The MLLPServer control implements the server side of the Minimal Lower Layer Protocol.
The MLLPServer control is used to exchange HL7 data with one or more connected MLLP clients.
Setting up MLLPServer to Listen for Client Connections
The first step in using the MLLPServer control is to configure it to listen for MLLP client connections. Start by setting the LocalPort property to the desired listening port. For multi-homed devices, also set the LocalHost property to the address of the network interface the MLLPServer control should listen on.
Finally, set the Listening property to True to begin listening for client connections.
mllpServer.LocalHost = "localhost"; mllpServer.LocalPort = 7777; // The following two lines are only necessary if using TLS/SSL. mllpServer.SSLEnabled = true; mllpServer.SSLCert = new Certificate(CertStoreTypes.cstPFXFile, "..\\path\\to\\cert.pfx", "password", "*"); mllpServer.Listening = true;
At this point the ConnectionRequest event will fire anytime a client wishes to connect (connection requests are accepted by default), and the Connected event will fire each time a client successfully connects.
While clients are connected, the server may interact with them by using their OFTPConnectionConnectionId to interact with the control's properties.
The MLLPServer control will automatically receive HL7 data sent from each client, and will automatically send acknowledgements back.
When the MLLPServer control is receiving data, immediately before data transfer begins the StartTransfer event fires. During data transfer, one or more Transfer events will fire. When data transfer is complete, the EndTransfer event fires. Any errors during data delivery will cause the Error event to fire.
Immediately before the server acknowledgement is sent the AckOut event fires. The Accept parameter of this event is used to determine the type of acknowledgement (ACK or NAK) to send back to the client.
HL7 data received by the MLLPServer control will be stored in one of the following ways:
- If an output file path has been set to the OutputFilename property, the data is written to that file.
- Otherwise, the data is stored in the OutputData property.
The MLLPServer control may also send data to MLLP clients. First, specify the data to send by doing one of the following:
- Set the InputFilename property to the path of a file with HL7 data.
- Set the HL7 data directly to the InputData property.
Once the data has been specified, simply call the Send method with the appropriate connection Id to send the HL7 data to the associated client. Once the client has received the data, it will respond with an acknowledgement, causing the control's AckIn event to fire.
Sending Data Example
mllpServer.Connections[connectionId].InputData = "HL7Data"; mllpServer.Send(connectionId);
The following is the full list of the properties of the control with short descriptions. Click on the links for further details.
|ConnectionCount||The number of records in the arrays.|
|Connected||Triggers a connection or disconnection.|
|ConnectionId||The Id of the connection.|
|InputData||The raw HL7 data to send.|
|InputFilename||The path of a file containing HL7 data to send.|
|LocalAddress||The address of the local interface through which the connection is passing.|
|OutputData||The raw HL7 data received.|
|OutputFilename||The path of a file in which to store received HL7 data.|
|RemoteHost||The address of the MLLP client associated with the connection.|
|RemotePort||The port of the MLLP client associated with the connection.|
|Timeout||The timeout value, in seconds, for the connection.|
|DefaultTimeout||An initial timeout value to be used by incoming connections.|
|KeepAlive||When True, KEEPALIVE packets are enabled (for long connections).|
|Listening||If True, the control accepts incoming connections on LocalPort.|
|LocalHost||The name of the local host or user-assigned IP interface through which connections are initiated or accepted.|
|LocalPort||The TCP port in the local host where the control listens.|
|SSLAuthenticateClients||If true, the server asks the client(s) for a certificate.|
|SSLCertEncoded||The certificate (PEM/base64 encoded).|
|SSLCertStore||The name of the certificate store for the client certificate.|
|SSLCertStorePassword||If the certificate store is of a type that requires a password, this property is used to specify that password in order to open the certificate store.|
|SSLCertStoreType||The type of certificate store for this certificate.|
|SSLCertSubject||The subject of the certificate used for client authentication.|
|SSLEnabled||Whether TLS/SSL is enabled.|
|Version||The MLLP version to use.|
The following is the full list of the methods of the control with short descriptions. Click on the links for further details.
|Config||Sets or retrieves a configuration setting.|
|Disconnect||Disconnect the specified client.|
|DoEvents||Processes events from the internal message queue.|
|Interrupt||Interrupts a synchronous send to the remote host.|
|Reset||Reset the control.|
|Send||Send HL7 data to the MLLP client associated with the specified connection Id.|
|Shutdown||Shuts down the server.|
The following is the full list of the events fired by the control with short descriptions. Click on the links for further details.
|AckIn||Fires immediately after receiving an acknowledgement from a client.|
|AckOut||Fires immediately before sending an acknowledgement to a client.|
|Connected||Fired immediately after a connection completes (or fails).|
|ConnectionRequest||Fired when a request for connection comes from a remote host.|
|Disconnected||Fired when a connection is closed.|
|EndTransfer||Fires after incoming HL7 data finishes transferring.|
|Error||Information about errors during data delivery.|
|Log||Provides logging information.|
|SSLClientAuthentication||Fired when the client presents its credentials to the server.|
|SSLConnectionRequest||Fires when an SSL connection is requested.|
|SSLStatus||Shows the progress of the secure connection.|
|StartTransfer||Fires before incoming HL7 data begins transferring.|
|Transfer||Fires during incoming data transfer.|
The following is a list of configuration settings for the control with short descriptions. Click on the links for further details.
