I am playing around with asyncapi/modelina CSharpGenerator. I would like to add inheritance to the generated class something like this
public class UserCreated: IEvent
{
}
Is that possible? Can we add additional dependencies other than the generated ones?
Inheritance is, unfortunately, one of those features that have gotten put on the backburner, and still is.
Fortunately, it is possible to accomplish it, but it does require you to overwrite the entire rendering behavior, which might not be maintainable in the long run. You can find the full example in this PR: https://github.com/asyncapi/modelina/pull/772
const generator = new CSharpGenerator({
presets: [
{
class: {
// Self is used to overwrite the entire rendering behavior of the class
self: async ({renderer, options, model}) => {
//Render all the class content
const content = [
await renderer.renderProperties(),
await renderer.runCtorPreset(),
await renderer.renderAccessors(),
await renderer.runAdditionalContentPreset(),
];
if (options?.collectionType === 'List' ||
model.additionalProperties !== undefined ||
model.patternProperties !== undefined) {
renderer.addDependency('using System.Collections.Generic;');
}
const formattedName = renderer.nameType(model.$id);
return `public class ${formattedName} : IEvent
{
${renderer.indent(renderer.renderBlock(content, 2))}
}`;
}
}
}
]
});
What is happening here is that we create a custom preset for the class renderer and overwrite the entire rendering process of itself.
This will generate based on this input:
public class Root : IEvent
{
private string[] email;
public string[] Email
{
get { return email; }
set { email = value; }
}
}
Regarding dependencies, please see https://github.com/asyncapi/modelina/blob/master/docs/presets.md#adding-new-dependencies. You can do this in the self preset hook.
You can read more about the presets here: https://github.com/asyncapi/modelina/blob/master/docs/presets.md
Related
In this section of docs not all use-cases of guard usage explained clearly:
NestJS Docs - Claims-based authorization
CaslAbilityFactory implemented for these use-cases:
Admins can manage (create/read/update/delete) all entities
Users have read-only access to everything
Users can update their articles (article.authorId === userId)
Articles that are published already cannot be removed (article.isPublished === true)
and explained only the most trivial use-case:
Users have read-only access to everything
It's demonstrated with this controller method:
#Get()
#UseGuards(PoliciesGuard)
#checkPolicies((ability: AppAbility) => ability.can(Action.Read, Article))
findAll() {
return this.articlesService.findAll();
}
but how should I annotate a method to check the 3rd or 4th use-cases:
Articles that are published already cannot be removed:
(article.isPublished === true)
#Delete()
#UseGuards(PoliciesGuard)
#checkPolicies(?????????????????????????????)
delete(#Body() article: Article) {
return this.articlesService.delete(article.id);
}
Is it possible, at all? For this requirement PoliciesGuard or handler declared in #checkPolicies should be able to access method arguments.
How can controller method arguments be accessed from a guard?
Of course a workaround solution if you call ability.can(...) directly from controller method:
#Delete()
#UseGuards(SomeGuards but NOT PoliciesGuard)
delete(#Body() article: Article) {
const ability = this.caslAbilityFactory.createForUser(<<user from request>>);
if (!ability.can(Action.Delete, article)) {
throw new UnauthorizedException();
}
return this.articlesService.delete(article.id);
}
But this solution doesn't fit the original declarative pattern.
You can achieve this in the PolicyGuard. This is mentioned in NestJS docs here
your policy guard will be like this
#Injectable()
export class PoliciesGuard extends RequestGuard implements CanActivate {
public constructor(private reflector: Reflector, private caslAbilityFactory: CaslAbilityFactory) {
super();
}
public async canActivate(context: ExecutionContext): Promise<boolean> {
const policyHandlers = this.reflector.get<PolicyHandler[]>(CHECK_POLICIES_KEY, context.getHandler()) || [];
const request = this.getRequest(context);
const { user } = request;
const ability = await this.caslAbilityFactory.createForUser(user?.userId);
return policyHandlers.every(handler => this.execPolicyHandler(handler, ability, request));
}
private execPolicyHandler(handler: PolicyHandler, ability: AppAbility, request: Request) {
if (typeof handler === 'function') {
return handler(ability, request);
}
return handler.handle(ability, request);
}
}
then the checkPolicy will accept this function
export class ReadArticlePolicyHandler implements IPolicyHandler {
handle(ability: AppAbility, request) {
const { query } = request;
const article = new Article();
article.scope = query.scope;
return ability.can(Action.Read, article) || ability.can(Action.Delete, article);
}
}
I've just learned about serenity-js and am giving it a go. I'm following the tutorial and noticed the follow example:
james.attemptsTo(
Start.withAnEmptyTodoList(),
AddATodoItem.called('Buy some milk')
)
The task for Start:
export class Start implements Task {
static withATodoListContaining(items: string[]) { // static method to improve the readability
return new Start(items);
}
performAs(actor: PerformsTasks): PromiseLike<void> { // required by the Task interface
return actor.attemptsTo( // delegates the work to lower-level tasks
// todo: add each item to the Todo List
);
}
constructor(private items: string[]) { // constructor assigning the list of items
} // to a private field
}
I really like this syntax and would like to continue this setup with more starting scenario's.
