Template sensor reading from json file

Configuration
1

I need to define a template sensor which monitors a json file. Previously I’d simply define it in yaml file and create a sensor to associate with it.
But as this is deprecated, how do I create a helper template sensor to monitor and read a value from a json file?

2

The file sensor only reads the last line of a file. Is that any use?

If not, can you receive the json directly from whatever creates the file instead?

If so then use the restful sensor:

3

This is an example that reads from an API:

- triggers:
    - trigger: time_pattern
      minutes: /10
  actions:
    - action: rest_command.get_filaments
      response_variable: get_filaments_response
  sensor:
    - name: Filaments list
      unique_id: filaments_list
      state: >
        {% if get_filaments_response["status"] != 200 %}
          unavailable
        {% else %}
          {{ now() }}
        {% endif %}
      attributes:
        payload: '{{ get_filaments_response["content"] }}'

For a file, you could replace the rest_command by a command_line that does a plain cat my_file.json (rest_command might support the file:/// protocol, but not sure)

4

I got the impression that File had been deprecated as I had to run a Repair recently and remove the file sensors from configuration.yaml. I’ve used a command_line now instead, still editing configuration.yaml, and that seems to be acceptable to HA.

5

No it has not been depreciated.

6

It was removed from YAML IIRC, that’s what they are likely thinking about.

1 Like
7

Yes probably this which triggered the Repair. But I’ve not found a way of continuing to use File within the gui.
So is adding command_line into configuration.yaml the correct solution or will that also be deprecated next?

8

Literally called File when you search integrations. :man_shrugging:

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9

Ah ha brilliant thanks. I hadn’t appreciated that it was now achieved using this. I’ll remove the command_line from configuration.yaml and use this File integration instead.
Thanks

10

I mean, if you want yaml and command_line works, no reason to change it. IMO

11

They added an action a couple months ago so you can get the file contents returned in a response variable. It’s not limited in the last line like the sensor.

2 Likes
12

Nice. I somehow missed or forgot that update.