Error response enhancements, CoreID auth client backend

src/service/Canonical.ts

@@ -2,7 +2,7 @@
  * Base type for a canonical definition.
  */
 import {Canon} from './Canon'
-import {universalPath, UniversalPath, ErrorWithContext} from '../util'
+import {universalPath, UniversalPath, ErrorWithContext, Safe} from '../util'
 import {Logging} from './Logging'
 import {Inject} from '../di'
 import * as nodePath from 'path'
@@ -192,6 +192,18 @@ export abstract class Canonical<T> extends Unit {
         return this.loadedItems[key]
     }
 
+    /** Get a canonical item by key as a Safe value. */
+    public safe(key: string): Safe {
+        return (new Safe(this.get(key))).onError((message, value) => {
+            throw new ErrorWithContext(`Invalid canonical value: ${message}`, {
+                canonicalKey: key,
+                canonicalItems: this.canonicalItems,
+                value,
+                message,
+            })
+        })
+    }
+
     /**
      * Register a namespace resolver with the canonical unit.
      *