Solution is to use REST API instead.

curl -X POST "http://192.168.1.2:8080/rest/v2/point-values?fireEvents=NEVER"

API follows JSON syntax "Square brackets hold arrays and values are separated by ,(comma)"

[
  {
    "annotation": "",
    "dataType": "NUMERIC",
    "timestamp": 1576117390000,
    "value": 227.1,
    "xid": "DP_a9b3bce6-98ea-493a-b840-2450f3ffc3ae"
  },
  {
    "annotation": "",
    "dataType": "NUMERIC",
    "timestamp": 1576117400000,
    "value": 228.1,
    "xid": "DP_a9b3bce6-98ea-493a-b840-2450f3ffc3ae"
  },
    {
    "annotation": "",
    "dataType": "NUMERIC",
    "timestamp": 1576117410000,
    "value": 229.1,
    "xid": "DP_a9b3bce6-98ea-493a-b840-2450f3ffc3ae"
  },
  {
    "annotation": "",
    "dataType": "NUMERIC",
    "timestamp": 1576117342000,
    "value": 220.1,
    "xid": "DP_a9b3bce6-98ea-493a-b840-2450f3ffc3ae"
  }
]

Full CURL with this body:

curl -X POST "http://192.168.1.2:8080/rest/v2/point-values?fireEvents=NEVER" -H "accept: application/json;charset=UTF-8" -H "Content-Type: application/json;charset=UTF-8" -H "X-XSRF-TOKEN: 58594b34-9a0d-4417-9b23-xxxx" -d "[ { \"annotation\": \"\", \"dataType\": \"NUMERIC\", \"timestamp\": 1576117390000, \"value\": 227.1, \"xid\": \"DP_a9b3bce6-98ea-493a-b840-2450f3ffc3ae\" }, { \"annotation\": \"\", \"dataType\": \"NUMERIC\", \"timestamp\": 1576117400000, \"value\": 228.1, \"xid\": \"DP_a9b3bce6-98ea-493a-b840-2450f3ffc3ae\" }, { \"annotation\": \"\", \"dataType\": \"NUMERIC\", \"timestamp\": 1576117410000, \"value\": 229.1, \"xid\": \"DP_a9b3bce6-98ea-493a-b840-2450f3ffc3ae\" }, { \"annotation\": \"\", \"dataType\": \"NUMERIC\", \"timestamp\": 1576117342000, \"value\": 220.1, \"xid\": \"DP_a9b3bce6-98ea-493a-b840-2450f3ffc3ae\" }]"

Something is seriously going wrong at mango-os. Or am I the only one that has noticed that more and more posts remain unanswered and that there is almost no participation from the company's staff.
Over the last few months there have been very few or no post by Jared Wiltshire, Joel Haggar, Phil Dunlap or Terry Packer.

Craig Web seemed to be posting for a while, but has also stopped a month ago.

The only one who seems to be frequently posting is Matt Fox, and he does not work at mango-os as far as I can see,

This forum is more or less the only reason we have chosen Mango. Other SCADAs mosty don't publicly post solutions and answers to issues. Is Mango-OS going this way?

@Rav-Panchalingam
Node Red.
https://flows.nodered.org/node/node-red-contrib-bacnet
https://cookbook.nodered.org/mqtt/publish-to-topic

Something is seriously going wrong at mango-os. Or am I the only one that has noticed that more and more posts remain unanswered and that there is almost no participation from the company's staff.
Over the last few months there have been very few or no post by Jared Wiltshire, Joel Haggar, Phil Dunlap or Terry Packer.

Craig Web seemed to be posting for a while, but has also stopped a month ago.

The only one who seems to be frequently posting is Matt Fox, and he does not work at mango-os as far as I can see,

This forum is more or less the only reason we have chosen Mango. Other SCADAs mosty don't publicly post solutions and answers to issues. Is Mango-OS going this way?

Congratulations.

I see references to 4.0, any info on that?

Thanks Fox.
Using normal HTTP Retriever the "Settable" works. Just not the with the JSON variant.

But even if there is a fix for the JSON version, I suspect that the HTTP JSON Retriever will, like the normal one, do a SET with a GET method Query. While there is no official method to do a HTTP "set", a POST or PUT would be a lot more appropriate than a GET.

