[ADF-814] application configuration service (#1969)

* app configuration service

* api improvements and readme update

* extend readme and add defaults

* unit tests for app config service

ng2-components/ng2-alfresco-core/src/services/app-config.service.ts

@@ -0,0 +1,88 @@
+/*!
+ * @license
+ * Copyright 2016 Alfresco Software, Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { Injectable, APP_INITIALIZER, NgModule, ModuleWithProviders } from '@angular/core';
+import { Http } from '@angular/http';
+import { ObjectUtils } from '../utils/object-utils';
+
+@Injectable()
+export class AppConfigService {
+
+    private config: any = {
+        'ecmHost': 'http://localhost:3000/ecm',
+        'bpmHost': 'http://localhost:3000/bpm',
+        'application': {
+            'name': 'Alfresco'
+        }
+    };
+
+    configFile: string = null;
+
+    constructor(private http: Http) {}
+
+    get<T>(key: string): T {
+        return <T> ObjectUtils.getValue(this.config, key);
+    };
+
+    load(resource: string = 'app.config.json'): Promise<any> {
+        console.log('Loading app config: ' + resource);
+        this.configFile = resource;
+        return new Promise((resolve, reject) => {
+            this.http.get(resource).subscribe(
+                data => {
+                    this.config = Object.assign({}, this.config, data.json() || {});
+                    resolve(this.config);
+                },
+                (err) => {
+                    const errorMessage = `Error loading ${resource}`;
+                    console.log(errorMessage);
+                    resolve(this.config);
+                }
+            );
+        });
+    }
+}
+
+export function InitAppConfigServiceProvider(resource: string): any {
+    return {
+        provide: APP_INITIALIZER,
+        useFactory: (configService: AppConfigService) => {
+            return () => configService.load(resource);
+        },
+        deps: [
+            AppConfigService
+        ],
+        multi: true
+    };
+}
+
+@NgModule({
+    providers: [
+        AppConfigService
+    ]
+})
+export class AppConfigModule {
+    static forRoot(resource: string): ModuleWithProviders {
+        return {
+            ngModule: AppConfigModule,
+            providers: [
+                AppConfigService,
+                InitAppConfigServiceProvider(resource)
+            ]
+        };
+    }
+}