From string to array in jsonata

General
1

Hello everyone,
Following a previous post on redis contrib node (Make redis config node more "dynamic") I am now struggling on the config node from https://flows.nodered.org/node/node-red-contrib-redis
In order to use a redis cluster, the config node as to be initialised with an array looking like this:

[
   {
      "host": "192.168.1.107",
      "port": 6380
   },
   {
      "host": "192.168.1.6",
      "port": 6379
   },
   {
      "host": "192.168.1.186",
      "port": 6379
   },
   {
      "host": "192.168.1.132",
      "port": 6379
   },
   {
      "host": "192.168.1.22",
      "port": 6379
   },
   {
      "host": "192.168.1.224",
      "port": 6379
   }
]

The node can be configured (for the redis server part) using jsonata.
I like to get this value out of an env variable, which is a string.

Unlike the json node, I cannot figure a way to transform a string "looking like an array" to an actual array using jsonata.
I can format the env variable differently if it helps, however, from with the redis node it must be an array as showed above.
Is there a way to achieve that through jsonata transformation ?

Thanks !

2

$eval() would be the way to convert a json string to an object, Or if you had a format like

host:port
host:port

you could split it.
e.g.

[{"id":"43d28cb357dde293","type":"inject","z":"b779de97.b1b46","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"[{\"host\":\"192.168.1.107\",\"port\":6380},{\"host\":\"192.168.1.6\",\"port\":6379},{\"host\":\"192.168.1.186\",\"port\":6379},{\"host\":\"192.168.1.132\",\"port\":6379},{\"host\":\"192.168.1.22\",\"port\":6379},{\"host\":\"192.168.1.224\",\"port\":6379}]","payloadType":"str","x":130,"y":2600,"wires":[["4d4ff611d3d2c527"]]},{"id":"4d4ff611d3d2c527","type":"change","z":"b779de97.b1b46","name":"","rules":[{"t":"set","p":"payload","pt":"msg","to":"$eval($$.payload)","tot":"jsonata"}],"action":"","property":"","from":"","to":"","reg":false,"x":280,"y":2600,"wires":[["387675af5fa81414"]]},{"id":"387675af5fa81414","type":"debug","z":"b779de97.b1b46","name":"debug 299","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","statusVal":"","statusType":"auto","x":450,"y":2600,"wires":[]},{"id":"de42835e6ad8b66b","type":"change","z":"b779de97.b1b46","name":"","rules":[{"t":"set","p":"payload","pt":"msg","to":"$split($$.payload, \"\\n\").($parts:=$split($,\":\");\t{\"host\": $parts[0],\"post\":$parts[1]})","tot":"jsonata"}],"action":"","property":"","from":"","to":"","reg":false,"x":480,"y":2660,"wires":[["387675af5fa81414"]]},{"id":"3619501058a5b350","type":"template","z":"b779de97.b1b46","name":"","field":"payload","fieldType":"msg","format":"handlebars","syntax":"mustache","template":"192.168.1.107:6380\n192.168.1.6:6379","output":"str","x":300,"y":2660,"wires":[["de42835e6ad8b66b"]]},{"id":"5043d3d9928e476d","type":"inject","z":"b779de97.b1b46","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":140,"y":2660,"wires":[["3619501058a5b350"]]}]

Obviously $$.payload would be $env("env_property_name")

3

If the string is valid json, the JSON node is the right thing to use.

4

I think @greengolfer is trying to set an array in the config field of the redis node (which allows jsonata), so can not use a json node.

5

Exactly... The redis config can't use incoming message. So, jsonata is the only way, I think.

6

What @E1cid suggested works (thanks a lot) though, it doesn't work with this contrib flow...

I have an env variable called cluster (!) with:
[ { "host": "192.168.1.107", "port": 6380 }, { "host": "192.168.1.6", "port": 6379 }, { "host": "192.168.1.186", "port": 6379 }, { "host": "192.168.1.132", "port": 6379 }, { "host": "192.168.1.22", "port": 6379 }, { "host": "192.168.1.224", "port": 6379 } ]

If I do as suggested $eval($$.$env("cluster")) in a inject node to test, it is fine the output is the expected array.

If I do the same think in the redis config node, it doesn't.
Looking at the flows.json, the config node looks like:

   {                                            
        "id": "c8318783347b07af",                
        "type": "redis-config",                  
        "name": "Cluster",                       
        "options": "$eval($$.$env(\"cluster\"))",
        "cluster": true,                         
        "optionsType": "jsonata"                 
    },

Which seems to be correct.
However, the node complains that the syntax is not correct.

Looking at the redis.js code, it looks like this:

  function RedisConfig(n) {
    RED.nodes.createNode(this, n);
    this.name = n.name;
    if (this.optionsType === "") {
      this.options = n.options;
    } else {
      this.options = RED.util.evaluateNodeProperty(
        n.options,
        n.optionsType,
        this
      );
    }

Not being fluent in javascript, I am stuck :frowning:

I have raised an issue on the other matter (clustering as env variable). No answer after a month. It looks that this redis contrib node has lost his parent(s). :cry:

7

Seems is the key word here as the $$ is not correct

$eval($env("cluster"))

As suggested here

8

Thanks. You are right.

For my defence :wink: in the inject node $eval($$.$env("cluster")) and $eval($env("cluster")) are giving the same thing on the debug.
Not as part of the redis config node. The latter works. Not the former. Mmmm...
One day I'll understand jsonata. Maybe.

9

Just for info : -
$$ means you are in base context, i.e msg
Now the . would mean one of two things.
1, path property expected
2, map over the array $$
As there is no array and no path property present, just a function, an error is thrown.
So $$ should only be used if you are referencing the msg context.

1 Like
10

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