What would be the proper approach to accomplish this?
For anyone having the same question this is how I resolved it (found a similar setup going through the serenity-js repo):
// Start.ts
export class Start {
public static withATodoListContaining = (items: string[]): StartWithATodoListContaining => new StartWithATodoListContaining(items);
}
// StartWithATodoListContaining.ts
export class StartWithATodoListContaining implements Task {
static withATodoListContaining(items: string[]) {
return new StartWithATodoListContaining(items);
}
performAs(actor: PerformsTasks): PromiseLike<void> {
return actor.attemptsTo(
// todo: add each item to the Todo List
);
}
constructor(private items: string[]) {
}
}
I am using the BLOC pattern for my latest Flutter app and I started out using something like this for my output streams:
class MyBloc {
// Outputs
final Stream<List<Todo>> todos;
factory MyBloc(TodosInteractor interactor) {
final todosController = BehaviorSubject<List<Todo>>()
..addStream(interactor.todos);
return MyBloc._(todosController);
}
MyBloc._(this.todos);
}
but slowly I found myself doing something more like this, using a method (or getter) after awhile:
class MyBloc {
final TodosInteractor _interactor;
// Outputs
Stream<List<Todo>> todos(){
return _interactor.todos;
}
MyBloc(this._interactor) { }
}
For people who want to see... getter for todos in TodosInteractor:
Stream<List<Todo>> get todos {
return repository
.todos()
.map((entities) => entities.map(Todo.fromEntity).toList());
}
When I look at the differing code, I see that the first example uses a field versus a method to expose the stream but I couldn't figure out why I would choose one over the other. It seems to me that creating another controller just to push through the stream is a little much... Is there a benefit to this other than being immutable in my todos stream definition? Or am I just splitting hairs?
Well maybe this will not be a best answer but it is a good practice expose your output stream using get methods. Below a example of a bloc class that i have written to a project using RxDart.
class CityListWidgetBloc {
final _cityInput = PublishSubject<List<Cidade>>();
final _searchInput = new PublishSubject<String>();
final _selectedItemsInput = new PublishSubject<List<Cidade>>();
// exposing stream using get methods
Observable<List<Cidade>> get allCities => _cityInput.stream;
Observable<List<Cidade>> get selectedItems => _selectedItemsInput.stream;
List<Cidade> _searchList = new List();
List<Cidade> _selectedItems = new List();
List<Cidade> _mainDataList;
CityListWidgetBloc() {
//init search stream
_searchInput.stream.listen((searchPattern) {
if (searchPattern.isEmpty) {
_onData(_mainDataList); // resend local data list
} else {
_searchList.clear();
_mainDataList.forEach((city) {
if (city.nome.toLowerCase().contains(searchPattern.toLowerCase())) {
_searchList.add(city);
}
});
_cityInput.sink.add(_searchList);
}
});
}
//getting data from firebase
getCity( {#required String key}) {
FirebaseStateCityHelper.getCitiesFrom(key, _onData);
//_lastKey = key;
}
searchFor(String pattern) {
_searchInput.sink.add(pattern);
}
void _onData(List<Cidade> list) {
_mainDataList = list;
list.sort((a, b) => (a.nome.compareTo(b.nome)));
_cityInput.sink.add(list);
}
bool isSelected(Cidade item) {
return _selectedItems.contains(item);
}
void selectItem(Cidade item) {
_selectedItems.add(item);
_selectedItemsInput.sink.add(_selectedItems);
}
void selectItems(List<Cidade> items){
_selectedItems.addAll( items);
_selectedItemsInput.sink.add( _selectedItems );
}
void removeItem(Cidade item) {
_selectedItems.remove(item);
_selectedItemsInput.sink.add(_selectedItems);
}
dispose() {
_cityInput.close();
_searchInput.close();
_selectedItemsInput.close();
}
}
I'm new in react native.I want store multiple small small strings to common singleton object class and want to access it from singleton object for all component. Can anyone help me singleton object implementation for react native.
Ex
Component 1 -- Login button -- >> success --> need to store userID into singleton object.
Component 2 --> get stored userID from singleton object. How can i implement it.
Here is a simple way of doing it...
export default class CommonDataManager {
static myInstance = null;
_userID = "";
/**
* #returns {CommonDataManager}
*/
static getInstance() {
if (CommonDataManager.myInstance == null) {
CommonDataManager.myInstance = new CommonDataManager();
}
return this.myInstance;
}
getUserID() {
return this._userID;
}
setUserID(id) {
this._userID = id;
}
}
And here is how to use it...
import CommonDataManager from './CommonDataManager';
// When storing data.
let commonData = CommonDataManager.getInstance();
commonData.setUserID("User1");
// When retrieving stored data.
let commonData = CommonDataManager.getInstance();
let userId = commonData.getUserID();
console.log(userId);
Hope this works out for you :)
I suggest making a static class that stores data using AsyncStorage.
