/// <summary>
/// Establishes a connection to the specified IMAP server.
/// </summary>
/// <remarks>
/// <para>Establishes a connection to an IMAP or IMAP/S server. If the schema
/// in the uri is "imap", a clear-text connection is made and defaults to using
/// port 143 if no port is specified in the URI. However, if the schema in the
/// uri is "imaps", an SSL connection is made using the
/// <see cref="ClientCertificates"/> and defaults to port 993 unless a port
/// is specified in the URI.</para>
/// <para>It should be noted that when using a clear-text IMAP connection,
/// if the server advertizes support for the STARTTLS extension, the client
/// will automatically switch into TLS mode before authenticating unless the
/// <paramref name="uri"/> contains a query string to disable it.</para>
/// <para>If the IMAP server advertizes the COMPRESS extension and either does not
/// support the STARTTLS extension or the <paramref name="uri"/> explicitly disabled
/// the use of the STARTTLS extension, then the client will automatically opt into
/// using a compressed data connection to optimize bandwidth usage unless the
/// <paramref name="uri"/> contains a query string to explicitly disable it.</para>
/// <para>If a successful connection is made, the <see cref="AuthenticationMechanisms"/>
/// and <see cref="Capabilities"/> properties will be populated.</para>
/// </remarks>
/// <param name="uri">The server URI. The <see cref="System.Uri.Scheme"/> should either
/// be "imap" to make a clear-text connection or "imaps" to make an SSL connection.</param>
/// <param name="cancellationToken">A cancellation token.</param>
/// <exception cref="System.ArgumentNullException">
/// The <paramref name="uri"/> is <c>null</c>.
/// </exception>
/// <exception cref="System.ArgumentException">
/// The <paramref name="uri"/> is not an absolute URI.
/// </exception>
/// <exception cref="System.ObjectDisposedException">
/// The <see cref="ImapClient"/> has been disposed.
/// </exception>
/// <exception cref="System.InvalidOperationException">
/// The <see cref="ImapClient"/> is already connected.
/// </exception>
/// <exception cref="System.OperationCanceledException">
/// The operation was canceled via the cancellation token.
/// </exception>
/// <exception cref="System.IO.IOException">
/// An I/O error occurred.
/// </exception>
/// <exception cref="ImapProtocolException">
/// An IMAP protocol error occurred.
/// </exception>
public void Connect(Uri uri, CancellationToken cancellationToken)
{
CheckDisposed ();
if (uri == null)
throw new ArgumentNullException ("uri");
if (!uri.IsAbsoluteUri)
throw new ArgumentException ("The uri must be absolute.", "uri");
if (IsConnected)
throw new InvalidOperationException ("The ImapClient is already connected.");
var imaps = uri.Scheme.ToLowerInvariant () == "imaps";
var port = uri.Port > 0 ? uri.Port : (imaps ? 993 : 143);
var query = uri.ParsedQuery ();
Stream stream;
string value;
var starttls = !imaps && (!query.TryGetValue ("starttls", out value) || Convert.ToBoolean (value));
var compress = !imaps && (!query.TryGetValue ("compress", out value) || Convert.ToBoolean (value));
#if !NETFX_CORE
var ipAddresses = Dns.GetHostAddresses (uri.DnsSafeHost);
Socket socket = null;
for (int i = 0; i < ipAddresses.Length; i++) {
socket = new Socket (ipAddresses[i].AddressFamily, SocketType.Stream, ProtocolType.Tcp);
cancellationToken.ThrowIfCancellationRequested ();
try {
socket.Connect (ipAddresses[i], port);
break;
} catch {
if (i + 1 == ipAddresses.Length)
throw;
}
}
if (imaps) {
var ssl = new SslStream (new NetworkStream (socket, true), false, ValidateRemoteCertificate);
ssl.AuthenticateAsClient (uri.Host, ClientCertificates, SslProtocols.Default, true);
stream = ssl;
} else {
stream = new NetworkStream (socket, true);
}
#else
socket = new StreamSocket ();
cancellationToken.ThrowIfCancellationRequested ();
socket.ConnectAsync (new HostName (uri.DnsSafeHost), port.ToString (), imaps ? SocketProtectionLevel.Tls12 : SocketProtectionLevel.PlainSocket)
.AsTask (cancellationToken)
.GetAwaiter ()
.GetResult ();
stream = new DuplexStream (socket.InputStream.AsStreamForRead (), socket.OutputStream.AsStreamForWrite ());
#endif
host = uri.Host;
logger.LogConnect (uri);
engine.Connect (new ImapStream (stream, logger), cancellationToken);
// Only query the CAPABILITIES if the greeting didn't include them.
