Brothers In Code

...a serious misallocation of .net resources

WCF Self-Hosted Read Herring - '...but there is no http base address'

I'd guess that most people who have delt with WCF have probably ran into the following error:

Service cannot be started. System.InvalidOperationException: The HttpGetEnabled property of ServiceMetadataBehavior is set to true and the HttpGetUrl property is a relative address, but there is no http base address.  Either supply an http base address or set HttpGetUrl to an absolute address.

The fix is spelled out pretty clearly in the error.  But today I ran into this error, despite having baseAddress set in my config.  Setting HttpGetEnabled to false allowed the service to start, but I had a service from another project that was configured with it set to true and it worked just fine.  After mucking with the config trying to get it to work, I started thinking outside the box and realized I should check to see if the service is actually running properly when it did start.  To my surprise I could not connect to my simple "hello world" service, and a quick "netstat -an" command showed that nothing was listening on the configured port.  That finally pushed me beyond the config and I started looking at other areas.

Finally I took a look at my windows service class (named WCFHostSvc) and noticed this line in my OnStart method:

serviceHost = new System.ServiceModel.ServiceHost(typeof(WCFHostSvc));

I realized I made a dumb mistake and passed in the windows service type rather than the WCF service type.  So the line should have been:

serviceHost = new System.ServiceModel.ServiceHost(typeof(MainWCFService));

Like I said, I made a dumb mistake.  Still, the error handling from the framework could have been a lot better here.  Rather than starting up as if nothing was wrong, why can't the ServiceHost constructor check the class and make sure it has at least one method to call?  Or better yet, check the type against the configured contract in the service configuration?

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