Import WMS Connection to data source manager with startup.py

Question

I search for a possibility to import WMS-connections to the data source manager with the startup.py in QGIS. I tried the following code, but always get errors:

from qgis.core import QgsOwsConnection
# WMS-URL
url = "https://geodienste.sachsen.de/wms_list_ttsib/guest?"

# Name WMS-Connection
conn_name = "test-layer"

# Add WMS-Connection
QgsOwsConnection.addWmsWcsConnectionSettings(url,conn_name)

I get this error and don't know how to solve it:

Traceback (most recent call last):
  File "C:\PROGRA~1\QGIS32~1.8\apps\Python39\lib\code.py", line 90, in runcode
    exec(code, self.locals)
  File "<input>", line 1, in <module>
  File "<string>", line 9, in <module>
TypeError: QgsOwsConnection.addWmsWcsConnectionSettings(): argument 1 has unexpected type 'str'

Answer 1

The OGC web service connections that are configured in the data source manager are stored using the QgsSettings API. This is based on QSettings which provides a way to store application specific settings in a key-value storage. You can read the docs on how that works in detail: https://doc.qt.io/qt-6/qsettings.html#details

All connections are stored under the entries following the pattern /qgis/connections-{service}/{connection_name}. Addressing your example the correct settings key will be /qgis/connections-wms/WMS Sachsen where WMS Sachsen is just a name I chose that will be shown in the list of connections.

from qgis.core import QgsSettings

url = "https://geodienste.sachsen.de/wms_list_ttsib/guest?"
conn_name = 'WMS Sachsen'

key = f'/qgis/connections-wms/{conn_name}/'

settings = QgsSettings()
settings.setValue(key + 'url', url)

# all the additional parameter settings. Change these to your needs.
settings.setValue(key + 'dpi-mode', 7)
settings.setValue(key + 'ignore-get-map-uri', False)
settings.setValue(key + 'ignore-get-feature-info-uri', False)
settings.setValue(key + 'smooth-pixmap-transform', False)
settings.setValue(key + 'ignore-axis-orientation', False)
settings.setValue(key + 'invert-axis-orientation', False)

If you use the code above in a startup.py file, the WMS connection will be available in the data source manager.

One final note on your initial attempt: Although the addWmsWcsConnectionSettings method sounds like it adds a new connection, it actually reads existing connection parameters from QgsSettings and populates a QgsDataSourceUri object. I find the name a bit misleading.