I have some WCF services which are running great locally; client can consume them and the server is putting data in the DB as expected. The problem is that when I deploy these to a staging machine, all I can see are HTTP 500 errors.
How do I start debugging the problem?
Given that it’s only on staging and not on my local dev machine, I assume it’s an IIS configuration problem somewhere.
When I use Fiddler to see what’s being sent and what the response is, I can see (as expected) correct request data, and only a 500 as the response — no further details.
I’m pretty green to WCF and IIS, so it’s probably something obvious; I’ve used aspnet_iisreg, deployed my .svc file and all the built DLLs/files from bin; maybe I missed something.
I looked in the IIS logs, but they’re pretty skimpy; no error information there, either (or maybe I’m looking in the wrong place?)
(More important than solving the specific problem is figuring out how to see enough details about errors so I can work through problems myself.)
Edit: I of course checked the event logs first — and surprisingly, didn’t find any mention of the exceptions. So I assume that the service is at least being invoked, and that something is faulting in the middle.
It turns out that the server was returning a 500 because of a huge dataset returned; WCF puts some limitations on the size of data (and strings) you can return, to prevent DOS attacks. I solved the problem by increasing the limits, and decreasing the size of data returned (where applicable).