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|
package imap
import (
"fmt"
"net/url"
"github.com/emersion/go-imap"
imapClient "github.com/emersion/go-imap/client"
"github.com/Necoro/feed2imap-go/internal/log"
)
const (
imapsPort = "993"
imapPort = "143"
)
type Client struct {
c *imapClient.Client
host string
}
func forceTLS(url *url.URL) bool {
return url.Scheme == "imaps" || url.Port() == imapsPort
}
func setDefaultScheme(url *url.URL) {
switch url.Scheme {
case "imap", "imaps":
return
default:
oldScheme := url.Scheme
if url.Port() == imapsPort {
url.Scheme = "imaps"
} else {
url.Scheme = "imap"
}
if oldScheme != "" {
log.Warnf("Unknown scheme '%s', defaulting to '%s'", oldScheme, url.Scheme)
}
}
}
func setDefaultPort(url *url.URL) {
if url.Port() == "" {
var port string
if url.Scheme == "imaps" {
port = imapsPort
} else {
port = imapPort
}
url.Host += ":" + port
}
}
func sanitizeUrl(url *url.URL) {
setDefaultScheme(url)
setDefaultPort(url)
}
func (client *Client) Disconnect() {
if client != nil {
connected := (client.c.State() & imap.ConnectedState) != 0
_ = client.c.Logout()
if connected {
log.Print("Disconnected from ", client.host)
}
}
}
func Connect(url *url.URL) (*Client, error) {
var c *imapClient.Client
var err error
sanitizeUrl(url)
forceTls := forceTLS(url)
if forceTls {
c, err = imapClient.DialTLS(url.Host, nil)
if err != nil {
return nil, fmt.Errorf("connecting (TLS) to %s: %w", url.Host, err)
}
log.Print("Connected to ", url.Host, " (TLS)")
} else {
c, err = imapClient.Dial(url.Host)
if err != nil {
return nil, fmt.Errorf("connecting to %s: %w", url.Host, err)
}
}
var client = Client{c, url.Host}
defer func() {
if err != nil {
client.Disconnect()
}
}()
if !forceTls {
var hasStartTls bool // explicit to avoid shadowing err
hasStartTls, err = c.SupportStartTLS()
if err != nil {
return nil, fmt.Errorf("checking for starttls for %s: %w", url.Host, err)
}
if hasStartTls {
if err = c.StartTLS(nil); err != nil {
return nil, fmt.Errorf("enabling starttls for %s: %w", url.Host, err)
}
log.Print("Connected to ", url.Host, " (STARTTLS)")
}
log.Print("Connected to ", url.Host, " (Plain)")
}
pwd, _ := url.User.Password()
if err = c.Login(url.User.Username(), pwd); err != nil {
return nil, fmt.Errorf("login to %s: %w", url.Host, err)
}
return &client, nil
}
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