How to Intercept all Nancy requests - nancy

I have seen this post: Nancy: how do I capture all requests irrespective of verb or path and followed along on the github article.
But it does not work. I have simply added a class in my project:
public class MyBootstrapper : Nancy.DefaultNancyBootstrapper
But this class is never instantiated, and the github documentation does not discuss this in any detail.
What do I need to do to cause my bootstrapper to be used?

I found it. There are two ways to add items to the pipeline. One by deriving a Bootstrap class, which failed for me. The other by implementing a class which honored the IApplicationStartup interface. That worked, and here is the code:
public class BeforeAllRequests : IApplicationStartup
{
public void Initialize(IPipelines pipelines)
{
pipelines.BeforeRequest.AddItemToStartOfPipeline(ctx => {
if (ctx != null)
{
Log.Debug("Request: " + ctx.Request.Url);
}
return null;
});
}
}

This worked for me (4 years later, maybe the Wiki changed since then): Bootstrapper

Related

Quarkus extension - How to have an interceptor working on beans provided by the extension itself

I'm working on a Quarkus extension that provides an interceptor (and its annotation) to add some retry logic around business methods this extension offers. Nothing new in there, and this is working when i annotate a public method of a bean in an application that uses this extension.
But the extension also provides some #ApplicationScoped beans that are also annotated, but the interceptor is not intercepting any of these.
Seems like an interceptor does not check / apply on the extension itself.
I would like to know if this is an intended behavior, or an issue in my extension setup, and if so how to fix it. Could not find anything about this in the documentation, but there is so much dos that i may have missed something.
Any idea about this ?
I finally found a way to make this work.
I was using a producer bean pattern to produce my beam as an #ApplicationScoped bean inside the extension.
#ApplicationScoped
public class ProxyProducer {
#Produces
#ApplicationScoped
public BeanA setUpBean(ExtensionConfig config)
{
return new BeamsClientProxy(new InternalBean(config.prop1, config.prop2));
}
}
with the following BeanA class (just an example)
public class BeanA {
private final InternalBean innerBean;
public BeanA(final InternalBean innerBean) {
this.innerBean = innerBean;
}
#MyInterceptedAnnotation
public void doSomething() {
}
}
Due to this setup, the bean is not considered by the interceptor (i guess because it's produced only the first time it's used / injected somewhere else)
Removing the producer pattern and annotating directly the BeanA fixed the issue.
Example:
#ApplicationScoped
public class BeanA {
private final InternalBean innerBean;
public BeanA(final ExtensionConfig config) {
this.innerBean = new InternalBean(config.prop1, config.prop2);
}
#MyInterceptedAnnotation
public void doSomething() {
}
}
with of course adding the following lines to register the bean directly on the extension processor:
#BuildStep
AdditionalBeanBuildItem proxyProducer() {
return AdditionalBeanBuildItem.unremovableOf(BeanA.class);
}
As a conclusion:
Changing the bean implementation to avoid the producer-based bean use case solved my issue (please refers to Ladicek comment below)
Edit:
As Ladicek explained, Quarkus doesn't support interception on producer-based beans.

Hystrix Javanica : Call always returning result from fallback method.(java web app without spring)

