Notification transfer as json partly empty

[charliesz]

Describe the bug
The notification body does not get fully transfered as json. I set a group tag and thought that in the notification body the ..."watch_tag": {{ watch_tag | default("test") | tojson }}, would show test unless there is a group tag set. The watch_tag is always empty "".

standard Notification Body:

{
"title": {{ watch_title | tojson }},
"url": {{ watch_url | tojson }},
"watch_uuid": {{ watch_uuid | tojson }},
"watch_tag": {{ watch_tag | default("test") |tojson }},
"preview_url": {{ preview_url | tojson }},
"diff_url": {{ diff_url | tojson }},
"diff": {{ diff | tojson }},
"diff_added": {{ diff_added | tojson }},
"diff_removed": {{ diff_removed | tojson }},
"diff_full": {{ diff_full | tojson }},
"diff_patch": {{ diff_patch | tojson }},
"current_snapshot": {{ current_snapshot | tojson }},
"triggered_text": {{ triggered_text | tojson }}
}<

Received notification:

JSON: {"current_snapshot": "", "diff": "", "diff_added": "", "diff_full": "", "diff_patch": "", "diff_removed": "", "diff_url": "192.168.178.210:5000/diff/", "preview_url": "192.168.178.210:5000/preview/", "title": "Change Detection", "triggered_text": "", "url": "http://192.168.178.210:5000/settings#notifications", "watch_tag": "", "watch_uuid": ""}<

The group tag is set.

Version
v0.50.7

How did you install?
Proxmox helper script:
[(https://community-scripts.github.io/ProxmoxVE/scripts?id=changedetection)]

To Reproduce

Steps to reproduce the behavior:

1. set a new watch and set a group tag
2. set the notification body to:

{
"title": {{ watch_title | tojson }},
"url": {{ watch_url | tojson }},
"watch_uuid": {{ watch_uuid | tojson }},
"watch_tag": {{ watch_tag | default("test") |tojson }},
"preview_url": {{ preview_url | tojson }},
"diff_url": {{ diff_url | tojson }},
"diff": {{ diff | tojson }},
"diff_added": {{ diff_added | tojson }},
"diff_removed": {{ diff_removed | tojson }},
"diff_full": {{ diff_full | tojson }},
"diff_patch": {{ diff_patch | tojson }},
"current_snapshot": {{ current_snapshot | tojson }},
"triggered_text": {{ triggered_text | tojson }}
}<

3. run the test notification and watch the received notification. (I sent it with post://192.168.178.200:8123/api/webhook/changedetection_update to homeassistant)
4. I set a automation in homeassistant to watch the webhook:

alias: Changedetection Webhook Debug
description: Zeigt empfangene Webhook-Daten an
trigger:

• platform: webhook
  webhook_id: changedetection_update
  allowed_methods:
  • POST
    local_only: true
    action:
• service: persistent_notification.create
  data:
  title: Changedetection Webhook
  message: >
  Empfangenes JSON:
  {{ trigger.json | tojson }}
  mode: single<

My shared link: http://192.168.178.210:5000/share-url/ed15cbba-425f-42e6-a017-ad7973fecc08

Expected behavior
the notification should have more information

Smartphone (please complete the following information):

• Device: Pixel 7
• OS: Android 16
• Browser: Firefox
• Version: 140.0.4 (Build #2016101258), null
  GV: 140.0.4-20250707120347
  AS: 140.0
  OS: Android 16

Additional context
It is interesting, that some information get transferred.

[dgtlmoon]

well thats because < is not JSON, look closer, actually its even in your error message :)

[dgtlmoon]

$ cat >test.json
 {"current_snapshot": "", "diff": "", "diff_added": "", "diff_full": "", "diff_patch": "", "diff_removed": "", "diff_url": "192.168.178.210:5000/diff/", "preview_url": "192.168.178.210:5000/preview/", "title": "Change Detection", "triggered_text": "", "url": "http://192.168.178.210:5000/settings#notifications", "watch_tag": "", "watch_uuid": ""}

$ cat test.json |python3 -mjson.tool
{
    "current_snapshot": "",
    "diff": "",
    "diff_added": "",
    "diff_full": "",
    "diff_patch": "",
    "diff_removed": "",
    "diff_url": "192.168.178.210:5000/diff/",
    "preview_url": "192.168.178.210:5000/preview/",
    "title": "Change Detection",
    "triggered_text": "",
    "url": "http://192.168.178.210:5000/settings#notifications",
    "watch_tag": "",
    "watch_uuid": ""
}

This IS valid JSON, you just have the < at the end for some unexplained reason :)

[charliesz]

Thanks I just put it in for a quote formation for better reading in and lost one "end of quote sign" <

When I mess something up with the json I don't get anything in the webhook.

Edit.
How do I get some input in the watch_tag? My group tags are all set.

[dgtlmoon]

When I mess something up with the json I don't get anything in the webhook.

I dont understand? can you rephrase it?

How do I get some input in the watch_tag? My group tags are all set.

I'm also not sure what you mean here

[charliesz]

1. If there's a formatting error in the notification body, I receive no output at all in the webhook.

2. I would like to send the Group tag. From what I understand, the Group tag corresponds to the watch_tag in the notification body. Unfortunately, it's not being passed through — the value is always empty.

Notification Body:
{
"title": {{ watch_title | tojson }},
"url": {{ watch_url | tojson }},
"watch_tag": {{ watch_tag | default("test") | tojson}},
"preview_url": {{ preview_url | tojson }},
"diff_url": {{ diff_url | tojson }}
}

Received json:
JSON: {
"diff_url": "192.168.178.210:5000/diff/",
"preview_url": "192.168.178.210:5000/preview/",
"title": "Change Detection",
"url": "http://192.168.178.210:5000/edit/daa2369a-b5a4-4312-9235-972c024c9d3#notifications", "watch_tag": ""
}

I set the group tag to "Caro" and I want to get "Caro" in the received notification messege. But "watch_tag" is always "" instead of "Caro".

[charliesz]

I'm still not sure what "watch_tag" ist looking for if not for the group tag.

I looked in my url-watches.json for the tags.
grep -i '"tag"' url-watches.json -A 5

"tag": "",
"tags": [],
"text_should_not_be_present": [],
"time_between_check": {
"weeks": null,

or

"tag": "",
"tags": [
"e8fe7e3a-9afc-47bb-ba31-bc855beeb9da"
],

So they are all empty or referring to e8fe... what I could not find as a folder in the changedetection directory.

Maybe someone can point to how I can manage to get the "group tag" transferred in my notification body.

I read in the docs that some entrys in the notification body stay empty during the test triggered by the test notification from the settings menu. Maybe it could be helpful to fill them with a prefix "test-" so instead of watch_uuid: "" it would be watch_uuid: "test-uuid".

Further it could be helpful to see the notification in changedetection that is send like the preview option for the filter.

But I'm very new to this topic and maybe that is not necessary for everyone.