argos/dmp-frontend/src/app/services/help-content/help-content.service.ts

/**
 * Created by stefania on 7/17/17.
 */
import { Injectable } from '@angular/core';
import { Http, Response } from '@angular/http';
import { Observable } from 'rxjs/Rx';
import { environment } from '../../../environments/environment';
import { PageHelpContent } from '../../models/help-content/page-help-content';
import { CachedContentItem } from './CachedContentItem';

@Injectable()
export class HelpContentService {
	private _helpServiceUrl = environment.HelpService.Url;
	cache = new Map<String, CachedContentItem>();

	constructor(private http: Http) {
	}

	getActivePageContent(route: string) {
		if (!this.cache.get(route) || !this.isValidCachedItem(route)) {
			return this.http.get(this._helpServiceUrl + '/page/route?q=' + route)
				.map(res => {
					this.cache.set(route, { timestamp: Date.now(), content: <PageHelpContent>res.json() });
					return res.json();
				})
				.catch(this.handleError);
		}
		return Observable.create(observer => observer.next(this.cache.get(route).content));
	}
	private extractData(res: Response) {
		const body = res.json();
		return body.data || {};
	}
	private handleError(error: Response | any) {
		// In a real world app, we might use a remote logging infrastructure
		// We'd also dig deeper into the error to get a better message
		let errMsg = '';
		if (error instanceof Response) {
			const body = error.text() || '';
			//const err = body.error || JSON.stringify(body);
			errMsg = `${error.status} - ${error.statusText || ''} ${body}`;
		} else {
			errMsg = (error.message) ? error.message :
				error.status ? `${error.status} - ${error.statusText}` : 'Server error';
			console.error(errMsg); // log to console instead
		}
		return Observable.throw(errMsg);
	}

	isValidCachedItem(route) {
		const cachedTimestamp = this.cache.get(route).timestamp;
		const currentTimestamp = Date.now();
		if (currentTimestamp - cachedTimestamp > 30000) { return false; } else { return true; }
	}
}