根据上下文值路由或阻止消息
问题
您希望根据另一个变量的当前值将消息路由到不同的流，或完全停止它。
解决方案
将切换变量保存到流上下文变量中，然后使用Switch节点检查该流上下文属性的值与对应于该节点不同输出的不同值进行比较。
示例
[{"id":"a62d8cdf.1bd82","type":"inject","z":"9138b11f.f64d5","name":"Inject","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"2","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":140,"y":585,"wires":[["b8bbbc41.f272"]]},{"id":"b8bbbc41.f272","type":"switch","z":"9138b11f.f64d5","name":"Context based routing","property":"state","propertyType":"flow","rules":[{"t":"eq","v":"1","vt":"num"},{"t":"eq","v":"2","vt":"num"},{"t":"eq","v":"3","vt":"num"}],"checkall":"true","repair":false,"outputs":3,"x":350,"y":585,"wires":[["9aa9c6b2.18a8e8"],["6ba4ec46.476794"],["a2e806c8.ffa168"]]},{"id":"9aa9c6b2.18a8e8","type":"debug","z":"9138b11f.f64d5","name":"Output 1","active":true,"tosidebar":true,"console":false,"tostatus":true,"complete":"payload","targetType":"msg","x":590,"y":525,"wires":[]},{"id":"6ba4ec46.476794","type":"debug","z":"9138b11f.f64d5","name":"Output 2","active":true,"tosidebar":true,"console":false,"tostatus":true,"complete":"payload","targetType":"msg","x":590,"y":585,"wires":[]},{"id":"a2e806c8.ffa168","type":"debug","z":"9138b11f.f64d5","name":"Output 3","active":true,"tosidebar":true,"console":false,"tostatus":true,"complete":"payload","targetType":"msg","x":590,"y":645,"wires":[]},{"id":"8aabdb51.e8b538","type":"inject","z":"9138b11f.f64d5","name":"Set state 0 - turn off","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"0","payloadType":"num","x":180,"y":675,"wires":[["e46083e4.1f17b"]]},{"id":"d1722dee.48db4","type":"inject","z":"9138b11f.f64d5","name":"Set state 1 - send to output 1","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"1","payloadType":"num","x":210,"y":720,"wires":[["e46083e4.1f17b"]]},{"id":"4bdb08de.706328","type":"inject","z":"9138b11f.f64d5","name":"Set state 2 - send to output 2","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"2","payloadType":"num","x":210,"y":765,"wires":[["e46083e4.1f17b"]]},{"id":"220ce0a6.cf81e","type":"inject","z":"9138b11f.f64d5","name":"Set state 3 - send to output 3","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"3","payloadType":"num","x":210,"y":810,"wires":[["e46083e4.1f17b"]]},{"id":"e46083e4.1f17b","type":"change","z":"9138b11f.f64d5","name":"Set flow.state","rules":[{"t":"set","p":"state","pt":"flow","to":"payload","tot":"msg"}],"action":"","property":"","from":"","to":"","reg":false,"x":470,"y":720,"wires":[[]]}]
讨论
在示例流程中，顶部流程表示消息流，该消息流可以通过Switch节点停止或路由到三个输出之一。
底部流程提供了一组Inject节点，用于更改flow.state上下文属性的当前值。
这可以作为一个简单的门控功能使用——基于您存储到flow.state上下文属性中的其他输入值。
这展示了如何通过单独的流程更改一个流程中的路由。
