Injected dependency is null - dependency-injection

Below are my two classes. Login and Activity. I want to inject Login into Activity. This occurs after Login has already been executed and parameters set. In file 2, login.UserName is always undefined and any other items I try to bind are undefined. Is there any thing that I am missing for proper binding?
//file 1
import {autoinject} from 'aurelia-framework';
import {HttpClient, json} from 'aurelia-fetch-client';
import {bindable} from 'aurelia-framework';
import 'fetch';
#autoinject
export class Login{
#bindable UserName:String
constructor(private http: HttpClient){
...redacted...
}
login(){
this.UserName="test";
}
}
//file 2
import {autoinject} from 'aurelia-framework';
import {HttpClient, json} from 'aurelia-fetch-client';
import 'fetch';
import {Login} from 'login/src/login';
#autoinject
export class Activity {
Login: Login;
constructor(private http: HttpClient, private login: Login) {
...redacted...
this.Login=login;
});
}

I think Activity class / custom-element is being injected with a different instance of the Login class / custom-element. Although the items are typically have container-controlled "singleton" lifetimes, UI components don't. I think you could get what you have to work by adding the #singleton to your Login ui component but you might be better off creating a separate class, possibly called "User" that you can inject into both the Login UI component and the Activity UI component.

Related

How to tell OpenAPI to use context-root of application in it's URL

I am running two different Payara Micro microservices in one cluster.
The issue I have is that when I try to access the OpenAPI URL of MyApp1 like http://mylink.com/myApp1/openapi it does not work. It actually works when I use URL http://mylink.com/openapi.
This becomes an issue when I want to see the API for the other microservice like http://mylink.com/myApp2/openapi which does not work.
Is there a way in Payara Micro of telling OpenAPI to use the application's context in it's path just like all the other URL in the application do?
As you can see in my previous comment, I've also struggled with the same situation.
Context - openapi and microprofile
First let me say that having /openapi URL in the root is the intended behaviour of microprofile-open. Documentation always uses /openapi path as the right to get the document LINK
In the implementation, is very clear that this behaviour is both wanted as enforced:
In the ServletContainerInitializer for OpenApi one can see the following code
// Only deploy to app root
if (!"".equals(ctx.getContextPath())) {
return;
}
Workaround aka Solution.
Now that is clear that we cannot configured this, since it's intended behaviour, one solution ( the one I'm proposing ) is to proxy the request to /YOUR_APP/openapi to /openapi.
Since my application is a jax-rs one, deployed on openshift, and I don't want to have a dedicated proxy application for this, I've just created a simple Resource/Controller to proxy this specific request for me.
The outstanding method behind:
#GET
#Path("")
public Response proxyOpenApiCall(){
log.debug("proxyOpenApiCall called");
String entity = client.target("http://localhost:8080")
.path("openapi").request()
.get(String.class);
return Response.ok(entity).build();
}
I was able to fix this with a small forward proxy. Therefore I create a new REST enpoint wich is callable from public and returns the content of internal http endpoint.
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import javax.enterprise.context.RequestScoped;
import javax.ws.rs.ApplicationPath;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.client.Client;
import javax.ws.rs.client.ClientBuilder;
import javax.ws.rs.core.Application;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
#RequestScoped
#ApplicationPath("/")
#Path("/")
public class OpenApiProxyRestFacade extends Application {
private Client client;
#PostConstruct
public void init() {
this.client = ClientBuilder.newClient();
}
#GET
#Path("/openapi")
#Produces(MediaType.APPLICATION_JSON)
public Response proxyOpenApiCall() {
String entity = client.target("http://localhost:9080").path("openapi").request().get(String.class);
return Response.ok(entity).build();
}
#GET
#Path("/openapi/ui")
#Produces(MediaType.APPLICATION_JSON)
public Response proxyOpenApiUiCall() {
String entity = client.target("http://localhost:9080/openapi").path("ui").request().get(String.class);
return Response.ok(entity).build();
}
#PreDestroy
public void destroy() {
this.client.close();
}
}
For openapi, you can set this property for change of url, so it is configurable after all
mp.openapi.extensions.path=/yourapi/whatever
and for the openapi-UI set this
openapi.ui.yamlUrl=/yourapi/whatever
Sources: I first googled for mp.openapi.xxx parameters, (I found them in source code) which led me to this url
https://download.eclipse.org/microprofile/microprofile-open-api-1.0/microprofile-openapi-spec.html
and after looking for more stuff there was one simple sentence mentioning that there is also mp.openapi.extensions and after googling those further I found this random doc here https://github.com/wildfly/wildfly/blob/main/docs/src/main/asciidoc/_admin-guide/subsystem-configuration/MicroProfile_OpenAPI.adoc

