Feature/http helpers

[emoralesb05]

Description

Http helper module, including interceptor wrapper.
#19

What's included?

• Extracted RESTService from core and added it to http module
• Added HttpInterceptorService as a http service wrapper to include interceptors into the request pipeline.
• Added docs for http module.

HttpInterceptorService

Service provided with methods that wrap the ng2 [Http] service and provide an easier experience for interceptor implementation.

To add a desired interceptor, it needs to implement the [IHttpInterceptor] interface.

export interface IHttpInterceptor {
  onRequest?: (requestOptions: RequestOptionsArgs) => RequestOptionsArgs;
  onResponse?: (response: Response) => Response;
  onResponseError?: (error: Response) => Response;
}

Every method is optional, so you can just implement the ones that are needed.

Example for usage:

import { Injectable } from '@angular/core';
import { IHttpInterceptor } from '@covalent/http';

@Injectable()
export class CustomInterceptor implements IHttpInterceptor {

  onRequest(requestOptions: RequestOptionsArgs): RequestOptionsArgs {
    ... // do something to requestOptions
    return requestOptions;
  }

  onResponse(response: Response): Response {
    ... // check response status and do something
    return response;
  }

  onResponseError(error: Response): Response {
    ... // check error status and do something
    return error;
  }
}

Also, you need to bootstrap the interceptor providers

import { HTTP_PROVIDERS } from '@angular/http';
import { provideInterceptors } from '@covalent/http';
import { CustomInterceptor } from 'dir/to/interceptor';

bootstrap(AppComponent, [
  HTTP_PROVIDERS,
  provideInterceptors([CustomInterceptor]),
]);

After that, just inject [HttpInterceptorService] and use it for your requests.

Properties:

Test Steps

• ng serve
• go to components -> http
• see docs and how its used.

Screenshots

[kyleledbetter]

is this suppose to be commented? i think what you have is valid but maybe having it on its own line would be more clear:

constructor(private _http: Http) { 
/* or constructor(private _http: HttpInterceptorService) { */

or

constructor(private _http: Http) { 
/// or constructor(private _http: HttpInterceptorService) {

[aciccarello]

If it is intentional I think there should be a note explaining the use cases or just pick one.

On a side note, is an inline comment any better?

constructor(private _http: HTTP /* or HttpInterceptorService */) {

[emoralesb05]

Yeah, maybe just having it inline works fine, ill change it. 👍 and add a note.