How to convert JS callback object to Dart - dart

I am integrating Dart with Keycloak. I have included keycloak.js ( https://github.com/keycloak/keycloak-js-bower/blob/master/dist/keycloak.js ) in index.html.
Dart class :
#JS()
library keycloak11;
import 'package:js/js.dart';
#JS('Keycloak')
class Keycloak1 {
external init(InitOptions opts);
external Keycloak1();
}
#JS()
#anonymous
class InitOptions {
external String get onLoad;
external set onLoad(String v);
external factory InitOptions({
String onLoad
});
}
in onActivate() of the page -
var kcl = new Keycloak1();
var promise = kcl.init(new InitOptions(onLoad : 'login-required'));
This takes me to the login page fine. How can I register success and error callbacks ?
In javascript, this works -
keycloak.init({onLoad: 'login-required'}).success(function (authenticated) {
if (!authenticated) {
alert('not authenticated');
} else {
alert('success');
}
}).error(function () {
alert('failed to initialize');
});

Related

How to integrate dependency injection with custom decorators

I'm trying to create a decorator that requires dependency injection.
For example:
#Injectable()
class UserService{
#TimeoutAndCache(1000)
async getUser(id:string):Promise<User>{
// Make a call to db to get all Users
}
}
The #TimeoutAndCache returns a new promise which does the following:
if call takes longer than 1000ms, returns a rejection and when the call completes, it stores to redis (so that it can be fetched next time).
If call takes less than 1000ms, simply returns the result
export const TimeoutAndCache = function timeoutCache(ts: number, namespace) {
return function log(
target: object,
propertyKey: string,
descriptor: TypedPropertyDescriptor<any>,
) {
const originalMethod = descriptor.value; // save a reference to the original method
descriptor.value = function(...args: any[]) {
// pre
let timedOut = false;
// run and store result
const result: Promise<object> = originalMethod.apply(this, args);
const task = new Promise((resolve, reject) => {
const timer = setTimeout(() => {
if (!timedOut) {
timedOut = true;
console.log('timed out before finishing');
reject('timedout');
}
}, ts);
result.then(res => {
if (timedOut) {
// store in cache
console.log('store in cache');
} else {
clearTimeout(timer);
// return the result
resolve(res);
}
});
});
return task;
};
return descriptor;
};
};
I need to inject a RedisService to save the evaluated result.
One way I could inject Redis Service in to the UserService, but seems kind ugly.
You should consider using an Interceptor instead of a custom decorator as they run earlier in the Nest pipeline and support dependency injection by default.
However, because you want to both pass values (for cache timeout) as well as resolve dependencies you'll have to use the mixin pattern.
import {
ExecutionContext,
Injectable,
mixin,
NestInterceptor,
} from '#nestjs/common';
import { Observable } from 'rxjs';
import { TestService } from './test/test.service';
#Injectable()
export abstract class CacheInterceptor implements NestInterceptor {
protected abstract readonly cacheDuration: number;
constructor(private readonly testService: TestService) {}
intercept(
context: ExecutionContext,
call$: Observable<any>,
): Observable<any> {
// Whatever your logic needs to be
return call$;
}
}
export const makeCacheInterceptor = (cacheDuration: number) =>
mixin(
// tslint:disable-next-line:max-classes-per-file
class extends CacheInterceptor {
protected readonly cacheDuration = cacheDuration;
},
);
You would then be able to apply the Interceptor to your handler in a similar fashion:
#Injectable()
class UserService{
#UseInterceptors(makeCacheInterceptor(1000))
async getUser(id:string):Promise<User>{
// Make a call to db to get all Users
}
}