Import dart:html in Service got exception No provider found for dynamic

I have a working UserService similar to HeroService from AngularDart tutorial with BrowserClient.
And now I need to use localStorage to save the API response.
After I import dart:html, I refresh my browser, suddenly I got error on console:
EXCEPTION: No provider found for dynamic: UserService -> dynamic.
When I remove the import, the service running well.
this is my UserService code.
import 'dart:convert';
import 'dart:html';
import 'package:http/http.dart';
import 'package:my_app/src/instance_logger.dart';
class UserService with InstanceLogger {
static final _headers = {'Content-Type': 'application/json'};
static const _authUrl = 'https://my.domain/api-token-auth/';
String get loggerPrefix => 'UserService'; // or set ''
final Client _http;
UserService(this._http);
dynamic _extractData(Response resp) => json.decode(resp.body)['data'];
Exception _handleError(dynamic e) {
log(e); // for demo purposes only
return Exception('Server error; cause: $e');
}
}
in Component meta-data:
providers: [ClassProvider(UserService)],
how to use dart:html within service? If I want to access localStorage.
thank you.
Both dart:html and package:http/http.dart unfortunately have a class named Client.
How you get around this collision is to hide an unwanted class from being imported with its package.
Change
import 'dart:html';
to
import 'dart:html' hide Client;
That will take care of the collision. You could alternatively give the import an alias such as:
import 'dart:html' as html;
Then you can use localStorage by using the prefix html.localStorage;
When I run into this problem I just hide the Client class from the dart:html import.

Dynamically inject repository in generic services with nestjs

I am building an authorization service for my nestjs app.
For every protected resource on my app (Media, Game, ...), I have a *RoleEntity associated (MediaRoleEntity, GameRoleEntity, ...) that defines what a user can do with a specific resource. Each one of this *RoleEntity implements RoleEntityInterface:
export interface RoleEntityInterface<T extends ResourceEntity> {
resource: T;
user: UserEntity;
role: string;
}
Each protected entity (MediaEntity, GameEntity, ...) extends ResourceEntity.
Now I want to build a generic provider RoleService, responsible for database interaction:
#Injectable()
export class RoleService<T extends ResourceEntity> {
readonly roleRepository: Repository<RoleEntityInterface<T>>;
async read(roleDto: Partial<RoleDto<T>>): Promise<RoleEntityInterface<T>> {
return this.roleRepository.findOne({
where: { ...roleDto },
});
}
async create(roleDto: RoleDto<T> | RoleDto<T>[]): Promise<void> {
await this.roleRepository.insert(roleDto);
}
}
And I want inject this service in guards, interceptors...
Problem, I don't know how to do that, more precisely:
How can I dynamically inject the roleRepository ? (I imagine some kind of factory has to be involved.)
REAL USE CASE
I want to be able to protect resources with a guard:
#Injectable()
export class RoleGuard<T extends ResourceEntity> implements CanActivate {
constructor(
private authService: AuthService,
private roleService: RoleService<T>,
private readonly reflector: Reflector,
) {}
...
}
Now in a controller, when I use
#Role('Admin')
#UseGuards(RoleGuard<MediaEntity>)
Get()
...
It would be perfect if the whole thing magically works :), ie correct roleService with correct roleRepository are properly injected.
I am completely new to nestjs and typescript (and never played with angular neither) so maybe the whole approach is wrong..

