How to filter json for value_json

Configuration
1

Dear all,

I have an MQTT sensor that serves a JSON string like this:

{"clients":[
  {
    "field1": "aaa",
    "field2": "1.2.3.4:45980",
    "field3": "10.8.0.3",
    "field4": "925KiB",
    "field5": "7.9MiB",
    "field6": "16:19:22",
    "field7": "1648559962",
    "field8": "206",
    "field9": "-",
    "field10": "UNDEF"
  },
  {
    "field1": "bbb",
    "field2": "4.3.2.1:40681",
    "field3": "10.8.0.2",
    "field4": "61KiB",
    "field5": "215KiB",
    "field6": "16:34:35",
    "field7": "1648560875",
    "field8": "207",
    "field9": "-",
    "field10": "UNDEF"
  }
]}

How do I filter the above to feed only one of the clients to my sensor?

I have this filter expression, that works as expected here:

$.clients[?(@.field1=="aaa")]

HA (template editor) wouldn’t accept this notation with this error:

TemplateSyntaxError: unexpected char '?' at 597

In the template documentation I haven’t found any filtering related content. Is it at all possible? If yes, how?

Thanks in advance for any pointers!

2

post your configuration for the MQTT sensor.

3

Well, there is no sensor, because HA complains about the filter expression I am trying to use. I use it in the template editor.

4

I could make the sensor to filter like this: value_json.clients[0] but it is not good as the ordinal number of an item is not always the same.

5

And what are you trying in the template editor? Please post something that I can work with.

6

Just share your mqtt configuration and what you’re trying in the editor. I don’t know why you’re being reluctant to post a configuration.

7 
{% set item = value_json | selectattr('field1', 'eq', 'aaa') | first | default %}
{{ item.field5 | default }}
8

It still doesn’t seem to work - it throws an error.

I’m trying this in the template editor:

{%
  set value_json = 

{"clients":[
  {
    "field1": "aaa",
    "field2": "1.2.3.4:45980",
    "field3": "10.8.0.3",
    "field4": "925KiB",
    "field5": "7.9MiB",
    "field6": "16:19:22",
    "field7": "1648559962",
    "field8": "206",
    "field9": "-",
    "field10": "UNDEF"
  },
  {
    "field1": "bbb",
    "field2": "4.3.2.1:40681",
    "field3": "10.8.0.2",
    "field4": "61KiB",
    "field5": "215KiB",
    "field6": "16:34:35",
    "field7": "1648560875",
    "field8": "207",
    "field9": "-",
    "field10": "UNDEF"
  }
]}

%}

{% set item value_json | selectattr('field1', 'eq', 'aaa') | first | default %}
{{ item.field5 | default }}

Gives me this error:

TemplateSyntaxError: expected token 'end of statement block', got 'value_json'

I thought you missed the = at the set item value_json part, but if I put it there like this:

{% set item = value_json | selectattr('field1', 'eq', 'aaa') | first | default %}
{{ item.field5 | default }}

It doesn’t give an error, but still, an empty string is returned.

I have no problem showing the sensor config, but I don’t have one. :frowning:
I tried this in template editor previously, but it failed miserably:

{{ value_json.clients[?(@.field1=="aaa")] }}
9

The template editor is for jinja.

That’s not jinja. Stop trying that.

{% set item = value_json.clients | selectattr('field1', 'eq', 'aaa') | first | default %}
{{ item.field5 | default }}
3 Likes
10

First: sorry about the late reply - it was night here.
Second: Yes, this did the trick. Now I understand how I should have done it. Thank you for your help, I really appreciate it.
Finally, here is my finished sensor, which now works the way I always wanted:

- platform: mqtt
  name: PiVpn-viktor-op3
  state_topic: "viktak/network/pivpn"
  value_template: >
    {% set c = value_json.clients | selectattr('field1', 'eq', 'viktor-op3') | first | default %}
    {% if c.field1 == 'viktor-op3' %}
      {{ 'Connected' }}
    {% else %}
      {{ 'Disconnected' }}
    {% endif %}

  json_attributes_topic: "viktak/network/pivpn"
  json_attributes_template: >-
    {% set c = value_json.clients | selectattr('field1', 'eq', 'viktor-op3') | first | default %}
    {% if c.field1 == 'viktor-op3' %}
      {% set name = c.field1 %}
      {% set remoteIP = c.field2 %}
      {% set virtualIP = c.field3 %}
      {% set bytesReceived = c.field4 %}
      {% set bytesSent = c.field5 %}
      {% set connectedSince = c.field6 %}
    {% else %}
      {% set name = 'n/a' %}
      {% set remoteIP = 'n/a' %}
      {% set virtualIP = 'n/a' %}
      {% set bytesReceived = 'n/a' %}
      {% set bytesSent = 'n/a' %}
      {% set connectedSince = 'n/a' %}
    {% endif %}
    {{
      {
      'Name' : name,
      'RemoteIP' : remoteIP,
      'VirtualIP' : virtualIP,
      'BytesReceived' : bytesReceived,
      'BytesSent' : bytesSent,
      'ConnectedSince' : connectedSince
      } | tojson
    }}

Thanks again for sticking with me and for setting me straight!!!