hybridgroup.gobot/platforms/nats/nats_adaptor.go

124 lines
2.9 KiB
Go

package nats
import (
"github.com/nats-io/nats"
"gobot.io/x/gobot"
"net/url"
"strings"
)
// Adaptor is a configuration struct for interacting with a NATS server.
// Name is a logical name for the adaptor/nats server connection.
// Host is in the form "localhost:4222" which is the hostname/ip and port of the nats server.
// ClientID is a unique identifier integer that specifies the identity of the client.
type Adaptor struct {
name string
Host string
clientID int
username string
password string
client *nats.Conn
connect func() (*nats.Conn, error)
}
// NewAdaptor populates a new NATS Adaptor.
func NewAdaptor(host string, clientID int, options ...nats.Option) *Adaptor {
hosts, err := processHostString(host)
return &Adaptor{
name: gobot.DefaultName("NATS"),
Host: hosts,
clientID: clientID,
connect: func() (*nats.Conn, error) {
if err != nil {
return nil, err
}
return nats.Connect(hosts, options...)
},
}
}
// NewAdaptorWithAuth populates a NATS Adaptor including username and password.
func NewAdaptorWithAuth(host string, clientID int, username string, password string, options ...nats.Option) *Adaptor {
hosts, err := processHostString(host)
return &Adaptor{
Host: hosts,
clientID: clientID,
username: username,
password: password,
connect: func() (*nats.Conn, error) {
if err != nil {
return nil, err
}
return nats.Connect(hosts, append(options, nats.UserInfo(username, password))...)
},
}
}
func processHostString(host string) (string, error) {
urls := strings.Split(host, ",")
for i, s := range urls {
s = strings.TrimSpace(s)
if !strings.HasPrefix(s, "tls://") && !strings.HasPrefix(s, "nats://") {
s = "nats://" + s
}
u, err := url.Parse(s)
if err != nil {
return "", err
}
urls[i] = u.String()
}
return strings.Join(urls, ","), nil
}
// Name returns the logical client name.
func (a *Adaptor) Name() string { return a.name }
// SetName sets the logical client name.
func (a *Adaptor) SetName(n string) { a.name = n }
// Connect makes a connection to the Nats server.
func (a *Adaptor) Connect() (err error) {
a.client, err = a.connect()
return
}
// Disconnect from the nats server.
func (a *Adaptor) Disconnect() (err error) {
if a.client != nil {
a.client.Close()
}
return
}
// Finalize is simply a helper method for the disconnect.
func (a *Adaptor) Finalize() (err error) {
a.Disconnect()
return
}
// Publish sends a message with the particular topic to the nats server.
func (a *Adaptor) Publish(topic string, message []byte) bool {
if a.client == nil {
return false
}
a.client.Publish(topic, message)
return true
}
// On is an event-handler style subscriber to a particular topic (named event).
// Supply a handler function to use the bytes returned by the server.
func (a *Adaptor) On(event string, f func(s []byte)) bool {
if a.client == nil {
return false
}
a.client.Subscribe(event, func(msg *nats.Msg) {
f(msg.Data)
})
return true
}