if (engine.CapabilitiesVersion == 0)
engine.QueryCapabilities (cancellationToken);
if (starttls && (engine.Capabilities & ImapCapabilities.StartTLS) != 0) {
var ic = engine.QueueCommand (cancellationToken, null, "STARTTLS\r\n");
engine.Wait (ic);
if (ic.Result == ImapCommandResult.Ok) {
#if !NETFX_CORE
var tls = new SslStream (stream, false, ValidateRemoteCertificate);
tls.AuthenticateAsClient (uri.Host, ClientCertificates, SslProtocols.Tls, true);
engine.Stream.Stream = tls;
#else
socket.UpgradeToSslAsync (SocketProtectionLevel.Tls12, new HostName (uri.DnsSafeHost))
.AsTask (cancellationToken)
.GetAwaiter ()
.GetResult ();
#endif
// Query the CAPABILITIES again if the server did not include an
// untagged CAPABILITIES response to the STARTTLS command.
if (engine.CapabilitiesVersion == 1)
engine.QueryCapabilities (cancellationToken);
}
} else if (compress && (engine.Capabilities & ImapCapabilities.Compress) != 0) {
var ic = engine.QueueCommand (cancellationToken, null, "COMPRESS DEFLATE\r\n");
engine.Wait (ic);
if (ic.Result == ImapCommandResult.Ok) {
var unzip = new DeflateStream (stream, CompressionMode.Decompress);
var zip = new DeflateStream (stream, CompressionMode.Compress);
engine.Stream.Stream = new DuplexStream (unzip, zip);
// Query the CAPABILITIES again if the server did not include an
// untagged CAPABILITIES response to the COMPRESS command.
if (engine.CapabilitiesVersion == 1)
engine.QueryCapabilities (cancellationToken);
}
}
}
/// <summary>
/// Establish a connection to the specified IMAP server.
/// </summary>
/// <remarks>
/// <para>Establishes a connection to the specified IMAP or IMAP/S server.</para>
/// <para>If the <paramref name="port"/> has a value of <c>0</c>, then the
/// <paramref name="options"/> parameter is used to determine the default port to
/// connect to. The default port used with <see cref="SecureSocketOptions.SslOnConnect"/>
/// is <c>993</c>. All other values will use a default port of <c>143</c>.</para>
/// <para>If the <paramref name="options"/> has a value of
/// <see cref="SecureSocketOptions.Auto"/>, then the <paramref name="port"/> is used
/// to determine the default security options. If the <paramref name="port"/> has a value
/// of <c>993</c>, then the default options used will be
/// <see cref="SecureSocketOptions.SslOnConnect"/>. All other values will use
/// <see cref="SecureSocketOptions.StartTlsWhenAvailable"/>.</para>
/// <para>Once a connection is established, properties such as
/// <see cref="AuthenticationMechanisms"/> and <see cref="Capabilities"/> will be
/// populated.</para>
/// </remarks>
/// <example>
/// <code language="c#" source="Examples\ImapExamples.cs" region="DownloadMessages"/>
/// </example>
/// <param name="host">The host name to connect to.</param>
/// <param name="port">The port to connect to. If the specified port is <c>0</c>, then the default port will be used.</param>
/// <param name="options">The secure socket options to when connecting.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <exception cref="System.ArgumentNullException">
/// <paramref name="host"/> is <c>null</c>.
