Json template sensor issue

[zavant (Anton)]

Hello.
My openmqttgateway compiled in pilight mode return json string (with weather stations data). Еach station has its own id, and I need to separate them into different sensors. So so i need to use templates. But I got an unexpected issuе, when debug my template in dev->template:

-1-
{% set val = states('sensor.gatewaypilight') %}
{{ val }}
-2-
{{ val.id }}
-3-
{% set val = {'id': 159, 'temperature': 23.5, 'humidity': 55.0, 'battery': 1} %}
{{ val }}
-4-
{{ val.id }}

And output:

-1-

{'id': 159, 'temperature': 23.5, 'humidity': 55.0, 'battery': 1}
-2-

-3-

{'id': 159, 'temperature': 23.5, 'humidity': 55.0, 'battery': 1}
-4-
159

So, I dn’t understand, why in step 2 I have empty value in val.id

[VDRainer]

Take a look at this topic.

MQTT - topic - help

I have 1 topic, but with 4 different sensors. Is there a way to create a template to get the differing data? home/rtl_433 {"time" : "2019-02-10 13:50:09", "brand" : "OS", "model" : "PCR800", "id" : 253, "channel" : 0, "battery" : "OK", "rain_rate" : 0.010, "rain_total" : 1.272} home/rtl_433 {"time" : "2019-02-10 13:50:22", "brand" : "OS", "model" : "WGR800", "id" : 187, "channel" : 0, "battery" : "OK", "gust" : 1.500, "average" : 1.100, "direction" : 180.000} home/rtl_433 {"time" : "2019-02-…

[Troon]

The post referenced by @VDRainer probably tells you what you need to know. To answer your exact question, though:

@zavant

So, I dn’t understand, why in step 2 I have empty value in val.id

Two things:

Firstly, you need to use the from_json filter to interpret the sensor’s state as JSON rather than a string (docs), so

{{ (val|from_json).id }}

Also, I’d be careful with keys like id that might well be an underlying property of the HA definition of a sensor. To guard against this, use this type of lookup instead:

{{ (val|from_json)["id"] }}

[zavant (Anton)]

@VDRainer

Take a look at this topic.
MQTT - topic - help

Thanks for the answer. I saw this topic and will do as it is written there, but my issue is a little different.

@Troon

Two things:

Firstly, you need to use the from_json filter to interpret the sensor’s state as JSON rather than a string (docs), so

{{ (val|from_json).id }}

Also, I’d be careful with keys like id that might well be an underlying property of the HA definition of a sensor. To guard against this, use this type of lookup instead:

{{ (val|from_json)["id"] }}

Yes, I tried these options too, and got the error for both cases:

Error rendering template: Expecting property name enclosed in double quotes: line 1 column 2 (char 1)

[Troon]

Really? I have only one sensor returning JSON:

and this in the template editor:

{% set val = states('sensor.camera_status') %}
1. {{ val }}
2. {{ val.bv }}
3. {{ val["bv"] }}
4. {{ val|from_json }}
5. {{ (val|from_json).bv }}
6. {{ (val|from_json)["bv"] }}

renders as this:

1. {"bt": 31.6, "bv": 4.171}
2. 
3. 
4. {'bt': 31.6, 'bv': 4.171}
5. 4.171
6. 4.171

[petro]

from_json won’t work because it’s not json. It’s a string representation of a dictionary. Json would require all strings to be wrapped in ".

@zavant Welcome to the community!

If you are using MQTT, I recommend adjusting the sensor.

Otherwise replace ' with " then convert use from_json.

{% set val = states('sensor.gatewaypilight').replace("'", '"') | from_json %}

[123 (Taras)]

I was faced with a similar situation recently and I used the replace("'", '"') technique but then pnbruckner suggested that I simply use to_json like this:

{% set val = states('sensor.gatewaypilight') | to_json %}

@zavant

Try the to_json filter, as shown here, and let us know if it works for you.

EDIT
My mistake. The use of to_json doesn’t apply here.

[zavant (Anton)]

@petro

from_json won’t work because it’s not json. It’s a string representation of a dictionary. Json would require all strings to be wrapped in ".

@zavant Welcome to the community!

If you are using MQTT, I recommend adjusting the sensor.

Otherwise replace ' with " then convert use from_json.

{% set val = states('sensor.gatewaypilight').replace("'", '"') | from_json %}

Great!! It’s works. Thank you very much!

[123 (Taras)]

The Jinja2 interpreter used by the Template Editor is lax about what it considers to be “proper JSON”. It readily accepts single-quotes within a dictionary. However, the JSON parser used for Template Sensors is strict and rejects the use of single quotes. That means a template that handles “single-quoted JSON” in the Template Editor is likely to fail when used in a Template Sensor (if supplied with “single-quoted JSON”).

[petro]

That’s not true. It’s the same code. The reason his worked is because it’s json.

Try it yourself with strings:

{% set foo = "{'a':1}" %}
{% set bar = foo | to_json %}
{{ bar.a }}
{% set bar = foo.replace("'",'"') | from_json %}
{{ bar.a }}
{% set bar = foo | from_json %} #ERRORS

[123 (Taras)]

Sorry, you lost me; not sure what’s “not true”. What I know is:

• to_json worked for me when I used it in a script to convert stringified JSON
• a Template Sensor fed single-quoted JSON is an unhappy Template Sensor

[petro]

@123

The Jinja2 interpreter used by the Template Editor is lax a

This is what I was referring to. I can’t quote the whole response because the site auto removes whole response quoting.

[123 (Taras)]

In the Template Editor, it accepts either single or double-quotes within a JSON dictionary. It’s been my experience that Template Sensors fed single-quoted JSON aren’t so accommodating.

[petro]

yeah, because those are dictionaries. Dictionary != string that represents a dictionary converted to JSON.

[petro]

To clarify, the difference is:

Dictionary as string

{% set foo = "{'a':1}" %}

vs

Dictionary

{% set foo = {'a': 1} %}

You’ll always get Dictionary as string from states.

[123 (Taras)]

Yes, I understand that when the Template Sensor receives the stringified JSON payload it converts it to a JSON dictionary … and if the stringified JSON uses single-quotes, the conversion process throws an error.

In retrospect my use of the word “lax” was misleading. If you’re defining a JSON dictionary in the Template Editor, it accepts either single or double-quotes. It’s the conversion process, from stringified JSON to JSON, that wants to see double-quotes. So when someone use the Template Editor to experiment with JSON dictionaries (not stringified but a proper dictionary) they may be led to believe that single-quotes are fair-game until they actually try feeding that format (stringified JSON) through the conversion process.

[petro]

Right, but maybe you were missing the fact that OP was grabbing the value dictionary from a state meaning its a string… Which is why to_json will not work as well as any of the templating attempts in the thread aside from wrapping the attempts in quotes to make it a string.

[123 (Taras)]

@petro

OP was grabbing the value dictionary from a state meaning its a string

Gotcha, yes, you’re right, I overlooked that key point. I proved it to myself by publishing two different payloads to an MQTT Sensor:

'{"a": 1}'

"{'a': 1}"

The first case, using double-quotes, is correctly converted by from_json (as per my description of the conversion process):

The second case, using single-quotes, fails to be converted by from_json (as expected):

Neither form of these strings benefits from the use of the to_json filter

I’ve retracted my initial suggestion (in my initial post) to use to_json.