WMS service basic authentication

I am building a leaflet map on a server without root access. I'd like to add a WMS service which is secured by basic authentication(username and password). There is a simple method in leaflet adding WMS services with L.tileLayer.wms but this does not work for secured WMS services. So is there a way I can authenticate at the wms server and receive the WMS tiles and parse them to leaflet? Adding the login credentials to the WMS URL (f.e. https://username:password@wmsserver.com)does not work for me.

When using basic authentication, you pass username and password in the header to the server:

Authorization: Basic <credentials>

<credentials> is the Base64 encoded username and password joined by a single colon :.

You could use leaflet-wms-header to pass along a custom header. Unfortunately, I don't have any WMS server with basic authentication at hand for testing but here is an example based on the example provided by leaflet-wms-header:

// untested code

var wmsLayer = L.TileLayer.wmsHeader(
    'https://GEOSERVER_PATH/geoserver/wms?',
    {
        layers: 'YOUR_LAYER',
        format: 'image/png',
        transparent: true,
    },
    [
        { 
            header: 'Authorization', 
            value: `Basic ${btoa(username + ':' + password)}` 
        },
    ],
    null
).addTo(map);

(btoa encodes the given string to a Base64 encoded string.)