Asynchronously accept a stream-type socket connection and act as the (server) end of the communications channel. This instance should have been created by -initWithFileDescriptor: with a stream-type socket created by the appropriate system routine. Posts a NSFileHandleConnectionAcceptedNotification when connection initiated, returning an NSFileHandle for the client side with that notification.

The modes array specifies NSRunLoop modes that the notification can be posted in.

Opens an outgoing network connection asynchronously.

• The address is the name (or IP dotted quad) of the machine to which the connection should be made.
• The service is the name (or number) of the port to which the connection should be made.
• The protocol is provided so support different network protocols, but at present only 'tcp' is supported. However, a protocol specification of the form 'socks-...' can be used to control socks5 support.
  If '...' is empty (ie the string is just 'socks-' then the connection is not made via a socks server.
  Otherwise, the text '...' must be the name of the host on which the socks5 server is running, with an optional port number separated from the host name by a colon.
  Alternatively a prefix of the form 'bind-' followed by an IP address may be used (for non-socks connections) to ensure that the connection is made from the specified address.
• If modes is nil or empty, uses NSDefaultRunLoopMode.

This method supports connection through a firewall via socks5. The socks5 connection may be controlled via the protocol argument, but if no socks information is supplied here, the GSSOCKS user default will be used, and failing that, the SOCKS5_SERVER or SOCKS_SERVER environment variables will be used to set the socks server. If none of these mechanisms specify a socks server, the connection will be made directly rather than through socks.

• The service is the name (or number) of the port to which the connection should be made.
• The protocol may at present only be 'tcp'

Return a flag to indicate whether compression has been turned on for the file handle... this is only available on systems where GNUstep was built with 'zlib' support for compressing/decompressing data.

On systems which support it, this method may be called after a file handle has been initialised to turn on compression or decompression of the data being written/read.

Returns YES on success, NO on failure.
Reasons for failure are -

• Not supported/built in to GNUstep
• File handle has been closed
• File handle is open for both read and write
• Failure in compression/decompression library

GSTLSCAFile

A string identifying the full path to the file containing any trusted certificate authorities to be used when verifying a certificate presented by the remote end of a connection.

GSTLSCertificateFile

The path to a PEM encoded certificate used to identify this end of the connection. This option must be set for handing an incoming connection, but is optional for outgoing connections.
This must be used in conjunction with GSTLSCertificateKeyFile.

GSTLSCertificateKeyFile

The path to a PEM encoded key used to unlock the certificate file for the connection. The key in the file may or may not be encrypted, but if it is encrypted you must specify GSTLSCertificateKeyPassword.

GSTLSCertificateKeyPassword

A string to be used as the password to decrypt a key which was specified using GSTLSKeyPassword.

GSTLSDebug

A boolean specifying whether diagnostic debug is to be enabled to log information about a connection where the handshake fails.

GSTLSIssuers

An array of distinguished names (in RFC4514 format) listing the permitted issuers of the remote certificate. If this is present and the issuer of the remote certificate is not in the array, the connection handshake is failed.

GSTLSOwners

An array of distinguished names (in RFC4514 format) listing the permitted owners/subjects of the remote certificate. If this is present and the owner/subject of the remote certificate is not in the array, the connection handshake is failed.

GSTLSPriority

A GNUTLS priority string describing the ciphers etc which may be used for the connection. In addition the string may be one of SSLv3, or TLSv1 to use the appropriate general settings for negotiating a connection of the specified type.

GSTLSRemoteHosts

A comma delimited list of host names to be allowed when verifying the certificate of the host we are connecting to.
If this is not specified, all the names provided by NSHost are used.

GSTLSRevokeFile

The full path of a file containing certificate revocation information for certificates issued by our trusted authorites but no longer valid.

GSTLSServerName

By default the TLS layer when making an HTTPS request sets the 'Server Name Indication' (SNI) to be the name of the host in the URL that is being fetched.
This option allows the SNI to be set for other connections and permits overriding of the default behavior for HTTPS requests. Setting the value of GSTLSServerName to an empty string will prevent the SNI from being sent in the TLS handshake (this is sometimes desirable to prevent information leakage; the SNI information is sent unencrypted).
Some web servers require SNI in order to tell what hostname an HTTPS request is for and decide which certificate to present to the client.

GSTLSVerify

A boolean specifying whether we should require the remote end to supply a valid certificate in order to establish an encrypted connection.