/// </exception>
/// <exception cref="System.ArgumentOutOfRangeException">
/// <paramref name="port"/> is not between <c>0</c> and <c>65535</c>.
/// </exception>
/// <exception cref="System.ArgumentException">
/// The <paramref name="host"/> is a zero-length string.
/// </exception>
/// <exception cref="System.ObjectDisposedException">
/// The <see cref="ImapClient"/> has been disposed.
/// </exception>
/// <exception cref="System.InvalidOperationException">
/// The <see cref="ImapClient"/> is already connected.
/// </exception>
/// <exception cref="System.NotSupportedException">
/// <paramref name="options"/> was set to
/// <see cref="MailKit.Security.SecureSocketOptions.StartTls"/>
/// and the IMAP server does not support the STARTTLS extension.
/// </exception>
/// <exception cref="System.OperationCanceledException">
/// The operation was canceled via the cancellation token.
/// </exception>
/// <exception cref="System.IO.IOException">
/// An I/O error occurred.
/// </exception>
/// <exception cref="ImapProtocolException">
/// An IMAP protocol error occurred.
/// </exception>
public override void Connect (string host, int port = 0, SecureSocketOptions options = SecureSocketOptions.Auto, CancellationToken cancellationToken = default (CancellationToken))
{
if (host == null)
throw new ArgumentNullException ("host");
if (host.Length == 0)
throw new ArgumentException ("The host name cannot be empty.", "host");
if (port < 0 || port > 65535)
throw new ArgumentOutOfRangeException ("port");
CheckDisposed ();
if (IsConnected)
throw new InvalidOperationException ("The ImapClient is already connected.");
Stream stream;
bool starttls;
Uri uri;
ComputeDefaultValues (host, ref port, ref options, out uri, out starttls);
#if !NETFX_CORE
var ipAddresses = Dns.GetHostAddresses (host);
Socket socket = null;
for (int i = 0; i < ipAddresses.Length; i++) {
socket = new Socket (ipAddresses[i].AddressFamily, SocketType.Stream, ProtocolType.Tcp);
try {
cancellationToken.ThrowIfCancellationRequested ();
socket.Connect (ipAddresses[i], port);
break;
} catch (OperationCanceledException) {
socket.Dispose ();
throw;
} catch {
socket.Dispose ();
if (i + 1 == ipAddresses.Length)
throw;
}
}
if (socket == null)
throw new IOException (string.Format ("Failed to resolve host: {0}", host));
engine.Uri = uri;
if (options == SecureSocketOptions.SslOnConnect) {
var ssl = new SslStream (new NetworkStream (socket, true), false, ValidateRemoteCertificate);
ssl.AuthenticateAsClient (host, ClientCertificates, DefaultSslProtocols, true);
stream = ssl;
} else {
stream = new NetworkStream (socket, true);
}
#else
var protection = options == SecureSocketOptions.SslOnConnect ? SocketProtectionLevel.Tls12 : SocketProtectionLevel.PlainSocket;
socket = new StreamSocket ();
try {
cancellationToken.ThrowIfCancellationRequested ();
socket.ConnectAsync (new HostName (host), port.ToString (), protection)
.AsTask (cancellationToken)
.GetAwaiter ()
.GetResult ();
} catch {
socket.Dispose ();
socket = null;
throw;
}
stream = new DuplexStream (socket.InputStream.AsStreamForRead (0), socket.OutputStream.AsStreamForWrite (0));
engine.Uri = uri;
#endif
if (stream.CanTimeout) {
stream.WriteTimeout = timeout;
stream.ReadTimeout = timeout;
}
ProtocolLogger.LogConnect (uri);
engine.Connect (new ImapStream (stream, socket, ProtocolLogger), cancellationToken);
try {
// Only query the CAPABILITIES if the greeting didn't include them.
