How to extract json values from MQTT payload to use in other nodes

Third party integrations Node-RED
1

Hello, I am trying to use Node-Red and Frigate together for automations.
I am listening to the friate/events MQTT topic and I get a payload like the following:

{"before":{"id":"1686592837.186892-9896gb","camera":"frank","frame_time":1686597538.83489,"snapshot_time":1686597538.83489,"label":"person","sub_label":null,"top_score":0.7265625,"false_positive":false,"start_time":1686592837.186892,"end_time":null,"score":0.57421875,"box":[531,531,824,718],"area":54791,"ratio":1.5668449197860963,"region":[508,396,832,720],"stationary":true,"motionless_count":4468,"position_changes":3,"current_zones":[],"entered_zones":[],"has_clip":false,"has_snapshot":true},"after":{"id":"1686592837.186892-9896gb","camera":"frank","frame_time":1686597598.958934,"snapshot_time":1686597538.83489,"label":"person","sub_label":null,"top_score":0.7265625,"false_positive":false,"start_time":1686592837.186892,"end_time":null,"score":0.57421875,"box":[527,537,800,718],"area":49413,"ratio":1.5082872928176796,"region":[493,352,861,720],"stationary":true,"motionless_count":5369,"position_changes":3,"current_zones":[],"entered_zones":[],"has_clip":false,"has_snapshot":true},"type":"update"}

I want to be able to extract and use some of the values like “id”, “label”, or “camera”
For example, I want to send a Discord Notification with a camera snapshot using a function node like this (this then goes into a Discord node):

msg.embed = {
    "message": "Check it out",
    "image": {
        "url": "http://192.168.1.15:8123/api/frigate/notifications/{{msg.payload.id}}/snapshot.jpg"
    }
};
msg.attachments = 'http://192.168.1.15:8123/api/frigate/notifications/{{msg.payload.id}}/snapshot.jpg';

return msg;

I’ve been able to send the snapshot using a hard coded event id, but I need help getting the actual id from the event.
The other thing that I want to do is to get the values from the payload into a Switch node to create conditional flows.

Can you help me do this?

2

One problem is that it is either “msg.payload.before.id” or “msg.payload.after.id”. But then you’re using a template-style structure in (presumably) a function node, which should be javascript.

msg.embed = {
    "message": "Check it out",
    "image": {
        "url": "http://192.168.1.15:8123/api/frigate/notifications/" + msg.payload.before.id + "/snapshot.jpg"
    }
};
msg.attachments = 'http://192.168.1.15:8123/api/frigate/notifications/{{msg.payload.id}}/snapshot.jpg';

return msg;

Oops - just noticed you have the same thing in msg.attachments that you should fix too.

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