package imap import ( "fmt" "net/url" "strings" imapClient "github.com/emersion/go-imap/client" "github.com/Necoro/feed2imap-go/internal/log" ) const ( imapsPort = "993" imapPort = "143" imapsSchema = "imaps" imapSchema = "imap" ) func forceTLS(url *url.URL) bool { return url.Scheme == imapsSchema || url.Port() == imapsPort } func setDefaultScheme(url *url.URL) { switch url.Scheme { case imapSchema, imapsSchema: return default: oldScheme := url.Scheme if url.Port() == imapsPort { url.Scheme = imapsSchema } else { url.Scheme = imapSchema } 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 == imapsSchema { port = imapsPort } else { port = imapPort } url.Host += ":" + port } } func sanitizeUrl(url *url.URL) { setDefaultScheme(url) setDefaultPort(url) } 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: c, host: url.Host, folders: folders{}} 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) } if err = client.fetchDelimiter(); err != nil { return nil, fmt.Errorf("fetching delimiter: %w", err) } client.toplevel = url.Path if client.toplevel[0] == '/' { client.toplevel = client.toplevel[1:] } client.toplevel = client.FolderName(strings.Split(client.toplevel, "/")) log.Printf("Determined '%s' as toplevel, with '%s' as delimiter", client.toplevel, client.delimiter) // Go to toplevel folder by default, so that the rest is relative if err = client.selectToplevel(); err != nil { return nil, err } return &client, nil }