go-sendxmpp/connect.go

// Copyright 2018 - 2021 Martin Dosch.
// Use of this source code is governed by the BSD-2-clause
// license that can be found in the LICENSE file.package main

import (
	"fmt"
	"net"
	"strings"

	"github.com/mattn/go-xmpp" // BSD-3-Clause
)

func connect(options xmpp.Options, directTLS bool) (*xmpp.Client, error) {

	// Lookup SRV records if server is not specified manually
	if options.Host == "" {
		server := options.User[strings.LastIndex(options.User, "@")+1:]
		// Lookup xmpp-client SRV records if direct TLS is not required
		if !directTLS {
			if _, addrs, err := net.LookupSRV("xmpp-client", "tcp", server); err == nil {
				if len(addrs) > 0 {
					for _, adr := range addrs {
						options.Host = fmt.Sprintf("%s:%d", adr.Target, adr.Port)
						// Connect to server
						client, err := options.NewClient()
						if err == nil {
							return client, err
						}
					}
				}
			}
			// Try port 5222 if no xmpp-client SRV records are provided.
			options.Host = server + ":5222"
			// Connect to server
			client, err := options.NewClient()
			if err == nil {
				return client, err
			}
			// Unset STartTLS as we try direct TLS now
			options.NoTLS = false
			options.StartTLS = false
		}
		// Lookup xmpps-client SRV records
		// TODO: Fallback to 5223 and 443 if no xmpps-client SRV records exist
		if _, addrs, err := net.LookupSRV("xmpps-client", "tcp", server); err == nil {
			if len(addrs) > 0 {
				for _, adr := range addrs {
					options.Host = fmt.Sprintf("%s:%d", adr.Target, adr.Port)
					// Connect to server
					client, err := options.NewClient()
					if err == nil {
						return client, err
					}
				}
			}
		}
	}
	client, err := options.NewClient()
	return client, err
}