Forging responses on intercepted call.

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Frosty Madness - 31 Oct 2005 11:35 GMT

I've implemented a custom RealProxy for an object I want to test. I'm
using a proxy because I want to log what calls are made to this object.

Using the example in MSDN on RealProxy, I can easily log what is passed
to the objects but here's the sticking point. I don't want to actuall
call the object in question, I'd like to return a 'forged' return
message.

Any suggestion as to how I'd do this?

Cheers,

Jack

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Robert Jordan - 31 Oct 2005 13:11 GMT

> I've implemented a custom RealProxy for an object I want to test. I'm
> using a proxy because I want to log what calls are made to this object.
[quoted text clipped - 5 lines]
>
> Any suggestion as to how I'd do this?

Well, you name it: don't call the target object from the Invoke
method of your custom proxy and fake the return message ;-)

public override IMessage Invoke (IMessage myMessage)
{
...

MethodResponse resp = new MethodResponse (
new Header[] {new Header("__Return", someFakedReturnValue)},
myMessage);

return resp;
}

Rob

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Frosty Madness - 01 Nov 2005 10:04 GMT

Thanks for that, works great. The MethodResponse class was the hole in
my knowledge. But there's a wrinkle...

In order to send back the out parameters, I need to check which of the
args are out or ref. How do I do that?

Cheers

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Robert Jordan - 01 Nov 2005 11:09 GMT

> Thanks for that, works great. The MethodResponse class was the hole in
> my knowledge. But there's a wrinkle...
>
> In order to send back the out parameters, I need to check which of the
> args are out or ref. How do I do that?

public override IMessage Invoke (IMessage myMessage)
{
...

MethodBase mb = RemotingServices.GetMethodBaseFromMethodMessage (
(IMethodMessage)myMessage);

ArrayList outParams = new ArrayList ();
foreach (ParamaterInfo p in mb.GetParameters ())
{
if (p.IsOut) outParams.Add(someFakedOutValue);
}

Header[] headers;
if (outParams.Count > 0)
{
headers = new Header[2];
headers[0] = new Header("__Return", someFakedReturnValue)};
headers[1] = new Header("__OutArgs", outParams.ToArray ());
}
else {
headers = new Header[1];
headers[0] = new Header("__Return", someFakedReturnValue)};
}

MethodResponse resp = new MethodResponse (headers, myMessage);

return resp;
}

Rob

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Forging responses on intercepted call.

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