Error response enhancements, CoreID auth client backend

src/http/session/Session.ts

@@ -1,5 +1,5 @@
 import {Injectable, Inject} from '../../di'
-import {ErrorWithContext} from '../../util'
+import {ErrorWithContext, Safe} from '../../util'
 import {Request} from '../lifecycle/Request'
 
 /**
@@ -60,4 +60,9 @@ export abstract class Session {
 
     /** Remove a key from the session data. */
     public abstract forget(key: string): void
+
+    /** Load a key from the session as a Safe value. */
+    public safe(key: string): Safe {
+        return new Safe(this.get(key))
+    }
 }