import { Injectable } from '@angular/core';
import { Http, Response } from '@angular/http';
import { Observable } from 'rxjs/Observable';
import { AsyncSubject } from 'rxjs/AsyncSubject';
import { of } from 'rxjs/observable/of';
import 'rxjs/add/operator/catch';
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/switchMap';
import { DocumentContents } from './document-contents';
export { DocumentContents } from './document-contents';
import { LocationService } from 'app/shared/location.service';
import { Logger } from 'app/shared/logger.service';
export const FILE_NOT_FOUND_ID = 'file-not-found';
export const FETCHING_ERROR_ID = 'fetching-error';
export const CONTENT_URL_PREFIX = 'generated/';
export const DOC_CONTENT_URL_PREFIX = CONTENT_URL_PREFIX + 'docs/';
const FETCHING_ERROR_CONTENTS = `
<div class="nf-container l-flex-wrap flex-center">
<div class="nf-icon material-icons">error_outline</div>
<div class="nf-response l-flex-wrap">
<h1 class="no-toc">Request for document failed.</h1>
<p>
We are unable to retrieve the "<current-location></current-location>" page at this time.
Please check your connection and try again later.
</p>
</div>
</div>
`;
@Injectable()
export class DocumentService {
private cache = new Map<string, Observable<DocumentContents>>();
currentDocument: Observable<DocumentContents>;
constructor(
private logger: Logger,
private http: Http,
location: LocationService) {
// Whenever the URL changes we try to get the appropriate doc
this.currentDocument = location.currentPath.switchMap(path => this.getDocument(path));
}
private getDocument(url: string) {
const id = url || 'index';
this.logger.log('getting document', id);
if ( !this.cache.has(id)) {
this.cache.set(id, this.fetchDocument(id));
}
return this.cache.get(id);
}
private fetchDocument(id: string): Observable<DocumentContents> {
const requestPath = `${DOC_CONTENT_URL_PREFIX}${id}.json`;
this.logger.log('fetching document from', requestPath);
const subject = new AsyncSubject();
this.http
.get(requestPath)
.map(response => response.json())
.catch((error: Response) => {
return error.status === 404 ? this.getFileNotFoundDoc(id) : this.getErrorDoc(id, error);
})
.subscribe(subject);
return subject.asObservable();
}
private getFileNotFoundDoc(id: string): Observable<DocumentContents> {
if (id !== FILE_NOT_FOUND_ID) {
this.logger.error(`Document file not found at '${id}'`);
// using `getDocument` means that we can fetch the 404 doc contents from the server and cache it
return this.getDocument(FILE_NOT_FOUND_ID);
} else {
return of({
id: FILE_NOT_FOUND_ID,
contents: 'Document not found'
});
}
}
private getErrorDoc(id: string, error: Response): Observable<DocumentContents> {
this.logger.error('Error fetching document', error);
this.cache.delete(id);
return Observable.of({
id: FETCHING_ERROR_ID,
contents: FETCHING_ERROR_CONTENTS
});
}
}