if (engine.CapabilitiesVersion == 0)
engine.QueryCapabilities (cancellationToken);
if (options == SecureSocketOptions.StartTls && (engine.Capabilities & ImapCapabilities.StartTLS) == 0)
throw new NotSupportedException ("The IMAP server does not support the STARTTLS extension.");
if (starttls && (engine.Capabilities & ImapCapabilities.StartTLS) != 0) {
var ic = engine.QueueCommand (cancellationToken, null, "STARTTLS\r\n");
engine.Wait (ic);
if (ic.Response == ImapCommandResponse.Ok) {
#if !NETFX_CORE
var tls = new SslStream (stream, false, ValidateRemoteCertificate);
tls.AuthenticateAsClient (host, ClientCertificates, DefaultSslProtocols, true);
engine.Stream.Stream = tls;
#else
socket.UpgradeToSslAsync (SocketProtectionLevel.Tls12, new HostName (host))
.AsTask (cancellationToken)
.GetAwaiter ()
.GetResult ();
#endif
// Query the CAPABILITIES again if the server did not include an
// untagged CAPABILITIES response to the STARTTLS command.
if (engine.CapabilitiesVersion == 1)
engine.QueryCapabilities (cancellationToken);
} else if (options == SecureSocketOptions.StartTls) {
throw ImapCommandException.Create ("STARTTLS", ic);
}
}
} catch {
engine.Disconnect ();
throw;
}
engine.Disconnected += OnEngineDisconnected;
OnConnected ();
}
/// <summary>
/// Establishes a connection to the specified IMAP server.
/// </summary>
/// <remarks>
/// <para>Establishes a connection to an IMAP or IMAP/S server. If the schema
/// in the uri is "imap", a clear-text connection is made and defaults to using
/// port 143 if no port is specified in the URI. However, if the schema in the
/// uri is "imaps", an SSL connection is made using the
/// <see cref="ClientCertificates"/> and defaults to port 993 unless a port
/// is specified in the URI.</para>
/// <para>It should be noted that when using a clear-text IMAP connection,
/// if the server advertizes support for the STARTTLS extension, the client
/// will automatically switch into TLS mode before authenticating unless the
/// <paramref name="uri"/> contains a query string to disable it.</para>
/// <para>If the IMAP server advertizes the COMPRESS extension and either does not
/// support the STARTTLS extension or the <paramref name="uri"/> explicitly disabled
/// the use of the STARTTLS extension, then the client will automatically opt into
/// using a compressed data connection to optimize bandwidth usage unless the
/// <paramref name="uri"/> contains a query string to explicitly disable it.</para>
/// <para>If a successful connection is made, the <see cref="AuthenticationMechanisms"/>
/// and <see cref="Capabilities"/> properties will be populated.</para>
/// </remarks>
/// <param name="uri">The server URI. The <see cref="System.Uri.Scheme"/> should either
/// be "imap" to make a clear-text connection or "imaps" to make an SSL connection.</param>
/// <param name="cancellationToken">A cancellation token.</param>
/// <exception cref="System.ArgumentNullException">
/// The <paramref name="uri"/> is <c>null</c>.
/// </exception>
/// <exception cref="System.ArgumentException">
/// The <paramref name="uri"/> is not an absolute URI.
/// </exception>
/// <exception cref="System.ObjectDisposedException">
/// The <see cref="ImapClient"/> has been disposed.
/// </exception>
/// <exception cref="System.InvalidOperationException">
/// The <see cref="ImapClient"/> is already connected.
/// </exception>
/// <exception cref="System.OperationCanceledException">
/// The operation was canceled via the cancellation token.
/// </exception>
/// <exception cref="System.IO.IOException">
/// An I/O error occurred.
/// </exception>
/// <exception cref="ImapProtocolException">
/// An IMAP protocol error occurred.