You mentioned in a comment that you are already using AsyncStorage, but don't like spreading this functionality throughout your app. (i.e. try-catches all over the place, each component needing to check if a key is available, etc.) If this functionality were in a single class, it would clean up your code a lot.
Another bonus to this approach is that you could swap out the implementation pretty easily, for example, you could choose to use an in-memory object or AsyncStorage or whatever and you would only have to change this one file
NOTE: AsyncStorage is not a safe way to store sensitive information. See this question for more info on the security of AsyncStorage and alternatives.
That said, this is how I imagine a global data holder class might look:
export default class dataManager {
static storeKeyValue(key, value) {
// your choice of implementation:
// check if key is used
// wrap in try-catch
// etc.
}
static getValueForKey(key) {
// get the value out for the given key
}
// etc...
}
Then to use this class anywhere in your app, just import wherever it's needed like so:
import dataManager from 'path/to/dataManager.js';
// store value
dataManager.storeKeyValue('myKey', 'myValue');
// get value
const storedValue = dataManager.getValueForKey('myKey');
EDIT: Using Flux, Redux, or a similar technology is probably the preferred/suggested way to do this in most cases, but if you feel the Singleton pattern works best for your app then this is a good way to go. See You Might Not Need Redux
There is a workaround for this, react native packager require all the modules in the compilation phase for a generating a bundle , and after first require it generates an internal id for the module, which is from then on referenced in the whole run-time memory , so if we export an instance of a class from the file, that object will be referenced every-time whenever that file is imported .
TLDR;
Solution I :
class abc {
}
module.exports = new abc()
Solution II : I assume you want to get your strings which are static and wont change , so you can declare them as static and access them directly with class name
FYI :this works with webpack also.
I might be too late for this, but I might as well share my own implementation based on Yeshan Jay's answer.
export default class Data {
static instance = null;
_state = {};
static get inst() {
if (Data.instance == null) {
Data.instance = new Data();
}
return this.instance;
}
static get state() {
return Data.inst._state;
}
static set state(state) {
Data.inst._state = state;
}
static setState(state) {
Data.inst._state = {...Data.inst._state, ...state}
}
}
And here's how you use it. It's pretty much mimicking React Component's state behavior, so you should feel at home with little to no adjustment, without the need to frequently modify the Singleton to add new properties now and then.
import Data from './Data'
// change the whole singleton data
Data.state = { userId: "11231244", accessToken: "fa7sd87a8sdf7as" }
// change only a property
Data.setState ({ userId: "1231234" })
// get a single property directly
console.log("User Id: ", Data.state.userId)
// get a single property or more via object deconstruction
const { userId, property } = Data.state
console.log("User Id: ", userId)
TS Class Example:
export class SingletonClass
{
private static _instance: SingletonClass;
public anyMetod(_value:any):any
{
return _value;
}
public static getInstance(): SingletonClass
{
if (SingletonClass._instance == null)
{
SingletonClass._instance = new SingletonClass();
}
return this._instance;
}
constructor()
{
if(SingletonClass._instance)
{
throw new Error("Error: Instantiation failed: Use SingletonClass.getInstance() instead of new.");
}
}
}
Use:
SingletonClass.getInstance().anyMetod(1);
From what I saw in the source code RequiresAuthentication() does an Authentication check for the whole module. Is there any way to do this per Route?
I had the same problem. However it turns out the RequiresAuthentication works at both the module level and the route level. To demonstrate, here is some code ripped out my current project (not all routes shown for brevity).
public class RegisterModule : _BaseModule
{
public RegisterModule() : base("/register")
{
Get["/basic-details"] = _ => View["RegisterBasicDetailsView", Model];
Get["/select"] = _ =>
{
this.RequiresAuthentication();
return View["RegisterSelectView", Model];
};
}
}
Of course the only problem with doing it this way is that all the protected routes in the module need to call RequiresAuthentication. In the case of my module above, I have another 5 routes (not shown) all of which need protecting, so that makes six calls to RequiresAuthentication instead of one at the module level. The alternative would be to pull the unprotected route into another module, but my judgement was that a proliferation of modules is worse than the additional RequiresAuthentication calls.
namespace Kallist.Modules {
#region Namespaces
using System;
using Nancy;
#endregion
public static class ModuleExtensions {
#region Methods
public static Response WithAuthentication(this NancyModule module, Func<Response> executeAuthenticated) {
if ((module.Context.CurrentUser != null) && !string.IsNullOrWhiteSpace(module.Context.CurrentUser.UserName)) {
return executeAuthenticated();
}
return new Response { StatusCode = HttpStatusCode.Unauthorized };
}
#endregion
}
}
I ran into the same issue, here's how I solved it.
var module = new MyModule();
module.AddBeforeHookOrExecute(context => null, "Requires Authentication");
_browser = new Browser(with =>
{
with.Module(module);
with.RequestStartup((container, pipelines, ctx) =>
{
ctx.CurrentUser = new User { UserId = "1234", UserName = "test"};
});
});
I can now use this.RequiresAuthentication() at the module level and run my unit tests.