DWD WarnApp Sensor (amtliche Warnungen des deutschen Wetterdienstes)

SirBronski · September 3, 2018, 7:57am

Depends which certs are included in the browsers or operating systems CA cert chain.
Chrome includes the intermediate CA certs of https://www.pki.dfn.de/ueberblick-dfn-pki/ which have been used to issue the cert “www.dwd.de”, which enabled Chrome to fully validate the cert, but Mozilla is lacking those CA certs.
I have added the two missing CA certs into my RasPis /etc/ssl/certs, now wget works, but home-assistant still doesn’t.

SirBronski · September 3, 2018, 12:46pm

After adding the missing CA certs to lib/python3.5/site-packages/certifi/cacert.pem the DWD weather warnings are working!

0rn0lf · September 3, 2018, 2:47pm

Is it possible to do this in hassio?

SirBronski · September 3, 2018, 3:30pm

I would think so, if you know how. You have to find out how to ssh to your RasPi (AFAIR port 222, instead of the hass.io-container which listens on default ssh-port 22) and find out where the files are. (in my case: /srv/homeassistant, then see above)

Or wait until the certs are updated in one of the next versions, which would be the correct solution.

diplix · September 4, 2018, 2:11pm

where exactly did you get the two CA certs? here? https://www.pki.dfn.de/wurzelzertifikate/globalroot2/

0rn0lf · September 4, 2018, 2:32pm

I had the exact same thing in my head. Maybe exported the cert from the homepage?

SirBronski · September 4, 2018, 5:05pm

I googled the names of the intermediate certs that I saw in the ‘www.dwd.de’-cert, payed attention that what I’ve found was from DFN-websites, compared the cert-fingerprints and downloaded them:
https://www.pki.dfn.de/fileadmin/PKI/zertifikate/DFN-Verein_Certification_Authority_2.pem
http://cdp.pca.dfn.de/dfn-ca-global-g2/pub/cacert/cacert.pem

diplix · September 5, 2018, 2:31am

that worked. thanks!

VDRainer · September 5, 2018, 7:49am

After sending an email to dwd about the cert, i got an answer today that they made some modifications.
Everything works now as before, no need to copy the certs.

THX to DWD!

0rn0lf · September 5, 2018, 2:33pm

Wow, thank you for your effort

Hummel95 · March 8, 2019, 5:40pm

Thanks for the plugin!

Occasionally, I see some “sensor xxx is taking over 10 seconds” log entries. That’s why I started changing the component so it uses the new WFS API instead of the JSON file. While the JSON file contains all regions, WFS allows filtering.
I looked at the data and realised that no warning level in terms of integer is provided. Nevertheless, there is a key “dwd:SEVERITY” containing a string rating.
Does any of you know how to map e.g. “Moderate” to an integer value?

My current progress and an example API response (attached at the end) can be found here:

github.com

Hummel95/home-assistant/blob/dev/homeassistant/components/dwd_weather_warnings/sensor.py

"""
Support for getting statistical data from a DWD Weather Warnings.

For more details about this platform, please refer to the documentation at
https://home-assistant.io/components/sensor.dwd_weather_warnings/

Data is fetched from DWD using WFS 2.0 services
https://www.dwd.de/DE/leistungen/opendata/help/warnungen/cap_dwd_profile_de_pdf.pdf?__blob=publicationFile&v=7

Warnungen vor extremem Unwetter (Stufe 4)
Unwetterwarnungen (Stufe 3)
Warnungen vor markantem Wetter (Stufe 2)
Wetterwarnungen (Stufe 1)
"""

import logging
import json
from datetime import timedelta

import voluptuous as vol

This file has been truncated. show original

Thanks!

Hummel95 · April 16, 2019, 8:27pm

Hi everyone,

I’ve found a mapping between serverity and int rating and continued working on the plugin
In case anyone wants to test: Please feel free (see github)
Working fine for me until now

runningman84 · April 18, 2019, 6:11am

Feel free to create a pull request with your solution. I think it is better to use the filtered API for low power devices…

stephan19 · April 4, 2020, 3:23pm

I want to reopen the discussion on this topic because i lately realized that there is something wrong with the warning level of the current implementation.

For example: For my region “Landkreis” currently a “FROST” warning is issued as level 1 (yellow) on the DWD homepage. The warning level of the HA sensor is 2 for the same region. This is not a HA sensor bug because the level 2 is issued by dwd in their json (https://www.dwd.de/DWD/warnungen/warnapp/json/warnings.json).

So i think it is time to switch to their new format like @Hummel95 did it already.

