MLLPServer Class

Properties   Methods   Events   Configuration Settings   Errors  

The MLLPServer class implements the server side of the Minimal Lower Layer Protocol.




The MLLPServer class 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 class 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 class should listen on.

Next, optionally enable TLS/SSL with the SSLEnabled and SSLCert properties (MLLPServer supports client authentication with the SSLAuthenticateClients property).

Finally, set the Listening property to True to begin listening for client connections.

Connecting Example

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 ConnectionId to retrieve an MLLPConnection object from the Connections map property.

Receiving Data

The MLLPServer class will automatically receive HL7 data sent from each client, and will automatically send acknowledgements back.

When the MLLPServer class 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 class will be stored in one of the following ways:

  • If an output stream has been specified for the connection using the OutputStream field, the data is written to that stream.
  • Otherwise, if an output file path has been set to the OutputFilename field, the data is written to that file.
  • Otherwise, the data is stored in the OutputData field.

Sending Data

The MLLPServer class may also send data to MLLP clients. First, specify the data to send by doing one of the following:

  • Set the InputStream field to a stream with HL7 data.
  • Set the InputFilename field to the path of a file with HL7 data.
  • Set the HL7 data directly to the InputData field.

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 class's AckIn event to fire.

Sending Data Example

mllpServer.Connections[connectionId].InputData = "HL7Data";

Property List

The following is the full list of the properties of the class with short descriptions. Click on the links for further details.

ConnectionsA map of connected clients.
DefaultTimeoutAn initial timeout value to be used by incoming connections.
KeepAliveWhen True, KEEPALIVE packets are enabled (for long connections).
ListeningIf True, the class accepts incoming connections on LocalPort.
LocalHostThe name of the local host or user-assigned IP interface through which connections are initiated or accepted.
LocalPortThe TCP port in the local host where the class listens.
SSLAuthenticateClientsIf true, the server asks the client(s) for a certificate.
SSLCertThe certificate to be used during SSL negotiation.
SSLEnabledWhether TLS/SSL is enabled.
VersionThe MLLP version to use.

Method List

The following is the full list of the methods of the class with short descriptions. Click on the links for further details.

ConfigSets or retrieves a configuration setting.
DisconnectDisconnect the specified client.
DoEventsProcesses events from the internal message queue.
InterruptInterrupts a synchronous send to the remote host.
ResetReset the class.
SendSend HL7 data to the MLLP client associated with the specified connection Id.
ShutdownShuts down the server.

Event List

The following is the full list of the events fired by the class with short descriptions. Click on the links for further details.

AckInFires immediately after receiving an acknowledgement from a client.
AckOutFires immediately before sending an acknowledgement to a client.
ConnectedFired immediately after a connection completes (or fails).
ConnectionRequestFired when a request for connection comes from a remote host.
DisconnectedFired when a connection is closed.
EndTransferFires after incoming HL7 data finishes transferring.
ErrorInformation about errors during data delivery.
LogProvides logging information.
SSLClientAuthenticationFired when the client presents its credentials to the server.
SSLConnectionRequestFires when an SSL connection is requested.
SSLStatusShows the progress of the secure connection.
StartTransferFires before incoming HL7 data begins transferring.
TransferFires during incoming data transfer.

Configuration Settings

The following is a list of configuration settings for the class with short descriptions. Click on the links for further details.

