node-red - 如何将 MQTT 数据发布到空白网页

Question

我想将通过 MQTT 接收的数据发布到空白 HTML 网页上，以便该网页的唯一内容是通过 MQTT 发送的原始 msg.payload。为此，我创建了以下流程。

我曾尝试使用 GET 和 POST 功能，也尝试过 websocket 功能，但没有运气，我希望有人能告诉我哪里出错了。预期的网页只是显示温度值的网页。

编辑：

标签： node-red

Answer 1

你似乎很亲近。一种简单的方法如下所示。

首先，将有效负载保存到流上下文变量中。我使用了注入节点，但您将替换为 MQTT 节点。

其次，您在节点中使用 HTTP 来触发将读取流上下文变量的流msg.payload。

当您将浏览器指向端点/mytemp时，您将看到温度。

[{"id":"6eba3ed8.e29ba","type":"tab","label":"Flow 4","disabled":false,"info":""},{"id":"a35c9258.340b1","type":"debug","z":"6eba3ed8.e29ba","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","x":570,"y":120,"wires":[]},{"id":"fb8bcf33.015ee","type":"http in","z":"6eba3ed8.e29ba","name":"/mytemp","url":"/mytemp","method":"get","upload":false,"swaggerDoc":"","x":180,"y":220,"wires":[["7bb7b19.2efd75"]]},{"id":"7bb7b19.2efd75","type":"change","z":"6eba3ed8.e29ba","name":"mytemp","rules":[{"t":"set","p":"payload","pt":"msg","to":"mytemp","tot":"flow"}],"action":"","property":"","from":"","to":"","reg":false,"x":340,"y":220,"wires":[["8b54468f.82d758","2b02d89.dfec028"]]},{"id":"8b54468f.82d758","type":"debug","z":"6eba3ed8.e29ba","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","x":550,"y":280,"wires":[]},{"id":"a691c7d8.da5d78","type":"inject","z":"6eba3ed8.e29ba","name":"","topic":"","payload":"21","payloadType":"num","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":190,"y":120,"wires":[["3af6ea2f.2c0476"]]},{"id":"3af6ea2f.2c0476","type":"change","z":"6eba3ed8.e29ba","name":"flow.mytemp","rules":[{"t":"set","p":"mytemp","pt":"flow","to":"payload","tot":"msg"}],"action":"","property":"","from":"","to":"","reg":false,"x":370,"y":120,"wires":[["a35c9258.340b1"]]},{"id":"2b02d89.dfec028","type":"http response","z":"6eba3ed8.e29ba","name":"","statusCode":"","headers":{},"x":570,"y":220,"wires":[]},{"id":"2f1ab064.3b768","type":"inject","z":"6eba3ed8.e29ba","name":"","topic":"","payload":"33","payloadType":"num","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":190,"y":160,"wires":[["3af6ea2f.2c0476"]]}]