversed to
// indicate the new origin.
func (m *Message) Response() *Message {
	resp := &Message{
		Header: Header{
			From: m.To,
			To:   m.From,
			ID:   m.ID,
		},
		Subject: m.Subject,
		Thread:  m.Thread,
		Type:    m.Type,
		XMLName: m.XMLName,
	}

	return resp
}