{"method":"GET","path":"/api","query":{"name":"airtemp","value":"25"},"headers":{"x-forwarded-for":"103.30.92.123","x-forwarded-proto":"http","x-forwarded-port":"80","host":"80a86fbe836e421a7363a19aee8ef3d8.m.pipedream.net","x-amzn-trace-id":"Root=1-5ec232c0-a1ad0510c55a8440ee963140","user-agent":"Apache-HttpClient/4.5.5 (Java/11.0.5-ea)","accept-encoding":"gzip,deflate"}}

I will probably write a script that retrieves and sets points through the devices REST API.

Your edit relates to HTTP receiver, not the retriever.

I have define a HTTP JSON Retriever Source and added a Set Point URL. This saves OK.

Data point definition saves and validates fine.
However, The when the "Settable" box and Set Point Name are configured saving the point returns an error.

Internal Server Error — java.lang.ClassCastException: class com.serotonin.m2m2.http.vo.HttpJsonRetrieverDataSourceVO cannot be cast to class com.serotonin.m2m2.http.vo.HttpRetrieverDataSourceVO (com.serotonin.m2m2.http.vo.HttpJsonRetrieverDataSourceVO and com.serotonin.m2m2.http.vo.HttpRetrieverDataSourceVO are in unnamed module of loader java.net.URLClassLoader @560513ce)

Any advice? Documentation is a little thin on this/

Version 3.7.1

A previous similar question was not really answered:
Re: How to set a value using http

No need for MangoUI other than now and then do Admin stuff, We use our own Dashboards.

The API will be used in device on-boarding. Admin creates User, JWT, DataSource (device). Sets new user role to DataSource. This info will be set in device, which creates its own DataPoints (15 to 50) and uploads measuring data to the system from then on.

The JWT is not ideal from a security stand point, but good enough got us at the moment.

Thanks. My goal is to keep the API request JSON as small as possible, so I omitted as much as possible to the POST request to create a DP. Too much.

You are right.

  "readPermission":"emon3175585",
  "setPermission":"emon3175585",

needed to be added.

{
  "name": "test12-test2",
  "xid": "test12-test2",
  "dataSourceXid" : "test12",
  "readPermission":"emon3175585",
  "setPermission":"emon3175585",
  "pointLocator" : {
       "startValue" : "0",
       "modelType" : "PL.VIRTUAL",
       "dataType" : "NUMERIC",
       "settable" : true,
       "changeType" : "NO_CHANGE",
       "max": 100,
       "maxChange": 0.01,
       "min": 0
    }
}

My concern is the API, so that is solved.

The GUI DP creation permission may still have a problem as there is no SAVE button.

There is no console error because there is no SAVE button to press.

Using the API with JWT issued to user emon3175585:

curl --location --request POST 'http://xx.xx.xx.xx:8080/rest/v2/data-points' \
--header 'Content-Type: application/json' \
--header 'Authorization: Bearer eyJhbGciOiJFUzUxMiJ9.eyJzdWIiOiJlbW9uMzE3NTU4NSIsImV4cCI6MTU4MTk5NjgxMywiaWQiOjQsInYiOjEsInR5cCI6ImF1dGgifQ.AClqeOT6yAQCjGMYfXaMlDVgAcVOftGy3TSCrjxWat-Iz2yFut5nP4wntnE1xas3VtieFbxVwffbhmXwngPhHi8VAEFPPoaCD11unJ5_VTVWJkwnx73Eq8L2sbI9abLVM_CXXXXXXXXXXXXXX' \
--data-raw '{
  "name": "test12-test2",
  "xid": "test12-test2",
  "dataSourceXid" : "test12",
  "pointLocator" : {
       "startValue" : "0",
       "modelType" : "PL.VIRTUAL",
       "dataType" : "NUMERIC",
       "settable" : true,
       "changeType" : "NO_CHANGE",
       "max": 100,
       "maxChange": 0.01,
       "min": 0
    }
}'

Results in error: 422 Unprocessable Entity

{
  "result": {
    "messages": [
      {
        "level": "ERROR",
        "message": "Must retain permission",
        "property": "readPermission"
      },
      {
        "level": "ERROR",
        "message": "Must retain permission",
        "property": "setPermission"
      }
    ]
  },
  "mangoStatusCode": 4002,
  "mangoStatusName": "VALIDATION_FAILED",
  "localizedMessage": "Validation failed"
}

Naturally. But that was set already:

Thanks for your fast response.

I am probably missing something.

New DataSource created by Admin. User (emon3175585) given permission to edit the DataSource.

Yet, when user (emon3175585) logs in, the user cannot create new DataPoint.