Is it possible to intercept a constructor call with dynamic proxy?
I registered a proxy on a class that only contains a constructor as a test but it's not intercepted.
I am guessing that it's currently not possible but maybe there's something special I need to do?
No it is not possible. For the simple reason that the creation of proxies is managed by ProxyGenerator which precludes using new with proxies.
Related
I am trying to create an HttpClient that can validate an SSL certificate after every TLS handshake and before any other data is fetched/sent.
So the flow would look like this:
Create an HttpClient
Execute a request
The client connects to the host via HTTPS
After the TLS handshake was done, the client now knows the certificate
Pass the certificate to a callback. Execute actual request when callback succeeds, abort the request otherwise
In case the callback was successful, proceed as usual (e.g. pass the response etc.)
I was looking into SecurityContext already. The problem is that it only validates against a fixed set of certificates, but I want to validate the certificate dynamically based on the certificate that was sent by the host.
Also, I saw that there is a badCertificateCallback method in HttpClient, but this does not serve my usecase well as I want to validate every certificate, not just the invalid/bad ones.
I was wondering whether I could theoretically create a class that uses HttpClient as a superclass and therefore modify it's behaviour, but I am wondering whether there is a more elegant way that doesn't break that easily when the implementation of HttpClient changes.
Another idea of mine is to set a SecurityContext that rejects every single certificate by default. I could then use the badCerificateCallback to do the checks normally done by SecurityContext (check against a list of trusted certificates) and add my own validation on top of that. Is anyone aware of any drawbacks this might have? I got a little bit uncertain when reading about the limitations regarding iOS.
Has anyone here done similar things before and could give me a hint? :)
Thanks in advance!
For your usecase, it is better that you have your own version of BetterHttpClient.
However, instead of BetterHttpClient inheriting from HttpClient, you can use composition. Compose HttpClient inside BetterHttpClient. This will give you more control over what you want to use/update from the existing implementation and also this will be better guarded against any changes that HttpClient will go through
Does MOQ give access to Castle's DynamicProxy generation? Or are there configurable static methods or something in the Castle namespace that would allow me to tune MOQ's proxy gen behavior?
Some Background
I am Mocking a WCF Service endpoint (IWhatever). WCF automatically adds Async call back options for methods (e.g. IWhatever.DoWork() is also realized as IWhatever.DoWorkAsync()).
I'm looking to use the Mock<IWhatever> object while self-hosting this service mock'd; basically spoof this external web service to my system. However, when [self-hosted] WCF tries to create a DoWorkAsync() method; it already exists... which ultimately throws errors when opening the self-hosted/mock'd IWhatever endpoint. ((NOTE: I don't have access to original contract to use directly)).
Sooo.. looks like Castle DynamicProxy allows for one to define which methods should be generated (see: http://kozmic.net/2009/01/17/castle-dynamic-proxy-tutorial-part-iii-selecting-which-methods-to/). I was thinking I would use to not intercept calls on methods ending with "[...]Async". However I don't see where I would add this customization rule in the proxy generation within MOQ; hence my question.
so i want to create some service that accesses external API, and i want to cache common requests from the API inside of that service, it depends on 3 other services, but i want to give it its own instance of cache, MemoryDistributedCache might later be changed for something else
services.AddSingleton<ISomeApi, SomeApi>(provider => new SomeApi(
Configuration.Get<Options>(),
new MemoryDistributedCache(new MemoryCache(new MemoryCacheOptions())),
provider.GetService<ILogger<SomeApi>>()
));
now from my Controllers i can access the api via DI, it works nicely but im not sure if its some sort of an anti-pattern or if there are better ways of doing it
i mean the real problem is separating the internal cache, requesting
IDistributedMemory from one service would give me the same object as if i request it from another service, they must be separated
This sounds like something you could use a proxy or decorator pattern for. The basic problem is that you have a service that does some data access, and another service responsible for caching the results of the first service. I realize you're not using a repository per se, but nonetheless the CachedRepository pattern should work for your needs. See here:
http://ardalis.com/introducing-the-cachedrepository-pattern
and
http://ardalis.com/building-a-cachedrepository-via-strategy-pattern
You can write your cached implementation such that it takes in the actual SomeApi type in its constructor if you don't need that part of the design to be flexible.
Say i'm having a web service that accepts two arguments and that is being called/consume in my application. Now after some time, the web service changes and accepts three arguments, hence in my application, would that be throwing an error, or i need to just update the web reference, or i need to recreate a web serivce or would that be working fine?
Let me know if any doubts
Thanks!
You could add optional parameters where if a parameter value isn't given to the method a default value is used.
From a "pure" architectural aspect, you should never change the signature of a method of a service once it's in use. You should version by creating a new method with a different namespace. But staying pure is sometimes difficult to do.
In your case you need to update the Web reference in the client application and then modify the code to pass in the appropriate parameter to the method in the service proxy.
seam actually proxies every class for interception. is there a difference between proxied classes and proxied classes that implement interfaces?? f.e. like in spring where a proxy instance is made implementing all interfaces specified in the class.
has someone any performance experiences between java.lang.reflect.Proxy vs. cglib or javassist? isn't instantiation over Proxy much faster than bytecode manipulation??
thanks in advance
there many comparison on the web like this:
Unproxied: 559009(ns) 5(ms)
cglib: 21374225(ns) 213(ms)
Proxy: 16506009(ns) 165(ms)
you can download the code and run it yourself.