/// </exception>
public void Connect(Uri uri, CancellationToken cancellationToken)
{
CheckDisposed();
if (uri == null)
{
throw new ArgumentNullException("uri");
}
if (!uri.IsAbsoluteUri)
{
throw new ArgumentException("The uri must be absolute.", "uri");
}
if (IsConnected)
{
throw new InvalidOperationException("The ImapClient is already connected.");
}
var imaps = uri.Scheme.ToLowerInvariant() == "imaps";
var port = uri.Port > 0 ? uri.Port : (imaps ? 993 : 143);
var query = uri.ParsedQuery();
Stream stream;
string value;
var starttls = !imaps && (!query.TryGetValue("starttls", out value) || Convert.ToBoolean(value));
var compress = !imaps && (!query.TryGetValue("compress", out value) || Convert.ToBoolean(value));
#if !NETFX_CORE
var ipAddresses = Dns.GetHostAddresses(uri.DnsSafeHost);
Socket socket = null;
for (int i = 0; i < ipAddresses.Length; i++)
{
socket = new Socket(ipAddresses[i].AddressFamily, SocketType.Stream, ProtocolType.Tcp);
cancellationToken.ThrowIfCancellationRequested();
try {
socket.Connect(ipAddresses[i], port);
break;
} catch {
if (i + 1 == ipAddresses.Length)
{
throw;
}
}
}
if (imaps)
{
var ssl = new SslStream(new NetworkStream(socket, true), false, ValidateRemoteCertificate);
ssl.AuthenticateAsClient(uri.Host, ClientCertificates, SslProtocols.Default, true);
stream = ssl;
}
else
{
stream = new NetworkStream(socket, true);
}
#else
socket = new StreamSocket();
cancellationToken.ThrowIfCancellationRequested();
socket.ConnectAsync(new HostName(uri.DnsSafeHost), port.ToString(), imaps ? SocketProtectionLevel.Tls12 : SocketProtectionLevel.PlainSocket)
.AsTask(cancellationToken)
.GetAwaiter()
.GetResult();
stream = new DuplexStream(socket.InputStream.AsStreamForRead(), socket.OutputStream.AsStreamForWrite());
#endif
host = uri.Host;
logger.LogConnect(uri);
engine.Connect(new ImapStream(stream, logger), cancellationToken);
// Only query the CAPABILITIES if the greeting didn't include them.
if (engine.CapabilitiesVersion == 0)
{
engine.QueryCapabilities(cancellationToken);
}
if (starttls && (engine.Capabilities & ImapCapabilities.StartTLS) != 0)
{
var ic = engine.QueueCommand(cancellationToken, null, "STARTTLS\r\n");
engine.Wait(ic);
if (ic.Result == ImapCommandResult.Ok)
{
#if !NETFX_CORE
var tls = new SslStream(stream, false, ValidateRemoteCertificate);
tls.AuthenticateAsClient(uri.Host, ClientCertificates, SslProtocols.Tls, true);
engine.Stream.Stream = tls;
#else
socket.UpgradeToSslAsync(SocketProtectionLevel.Tls12, new HostName(uri.DnsSafeHost))
.AsTask(cancellationToken)
.GetAwaiter()
.GetResult();
#endif
// Query the CAPABILITIES again if the server did not include an
// untagged CAPABILITIES response to the STARTTLS command.
if (engine.CapabilitiesVersion == 1)
{
engine.QueryCapabilities(cancellationToken);
}
}
}
else if (compress && (engine.Capabilities & ImapCapabilities.Compress) != 0)
{
var ic = engine.QueueCommand(cancellationToken, null, "COMPRESS DEFLATE\r\n");
engine.Wait(ic);
if (ic.Result == ImapCommandResult.Ok)
{
var unzip = new DeflateStream(stream, CompressionMode.Decompress);
var zip = new DeflateStream(stream, CompressionMode.Compress);
engine.Stream.Stream = new DuplexStream(unzip, zip);
// Query the CAPABILITIES again if the server did not include an
// untagged CAPABILITIES response to the COMPRESS command.
if (engine.CapabilitiesVersion == 1)
{
engine.QueryCapabilities(cancellationToken);
}
}
}
}