Passing global constants to angular 4 from ASP.NET MVC

I am shifting from Razor views to Angular 4, and trying to figure out how to pass global constants from the server to Angular without relying on Ajax calls.
So the server constants will be transaction status for example:
Id: 1->Active
Id: 2-> Inactive
Id: 3->Cancelled etc
So these statuses are saved in the db and are used to query various transactions, Thus will be required in lots of components
In Razor views, I used to pass these values together with the viewmodel. But in Angular currently I can see two options:
Make Ajax calls in ngOnInit of each component that requires these constants
Make a static model to hold these values
Option 1 increases the number of server calls by quite a bit -> so I am trying to avoid this.
Option 2 will require me to change status in multiple places in my application if a new status is added for example, which i am also not fond of.
I am looking for a way to send all my constants to Angular as the application loads or page is reloaded for example.
You need to use ReplaySubject
as per rxjs documentation
ReplaySubject:Represents an object that is both an observable sequence as well as an observer. Each notification is broadcasted to all subscribed
Look at this code snippet
export class GlobalConstants{
Status:number[];
}
import { Observable, ReplaySubject } from 'rxjs';
import { GlobalConstants } from '../models/GlobalConstants';
#Injectable()
export class YourService {
//This line will cache the latest list you will get from the server
private dataSubject = new ReplaySubject<GlobalConstants>();
//you will use this observer in your components to subscribe to the getStatus result
yourStatusList$: Observable<GlobalConstants> = this.dataSubject.asObservable();
constructor(private http: Http) {
this.getStatus()
}
getStatus() {
return this.http.get('url').subscribe(res => {
this.dataSubject.next(res);
})
}
export class ExampleComponent {
public statusList;
public constructor(private _yourService: YourService) {
this.getStatus();
}
getStatus(): void {
this._yourService.yourStatusList$.subscribe(
result => {
this.statusList = result;
}
)
}
}
what will happen is when angular create the service it will call getStatus method one time per the app life cycle and then fetch your status list from the server then u will need to subscribe in your components to yourStatusList$ , for each subscrbition you will get latest cached list and if the list changed in your server u just need to call YourService.getStatus then u will fetch the status list again and all component subscribed to this observer will get notified by the new list
let's take your two challenges
1-Make Ajax calls in ngOnInit of each component that requires these constants
-by using this code your app will make one call to the server to fetch status list so u don't need to make Ajax call in ngOnInit of each component
2-Make a static model to hold these values will require me to change status in multiple places in my application if a new status is added
-if new status is added you just need to call YourService.getStatus one time in any place in your code and all components subscribed to your yourStatusList will get notified by the new status list
NOTE: you must n't use providers: [yourService] in your component cause if u used it it will create a new object and will not use the global object , just add your service in #NgModule providers and use component constructor to inject the service object
It may be best to have a service cache the information in a local variable. Then, when you inject the service into your components, and one calls a service function, the service checks the local variable. If something is in the variable, use it, if not, load the data and cache it for later use.
Since the service is a singleton, the data should only load once unless you create some mechanism to timeout the value. So, the first time the service is called, the data will be fetched. After that, the local variable (below called globals) should be used.
Service:
import { Injectable } from '#angular/core';
import { HttpClient } from '#angular/common/http';
#Injectable()
export class GlobalsService {
private globals: any;
constructor(private httpClient: HttpClient) { }
getGlobals(): any {
if (this.globals) {
return this.globals;
} else {
// call your API to get global data from DB
this.httpClient.get<any>('...').subscribe((data: any) => {
this.globals = data;
return this.globals;
});
}
}
}
Component using the service:
import { GlobalsService } from './../globals.service';
import { Component, OnInit } from '#angular/core';
#Component({
selector: 'app-tester',
templateUrl: './tester.component.html',
styleUrls: ['./tester.component.css']
})
export class TesterComponent implements OnInit {
constructor(private globalsService: GlobalsService) { }
ngOnInit() {
// Do something here with the globals from the service
const gbls = this.globalsService.getGlobals();
if (gbls) {
// ... maybe put these in a variable for later use, what ever you need
}
}
}
Doing this will keep you from having to do the Ajax call you mention, and avoid you have to keep code in more than one place. The service pattern offers a nice central place to keep this data for the lifetime of the application. All you need to do is inject the service into the component, or other services, where it is needed.
You can add you constants as attributes on your app element inside you razor view
<app someatt="{ your json data here }">Loading...</app>
then on you app's root component access them like this:
export class AppComponent implements OnInit {
constructor(
private el: ElementRef
) {
}
ngOnInit() {
console.log(this.el.nativeElement.attributes["someatt"].value);
}
}
then you can have a global service with its statuses data set here on ngOnInit and consumed in all your components

