YAMLの相互変換
課題
メッセージプロパティをYAML文字列に変換したり、JavaScriptのオブジェクトに変換したりしたい。
解決
YAML ノードを使用して、それぞれ2つのフォーマットを変換します。
例
[{"id":"f231967.0251a68","type":"inject","z":"64133d39.bb0394","name":"YAML String","topic":"","payload":"{\"a\":1}","payloadType":"str","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":110,"y":320,"wires":[["a0110756.ecfa48"]]},{"id":"8f8f31b7.1f916","type":"debug","z":"64133d39.bb0394","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","x":590,"y":320,"wires":[]},{"id":"5138ba3.c972444","type":"inject","z":"64133d39.bb0394","name":"Object","topic":"","payload":"{\"a\":1, \"b\":[1,2,3]}","payloadType":"json","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":90,"y":360,"wires":[["2fa653cc.60d3dc"]]},{"id":"50f2f4c.4a6e60c","type":"debug","z":"64133d39.bb0394","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","x":430,"y":360,"wires":[]},{"id":"a0110756.ecfa48","type":"template","z":"64133d39.bb0394","name":"","field":"payload","fieldType":"msg","format":"yaml","syntax":"plain","template":"a: 1\nb:\n - 1\n - 2\n - 3","output":"str","x":280,"y":320,"wires":[["104b80e2.51068f"]]},{"id":"2fa653cc.60d3dc","type":"yaml","z":"64133d39.bb0394","property":"payload","name":"","x":250,"y":360,"wires":[["50f2f4c.4a6e60c"]]},{"id":"104b80e2.51068f","type":"yaml","z":"64133d39.bb0394","property":"payload","name":"","x":430,"y":320,"wires":[["8f8f31b7.1f916"]]}]
議論
例では、最初のフローが次のようなYAML文字列を生成します:
a: 1
b:
- 1
- 2
- 3
そして、YAML ノードはそれを等価なJavaScriptオブジェクトに変換します:
2つめのフローでは逆を行っており、{ a: 1, b: [1,2,3] } というオブジェクトを生成し、YAMLに変換しています。
