I have an ArchUnit rule that check that my core.service classes do not access javax.persistence nor org.hibernate classes:
#ArchTest
ArchRule only_sql_adapter_pull_jpa_dependencies =
noClasses().that().resideOutsideOfPackage("..infrastructure.outbound.sql..")
.should().accessClassesThat().resideInAnyPackage("javax.persistence..", "org.hibernate..");
The problem is that the following legitimate access to the PersistenceException.getMessage in one of my core.service class is flagged as an error:
package my.application.core.service
try {
persistenceService.save(myOject);
} catch (PersistenceException e) {
log.error("service failed with {}", e.getMessage());
// the call to e.getMessage() raise an Architecture Violation
// because PersistenceException is part of the javax.persistence package
}
I want my core.service classes to be refused access to classes in javax.persistence in general but allowed access to javax.persistence.PersistenceException and derived because this one access is legitimate.
How can I modify the ArchRule above to achieve this ?
Instead of the fluent API accessClassesThat(), you can use accessClassesThat(DescribedPredicate<? super JavaClass> predicate) with a composed predicate:
import static com.tngtech.archunit.base.DescribedPredicate.not;
import static com.tngtech.archunit.core.domain.JavaClass.Predicates.assignableTo;
import static com.tngtech.archunit.core.domain.JavaClass.Predicates.resideInAnyPackage;
import static com.tngtech.archunit.lang.conditions.ArchPredicates.are;
import static com.tngtech.archunit.lang.syntax.ArchRuleDefinition.noClasses;
// ...
#ArchTest
ArchRule only_sql_adapter_pull_jpa_dependencies =
noClasses().that().resideOutsideOfPackage("..infrastructure.outbound.sql..")
.should().accessClassesThat(
resideInAnyPackage("javax.persistence..", "org.hibernate..")
.and(are(not(assignableTo(PersistenceException.class))))
);
Unrelated to your question:
Did you consider using dependOnClassesThat, which is less specific than accessClassesThat?
Related
I am writing a node app in typescript. I have written a class decorator #myDecorator, and the purpose of #myDecorator is such that I need to keep track of all the classes to which it's applied.
My question: how do I make sure all of those decorated classes are loaded before making use of that behavior? Some example code will help to make this more concrete:
Declaration of the decorator in file myDecorator.ts:
type ConstructorType = { new (...args: any[]): any };
// keep track of decorated classes
const registeredClasses: Map<string, ConstructorType> = new Map();
// class decorator
export function myDecorator<T extends ConstructorType>(targetConstructor: T) {
// create the modified class
const newClass = class extends targetConstructor { /* ... */ }
// register the modified class
registeredClasses.set(targetConstructor.name, newClass);
// and return it
return newClass;
}
export function doSomethingWithMyDecoratedClasses() {
//... some behavior that relies on `registeredClasses`
}
Declaration of a decorated class in file someClass.ts
import {myDecorator} from 'myDecorator.ts'
#myDecorator
class SomeClass { /* ... */ }
Making use of doSomethingWithMyDecoratedClasses in anotherFile.ts:
import { doSomethingWithMyDecoratedClasses } from 'myDecorator.ts`
//...
doSomethingWithMyDecoratedClasses()
//...
The problem is that I need to make sure that SomeClass has been added to registeredClasses before I make this call to doSomethingWithMyDecoratedClasses. And, in fact, I've written a number of such classes in my app, and I need to make sure they are all registered.
My current best understanding is that I need to call import 'someClass.ts' in anotherFile.ts (and, in fact, import all files where decorated classes are declared), so really I need to import someClass1.ts, import someClass2.ts, ...
Is that the best/only approach? Is there a recommended pattern for doing so?
Most applications have an index file that is responsible for importing the top level things. If you import doSomethingWithMyDecoratedClasses there, you'll guarantee that everything else is imported first.
An alternative would be to not call it in the root level of a module, and instead wait for an event.