Can you only inject services into services through bootstrap?

I am trying to wire up a basic Angular2 app that uses the Http service. (Most of the tutorials I've seen do this by having a Component consume the Http service, which seems wrong unless the basic philosophy of thin controllers has changed – but that's a different question.)
I would like to create a service that uses Angular's Http service. But I can't figure out how to inject the Http service other than this:
boot.ts:
import {bootstrap} from 'angular2/platform/browser';
import {AppComponent} from './app.component';
import {HTTP_PROVIDERS } from 'angular2/http';
bootstrap(AppComponent, [HTTP_PROVIDERS]);
myService.ts:
import {Injectable} from 'angular2/core';
import {Http} from 'angular2/http';
#Injectable()
export class aService{
constructor(http:Http){
}
/** do some stuff *//
}
This works, but it seem very wrong to require the user of the service to know the service's dependencies and be required to inject them into the bootstrap process. It seems like there should be a way to directly hand a providers array to a service the same way you can a component, but I can't find it. Am I just missing something?
Update
This way if a parent injector provides an implementation for OtherService this one is used, otherwise OtherServiceImpl is used (default).
#Injectable()
class SomeService {
OtherService _other;
SomeService(Injector injector) {
_other = injector.getOptional(OtherService);
if (_other == null) {
_other = injector.resolveAndCreateChild([
provide(OtherService, useClass: OtherServiceImpl)
]).get(OtherService);
}
_other.doSomething();
}
}
If you provide another one like
bootstrap(AppElement, [
provide(OtherService, useClass: OtherServiceImpl2)
]);
OtherServiceImpl2 is used.
See also https://github.com/angular/angular/issues/5622
Original
You could just make the http service optional (using the #Optional() annotation) and if none is provided just create an instance inside the constructor with new Http().
This way the user doesn't need to know about the services dependencies, but is able to pass alternative implementations if necessary (for example for testing).
If creating the dependeny inside the service requires DI itself, you can inject an injector and use it to get dependencies.
See also optional dependencies in http://blog.thoughtram.io/angular/2015/05/18/dependency-injection-in-angular-2.html
What also could work (not tried myself yet) is just to create a child injector and instruct it to skip self
From the SkipSelfMetadata documentation
class Dependency {
}
#Injectable()
class NeedsDependency {
dependency;
constructor(#SkipSelf() dependency:Dependency) {
this.dependency = dependency;
}
}
var parent = Injector.resolveAndCreate([Dependency]);
var child = parent.resolveAndCreateChild([NeedsDependency]);
expect(child.get(NeedsDependency).dependency instanceof Depedency).toBe(true);
var inj = Injector.resolveAndCreate([Dependency, NeedsDependency]);
expect(() => inj.get(NeedsDependency)).toThrowError();
I don't know yet if this still resolves from "self" if parent can't provide the requested type.

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