Read/write GVL as a block using REST API

[redford]

Hello, we have basically been able to establish communication via RestAPI. We could already read out single values/variables from the nodes of the PLC.

However, we have not yet found a way to read or write all variables of the GVL as a block. The Swagger-Docu doesn't give us much information.

We tried to create a subscription, that worked too, but nothing happens when when we start it.

Anyone can help?

[CodeShepherd · Accepted solution]

In short you cannot read out a whole structure just using the head node. See this topic.

You could do a bulk read or bulk subscribe. For this case you will have to give all paths of all nodes and subnodes you like to get to the read/subscribe function.

Read, response is a single http standard:

https://127.0.0.1:8443/automation/api/v2/bulk?type=read

[
 {
   "address": "framework/metrics/system/cpu-utilisation-percent",
   "type": "double"
  },
 {
   "address": "framework/metrics/system/memfree-mb",
   "type": "double"
  },
  {
   "address": "framework/metrics/system/memused-percent",
   "type": "double"
  }
]

Subscribe, response is a server send event (SSE) stream:

https://127.0.0.1:8443/automation/api/v2/events?nodes=datalayer/retain/stats/sync-counter,datalayer/retain/stats/free,framework/metrics/system/cpu-utilisation-percent&publishIntervalMs=1000