After i read this thread i did some further investigations and found out that we could improve this sensor much more because the DWD offers more and more detailed informations with their new API. With their new API not only “Landkreise” can be queried by also “Gemeinden” or “Stadtteile” of bigger cities. The following file contains a list of all available so called warncells witch can be queried.
https://www.dwd.de/DE/leistungen/opendata/help/warnungen/cap_warncellids_csv.html
Cell starting with “1” represent “Landkreise”. Cells starting with “2” represent “Binnenseen”. Cells starting with “4” represent “Nord- und Ostsee”. Cells starting with “5” represent “Küste”. Cells starting with “7” or “8” represent “Gemeinden” or “Stadtteile”.

With the following query one can check if the warncellid is correct

https://maps.dwd.de/geoserver/dwd/ows?service=WFS&version=2.0.0&request=GetFeature&typeName={region_type}&CQL_FILTER=WARNCELLID=%27{warncellid}%27&OutputFormat=application/json

{region_type} must be the right one of the following
dwd:Warngebiete_Kreise
dwd:Warngebiete_Binnenseen
dwd:Warngebiete_See
dwd:Warngebiete_Kueste
dwd:Warngebiete_Gemeinden

{warncellid} your desired warncellid

The query to get the warnings for your cell is

https://maps.dwd.de/geoserver/dwd/ows?service=WFS&version=2.0.0&request=GetFeature&typeName={region_type}&CQL_FILTER={cql_filter_property}=%27{warncellid}%27&OutputFormat=application/json

{region_type} must be the right one of the following
dwd:Warnungen_Kreise
dwd:Warnungen_Binnenseen
dwd:Warnungen_See
dwd:Warnungen_Kueste
dwd:Warnungen_Gemeinden

{cql_filter_proerty} must be
GC_WARNCELLID for dwd:Warnungen_Kreise
WARNCELLID for all other types

{warncellid} your desired warncellid

I already started working on an improvement of Hummel95’s solution and it’s working fine so far but a found one problem i want to start a discussion about. In the current sensors configuration one has to enter the region’s name to configure the sensor. This is fine for “Landkreise”. The problem is that the region’s name is not unique for “Gemeinden” e.g. “Gemeinde Oberhausen” exists two times in the warncell list.

Is it therefore ok to change the required configuration from “region_name” to “warncellid” in configurations.yaml?
After an update of the sensor all users would have to update their configurations.yaml to get the sensor working again. Otherwise it cannot be guaranteed that the right cell is selected.

Hummel95 · April 4, 2020, 5:26pm

Hi Stephan,

Thanks for working on this! I stopped running home-assistant last year but I’m planning on installing it again soon.

In my opinion changing the configuration parameter to warncellid makes sense especially since it’s justified by an increased prediction accuracy.

If you haven’t checked out my pull request please do so. The HA team requested some changes in the code to comply with their rules. https://github.com/home-assistant/core/pull/23234

Thanks!

stephan19 · April 4, 2020, 6:54pm

After reading the pull request i realize that there is more work to do than i initially thought.

First step: Splitting sensor and API
Check if one of the on PyPI available DWD APIs fits our needs, or if not program a new one.

After a quick check it seems that there is no DWD API on PyPI which uses there OWS service.

I think i will start trying, never did this before, to develop a dwdows PyPI package which than can be used for the “Warnwetter” and maybe a “Pollenflug” or “Biowetter” sensor.

stephan19 · April 19, 2020, 1:40pm

I just finished my first version of the API, i called it dwdwfsapi because the DWD calls its underlying service Web Feature Service (WFS).

For those who are interested:
Link to PyPI
Link to GitHub

The next days i will start with step two: embedding the API in home-assistant

runningman84 · April 21, 2020, 4:18pm

Feel free to replace my current code…

sillywalks · May 18, 2020, 5:11am

I know this is slightly off topic, but seen as darksky (which most people were using for forecasts) has been bought by apple is there any chance to upgrade the dwd integration to also pull weather data and forecasts?
Using the warnwetter app gives me the best forecasts for my area anyway and I would love to have that level of exactness in home assistant.
Of course this would be only interesting for us Germans but then I guess the warning levels currently supported are also of not much use for someone in Australia
Sadly I know nothing about coding and using the api but it looks like you are quite well versed in this…
So maybe someone is up for the task of integrating the weather data as well! Thanks!

Pirol62 · August 7, 2020, 2:16pm

Try to use Yr.NO. It’s very accurate in Dus and uses the same weather forecast model like DWD.