Electron - ipcRenderer not working in Async Class

i have a class with a Constructor and Async functions.
I have done module.exports so that i could call my Class from my GUI.js file and in my GUI.js file, i have required that class, and everything works fine.
But inside my class, im trying to do this ipcRenderer.send('message', 'Hello');
And im getting this error:
TypeError: Cannot read property 'send' of undefined
is it possible to remote the ipcRenderer in my GUI.js?
Thanks.
i have required the module in my main file, and in my renderer file it sends ipcRenderer.send('startMyClass');
And in my Main file: ipcMain.on('startMyClass', (event, args) => {
const client = new myClass();
client.Start();
})
This is my class/index.js file that is being required in my main file.
const request = require('request-promise');
const cheerio = require('cheerio');
const { ipcRenderer } = require('electron')
class myClass {
constructor() {
this._jar = request.jar();
this._request = request.defaults({ jar: this._jar });
}
async Start() {
await this.Test();
};
async Test() {
ipcRenderer.send('myMessage', 'Hello');
}
}
module.exports = myClass;
EDIT:
If i dont require it, and have the whole class in my main file, i can do event.sender.send('myMSG', 'hello');
But i want to do it in my class, that's NOT in the same file as my main.
Sending message from Main to Renderer should be done by sending to a specific webContents. That's why event.sender.send('myMSG', 'hello') works, while ipcRenderer.send not. The latter sends from Renderer to Main as stated in docs (and also, cannot be accessed from Main process as your Error told you it's undefined).
As explainded in ipcMain's docs you should access the webContents you want to send to and call send on that.
So to correct your code you can
Pass a reference to the main window to myClass and call send on that
class myClass {
constructor(args) {
// ...
this.mainWindow = args.win
}
// ...
async Test() {
this.mainWindow.webContents.send('myMessage', 'Hello');
}
}
Or send to the actually focused window (BrowserWindow.getFocusedWindow()) if that fits your needs
class myClass {
// ...
async Test() {
BrowserWindow.getFocusedWindow().webContents.send('myMessage', 'Hello');
}
}

converting a javascript object returned from a javascript API to a dart class

I'm trying to create a dart implementation of the auth0 javascript API using the js package from https://pub.dartlang.org/packages/js.
so I'm loading https://cdn.auth0.com/js/lock/10.0.0/lock.min.js in the index.html and I created the following auth0lock dart class:
#JS()
library auth0lock;
import 'package:js/js.dart';
#JS('Auth0Lock')
class Auth0LockJS {
external factory Auth0LockJS(String token, String domain, Object options);
external on(String event, Function func);
external show();
}
class Auth0Lock {
Auth0LockJS auth0;
Auth0Lock(String token, String domain, Object options) {
this.auth0 = new Auth0LockJS(token,domain,options);
}
on(String event, Function func) {
this.auth0.on(event,allowInterop(func));
}
show() {
this.auth0.show();
}
}
#anonymous
#JS()
class AuthResult {
external factory AuthResult({
String accessToken,
String idToken,
String idTokenPayload,
String state
});
external String get accessToken;
external set accessToken(String v);
external String get idToken;
external set idToken(String v);
external Object get idTokenPayload;
external set idTokenPayload(Object v);
external String get state;
external set state(String v);
}
I'm writing an angular2-dart application so I created an authentication service that uses the auth0lock.dart file that I showed previously using the following code:
#Injectable()
class Auth {
Auth0Lock lock;
authenticatedEvent(AuthResult authResult) {
print(authResult);
}
Auth() {
this.lock = new Auth0Lock(configObj.auth0.apiKey, configObj.auth0.domain,{});
this.lock.on("authenticated", authenticatedEvent);
}
updateProfileName(data) {
var profile = data['profile'] != null ? data['profile'] : data;
print(profile['name']);
}
authenticated() {
return false;
}
login() {
this.lock.show();
}
}
now... everything actually works! I created in the auth_service.dart file a variable typed AuthLock named lock. I instance is with parameters, run the show() function, connect to the authenticated event and the function is fired with the authentication is completed.
I created a class AuthResult but it ignores it and I get a javascript object returned from the function handler.
I program the code using Intellij and execute with dartium. so when I place a breakpoint on the print(authResult);line in the auth_service.dart file, the debugger shows that the authResult Object contains 2 properties, JavaScript View of type Object and class of type JSObjectimpl. the Javascript View contains all the properties that are returned by this function handler.
how do I convert it to a regular class in dart ? obviously I created the AuthResult class wrong cause the function handler doesn't return this type. so what am I missing?
thanks!
update
inside the authenticatedEvent function I tried printing authResult.values, that produced the error that a class of type JSObjectImpl doesn't have that function. so the return object is type JSObjectImpl. the weird thing is that I have no idea where JSObjectImpl is defined so I removed the variable type of authResult and tried to use the variables inside directory with the following code:
authenticatedEvent(authResult) {
var a = authResult.accessToken;
print(a);
}
this works. why I can't find JSObjectImpl type in dart? any quick way to convert this to a dart class?
thanks
Perhaps you just need to remove #anonymous from AuthResult
A simplified but complete and similar example
index.html
<!doctype html>
<html>
<head>
<script>
var Apple = function(type) {
this.type = type;
this.color = "red";
this.getInfo2 = function() {
return this.color + ' ' + this.type + ' apple';
};
};
Apple.prototype.getInfo = function() {
return this.color + ' ' + this.type + ' apple';
};
function callback(f) {
console.log(f);
f(new Apple('Golden Delicious'));
}
</script>
</head>
<body>
<script type="application/dart" src="index.dart"></script>
<script src="packages/browser/dart.js"></script>
</body>
</html>
index.dart
#JS()
library typed_callback.web;
import 'package:js/js.dart';
#JS()
class Apple {
external String get type;
external set type(String type);
external String get color;
external set color(String color);
external String getInfo();
external String getInfo2();
external Apple(String type);
}
typedef void Callback(Apple a);
#JS('callback')
external void callback(Callback /* or just Function */ f);
f(Apple apple) {
print(apple.getInfo());
print(apple); // prints the stringified JS object [object Object]
}
main() async {
callback(allowInterop(f));
}

