How do I apply a custom payloadConverter in MessagingMessageConverter. It defaults to the SimpleMessageConverter class.
I can easily apply a messageConverter onto the rabbitTemplate, but it only affects the outgoing message.
The MessagingMessageConverter belongs to the MessagingMessageListenerAdapter.
Do I need to create a containerFactory in order to apply a payloadConverter?
Yes, you set the converter on the container factory; you can either define your own bean or modify the one created by Boot. I assume you are using boot because otherwise you would have already had to define a factory.
#Component
class ContainerCustomizer {
public ContainerCustomizer(AbstractRabbitListenerContainerFactory<?> factory) {
factory.setMessageConverter(...);
}
}
Related
I have my normal Entity Framework context, which is like this:
public class LikvidoWebsitesApiContext : IdentityDbContext<ApplicationUser>, ILikvidoWebsitesApiContext
{
// code
}
I have made an interface, which has my DBSets.
In my normal solution, I set it up in Ninject like this:
kernel.Bind<ILikvidoWebsitesApiContext>().To<LikvidoWebsitesApiContext>().InRequestScope();
I use the context in my services by adding the ILikvidoWebsitesApiContext inside the constructor, and then I can use the database.
My question is: how do I set this up in the unit Test?
I have tried to do the following:
kernel.Bind(typeof(ILikvidoWebsitesApiContext))
.To(typeof(Mock<LikvidoWebsitesApiContext>))
.Register(true);
(Using the Moq framework)
However, this gives the:
System.InvalidCastException: 'Unable to cast object of type 'Moq.Mock`1[Likvido.Domain.Services.Data.LikvidoWebsitesApiContext]' to type 'Likvido.Domain.Services.Data.ILikvidoWebsitesApiContext'.'
Which do make sense, but I am very unsure how to fix it?
After a quick look at the Ninject wiki I came across
Providers, Factory Methods and the Activation Context
Where they show how to use a Provider to build up instances.
Following the suggestion in the wiki it was advised to extend Provider<T> which includes strong typing.
public MoqContextProvider : Provider<ILikvidoWebsitesApiContext> {
protected override ILikvidoWebsitesApiContext CreateInstance(IContext context) {
var mock = new Mock<ILikvidoWebsitesApiContext>();
// Set up of mock members
return mock.Object;
}
}
And then it is just a matter of plugging into the container
kernel.Bind<ILikvidoWebsitesApiContext>().ToProvider(new MoqContextProvider());
There was also a suggestion about using Factory Methods
A lighter weight alternative to writing IProvider implementations is to bind a service to a delegate method.
kernal.Bind<ILikvidoWebsitesApiContext>()
.ToMethod(context => {
var mock = new Mock<ILikvidoWebsitesApiContext>();
// Set up of mock members
return mock.Object;
});
The provided Func will be bound to the service type for deferred binding and called later when a new instance of the service (i.e. ILikvidoWebsitesApiContext) is required.
Remember that when using Moq you need to set up the desired behavior of the mocks.
I'm struggling with a particular dependency injection problem and I just can't seem to figure it out. FYI: I'm new to guice, but I have experience with other DI frameworks - that's why I believe this shouldn't be to complicated to achieve.
What am I doing:
I'm working on Lagom multi module project and using Guice as DI.
What I would like to achieve:
Inject multiple named instances of some interface implementation (lets' call it publisher, since it will publishing messages to kafka topic) to my service.
This 'publisher' has injected some Lagom and Akka related services (ServiceLocator, ActorSystem, Materializer, etc..).
Now I would like to have two instances of such publisher and each will publish messages to different topic (So one publisher instance per topic).
How would I achieve that?
I have no problem with one instance or multiple instances for the same topic, but if I want to inject different topic name for each instance I have a problem.
So my publisher implementation constructor looks like that:
#Inject
public PublisherImpl(
#Named("topicName") String topic,
ServiceLocator serviceLocator,
ActorSystem actorSystem,
Materializer materializer,
ApplicationLifecycle applicationLifecycle) {
...
}
If I want to create one instance I would do it like this in my ServiceModule:
public class FeedListenerServiceModule extends AbstractModule implements ServiceGuiceSupport {
#Override
protected void configure() {
bindService(MyService.class, MyServiceImpl.class);
bindConstant().annotatedWith(Names.named("topicName")).to("topicOne");
bind(Publisher.class).annotatedWith(Names.named("publisherOne")).to(PublisherImpl.class);
}
}
How would I bind multiple publishers each for it's own topic?
I was playing around with implementing another private module:
public class PublisherModule extends PrivateModule {
private String publisherName;
private String topicName;
public PublisherModule(String publisherName, String topicName) {
this.publisherName = publisherName;
this.topicName = topicName;
}
#Override
protected void configure() {
bindConstant().annotatedWith(Names.named("topicName")).to(topicName);
bind(Publisher.class).annotatedWith(Names.named(publisherName)).to(PublisherImpl.class);
}
}
but this led me nowhere since you can't get injector in you module configuration method:
Injector injector = Guice.createInjector(this); // This will throw IllegalStateException : Re-entry is not allowed
injector.createChildInjector(
new PublisherModule("publisherOne", "topicOne"),
new PublisherModule("publisherTwo", "topicTwo"));
The only solution which is easy and it works is that I change my PublisherImpl to abstract, add him abstract 'getTopic()' method and add two more implementations with topic override.
