ng-hal

ng-hal

An HAL Navigator for Angular2

Usage

$ npm install ng2-hal

Import HalModule to your application, similar to the following example:

import { HalModule } from 'ng-hal';

@NgModule({
  declarations: [ AppComponent ],
  bootstrap:    [ AppComponent ],
  imports:      [
    BrowserModule,
    HttpModule,
    FormsModule,
    HalModule
  ]
})
export class AppModule {}

To retrieve HAL/JSON documents, inject Navigator into one our your components or services. Usage Example:

import { Navigator } from 'ng-hal';

@Injectable()
export class Foo {

  constructor(private navigator: Navigator) {}

  demo() {
    this.navigator
      .get('/my/hal-document.json')
      .subscribe((doc: HalDocument) => console.log(doc));
  }
}

Demo application

http://spektrakel.de/ng-hal

API Design Considerations

• Navigator API is almost identical to Angular's Http API.
  • follow is a short-cut Observable operation that is derived from mergeMap/flatMap.
• HalDocument gives you a Resource object and the original Request/Response pair.
• Resource is a normalized view of the JSON document. You can, however, obtain the unmodified JSON object.

Reading List

• HAL - Hypertext Application Language: specification
• JSON Hypertext Application Language: draft-kelly-json-hal-08
• URI Templates: RFC 6570

Heads up!

This is still very much work-in-progress.

TODOs

• URI templating
• Link API: uri templating as instance methods on Link
  • requires: Resource implementation to map Object (declares as ts interface Link) to class instances
• publish to npm
• ConversionStrategy:
  • in later version, it would be nice to chose between hal+json and hal+xml
  • also: have a multiple strategies registered, then choose the right one dependent on Content-Type
• npm test: add unit testing
• Navigator API: convenient shortcut for follow-on navigation
  • e.g., follow((hal: HalDocument) => Observable<HalDocument>)
  • currently, mergeMap() achieves desired behaviour – just an alias?
• ConversionStrategy API: (res: Response) => boolean and (res: Response) => Resource is good
• HalDocument API: a tuple of (Request, Response, Resource)?
• npm test: for now, only build and linting

Version History

• v0.2.0 renamed to ng-hal, version bumps
• v0.1.0 first version on public npm registry

License

Copyright (c) 2016 David Herges

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

Credits

• basti1302/halfred: resource parsing and normalization for application/hal+json
• geraintluff/uri-templates: URI templates according to RFC6570
• Daniel Rosenwasser: for helping out on TypeScript #10463
• AngularClass/angular2-webpack-starter: build tools