How to bind JavaScript callback in stable 1.1.1 Dart and bind Dart callback in JavaScript (Dart2Js2Dart)?

I want to write some Dart function "oKey" which calls JavaScript function "jsOnKey" (with success or exception too since cannot predict).
Next I want that JavaScript function "onKey" will call Dart function "callbackFromJs" to return control to Dart again (with success or exception).
Can you help me with this full flow - please assume SUCCESS or EXCEPTION on each border - I can not rely on 3rd party code - DART 2 JS 2 DART?
To make more context to this general question I put example code.
import 'dart:html';
void onKey(Event event) {
// I want to call something in javascript
// function callbackFromDart () {
// /* something */;
// /* call callbackJs in Dart - return control to dart */
// }
}
void callbackFromJs() {
// It should be called from JavaScript
}
void main() {
InputElement nameElement = querySelector('input[name=name]');
nameElement..placeholder = 'Enter text'
..onKeyUp.listen(onKey);
InputElement descriptionElement = querySelector('input[name=description]');
descriptionElement..placeholder = 'Enter text'
..onKeyUp.listen(onKey);
}
First have a look at Using JavaScript from Dart.
For your case you can simply pass callbacks to handle what you call Js 2 Dart :
import 'dart:js' as js;
void onKey(Event event) {
onSuccess() {
// Dart callback called from Js
}
onError() {
// Dart callback called from Js
}
// assuming your js function takes 2 callbacks as parameters
try {
// in JS : function a() { throw "throw from js"; }
js.context.callMethod('myTopLevelFunction', [onSuccess, onError]);
}
catch (e) {
print('js error catch on Dart side : $e');
}
}
The Dart exceptions can be catch with the same kind of code on Js side.

How do I access `this` from JavaScript via JS - Dart interop?

I need to access a JavaScript object's this from a Dart function. I'm effectively adding a new method to a JavaScript object, via Dart-JS interop. I need to access properties that are on the JavaScript object from the method defined in Dart.
The Callback constructor can pass the this from JavaScript. According to the API docs for Callback:
new Callback.many(Function f, {bool withThis: false})
new Callback.once(Function f, {bool withThis: false})
Here is an example:
Dart code:
import 'dart:html';
import 'package:js/js.dart' as js;
void main() {
var greeter = js.context['greeter'];
var msg = greeter['greet']('Bob');
greeter['doCoolStuff'] = new js.Callback.many(doCoolStuff, withThis: true);
}
doCoolStuff(jsThis) {
print(jsThis['msg']);
}
Notice the use of withThis: true when creating the Callback. The this from JavaScript is passed in as the first argument to the callback function. In this case, I give it a name of jsThis.
JavaScript code:
function Greeter() {
this.msg = 'hello';
var that = this;
document.getElementById('clickme').addEventListener('click', function() {
that.doCoolStuff();
});
}
Greeter.prototype.greet = function(name) {
return this.msg + ' ' + name;
}
var greeter = new Greeter();
document.getElementById('clickme').addEventListener('click', function() {
greeter.doCoolStuff(); // comes from Dart land
});

Resources