Implement cache priming prototype

Microsoft.AspNet.AngularServices/npm/src/CachePrimedHttp.ts

@@ -0,0 +1,63 @@
+import { provide, Injectable, Provider } from 'angular2/core';
+import { Connection, ConnectionBackend, Http, XHRBackend, RequestOptions, Request, RequestMethods, Response, ResponseOptions, ReadyStates } from 'angular2/http';
+
+@Injectable()
+export class CachePrimedConnectionBackend extends ConnectionBackend {
+    private _preCachedResponses: PreCachedResponses;
+    
+    constructor(private _underlyingBackend: ConnectionBackend, private _baseResponseOptions: ResponseOptions) {
+        super();
+        this._preCachedResponses = (<any>window).__preCachedResponses || {};
+    }
+    
+    public createConnection(request: Request): Connection {
+        let cacheKey = request.url;
+        if (request.method === RequestMethods.Get && this._preCachedResponses.hasOwnProperty(cacheKey)) {
+            return new CacheHitConnection(request, this._preCachedResponses[cacheKey], this._baseResponseOptions);
+        } else {
+            return this._underlyingBackend.createConnection(request);
+        }
+    }
+}
+
+class CacheHitConnection implements Connection {
+    readyState: ReadyStates;
+    request: Request;
+    response: any;
+
+    constructor (req: Request, cachedResponse: PreCachedResponse, baseResponseOptions: ResponseOptions) {
+        this.request = req;
+        this.readyState = ReadyStates.Done;
+        
+        // Workaround for difficulty consuming CommonJS default exports in TypeScript. Note that it has to be a dynamic
+        // 'require', and not an 'import' statement, because the module isn't available on the server.
+        // All this badness goes away with the next update of Angular 2, as it exposes Observable directly from angular2/core.
+        // --
+        // The current version of Angular exposes the following SystemJS module directly (it is *not* coming from the
+        // @reactivex/rxjs NPM package - it's coming from angular2).
+        let obsCtor: any = require('@reactivex/rxjs/dist/cjs/Observable');
+        this.response = new obsCtor(responseObserver => {
+            let response = new Response(new ResponseOptions({ body: cachedResponse.body, status: cachedResponse.statusCode }));
+            responseObserver.next(response);
+            responseObserver.complete();
+        });
+    }
+}
+
+declare var require: any; // Part of the workaround mentioned below. Can remove this after updating Angular.
+
+interface PreCachedResponses {
+    [url: string]: PreCachedResponse;
+}
+
+interface PreCachedResponse {
+    statusCode: number;
+    body: string;
+}
+
+export const CACHE_PRIMED_HTTP_PROVIDERS = [
+    provide(Http, {
+        useFactory: (xhrBackend, requestOptions, responseOptions) => new Http(new CachePrimedConnectionBackend(xhrBackend, responseOptions), requestOptions),
+        deps: [XHRBackend, RequestOptions, ResponseOptions]
+    }),
+];

Microsoft.AspNet.AngularServices/npm/src/Exports.ts

@@ -1 +1,2 @@
+export * from './CachePrimedHttp';
 export * from './Validation';