Test if html5 geolocation permission already has been granted

Question

Does anyone know if there is a way to test if prior html5 geolocation permission has been granted?

I try to make a script that does not request the geolocation unless the permission for the page has already been given. Does not nessicerily have to be html5; other frameworks are also ok.

Answer 1

The first part actually answers your question, at least on Chrome 43+ and Firefox 46+ (see https://developer.mozilla.org/en-US/docs/Web/API/Permissions_API):

navigator.permissions &&
navigator.permissions.query({name: 'geolocation'}).then(function(PermissionStatus) {
    if('granted' === PermissionStatus.state) {
        navigator.geolocation.getCurrentPosition(function(geoposition) {
            console.log(geoposition) /* You can use this position without prompting the user if the permission had already been granted */
        })
    }
})

Answer 2

Best you can do is to keep track of this yourself...

// In chrome you can now do this    
navigator.permissions.query({name: 'geolocation'}).then(function(PermissionStatus){
    console.log(PermissionStatus.state) // prompt, granted, denied
    // even listen for changes
    PermissionStatus.onchange = function(){
        console.log(this.state)
    }
})

fallback method:

// initialization
if( sessionStorage.getItem("geo_access") === null ){
    // just assume it is prompt
    sessionStorage.setItem("geo_access", "prompt");
}

function ask(){
    navigator.geolocation.getCurrentPosition(function(){
        sessionStorage.setItem("geo_access", "granted");

    }, function(err){
        if(err.code == 1){ // PERMISSION_DENIED
            sessionStorage.setItem("geo_access", "denied");
        }
        sessionStorage.setItem("geo_access", "prompt");
    });
};

// Then somewhere
ask();