I am trying to integrate Hystrix javanica into my existing java EJB web application and facing 2 issues with running it.
When I try to invoke following service it always returns response from fallback method and I see that the Throwable object in fallback method has "com.netflix.hystrix.exception.HystrixTimeoutException" exception.
Each time this service is triggered, HystrixCommad and fallback methods are called multiple times around 50 times.
Can anyone suggest me with any inputs? Am I missing any configuration?
I am including following libraries in my project.
project libraries
I have setup my aspect file as follows:
<aspectj>
<weaver options="-verbose -showWeaveInfo"></weaver>
<aspects>
<aspect name="com.netflix.hystrix.contrib.javanica.aop.aspectj.HystrixCommandAspect"/>
</aspects>
</aspectj>
Here is my config.properties file in META-INF/config.properties
hystrix.command.default.execution.timeout.enabled=false
Here is my rest service file
#Path("/hystrix")
public class HystrixService {
#GET
#Path("clusterName")
#Produces({ MediaType.APPLICATION_JSON })
public Response getClusterName(#QueryParam("id") int id) {
ClusterCmdBean clusterCmdBean = new ClusterCmdBean();
String result = clusterCmdBean.getClusterNameForId(id);
return Response.ok(result).build();
}
}
Here is my bean class
public class ClusterCmdBean {
#HystrixCommand(groupKey = "ClusterCmdBeanGroup", commandKey = "getClusterNameForId", fallbackMethod = "defaultClusterName")
public String getClusterNameForId(int id) {
if (id > 0) {
return "cluster"+id;
} else {
throw new RuntimeException("command failed");
}
}
public String defaultClusterName(int id, Throwable e) {
return "No cluster - returned from fallback:" + e.getMessage();
}
}
Thanks for the help.
If you want to ensure you are setting the property, you can do that explicitly in the circuit annotation itself:
#HystrixCommand(commandProperties = {
#HystrixProperty(name = "execution.timeout.enabled", value = "false")
})
I would only recommend this for debugging purposes though.
Something that jumps out to me is that Javanica uses AspectJ AOP, which I have never seen work with new MyBean() before. I've always have to use #Autowired with Spring or similar to allow proxying. This could well just be something that is new to me though.
If you set a breakpoint inside the getClusterNameForId can you see in the stack trace that its being called via reflection (which it should be AFAIK)?
Note you can remove commandKey as this will default to the method name. Personally I would also remove groupKey and let it default to the class name.

Registering Startup Class In Nancy Using AutoFac Bootstrapper

I've been reading through a lot of the Jabbr code to learn Nancy and trying to implement many of the same patterns in my own application. One of the things I can't seem to get working is the concept of an on application start class. The Jabbr code base has an App_Start folder with a Startup.cs file (here) in it with the following implementation.
public partial class Startup
{
public void Configuration(IAppBuilder app)
{
...
SetupNancy(kernel, app);
...
}
}
private static void SetupNancy(IKernel kernel, IAppBuilder app)
{
var bootstrapper = new JabbRNinjectNancyBootstrapper(kernel);
app.UseNancy(bootstrapper);
}
When I tried to do something similar to that in my project the Startup.cs file was just ignored. I searched the Jabbr code base to see if it was used anywhere but I wasn't able to find anything and the only differences I could see is Jabbr uses Ninject while I wanted to use AutoFac
Is there a way to register a startup class in nancy?
Take a look at my project over on GitHub, you'll be interested in the Spike branch and may have to unload the ChainLink.Web project to run I can't remember.
I had some trouble finding a way to configure the ILifetimeScope even after reading the accepted answer here by TheCodeJunkie. Here's how you do the actual configuration:
In the bootstrapper class derived from the AutofacNancyBootstrapper, to actually configure the request container, you update the ILifetimeScope's component registry.
protected override void ConfigureRequestContainer(
ILifetimeScope container, NancyContext context)
{
var builder = new ContainerBuilder();
builder.RegisterType<MyDependency>();
builder.Update(container.ComponentRegistry);
}
The application container can be updated similarly in the ConfigureApplicationContainer override.
You should install the Nancy.Bootstrappers.Autofac nuget, inherit from the AutofacNancyBootstrapper type and override the appropriate method (depending on your lifetime scope requirements: application or request). For more info check the readme file https://github.com/nancyfx/nancy.bootstrappers.autofac
HTH
After following the advice from TheCodeJunkie you can use the Update method on the ILifetimeScope container parameter which gives you a ContainerBuilder through an Action:
protected override void ConfigureRequestContainer(ILifetimeScope container, NancyContext context)
{
container.Update(builder =>
{
builder.RegisterType<MyType>();
});
}

