@covalent/http

HttpInterceptorService

API Summary

Methods:

Name	Type	Description
delete	function(url: string, options: RequestOptionsArgs)	Uses underlying ng2 [http] to request a DELETE method to a URL, executing the interceptors as part of the request pipeline.
get	function(url: string, options: RequestOptionsArgs)	Uses underlying ng2 [http] to request a GET method to a URL, executing the interceptors as part of the request pipeline.
head	function(url: string, options: RequestOptionsArgs)	Uses underlying ng2 [http] to request a HEAD method to a URL, executing the interceptors as part of the request pipeline.
patch	function(url: string, data: any, options: RequestOptionsArgs)	Uses underlying ng2 [http] to request a PATCH method to a URL, executing the interceptors as part of the request pipeline.
post	function(url: string, data: any, options: RequestOptionsArgs)	Uses underlying ng2 [http] to request a POST method to a URL, executing the interceptors as part of the request pipeline.
put	function(url: string, data: any, options: RequestOptionsArgs)	Uses underlying ng2 [http] to request a PUT method to a URL, executing the interceptors as part of the request pipeline.
request	`function(url: string	Request, options: RequestOptionsArgs)`

Usage

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;
  onRequestError?: (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.

Setup

Create your custom interceptors by implementing [IHttpInterceptor]:

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

@Injectable()
export class CustomInterceptor implements IHttpInterceptor {

   onRequest(requestOptions: RequestOptionsArgs): RequestOptionsArgs {
    ... // do something to requestOptions before a request
    ... // if something is wrong, throw an error to execute onRequestError (if there is an onRequestError hook)
    if (/*somethingWrong*/) {
      throw new Error('error message for subscription error callback');
    }
    return requestOptions;
  }

  onRequestError(requestOptions: RequestOptionsArgs): RequestOptionsArgs {
    ... // do something to try and recover from an error thrown `onRequest` 
    ... // and return the requestOptions needed for the request
    ... // else return 'undefined' or throw an error to execute the error callback of the subscription
    if (cantRecover) {
      throw new Error('error message for subscription error callback'); // or return undefined;
    }
    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;
  }
}

Then, import the [CovalentHttpModule] using the forRoot() method with the desired interceptors and paths to intercept in your NgModule:

import { NgModule, Type } from '@angular/core';
import { HttpModule } from '@angular/http';
import { CovalentHttpModule, IHttpInterceptor } from '@covalent/http';
import { CustomInterceptor } from 'dir/to/interceptor';

const httpInterceptorProviders: Type<IHttpInterceptor>[] = [
  CustomInterceptor,
  ...
];

@NgModule({
  imports: [
    HttpModule, /* or CovalentCoreModule */
    CovalentHttpModule.forRoot({
      interceptors: [{
        interceptor: CustomInterceptor, paths: ['**'],
      }],
    }),
    ...
  ],
  providers: [
    httpInterceptorProviders,
    ...
  ],
  ...
})
export class MyModule {}

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

Paths

The following characters are accepted as a path to intercept

• ** is a wildcard for [a-zA-Z0-9-_] (including /)
• * is a wildcard for [a-zA-Z0-9-_] (excluding /)
• [a-zA-Z0-9-_]

Examples

Example 1

/users/*/groups intercepts:

• www.url.com/users/id-of-user/groups
• www.url.com/users/id/groups

/users/*/groups DOES NOT intercept:

• www.url.com/users/id-of-user/groups/path
• www.url.com/users/id-of-user/path/groups
• www.url.com/users/groups

Example 2

/users/**/groups intercepts:

• www.url.com/users/id-of-user/groups
• www.url.com/users/id/groups
• www.url.com/users/id-of-user/path/groups

/users/**/groups DOES NOT intercept:

• www.url.com/users/id-of-user/groups/path
• www.url.com/users/groups

Example 3

/users/** intercepts:

• www.url.com/users/id-of-user/groups
• www.url.com/users/id/groups
• www.url.com/users/id-of-user/path/groups
• www.url.com/users/id-of-user/groups/path
• www.url.com/users/groups

/users/** DOES NOT intercept:

• www.url.com/users

Example 4

/users** intercepts:

• www.url.com/users/id-of-user/groups
• www.url.com/users/id/groups
• www.url.com/users/id-of-user/path/groups
• www.url.com/users/id-of-user/groups/path
• www.url.com/users/groups
• www.url.com/users

RESTService

API Summary

Methods:

Name	Type	Description
query	function(query?: IRestQuery, transform?: IRestTransform)	Creates a GET request to the generated endpoint URL.
get	`function(id: string	number, transform?: IRestTransform)`
create	function(obj: T, transform?: IRestTransform)	Creates a POST request to the generated endpoint URL.
update	`function(id: string	number, obj: T, transform?: IRestTransform)`
delete	`function(id: string	number, transform?: IRestTransform)`
buildUrl	`function(id?: string	number, query?: IRestQuery)`

Usage

Abstract class provided with methods that wraps http services to facilitate REST API calls.

Example:

import { Injectable } from '@angular/core';
import { Response, Http, Headers } from '@angular/http';
import { RESTService, HttpInterceptorService } from '@covalent/http';

@Injectable()
export class CustomRESTService extends RESTService<any> {

  constructor(private _http: Http /* or HttpInterceptorService */) {
    super(_http, {
      baseUrl: 'www.api.com',
      path: '/path/to/endpoint',
      headers: new Headers(),
      dynamicHeaders: () => new Headers(),
      transform: (res: Response): any => res.json(),
    });
  }
}

Note: the constructor takes any object that implements the methods in [IHttp] interface. This can be the ng2 [Http] service, the covalent [HttpInterceptorService] or a custom service.

export interface IHttp {
  delete: (url: string, options?: RequestOptionsArgs) => Observable<Response>;
  get: (url: string, options?: RequestOptionsArgs) => Observable<Response>;
  head: (url: string, options?: RequestOptionsArgs) => Observable<Response>;
  patch: (url: string, body: any, options?: RequestOptionsArgs) => Observable<Response>;
  post: (url: string, body: any, options?: RequestOptionsArgs) => Observable<Response>;
  put: (url: string, body: any, options?: RequestOptionsArgs) => Observable<Response>;
  request: (url: string | Request, options: RequestOptionsArgs) => Observable<Response>;
}