feat: 🎸 add legacy short URL locator

src/plugins/share/server/url_service/short_urls/relative_path_locator.ts

@@ -0,0 +1,40 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+import type { SerializableState } from 'src/plugins/kibana_utils/common';
+import type { KibanaLocation, LocatorDefinition } from '../../../common/url_service';
+
+export interface RelativePathLocatorParams extends SerializableState {
+  url: string;
+}
+
+export class RelativePathLocatorDefinition implements LocatorDefinition<RelativePathLocatorParams> {
+  public readonly id = 'RELATIVE_PATH_LOCATOR';
+
+  public async getLocation(params: RelativePathLocatorParams): Promise<KibanaLocation> {
+    const { url } = params;
+
+    const match = url.match(/^.*\/app\/([^\/#]+)(.+)$/);
+
+    if (!match) {
+      throw new Error('Unexpected URL path.');
+    }
+
+    const [, app, path] = match;
+
+    if (!app || !path) {
+      throw new Error('Could not parse URL path.');
+    }
+
+    return {
+      app,
+      path,
+      state: {},
+    };
+  }
+}