ACKCharThe positive acknowledgement character.
EndBlockCharThe character that denotes the end of HL7 data.
EOLCharThe character that denotes the end of a message block.
LogLevelThe level of detail that is logged.
NAKCharThe negative acknowledgement character.
ReceiveTimeoutMaximum number of seconds to wait after receiving a StartBlockChar.
StartBlockCharThe character that denotes the beginning of HL7 data.
CloseStreamAfterTransferIf true, the class will close the upload or download stream after the transfer.
ConnectionTimeoutSets a separate timeout value for establishing a connection.
FirewallAutoDetectTells the class whether or not to automatically detect and use firewall system settings, if available.
FirewallHostName or IP address of firewall (optional).
FirewallListenerIf true, the class binds to a SOCKS firewall as a server (IPPort only).
FirewallPasswordPassword to be used if authentication is to be used when connecting through the firewall.
FirewallPortThe TCP port for the FirewallHost;.
FirewallTypeDetermines the type of firewall to connect through.
FirewallUserA user name if authentication is to be used connecting through a firewall.
KeepAliveIntervalThe retry interval, in milliseconds, to be used when a TCP keep-alive packet is sent and no response is received.
KeepAliveTimeThe inactivity time in milliseconds before a TCP keep-alive packet is sent.
LingerWhen set to True, connections are terminated gracefully.
LingerTimeTime in seconds to have the connection linger.
LocalHostThe name of the local host through which connections are initiated or accepted.
LocalPortThe port in the local host where the class binds.
MaxLineLengthThe maximum amount of data to accumulate when no EOL is found.
MaxTransferRateThe transfer rate limit in bytes per second.
ProxyExceptionsListA semicolon separated list of hosts and IPs to bypass when using a proxy.
TCPKeepAliveDetermines whether or not the keep alive socket option is enabled.
TcpNoDelayWhether or not to delay when sending packets.
UseIPv6Whether to use IPv6.
UseNTLMv2Whether to use NTLM V2.
LogSSLPacketsControls whether SSL packets are logged when using the internal security API.
ReuseSSLSessionDetermines if the SSL session is reused.
SSLCACertsA newline separated list of CA certificate to use during SSL client authentication.
SSLCheckCRLWhether to check the Certificate Revocation List for the server certificate.
SSLCipherStrengthThe minimum cipher strength used for bulk encryption.
SSLContextProtocolThe protocol used when getting an SSLContext instance.
SSLEnabledCipherSuitesThe cipher suite to be used in an SSL negotiation.
SSLEnabledProtocolsUsed to enable/disable the supported security protocols.
SSLEnableRenegotiationWhether the renegotiation_info SSL extension is supported.
SSLIncludeCertChainWhether the entire certificate chain is included in the SSLServerAuthentication event.
SSLNegotiatedCipherReturns the negotiated ciphersuite.
SSLNegotiatedCipherStrengthReturns the negotiated ciphersuite strength.
SSLNegotiatedCipherSuiteReturns the negotiated ciphersuite.
SSLNegotiatedKeyExchangeReturns the negotiated key exchange algorithm.
SSLNegotiatedKeyExchangeStrengthReturns the negotiated key exchange algorithm strength.
SSLNegotiatedProtocolReturns the negotiated protocol version.
SSLProviderThe name of the security provider to use.
SSLServerCACertsA newline separated list of CA certificate to use during SSL server certificate validation.
SSLTrustManagerFactoryAlgorithmThe algorithm to be used to create a TrustManager through TrustManagerFactory.
TLS12SignatureAlgorithmsDefines the allowed TLS 1.2 signature algorithms when UseInternalSecurityAPI is True.
TLS12SupportedGroupsThe supported groups for ECC.
TLS13KeyShareGroupsThe groups for which to pregenerate key shares.
TLS13SignatureAlgorithmsThe allowed certificate signature algorithms.
TLS13SupportedGroupsThe supported groups for (EC)DHE key exchange.
AbsoluteTimeoutDetermines whether timeouts are inactivity timeouts or absolute timeouts.
FirewallDataUsed to send extra data to the firewall.
InBufferSizeThe size in bytes of the incoming queue of the socket.
OutBufferSizeThe size in bytes of the outgoing queue of the socket.
BuildInfoInformation about the product's build.
GUIAvailableTells the class whether or not a message loop is available for processing events.
LicenseInfoInformation about the current license.
UseDaemonThreadsWhether threads created by the class are daemon threads.
UseInternalSecurityAPITells the class whether or not to use the system security libraries or an internal implementation.

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IPWorks EDI 2020 Java Edition - Version 20.0 [Build 8162]