Angular in-memory-web-api

UPDATE NOTICE

As of v.0.1.0, the npm package was renamed from angular2-in-memory-web-api to its current name, angular-in-memory-web-api. All versions after 0.0.21 are shipped under this name. Be sure to update your package.json and import statements.

An in-memory web api for Angular demos and tests.

It will intercept HTTP requests that would otherwise go to the remote server via the Angular XHRBackend service

This in-memory web api service processes an HTTP request and returns an Observable of HTTP Response object in the manner of a RESTy web api. It natively handles URI patterns in the form :base/:collectionName/:id?

Examples:

  // for store with a 'heroes' collection
  GET api/heroes          // all heroes
  GET api/heroes/42       // the character with id=42
  GET api/heroes?name=^j  // 'j' is a regex; returns heroes whose name starting with 'j' or 'J'
  GET api/heroes.json/42  // ignores the ".json"

Also accepts "commands":

  POST "resetDb",
  GET/POST "config" - get or (re)set the config

Basic usage

Create an InMemoryDataService class that implements InMemoryDataService.

At minimum it must implement createDb which creates a "database" hash whose keys are collection names and whose values are arrays of collection objects to return or update. For example:

import { InMemoryDbService } from 'angular-in-memory-web-api';

export class InMemHeroService implements InMemoryDbService {
  createDb() {
    let heroes = [
      { id: '1', name: 'Windstorm' },
      { id: '2', name: 'Bombasto' },
      { id: '3', name: 'Magneta' },
      { id: '4', name: 'Tornado' }
    ];
    return {heroes};
  }
}

Register this module and your service implementation in AppModule.imports calling the forRoot static method with this service class and optional configuration object:

// other imports
import { HttpModule }           from '@angular/http';
import { InMemoryWebApiModule } from 'angular-in-memory-web-api';

import { InMemHeroService }     from '../app/hero-data';
@NgModule({
 imports: [
   HttpModule,
   InMemoryWebApiModule.forRoot(InMemHeroService),
   ...
 ],
 ...
})
export class AppModule { ... }

See examples in the Angular.io such as the Server Communication and Tour of Heroes chapters.

Always import the InMemoryWebApiModule after the HttpModule to ensure that the XHRBackend provider of the InMemoryWebApiModule supersedes all others.

Bonus Features

Some features are not readily apparent in the basic usage example.

The InMemoryBackendConfigArgs defines a set of options. Add them as the second forRoot argument:

   InMemoryWebApiModule.forRoot(InMemHeroService, { delay: 500 }),

Simple query strings

Pass custom filters as a regex pattern via query string. The query string defines which property and value to match.

Format: /app/heroes/?propertyName=regexPattern

The following example matches all names start with the letter 'j' or 'J' in the heroes collection.

/app/heroes/?name=^j

Search pattern matches are case insensitive by default. Set config.caseSensitiveSearch = true if needed.

Pass thru to a live XHRBackend

If an existing, running remote server should handle requests for collections that are not in the in-memory database, set Config.passThruUnknownUrl: true. This service will forward unrecognized requests via a base version of the Angular XHRBackend.

parseUrl override

The parseUrl method breaks down the request URL into a ParsedUrl object. ParsedUrl is a public interface whose properties guide the in-memory web api as it processes the request.

Request URLs for your api may not match the api imagined by the default parseUrl and may even cause it to throw an error. You can override the default by implementing a parseUrl method in your InMemoryDbService. Such a method must take the incoming request URL string and return a ParsedUrl object.

responseInterceptor

You can morph the response returned by the default HTTP methods, called by collectionHandler, to suit your needs by adding a responseInterceptor method to your InMemoryDbService class. The collectionHandler calls your interceptor like this:

responseOptions = this.responseInterceptor(responseOptions, requestInfo);

HTTP method interceptors

If you make requests this service can't handle but still want an in-memory database to hold values, override the way this service handles any HTTP method by implementing a method in your InMemoryDbService that does the job.

The InMemoryDbService method name must be the same as the HTTP method name but all lowercase. This service calls it with an HttpMethodInterceptorArgs object. For example, your HTTP GET interceptor would be called like this: e.g., yourInMemDbService["get"](interceptorArgs). Your method must return an Observable<Response>

The HttpMethodInterceptorArgs (as of this writing) are:

requestInfo: RequestInfo;           // parsed request
db: Object;                         // the current in-mem database collections
config: InMemoryBackendConfigArgs;  // the current config
passThruBackend: ConnectionBackend; // pass through backend, if it exists

Examples

The file examples/hero-data.service.ts is an example of a Hero-oriented InMemoryDbService, derived from the HTTP Client sample in the Angular documentation.

Add the following line to AppModule.imports

InMemoryWebApiModule.forRoot(HeroDataService)

That file also has a HeroDataOverrideService derived class that demonstrates overriding the parseUrl method and an HTTP GET interceptor.

Add the following line to AppModule.imports to see it in action:

InMemoryWebApiModule.forRoot(HeroDataOverrideService)

To Do

• add tests (shameful omission!)

Build Instructions

Mostly gulp driven.

The following describes steps for updating from one Angular version to the next

This is essential even when there are no changes of real consequence. Neglecting to synchronize Angular 2 versions triggers typescript definition duplication error messages when compiling your application project.

• gulp bump - up the package version number

• update CHANGELOG.MD to record the change

• update the dependent version(s) in package.json

• npm install the new package(s) (make sure they really do install!)
  npm list --depth=0

• consider updating typings, install individually/several:

  npm install @types/jasmine @types/node --save-dev

• gulp clean - clear out all generated text

• npm run tsc to confirm the project compiles w/o error (sanity check)

-- NO TESTS YET ... BAD --

• gulp build

• commit and push

• npm publish

• Fix and validate angular.io docs samples

• Add two tags to the release commit with for unpkg

  • the version number
  • 'latest'