Http_request post body empty!

ESPHome
1

Hi all,
I’ve a strange problem. I’d like to post an http_request in json format.
The request is sent successfully (I receive it on the other end), BUT, all the keys are empty !
Here’s the code:

    then:
      - http_request.post:
          url: http://maker.ifttt.com/trigger/ESP_REBOOT/with/key/xxxx2DwCqeE0K11Pie_vek7Lj09dTE8Kswo86aRgZre
          json: |-
            root["value1"] = "LINKY";
            root["value2"] = id(boot_reason_text).state;
            root["value3"] = ESP.getResetInfoPtr()->exccause;

I could figure out, that I’m wrong for value2 and value3. But I cannot be wrong for value1, correct ?
Does anyone have an idea what is missing ?

Thx in advance for your help,
Fred

2

Well, it looks like the ESPHome documention lakes a couple of details.
I’ve added:

headers:
  Content-Type: application/json

Now it works fine, I receive the data completely !