Fix resource interpolation to also affect event.resource

Author: inlined

src/providers/database.ts

@@ -85,8 +85,13 @@ export class RefBuilder {
       eventType: 'ref.write',
       resource: this.resource,
       dataConstructor,
-      before: (payload) => this.apps.retain(payload),
-      after: (payload) => this.apps.release(payload),
+      before: (event) => {
+        _.forEach(event.params, (val, key) => {
+          event.resource = _.replace(event.resource, `{${key}}`, val);
+        });
+        this.apps.retain(event);
+      },
+      after: (event) => this.apps.release(event),
     });
   }
 }
@@ -105,9 +110,6 @@ export class DeltaSnapshot implements firebase.database.DataSnapshot {
   constructor(private app: firebase.app.App, private adminApp: firebase.app.App, event: Event<any>) {
     if (event) {
       let resourceRegex = `projects/([^/]+)/instances/([^/]+)/refs(/.+)?`;
-      _.forEach(event.params, (val, key) => {
-        event.resource = _.replace(event.resource, `{${key}}`, val);
-      });
       let match = event.resource.match(new RegExp(resourceRegex));
       if (!match) {
         throw new Error(`Unexpected resource string for Firebase Realtime Database event: ${event.resource}. ` +