CODEWITHSUNDEEP
javascriptjsonnode.jsibm-cloudnode-red
Romeo Kienzler
Romeo Kienzler

Reputation: 3539

How can I transform a JSON array of object contained in one message to multiple JSON object messages?

currently creating an ETL flow running in Node-RED, running on Node.js, running on Bluemix running on CloudFoundry.

I'm querying a Cloudant DB and get the result of the query returned as on single JSON array containing all documents as JSON objects.

No I want to individually process those in a pipe-lined fashion. How can this be archieved in Node-RED?

Thanks a lot!

JSON

[{
  "id": "c8342b2a.bf0df",
  "type": "cloudant in",
  "z": "2f0a54f6.110ccc",
  "service": "nokeredrkie-cloudantNoSQLDB",
  "cloudant": "",
  "name": "",
  "database": "tweets",
  "search": "_all_",
  "design": "",
  "index": "",
  "x": 295.70001220703125,
  "y": 450.9333190917969,
  "wires": [
    ["5e83a34.48cdd5c"]
  ]
}, {
  "id": "c9411e75.2b1b7",
  "type": "debug",
  "z": "2f0a54f6.110ccc",
  "name": "",
  "active": true,
  "console": "false",
  "complete": "payload",
  "x": 646.699951171875,
  "y": 470.7333679199219,
  "wires": []
}, {
  "id": "3f1d2018.8f5ec8",
  "type": "inject",
  "z": "2f0a54f6.110ccc",
  "name": "",
  "topic": "",
  "payload": "",
  "payloadType": "date",
  "repeat": "",
  "crontab": "",
  "once": true,
  "x": 126.70001220703125,
  "y": 472.6666564941406,
  "wires": [
    ["c8342b2a.bf0df"]
  ]
}, {
  "id": "5e83a34.48cdd5c",
  "type": "function",
  "z": "2f0a54f6.110ccc",
  "name": "",
  "func": "//msg.payload = JSON.parse(msg.payload);\nmsg.payload = msg.payload[1].tweet.user.screen_name;\nreturn msg;",
  "outputs": 1,
  "noerr": 0,
  "x": 444.70001220703125,
  "y": 489.4000549316406,
  "wires": [
    ["c9411e75.2b1b7"]
  ]
}]

Upvotes: 1

Views: 4347

Answers (1)

hardillb
hardillb

Reputation: 59668

Output the Cloudant node to Function node with something like this:

var msgs = [];
for (var i = 0; i< msg.payload.length; i++) {
  msgs.push({payload: msg.payload[i]});
}

return [msgs]

This will stream each item in the array to the next node in the flow

Edit: need to wrap the array in another set of [] to get all the messages out the same output.

Upvotes: 2

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