TWSocketServer
Main page -> ICS component reference -> TWSocketServer and TSslWSocketServer
Contents
Overview
| unit | OverbyteIcsWSocketS.pas | |
| inheritance | TWSocket |
TWSocketServer will normally be used to listen on a given TCP port. When a client connects, it will instantiate a new TWSocketClient component to handle communication with client. Normally you will derive your own component from TWSocketClient to add private data and methods to handle your processing needs. You tell TWSocketServer which component class it has to instantiate using ClientClass property. You have to initialize each instance created to handle each client from OnClientConnect event handler. TWSocketServer maintain a list of connected clients. You can access it using Client[] indexed property. ClientCount property is the size of Client[] array.
Since it is derived from TWSocket and TSslWSocket, lots of properties and events are unused and not listed here. Properties and events that have a meaning in both server or client component are listed here.
Note that TWSocketServer is only usable for incoming TCP connections. Use TWSocket if you need to use UDP.
Note: When a TWSocketClient is closed, it automatically frees itself. With a normal TWSocket, the programmer is responsible for freeing the object.
Properties
| Addr | Server listen IP address, IPv4 or IPv6, maybe 0.0.0.0 or :: to listen on all available addresses, ignored if any IcsHosts specified. IP address must exist and not be in use elsewhere for the same port. | ||||
| Banner | A short message line sent when each client connects. Should generally be blank. | ||||
| BannerTooBusy | A short message sent when a client connects and the number of clients already exceeds the MaxClients limit. | ||||
| CertExpireDays | When using IcsHosts, the number of days before an SSL server certificate is due to expire that warnings will be generated (by the method RecheckSslCerts, perhaps triggering automatic SSL certificate ordering. | ||||
| Client | Currently active clients of ClientClass, indexed base zero. Note the index value may change each time a new client connects or disconnects, so check CliId to confirm it's the correct one. | ||||
| ClientClass | The class type the application has derived from TSslWSocketClient for client application code. | ||||
| ClientCount | Number of connected clients. | ||||
| DHParams | Specifies a DHParams file name, created using the PenTools sample, or use the provided dhparam1024.pem or dhparam2048.pem files. Used for DH and DHE ciphers, but not needed for modern ECDHE ciphers. Rather than a file name, may be an ASCII PEM string containing the DHParams without any line endings. | ||||
| Handle | Handle of the hidden window used for socket operation. | ||||
| HSocket | Underlying winsock socket handle. | ||||
| IcsHosts | Allows one or more TIcsHosts to be set, as TIcsHostCollection, an alternate way for specifying multiple listeners that allows multiple hosts to be specified, each with one or two IP addresses and non-SSL and SSL port bindings, SSL certificates and private key (perhaps combined in a bundle), SSL context and security level, and other web server host related properties (used by higher level components). Each IcsHost has one or more HostNames to which it will recognise, that can share IP addresses. | ||||
| LastError | Last error which occurred. | ||||
| ListenBacklog | How many new client connections should be queued by Windows while the server accepts them, before the server starts rejecting new connections by immediately closing them. Recommended as 15 for heavy use servers, may be up to 250. | ||||
| MaxClients | Maximum number of simultaneous clients the server should accept if non-zero. Any further clients will receive then BannerTooBusy response and the connection closed, until earlier connections are closed. | ||||
| MultiListenSockets | Allows one or more extra server listen IP addresses and ports to be specified, as type TWSocketMultiListenCollection, allowing server to listen on several IP addresses/ports at the same time, in addition to the that specified as Addr/Port props. Each TWSocketMultiListenItem has Addr, Port, SocketFamily, SslEnable and ListenBacklog properties. Better to use IcsHosts for new applications which does the same, ignored if any IcsHosts specified. | ||||
| MultiListenIndex | Read only, which listen socket accepted last connection, -1 if default Addr.Poprt used, 0 or above is index into MultiListenSockets collection. | ||||
| Port | TCP port or service name to listen to, usually 80 or 443, ignored if any IcsHosts specified. | ||||
| PortNum | Readonly property with numeric value corresponding to Port. | ||||
| Proto | Protocol used. Must be 'tcp'. | ||||
| RootCA | Specifying a file name containing a PEM bundle of trusted root SSL certificates allows validation of SSL server certificate chains. ICS includes RootCaCertsBundle.pem (large) and TrustedCABundle.pem (medium size), and a default built-in (small) that will be used if no file is specified. | ||||
| SocketErrs | How socket error messages should be presented as type TSocketErrs, wsErrTech or wsErrFriendly. | ||||
| SocketFamily | IP address socket family as TSocketFamily, from sfIPv4, sfIPv6. | ||||
| SslCertAutoOrder | True if IcsHosts are allowed to order and install SSL certificates automatically. Requires SslX509Certs property to be set, and CertSupplierProto set for any IcsHost that will order certificates. | ||||
| SslEnable | True if an SSL connection should be negotiated. ignored if any IcsHosts specified. | ||||
| SslCliCertMethod | Allows server to request a client SSL certificate from the browser or remote application, as type TSslCliCertMethod, with sslCliCertNone, sslCliCertOptional or sslCliCertRequire. Require will close the connection unless a valid certificate is received and validated against RootCA. Beware requesting a client certificate usually causes the browser to prompt the user for which certificate to send which can be obtrusive. | ||||
| SslContext | Assign to an TSslContext component for SSL support, where SSL certificates, keys, protocols and ciphers are specified, ignored if any IcsHosts specified. | ||||
| SslX509Certs | Assign to a TSslX509Certs component if automatic SSL certificate ordering is required. Ir ia very important that the onCertProg is used to log progress messages from the certificate ordering process in case of errors. The onCertsChallengeDNS event is called if a DNS server should be updated, onCertsOAuthAuthUrl if 0Auth2 authenication is needed, and onCertsNewCert when a new certificate is available which should be logged and the RecheckSslCerts method called to cause the server to load it. | State | Gives the state of the component. |
Methods
| Abort | Abort current asynchronous operation. | |
| Close | Stops listening, does not disconnect connected clients. | |
| CloseDelayed | Same as Close however it's executed delayed, after current event has finished. | |
| Create | Create a new instance of the component. | |
| Destroy | Destroy the current instance. | |
| IsClient | Check if a component reference is one of the connected clients. | |
| Listen | Start accepting connections. | |
| MessageLoop | Internal message loop. | |
| MessagePump | Internal message pump. | |
| ProcessMessage | Process a single message. | |
| ProcessMessages | Process messages until message queue is empty. | |
| Release | Destroy the current instance after the current event is terminated. | |
| ThreadAttach | Detach from current thread. | |
| ThreadDetach | Attach to current thread. |
Events
| OnBgException | When a background exception occurs. | |
| OnChangeState | When the component state changes. | |
| OnClientConnect | When a new client is connecting. | |
| OnClientCreate | When a new client component instance is created. | |
| OnClientDisconnect | When a client disconnects. | |
| OnError | When an error occurs. Better to use exception handling. | |
| OnMessagePump | To call your own external message pump instead of built-in one. |
How to
