112 lines
2.4 KiB
Go
112 lines
2.4 KiB
Go
package messenger
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import (
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"fmt"
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"math/rand"
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"net/smtp"
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"time"
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"github.com/jordan-wright/email"
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)
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const emName = "email"
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// Server represents an SMTP server's credentials.
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type Server struct {
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Name string
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Host string `koanf:"host"`
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Port int `koanf:"port"`
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AuthProtocol string `koanf:"auth_protocol"`
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Username string `koanf:"username"`
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Password string `koanf:"password"`
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SendTimeout time.Duration `koanf:"send_timeout"`
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MaxConns int `koanf:"max_conns"`
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mailer *email.Pool
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}
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type emailer struct {
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servers map[string]*Server
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serverNames []string
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numServers int
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}
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// NewEmailer creates and returns an e-mail Messenger backend.
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// It takes multiple SMTP configurations.
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func NewEmailer(srv ...Server) (Messenger, error) {
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e := &emailer{
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servers: make(map[string]*Server),
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}
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for _, server := range srv {
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s := server
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var auth smtp.Auth
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if s.AuthProtocol == "cram" {
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auth = smtp.CRAMMD5Auth(s.Username, s.Password)
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} else {
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auth = smtp.PlainAuth("", s.Username, s.Password, s.Host)
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}
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pool, err := email.NewPool(fmt.Sprintf("%s:%d", s.Host, s.Port), s.MaxConns, auth)
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if err != nil {
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return nil, err
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}
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s.mailer = pool
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e.servers[s.Name] = &s
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e.serverNames = append(e.serverNames, s.Name)
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}
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e.numServers = len(e.serverNames)
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return e, nil
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}
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// Name returns the Server's name.
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func (e *emailer) Name() string {
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return emName
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}
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// Push pushes a message to the server.
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func (e *emailer) Push(fromAddr string, toAddr []string, subject string, m []byte, atts []*Attachment) error {
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var key string
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// If there are more than one SMTP servers, send to a random
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// one from the list.
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if e.numServers > 1 {
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key = e.serverNames[rand.Intn(e.numServers)]
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} else {
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key = e.serverNames[0]
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}
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// Are there attachments?
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var files []*email.Attachment
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if atts != nil {
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files = make([]*email.Attachment, 0, len(atts))
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for _, f := range atts {
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a := &email.Attachment{
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Filename: f.Name,
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Header: f.Header,
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Content: make([]byte, len(f.Content)),
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}
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copy(a.Content, f.Content)
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files = append(files, a)
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}
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}
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srv := e.servers[key]
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err := srv.mailer.Send(&email.Email{
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From: fromAddr,
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To: toAddr,
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Subject: subject,
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HTML: m,
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Attachments: files,
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}, srv.SendTimeout)
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return err
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}
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// Flush flushes the message queue to the server.
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func (e *emailer) Flush() error {
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return nil
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}
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