Unable to return collections or arrays from JAX-WS Web Service

I found that I was unable to return collections from my JAX-WS Web Service.
I appreciate that the Java Collections API may not be supported by all clients, so I switched to return an array, but I can't seem to do this either.
I've set up my web service as follows:
#WebService
public class MyClass {
public ReturnClass[] getArrayOfStuff() {
// extremely complex business logic... or not
return new ReturnClass[] {new ReturnClass(), new ReturnClass()};
}
}
And the ReturnClass is just a POJO. I created another method that returns a single instance, and that works. It just seems to be a problem when I use collections/arrays.
When I deploy the service, I get the following exception when I use it:
javax.xml.bind.MarshalException - with linked exception:
[javax.xml.bind.JAXBException: [LReturnClass; is not known to this context]
Do I need to annotate the ReturnClass class somehow to make JAX-WS aware of it?
Or have I done something else wrong?
I am unsure of wheter this is the correct way to do it, but in one case where I wanted to return a collection I wrapped the collection inside another class:
#WebService
public class MyClass {
public CollectionOfStuff getArrayOfStuff() {
return new CollectionOfStuff(new ReturnClass(), new ReturnClass());
}
}
And then:
public class CollectionOfStuff {
// Stuff here
private List<ReturnClass> = new ArrayList<ReturnClass>();
public CollectionOfStuff(ReturnClass... args) {
// ...
}
}
Disclaimer: I don't have the actual code in front of me, so I guess my example lacks some annotations or the like, but that's the gist of it.

Issue intercepting property in Silverlight application

I am using Ninject as DI container in a Silverlight application. Now I am extending the application to support interception and started integrating DynamicProxy2 extension for Ninject. I am trying to intercept call to properties on a ViewModel and ending up getting following exception:
“Attempt to access the method failed: System.Reflection.Emit.DynamicMethod..ctor(System.String, System.Type, System.Type[], System.Reflection.Module, Boolean)”
This exception is thrown when invocation.Proceed() method is called. I tried two implementations of the interceptor and they both fail
public class NotifyPropertyChangedInterceptor: SimpleInterceptor
{
protected override void AfterInvoke(IInvocation invocation)
{
var model = (IAutoNotifyPropertyChanged)invocation.Request.Proxy;
model.OnPropertyChanged(invocation.Request.Method.Name.Substring("set_".Length));
}
}
public class NotifyPropertyChangedInterceptor: IInterceptor
{
public void Intercept(IInvocation invocation)
{
invocation.Proceed();
var model = (IAutoNotifyPropertyChanged)invocation.Request.Proxy;
model.OnPropertyChanged(invocation.Request.Method.Name.Substring("set_".Length));
}
}
I want to call OnPropertyChanged method on the ViewModel when property value is set.
I am using Attribute based interception.
[AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
public class NotifyPropertyChangedAttribute : InterceptAttribute
{
public override IInterceptor CreateInterceptor(IProxyRequest request)
{
if(request.Method.Name.StartsWith("set_"))
return request.Context.Kernel.Get<NotifyPropertyChangedInterceptor>();
return null;
}
}
I tested the implementation with a Console Application and it works alright.
I also noted in Console Application as long as I had Ninject.Extensions.Interception.DynamicProxy2.dll in same folder as Ninject.dll I did not have to explicitly load DynamicProxy2Module into the Kernel, where as I had to explicitly load it for Silverlight application as follows:
IKernel kernel = new StandardKernel(new DIModules(), new DynamicProxy2Module());
Could someone please help? Thanks
Reflection can be really tricky in silverlight because of security issues.
Check Gabe's answer for this question, it's the same problem.
The good news is that you can achieve the same functionality you want using dynamic instead of proxies. Just extend your ViewModel from DynamicObject and override the TrySetMember method.
I hope it helps :)

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