feat(platform-server): Implement PlatformLocation for platformServer() (#14405)

This gives server-side apps a current URL including hash, but doesn't implement a state stack,
so back-and-forward navigation isn't possible.

PR Close #14405

modules/@angular/platform-server/src/location.ts

@@ -0,0 +1,81 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import * as url from 'url';
+
+import {Injectable} from '@angular/core';
+import {LocationChangeEvent, LocationChangeListener, PlatformLocation} from '@angular/common';
+import {getDOM} from './private_import_platform-browser';
+import {scheduleMicroTask} from './facade/lang';
+
+import {Subject} from 'rxjs/Subject';
+
+
+/**
+ * Server-side implementation of URL state. Implements `pathname`, `search`, and `hash`
+ * but not the state stack.
+ */
+@Injectable()
+export class ServerPlatformLocation implements PlatformLocation {
+  private _path: string = '/';
+  private _search: string = '';
+  private _hash: string = '';
+  private _hashUpdate = new Subject<LocationChangeEvent>();
+
+  getBaseHrefFromDOM(): string {
+    return getDOM().getBaseHref();
+  }
+  
+  onPopState(fn: LocationChangeListener): void {
+    // No-op: a state stack is not implemented, so
+    // no events will ever come.
+  }
+  
+  onHashChange(fn: LocationChangeListener): void {
+    this._hashUpdate.subscribe(fn);
+  }
+
+  get pathname(): string { return this._path; }
+  get search(): string { return this._search; }
+  get hash(): string { return this._hash; }
+
+  get url(): string {
+    return `${this.pathname}${this.search}${this.hash}`;
+  }
+
+  private setHash(value: string, oldUrl: string) {
+    if (this._hash === value) {
+      // Don't fire events if the hash has not changed.
+      return;
+    }
+    this._hash = value;
+    const newUrl = this.url;
+    scheduleMicroTask(() => this._hashUpdate.next(
+        {type: 'hashchange', oldUrl, newUrl} as LocationChangeEvent));
+  }
+
+  replaceState(state: any, title: string, newUrl: string): void {
+    const oldUrl = this.url;
+    const parsedUrl = url.parse(newUrl, true);
+    this._path = parsedUrl.path;
+    this._search = parsedUrl.search;
+    this.setHash(parsedUrl.hash, oldUrl);
+  }
+
+  pushState(state: any, title: string, newUrl: string): void {
+    this.replaceState(state, title, newUrl);
+  }
+
+  forward(): void {
+    throw new Error('Not implemented');
+  }
+
+  back(): void {
+    throw new Error('Not implemented');
+  }
+}

modules/@angular/platform-server/src/parse5_adapter.ts

@@ -547,7 +547,15 @@ export class Parse5DomAdapter extends DomAdapter {
       return this.defaultDoc().body;
     }
   }
-  getBaseHref(): string { throw 'not implemented'; }
+  getBaseHref(): string {
+    const base = this.querySelector(this.defaultDoc(), 'base');
+    let href = '';
+    if (base) {
+      href = this.getHref(base);
+    }
+    // TODO(alxhub): Need relative path logic from BrowserDomAdapter here?
+    return isBlank(href) ? null : href;
+  }
   resetBaseElement(): void { throw 'not implemented'; }
   getHistory(): History { throw 'not implemented'; }
   getLocation(): Location { throw 'not implemented'; }

modules/@angular/platform-server/src/server.ts

@@ -11,28 +11,17 @@ import {platformCoreDynamic} from '@angular/compiler';
 import {Injectable, NgModule, PLATFORM_INITIALIZER, PlatformRef, Provider, RootRenderer, createPlatformFactory, isDevMode, platformCore} from '@angular/core';
 import {BrowserModule} from '@angular/platform-browser';
 
+import {ServerPlatformLocation} from './location';
 import {Parse5DomAdapter} from './parse5_adapter';
 import {DebugDomRootRenderer} from './private_import_core';
-import {SharedStylesHost} from './private_import_platform-browser';
+import {DomAdapter, SharedStylesHost} from './private_import_platform-browser';
 import {ServerRootRenderer} from './server_renderer';
 
+
 function notSupported(feature: string): Error {
   throw new Error(`platform-server does not support '${feature}'.`);
 }
 
-class ServerPlatformLocation extends PlatformLocation {
-  getBaseHrefFromDOM(): string { throw notSupported('getBaseHrefFromDOM'); };
-  onPopState(fn: any): void { notSupported('onPopState'); };
-  onHashChange(fn: any): void { notSupported('onHashChange'); };
-  get pathname(): string { throw notSupported('pathname'); }
-  get search(): string { throw notSupported('search'); }
-  get hash(): string { throw notSupported('hash'); }
-  replaceState(state: any, title: string, url: string): void { notSupported('replaceState'); };
-  pushState(state: any, title: string, url: string): void { notSupported('pushState'); };
-  forward(): void { notSupported('forward'); };
-  back(): void { notSupported('back'); };
-}
-
 export const INTERNAL_SERVER_PLATFORM_PROVIDERS: Array<any /*Type | Provider | any[]*/> = [
   {provide: PLATFORM_INITIALIZER, useValue: initParse5Adapter, multi: true},
   {provide: PlatformLocation, useClass: ServerPlatformLocation},