JSON Messages for WebSocket Connections

PCo supports the following six JSON messages:

Message	Description
GetTemplates	This message lists all notification templates for the running agent instances for which you have created a WebSocket destination system. Example `{ Action: "GetTemplates" }`
GetFeatures	This message lists all functions that are supported by the running agent instance. Example `{ Action: "GetFeatures" }`
Subscribe	With this message, you can subscribe to the current WebSocket to receive notifications by using the given template. Sample Code SUBSCRIBE command in JSON Format: { Action: "Subscribe", Params: { TagNames: [ { Name: "Data Type Examples.16 Bit Device.R Registers.Double1", IsNative:true, "Alias":"Double1"} , { Name: "Data Type Examples.16 Bit Device.R Registers.Short1", IsNative:true, "Alias":"Short1"}, ], "Template":"myTemplate" } }
Unsubscribe	With the Unsubscribe message you can remove subscriptions. You can specify that the WebSocket is no longer subscribed to specific tags or entire notifications. If you want the WebSocket client to remove the subscription for the entire notification, the parameters must not be set. To reduce the load on the source system, the Web clients need to send this command before the WebSocket closes (when you leave the website). Otherwise, the subscription for the notification is maintained. Sample Code UNSUBSCRIBE command in JSON Format: { Action: "Unsubscribe", Params: { TagNames: [ { Name: "Data Type Examples.16 Bit Device.R Registers.Double1", IsNative:true, "Alias":"Double1"} , { Name: "Data Type Examples.16 Bit Device.R Registers.Short1", IsNative:true, "Alias":"Short1"}, ], } }
Reconnect	With the Reconnect message, you can reconnect the WebSocket with an existing notification using the given handle. Sample Code Reconnect command in JSON Format: { Action: "Reconnect", Params: { Handle : "87726337-1d44-47b3-8f65-91508b6c085e" } }
Retrieve	With this message you can read tag values for the query process. Sample Code RETRIEVE command in JSON Format: { Action: "Retrieve", Params: { TagNames: [ { Name: "Data Type Examples.16 Bit Device.K Registers.Short1", IsNative:true, Alias:"Short1"}, { Name: "Data Type Examples.16 Bit Device.K Registers.Short2", IsNative:true, Alias:"Short2"} ], } }
Retrieve (with Metadata and Secondaries)	With this message you can read tag values (with metadata and secondaries) for the query process. Sample Code RETRIEVE command with Metadata and Secondaries in JSON Format: { Action: "Retrieve", Params: { TagNames: [ { Name: "Data Type Examples.16 Bit Device.K Registers.Short1", IsNative:true, Alias:"Short1"}, { Name: "Data Type Examples.16 Bit Device.K Registers.Short2", IsNative:true, Alias:"Short2"} ], MetaDataList: [ "Item Description", "DDE Access Name" ], SecondaryList: [ "Quality", "Item Timestamp" ] } }
Response	With this message you can respond to retrieve commands. The response contains metadata and secondaries. Sample Code Response for RETRIEVE command with Metadata and Secondaries in JSON Format { "TagValues":[ { "Alias":"Short1", "DateTime":"\/Date(1435063691578)\/", "Value":"0", "MetaData":[ { "Name":"Item Description", "Value":"16-Bit signed integer" }, { "Name":"DDE Access Name", "Value":"Data Type Examples_16 Bit Device" } ], "Secondary":[ { "Name":"Quality", "Value":"Good, Non-specific, Not limited" }, { "Name":"Item Timestamp", "Value":"23.06.2015 12:48:11" } ] }, { "Alias":"Short2", "DateTime":"\/Date(1435063691578)\/", "Value":"0", "MetaData":[ { "Name":"Item Description", "Value":"16-Bit signed integer" }, { "Name":"DDE Access Name", "Value":"Data Type Examples_16 Bit Device" } ], "Secondary":[ { "Name":"Quality", "Value":"Good, Non-specific, Not limited" }, { "Name":"Item Timestamp", "Value":"23.06.2015 12:48:11" } ] } ], "Success":true, "Error": { "Code":null, "Message":{"Value":null} } }
Store	With this message, you can write tag values using the given time stamp. Sample Code STORE command in JSON Format: { Action: "Store", Params: { TagValues: [ { TagName: { Name: 'Data Type Examples.16 Bit Device.K Registers.Short1', IsNative: true, Alias: 'Test' }, Value: '111', DateTime: '2015-03-10T12:00:00' }, { TagName: {Name: 'Data Type Examples.16 Bit Device.K Registers.Short2', IsNative: true, Alias: 'Test2' }, Value: '222', DateTime: '2015-03-10T12:00:00' } ] } }