I am using inversify for an mean stack application developed with typescript. Following the instructions here at this url: https://www.npmjs.com/package/inversify, I created the inversify.config.ts file and added the code relevant to my needs. I am receiving the following error for one of my binding:
"Error:(39, 71) TS2349:Cannot invoke an expression whose type lacks a call signature. Type 'typeof ExampleRepository' has no compatible call signatures.".
inversify.config.ts:
myContainer.bind<IExampleRepository<IGroup>>(TYPES.IExampleRepository).to(ExampleRepository<IGroup>).whenTargetNamed("exampleRepository");
types.ts:
IExampleRepository: Symbol("ExampleRepository")
How would the inversify.config.ts entry have to change to accomodate this need? What am I doing wrong here? Can inversify handle this scenario?
I think that if your interface is generic IExampleRepository<T> then your ExampleRepository doesn't need the <IGroup> generic on it.
import { Container, injectable } from "inversify";
const TYPES = {
IExampleRepository: Symbol("IExampleRepository"),
};
class IGroup {
}
interface IExampleRepository<T> {
group: T;
}
#injectable()
class ExampleRepository implements IExampleRepository<IGroup> {
group: IGroup
}
const myContainer = new Container();
myContainer.bind<IExampleRepository<IGroup>>(TYPES.IExampleRepository).to(ExampleRepository).whenTargetNamed("exampleRepository");
`
Please provide more example code for IExampleRepository and Examplerepository. That might help get a better answer.
I am wondering how would you use typescript IOC specifically node app.
In case of external module-based architecture there is no any classes in the app. Just pure modules because my app heavily depends on node_modules.
How would I integrate IOC solution in such case? Any thoughts?
Here is my specific case I want to use IOC for:
I have mongoose model:
interface IStuffModel extends IStuff, mongoose.Document { }
var Stuff= mongoose.model<IStuffModel>('Stuff', Schemas.stuffSchema);
export = Stuff;
And related fake class:
export class Stuff implements IStuff {
//do stuff
}
How would I integrate IOC solution in such case
Here is a very popular library that I recommend : https://github.com/inversify/InversifyJS
External modules
Using external modules doesn't change the code at all. Instead of
kernel.bind(new TypeBinding<FooBarInterface>("FooBarInterface", FooBar));
Production
You just have
import {ProdFooBar} from "./prodFooBar";
kernel.bind(new TypeBinding<FooBarInterface>("FooBarInterface", ProdFooBar));
Test
import {MockFooBar} from "./mockFooBar";
kernel.bind(new TypeBinding<FooBarInterface>("FooBarInterface", MockFooBar));
As Basarat indicated in his answer, I have developed an IoC container called InversifyJS with advanced dependency injection features like contextual bindings.
You need to follow 3 basic steps to use it:
1. Add annotations
The annotation API is based on Angular 2.0:
import { injectable, inject } from "inversify";
#injectable()
class Katana implements IKatana {
public hit() {
return "cut!";
}
}
#injectable()
class Shuriken implements IShuriken {
public throw() {
return "hit!";
}
}
#injectable()
class Ninja implements INinja {
private _katana: IKatana;
private _shuriken: IShuriken;
public constructor(
#inject("IKatana") katana: IKatana,
#inject("IShuriken") shuriken: IShuriken
) {
this._katana = katana;
this._shuriken = shuriken;
}
public fight() { return this._katana.hit(); };
public sneak() { return this._shuriken.throw(); };
}
2. Declare bindings
The binding API is based on Ninject:
import { Kernel } from "inversify";
import { Ninja } from "./entities/ninja";
import { Katana } from "./entities/katana";
import { Shuriken} from "./entities/shuriken";
var kernel = new Kernel();
kernel.bind<INinja>("INinja").to(Ninja);
kernel.bind<IKatana>("IKatana").to(Katana);
kernel.bind<IShuriken>("IShuriken").to(Shuriken);
export default kernel;
3. Resolve dependencies
The resolution API is based on Ninject:
import kernel = from "./inversify.config";
var ninja = kernel.get<INinja>("INinja");
expect(ninja.fight()).eql("cut!"); // true
expect(ninja.sneak()).eql("hit!"); // true
The latest release (2.0.0) supports many use cases:
Kernel modules
Kernel middleware
Use classes, string literals or Symbols as dependency identifiers
Injection of constant values
Injection of class constructors
Injection of factories
Auto factory
Injection of providers (async factory)
Activation handlers (used to inject proxies)
Multi injections
Tagged bindings
Custom tag decorators
Named bindings
Contextual bindings
Friendly exceptions (e.g. Circular dependencies)
You can learn more about it at https://github.com/inversify/InversifyJS
In the particular context of Node.js there is a hapi.js example that uses InversifyJS.