|ACKChar||The positive acknowledgement character.|
|EndBlockChar||The character that denotes the end of HL7 data.|
|EOLChar||The character that denotes the end of a message block.|
|LogLevel||The level of detail that is logged.|
|NAKChar||The negative acknowledgement character.|
|ReceiveTimeout||Maximum number of seconds to wait after receiving a StartBlockChar.|
|StartBlockChar||The character that denotes the beginning of HL7 data.|
|ConnectionTimeout||Sets a separate timeout value for establishing a connection.|
|FirewallAutoDetect||Tells the control whether or not to automatically detect and use firewall system settings, if available.|
|FirewallHost||Name or IP address of firewall (optional).|
|FirewallPassword||Password to be used if authentication is to be used when connecting through the firewall.|
|FirewallPort||The TCP port for the FirewallHost;.|
|FirewallType||Determines the type of firewall to connect through.|
|FirewallUser||A user name if authentication is to be used connecting through a firewall.|
|KeepAliveInterval||The retry interval, in milliseconds, to be used when a TCP keep-alive packet is sent and no response is received.|
|KeepAliveTime||The inactivity time in milliseconds before a TCP keep-alive packet is sent.|
|Linger||When set to True, connections are terminated gracefully.|
|LingerTime||Time in seconds to have the connection linger.|
|LocalHost||The name of the local host through which connections are initiated or accepted.|
|LocalPort||The port in the local host where the control binds.|
|MaxLineLength||The maximum amount of data to accumulate when no EOL is found.|
|MaxTransferRate||The transfer rate limit in bytes per second.|
|ProxyExceptionsList||A semicolon separated list of hosts and IPs to bypass when using a proxy.|
|TCPKeepAlive||Determines whether or not the keep alive socket option is enabled.|
|TcpNoDelay||Whether or not to delay when sending packets.|
|UseIPv6||Whether to use IPv6.|
|LogSSLPackets||Controls whether SSL packets are logged when using the internal security API.|
|OpenSSLCADir||The path to a directory containing CA certificates.|
|OpenSSLCAFile||Name of the file containing the list of CA's trusted by your application.|
|OpenSSLCipherList||A string that controls the ciphers to be used by SSL.|
|OpenSSLPrngSeedData||The data to seed the pseudo random number generator (PRNG).|
|ReuseSSLSession||Determines if the SSL session is reused.|
|SSLCACerts||A newline separated list of CA certificate to use during SSL client authentication.|
|SSLCheckCRL||Whether to check the Certificate Revocation List for the server certificate.|
|SSLCipherStrength||The minimum cipher strength used for bulk encryption.|
|SSLEnabledCipherSuites||The cipher suite to be used in an SSL negotiation.|
|SSLEnabledProtocols||Used to enable/disable the supported security protocols.|
|SSLEnableRenegotiation||Whether the renegotiation_info SSL extension is supported.|
|SSLIncludeCertChain||Whether the entire certificate chain is included in the SSLServerAuthentication event.|
|SSLNegotiatedCipher||Returns the negotiated ciphersuite.|
|SSLNegotiatedCipherStrength||Returns the negotiated ciphersuite strength.|
|SSLNegotiatedCipherSuite||Returns the negotiated ciphersuite.|
|SSLNegotiatedKeyExchange||Returns the negotiated key exchange algorithm.|
|SSLNegotiatedKeyExchangeStrength||Returns the negotiated key exchange algorithm strength.|
|SSLNegotiatedProtocol||Returns the negotiated protocol version.|
|SSLProvider||The name of the security provider to use.|
|SSLSecurityFlags||Flags that control certificate verification.|
|SSLServerCACerts||A newline separated list of CA certificate to use during SSL server certificate validation.|
|TLS12SignatureAlgorithms||Defines the allowed TLS 1.2 signature algorithms when UseInternalSecurityAPI is True.|
|TLS12SupportedGroups||The supported groups for ECC.|
|TLS13KeyShareGroups||The groups for which to pregenerate key shares.|
|TLS13SignatureAlgorithms||The allowed certificate signature algorithms.|
|TLS13SupportedGroups||The supported groups for (EC)DHE key exchange.|
|AbsoluteTimeout||Determines whether timeouts are inactivity timeouts or absolute timeouts.|
|FirewallData||Used to send extra data to the firewall.|
|InBufferSize||The size in bytes of the incoming queue of the socket.|
|OutBufferSize||The size in bytes of the outgoing queue of the socket.|
|CodePage||The system code page used for Unicode to Multibyte translations.|
|UseInternalSecurityAPI||Tells the control whether or not to use the system security libraries or an internal implementation.|