But this solution is lame. Adding additional inheritance for code reuse is not exactly the best practice. Also I believe that Guice for sure must support such feature.
Any advises are welcome.
KR, Nejc
Don't create a new Injector within a configure method. Instead, install the new modules you create. No child injectors needed—as in the PrivateModule documentation, "Private modules are implemented using parent injectors", so there's a child injector involved anyway.
install(new PublisherModule("publisherOne", "topicOne"));
install(new PublisherModule("publisherTwo", "topicTwo"));
Your technique of using PrivateModule is the one I'd go with in this situation, particularly given the desire to make the bindings available through binding annotations as you have it, and particularly if the full set of topics is known at runtime. You could even put the call to install in a loop.
However, if you need an arbitrary number of implementations, you may want to create an injectable factory or provider to which you can pass a String set at runtime.
public class PublisherProvider {
// You can inject Provider<T> for all T bindings in Guice, automatically, which
// lets you configure in your Module whether or not instances are shared.
#Inject private final Provider<ServiceLocator> serviceLocatorProvider;
// ...
private final Map<String, Publisher> publisherMap = new HashMap<>();
public Publisher publisherFor(String topicName) {
if (publisherMap.containsKey(topicName)) {
return publisherMap.get(topicName);
} else {
PublisherImpl publisherImpl = new PublisherImpl(
topicName, serviceLocatorProvider.get(), actorSystemProvider.get(),
materializerProvider.get(), applicationLifecycleProvider.get());
publisherMap.put(topicName, publisherImpl);
return publisherImpl;
}
}
}
You'd probably want to make the above thread-safe; in addition, you can avoid the explicit constructor call by using assisted injection (FactoryModuleBuilder) or AutoFactory, which will automatically pass through explicit parameters like topicName while injecting DI providers like ServiceLocator (which hopefully has a specific purpose, because you may not need much service-locating within a DI framework anyway!).
(Side note: Don't forget to expose your annotated binding for your PrivateModule. If you don't find yourself injecting your topicName anywhere else, you might also consider using individual #Provides methods with the assisted injection or AutoFactory approach above, but if you expect each Publisher to need a differing object graph you might choose the PrivateModule approach anyway.)
Guice's approach to dependency injection is that the DI framework complements your instantiation logic, it doesn't replace it. Where it can, it will instantiate things for you, but it doesn't try to be too clever about it. It also doesn't confuse configuration (topic names) with dependency injection - it does one thing, DI, and does that one thing well. So you can't use it to configure things, the way you can with Spring for example.
So if you want to instantiate an object with two different parameters, then you instantiate that object with two different parameters - ie, you invoke new twice. This can be done by using provider methods, which are documented here:
https://github.com/google/guice/wiki/ProvidesMethods
In your case, it might look something like adding the following method to your module:
#Provides
#Named("publisherOne")
#Singleton
Publisher providePublisherOne(ServiceLocator serviceLocator,
ActorSystem actorSystem,
Materializer materializer,
ApplicationLifecycle applicationLifecycle) {
return new PublisherImpl("topicOne", serviceLocator,
actorSystem, materializer, applicationLifecycle);
}
Also, you probably want it to be a singleton if you're adding a lifecycle hook, otherwise you could run into memory leaks each time you add a new hook every time it's instantiated.
I want to implement the concept of Trigger objects in Grails for my domain classes. Grails allows me to define methods like beforeInsert() in my domain classes to handle insert, update and delete events, similar to how SQL databases have the concept of database triggers. But to separate concerns I'd like to move all of the trigger logic outside of the domain class.
Ideally I can simply define a static list of trigger classes in my domain class and then iterate through those in the beforeInsert() method. Sample code shown below.
static beforeInsertTriggers = [AccountNameTrigger, AccountDumpTrigger]
def beforeInsert() {
for (Class<Trigger> triggerClass : beforeInsertTriggers) {
triggerClass.newInstance().using(this).execute()
}
}
I've created a sample Grails 2.5.4 project on GitHub illustrating what I'm trying to do. But the problem is that the triggers literally are standalone islands of logic without the ability to autowire services. How can I better set up this Trigger pattern or something similar? So I may autowire services and other beans into the Trigger instances?
I am also trying to keep the design simple and readable.
Avoid cluttering the domain class with fields and properties that are not related to the data model. To me this means no autowired beans in the domain class.
Define the list of triggers using the trigger class names (or bean names, if need be). This may be overly idealistic, but hey...
For what it's worth, part of my inspiration also comes from how Salesforce implements triggers as distinct units of self-contained code.
Register your Triggers as Singleton Beans and there you can inject other services/beans. You can create your custom beans via resources.groovy.
Lets take the example of AccountDumpTrigger. Lets make a simple change to it:
package grails.domain.trigger.demo.triggers
import grails.domain.trigger.demo.Account
import org.codehaus.groovy.grails.commons.GrailsApplication
/**
* Created by marty on 6/25/16.