I have built a simple dependency injection container that I pass around my classes that need it, everything works and all is good.
My question is that say I have 2 classes such as
class A {
public function __construct() {
}
}
class B {
public function __construct(A $a) {
}
}
Should I enforce the typehinting in the class itself or in the injection container such as;
$di->set('A', function() {
return new A();
});
$di->set('B', function(A $a) {
return new B($a);
});
Should I do both or either/or.
For answers why is it better to use one over the other etc?
Thanks.
I would use the first case, enforce the type hinting in the class itself.
This will make it clear for readers of the code what are the actual dependencies of the class.
If you decide to change the DI container (or hypothetically remove it) or reuse the classes in other project, it is good to have the type hinting in the class itself.
The DI container is there simply to help you manage dependencies.
I am specifically using breezejs and the server code for breeze js converts the dbcontext into a form which is useable on the clientside using EdmxWriter.WriteEdmx. There are many properties which I have added JsonIgnore attributes to so that they don't get passed to the client side. However, the metadata that is generated (and passed to the clientside) from EdmxWriter.WriteEdmx still has those properties. Is there any additional attribute that I can add to those properties that I want ignored so that they are ignored by EdmxWriter.WriteEdmx? Or, would I need to make a separate method so as not to have any other unintended side effects.
You can sub-class your DbContext with a more restrictive variant that you use solely for metadata generation. You can continue to use your base context for persistence purposes.
The DocCode sample illustrates this technique with its NorthwindMetadataContext which hides the UserSessionId property from the metadata.
It's just a few extra lines of code that do the trick.
public class NorthwindMetadataContext : NorthwindContext
{
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
// Hide from clients
modelBuilder.Entity<Customer>().Ignore(t => t.CustomerID_OLD);
// Ignore UserSessionId in metadata (but keep it in base DbContext)
modelBuilder.Entity<Customer>().Ignore(t => t.UserSessionId);
modelBuilder.Entity<Employee>().Ignore(t => t.UserSessionId);
modelBuilder.Entity<Order>().Ignore(t => t.UserSessionId);
// ... more of the same ...
}
}
The Web API controller delegates to the NorthwindRepository where you'll see that the Metadata property gets metadata from the NorthwindMetadataContext while the other repository members reference an EFContextProvider for the full NorthwindContext.
public class NorthwindRepository
{
public NorthwindRepository()
{
_contextProvider = new EFContextProvider<NorthwindContext>();
}
public string Metadata
{
get
{
// Returns metadata from a dedicated DbContext that is different from
// the DbContext used for other operations
// See NorthwindMetadataContext for more about the scenario behind this.
var metaContextProvider = new EFContextProvider<NorthwindMetadataContext>();
return metaContextProvider.Metadata();
}
}
public SaveResult SaveChanges(JObject saveBundle)
{
PrepareSaveGuard();
return _contextProvider.SaveChanges(saveBundle);
}
public IQueryable<Category> Categories {
get { return Context.Categories; }
}
// ... more members ...
}
Pretty clever, eh?
Just remember that the UserSessionId is still on the server-side class model and could be set by a rogue client's saveChanges requests. DocCode guards against that risk in its SaveChanges validation processing.
You can sub-class your DbContext with a more restrictive variant that you use solely for metadata generation. You can continue to use your base context for persistence purposes.
The DocCode sample illustrates this technique with its NorthwindMetadataContext which hides the UserSessionId property from the metadata.
It's just a few extra lines of code that do the trick.
The Web API controller delegates to the NorthwindRepository where you'll see that the Metadata property gets metadata from the NorthwindMetadataContext while the other repository members reference an EFContextProvider for the full NorthwindContext.
Pretty clever, eh?
If you use the [NotMapped] attribute on a property, then it should be ignored by the EDMX process.