WebSocket Server

The WebSocket Server provides a JSON API via bidirectional WebSocket protocol for access to OPC UA variables. Its configuration starts with XML tag WebSocketServer in OpcUaWebServerModel.xml.

Default Configuration

<WebSocketServer>
    <Address>0.0.0.0</Address>
    <Port>8081</Port>
    <MaxConnections>100</MaxConnections>
    <RequestTimeout>5000</RequestTimeout>
    <IdleTimeout>3600000</IdleTimeout>

    <SSL>on</SSL>
    <CSRFile>@CONF_DIR@/ssl/crt/websocket.crt</CSRFile>
    <KeyFile>@CONF_DIR@/ssl/key/websocket.pem</KeyFile>
</WebSocketServer>

Configuration Settings

XML tag	Description
IP Address	IP address bound by the WebSocket server
Port	Port bound by the WebSocket server
MaxConnections	Maximum number of simultaneous connections that this server supports.
RequestTimeout	Time after the TCP connection establishment in milliseconds, that the server waits for the request from the client before closing the connection.
IdleTimeout	Time after the last message in milliseconds that the server waits before closing the connection.
SSL	activates (“on”) or deactivates (“off”) the websocket security. The SSL tag is optional. If the SSL tag is not available, the websocket security is deactivated
CSRFile	Name of the certificate file. The tag must be specified when the websocket security is switched on
KeyFile	Name of the private key file. The tag must be specified when the websocket security is switched on.

OPC UA Client

In order to have access to OPC UA servers we have to include its communication settings and nodes in OpcUaClient part into OpcUaWebServerModel.xml file:

<OpcUaClient>
  <ClientConfigFile>@CONF_DIR@/OpcUaClient0.xml</ClientConfigFile>
  <ClientConfigFile>@CONF_DIR@/OpcUaClient1.xml</ClientConfigFile>
</OpcUaClient>

Example of OpcUaClient Configuration File

<?xml version="1.0" encoding="utf-8"?>
<OpcUaClient Name="ASNeG-Demo_0" xmlns="http://ASNeG/OpcUaClient.xsd">
  <Endpoint>
    <ServerUri>opc.tcp://127.0.0.1:8889</ServerUri>
    <SecurityMode>SignAndEncrypt</SecurityMode>
    <SecurityPolicyUri>http://opcfoundation.org/UA/SecurityPolicy#Basic128Rsa15</SecurityPolicyUri>
    <UserAuth>
      <Type>UserName</Type>
      <UserName>user1</UserName>
      <Password>password1</Password>
      <SecurityPolicyUri>http://opcfoundation.org/UA/SecurityPolicy#Basic128Rsa15<SecurityPolicyUri>
    </UserAuth>
  </Endpoint>
  <NamespaceUri>
    <Uri>http://ASNeG-Demo.de/Test-Server-Lib/</Uri>
  </NamespaceUri>
  <NodeList>
    <Node ValueName="TimerInterval" NodeId="ns=1;i=3" NodeType="UInt32">
      <MetaData>
        <DisplayName>TimerInterval</DisplayName>
      </MetaData>
    </Node>
    <Node ValueName="Boolean" NodeId="ns=1;i=220" NodeType="Boolean">
      <MetaData>
        <DisplayName>Switch</DisplayName>
        <Limits>
          <Min>0</Min>
          <Max>1</Max>
        </Limits>
      </MetaData>
    </Node>
  </NodeList>
</OpcUaClient>

Note

You need client configuration files only for WebSocket Server. WebSocket Gateway receives the information about communication and security through JSON API.

OpcUaClient Configuration Settings

XML tag			Description
Endpoint			Endpoint of the OPC UA Server, which the client connect to
	ServerUri		URI of the OPC UA Server
	SecurityMode		Security Mode can be “None”, “Sign” and “SignAndCrypt”. Default value is “None”.
	SecurityPolicyUri		Security Policy URI used to encrypt OPC UA messages. See https://opcfoundation.org/UA/SecurityPolicy/
	UserAuth		Authentication settings, which the client use to connect with the OPC UA server
		Type	Type of the authentication can be “Anonymous” or “UserName”
		Username	Name of the authenticated user. Only for “Username” type.
		Password	Password of the authenticated user. Only for “Username” type.
		SecurityPolicy	Security Policy URI used to encrypt password. If it is empty the password is not encrypted.
NamespaceUri			List of Namespace URIs
	Uri		Namespace URI
NodeList			List of OPC UA Variables for access from WebSocket Server.
	Node		OPC UA Variables
	Attr	ValueName	Name of the variable to access with JSON API
	Attr	NodeId	ID of the corresponding Variable in the OPCUA Server
	Attr	ValueType	Type of the OPC UA Variable. Use OPC UA names
	Attr	Array	Equals 1 if the variable is an array
		MetaData	Additional data that can be available through JSON API.

WebSocket Gateway

The WebSocket Server provides a JSON API via bidirectional WebSocket protocol for access to OPC UA variables. Its configuration starts with XML tag WebSocketServer in OpcUaWebServerModel.xml.

Default Configuration

<WebSocketServer>
    <Address>0.0.0.0</Address>
    <Port>8081</Port>
    <RequestTimeout>5000</RequestTimeout>
    <IdleTimeout>3600000</IdleTimeout>

    <SSL>on</SSL>
    <CSRFile>@CONF_DIR@/ssl/crt/websocket.crt</CSRFile>
    <KeyFile>@CONF_DIR@/ssl/key/websocket.pem</KeyFile>
</WebSocketServer>

Configuration Settings

XML tag	Description
IP Address	IP address bound by the WebSocket server
Port	Port bound by the WebSocket server
RequestTimeout	Time after the TCP connection establishment in milliseconds, that the server waits for the request from the client before closing the connection.
IdleTimeout	Time after the last message in milliseconds that the server waits before closing the connection.
SSL	activates (“on”) or deactivates (“off”) the websocket security. The SSL tag is optional. If the SSL tag is not available, the websocket security is deactivated
CSRFile	Name of the certificate file. The tag must be specified when the websocket security is switched on
KeyFile	Name of the private key file. The tag must be specified when the websocket security is switched on.

Note

NodeId has the format common for OPC UA standard (e.g. “i=208;ns=0”), but be careful! “ns” means the namsespace index in NapespaceUri list not the name space of the server.