*/
class AccountDumpTrigger extends AbstractTrigger<Account> {
GrailsApplication grailsApplication
#Override
void execute() {
println grailsApplication.isInitialised()
println resource.dump()
}
}
And code in resources.groovy or in your plugin's doWithSpring closure:
accountDumpTrigger(grails.domain.trigger.demo.triggers.AccountDumpTrigger) { bean ->
bean.factoryMethod = 'getInstance'
/*
either refer each bean individually or you can use:
bean.autowire = "byType"
OR
bean.autowire = "byName"
*/
grailsApplication = ref("grailsApplication")
}
And inside your domain:
static beforeInsertTriggers = [AccountDumpTrigger]
def beforeInsert() {
for (Class<Trigger> triggerClass : beforeInsertTriggers) {
triggerClass.instance.using(this).execute()
}
}
And instead of writing your code inside beforeInsert you can also do the same by registering an implementation of AbstractPersistenceEventListener. This way you don't have to repeat your code. Also yo can move it to a parent class.
So I have a need for injecting a number of different services into an authorization attribute I'm using. For simplicity I will leave this to show the configuration manager.
public class FeatureAuthorizeAttribute : AuthorizeAttribute
{
public IConfigurationManager ConfigurationManager;
private readonly string _feature;
public FeatureAuthorizeAttribute(string feature)
{
_feature = feature;
var test = ConfigurationManager.GetCdnPath();
}
}
Which would be used as follows
[FeatureAuthorize("Admin")]
I have tried to use constructor injection
public FeatureAuthorizeAttribute(string feature, IConfigurationManager configurationManager)
{
ConfigurationManager = configurationManager;
_feature = feature
}
However this just causes an error when I attempt
[FeatureAuthorize("Admin", IConfigurationManager)]
Which seems like the wrong way to go about it in the first place. I'm assuming that I need to register my custom authorization attribute with the container to get it to start picking up
Instead of trying to use Dependency Injection with attributes (which you can't do in any sane, useful way), create Passive Attributes.
Specifically, in this case, assuming that this is an ASP.NET MVC scenario, you can't derive from AuthorizeAttribute. Instead, you should make your Authorization service look for your custom attribute, and implement IAuthorizationFilter. Then add the filter to your application's configuration.
More details can be found in this answer: https://stackoverflow.com/a/7194467/126014.
I am in the process of creating a custom membership provider for an ASP.Net MVC website. The provider is being created as a separate class as part of a bigger library. There is a need for the back-end data store to be flexible as it could be an Xml File or SQL database. My initial thought was to create an interface for the data store and inject this into provider using dependency injection.
The end result is required is that a developer can inherit the data store interface and provide the required methods to update the data, which will then be used by the custom membership providers.
However through my own lack of skill I can't figure out how to inject the class into the membership provider when adding it to the website? What needs to be done to link the data store to the provider? What would be the simplest way to enable this in the website?
If you are configuring the custom membership providers via the <membership> element in the Web.config file, then I can see the issues you will have with dependency injection.
The providers are constructed and managed by the framework, and there is no opportunity for you to intercept that construction to provide additional dependency injection for the IDataStore interface.
If my assumption is correct, then what you can do is override the Initialize() method in your custom provider, and do the dependency injection there. You can have a custom name/value setting in the provider configuration which points to a type that implements IDataStore, which is passed as part of a dictionary to the Initialize() method.
Then, you activate an instance of the data store type and set it on the appropriate property:
public class MyMembershipProvider : MembershipProvider
{
public IDataStore DataStore
{
get;
set;
}
public override Initialize(string name, NameValueCollection config)
{
var dataStoreType = config["dataStoreProvider"];
if (!String.IsNullOrEmpty(dataStoreType))
{
var type = Type.GetType(dataStoreType);
DataStore = (IDataStore) Activator.CreateInstance(type);
}
}
}
Initialize() will be called by the framework after it constructs an instance of your provider, so that is the perfect place to do any additional setup work such as this.
For testing scenarios, you just set the data store property on the provider instance itself, as you will be constructing it directly in your tests.
Isn't this better? I use it with MVC3 and ninject. It's enough to add a property to your custom membership provider class. Remember to add "using System.Web.Mvc;" on top.
public IRepository Repository
{
get
{
return DependencyResolver.Current.GetService<IRepository>();
}
}
The simplest way to do dependency injection that I've seen (and actually the only one I've used so far...) is to have a constructor of your dependent class take the interface as a parameter, and assign it to a private field. If you want, you can also add a "default" constructor, which chains to the first one with a default value.
Simplified, it would look something like this:
public class DependentClass
{
private IDataStore _store;
// Use this constructor when you want strict control of the implementation
public DependentClass(IDataStore store)
{
this._store = store;
}
// Use this constructor when you don't want to create an IDataStore instance
// manually every time you create a DependentClass instance
public DependentClass() : this(new DefaultDataStore()) { }
}
The concept is called "Constructor chaining", and there's a lot of articles on the web on how to do it. I find this tutorial very explanatory of the DI pattern.