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sharedinbox/lib/data/imap/tls_error.dart
T

36 lines
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Dart

/// Wraps a low-level TLS handshake failure (typically from `dart:io`) into a
/// message that points the user at the most likely fix: a TLS-mode mismatch
/// between the client (implicit TLS or plaintext) and the server's listener
/// on that port.
///
/// `WRONG_VERSION_NUMBER` is BoringSSL's way of saying "I tried to read a TLS
/// record but the bytes don't look like TLS at all" — almost always because
/// the server on that port is plaintext or expects STARTTLS first.
class TlsModeMismatchException implements Exception {
TlsModeMismatchException(this.host, this.port, this.original);
final String host;
final int port;
final Object original;
@override
String toString() =>
"TLS mode mismatch on $host:$port — the server isn't speaking implicit "
"TLS on this port. Try toggling 'SSL/TLS' off (server uses STARTTLS), "
'or change the port (e.g. 465 for implicit-TLS SMTP, 587 for SMTP+'
'STARTTLS, 993 for IMAPS, 143 for IMAP+STARTTLS, 4190 for ManageSieve+'
'STARTTLS). Original error: $original';
}
/// If [error] is a TLS handshake failure caused by a wrong-version-number
/// (i.e. the server is not speaking TLS), throw a [TlsModeMismatchException]
/// with [host]/[port] context. Otherwise rethrow [error] unchanged.
Never rethrowAsTlsHint(Object error, StackTrace stack, String host, int port) {
if (error.toString().contains('WRONG_VERSION_NUMBER')) {
Error.throwWithStackTrace(
TlsModeMismatchException(host, port, error),
stack,
);
}
Error.throwWithStackTrace(error, stack);
}