What am I missing about WCF?

Question

I've been developing in MS technologies for longer than I care to remember at this stage. When .NET arrived on the scene I thought they hit the nail on the head and with each iteration and version I thought their technologies were getting stronger and stronger and looked forward to each release.

However, having had to work with WCF for the last year I must say I found the technology very difficult to work with and understand. Initially it's quite appealing but when you start getting into the guts of it, configuration is a nightmare, having to override behaviours for message sizes, number of objects contained in a messages, the complexity of the security model, disposing of proxies when faulted and finally moving back to defining interfaces in code rather than in XML.

It just does not work out of the box and I think it should. We found all of the above issues while either testing ourselves or else when our products were out on site.

I do understand the rationale behind it all, but surely they could have come up with simpler implementation mechanism.

I suppose what I'm asking is,

• Am I looking at WCF the wrong way?
• What strengths does it have over the alternatives?
• Under what circumstances should I choose to use WCF?

OK Folks, Sorry about the delay in responding, work does have a nasty habit of get in the way sometimes :)

Some clarifications My main paint point with WCF I suppose falls down into the following areas While it does work out of the box, your left with some major surprises under the hood. As pointed out above basic things are restricted until they are overridden

1. Size of string than can be passed can't be over 8K
2. Number of objects that can be passed in a single message is restricted
3. Proxies not automatically recovering from failures
4. The amount of configuration while it's there is a good thing, but understanding it all and what to use what and under which circumstances can be difficult to understand. Especially when deploying software on site with different security requirements etc. When talking about configuration, we've had to hide lots of ours in a back-end database because security and network people on-site were trying to change things in configuration files without understanding it.
5. Keeping the configuration of the interfaces in code rather than moving to explicitly defined interfaces in XML, which can be published and consumed by almost anything. I know we can export the XML from the assembly, but it's full of rubbish and certain code generators choke on it.

I know the world moves on, I've moved on a number of times over the last (ahem 22 years I've been developing) and am actively using WCF, so don't get me wrong, I do understand what it's for and where it's heading.

I just think there should be simpler configuration/deployment options available, easier set-up and better management for configuration (SQL config provider maybe, rather than just the web.config/app.config files).

Answer 1

I use WCF all the time now and I share your pain. It seems like it was grossly over-engineered, but we are going to be stuck with it for a long, long time so I'm trying to learn it.

One thing I am certain about, XML sucks. I've had nothing but problems using XML to control it and have since switched to handling everything via code.

Answer 2

The concerns you listed were:

---

1. Size of string than can be passed can't be over 8K
2. Number of objects that can be passed in a single message is restricted
3. Proxies not automatically recovering from failures
4. The amount of configuration while it's there is a good thing, but understanding it all and what to use what and under which circumstances can be difficult to understand. Especially when deploying software on site with different security requirements etc. When talking about configuration, we've had to hide lots of ours in a back-end database because security and network people on-site were trying to change things in configuration files without understanding it.
5. Keeping the configuration of the interfaces in code rather than moving to explicitly defined interfaces in XML, which can be published and consumed by almost anything. I know we can export the XML from the assembly, but it's full of rubbish and certain code generators choke on it.

---

here's my take:

(1) addressed a valid concern that customers had with ASMX. It was too wide-open, with no way to easily control it. The 8k limit is easily lifted if you know where to look. I guess you can count that as a surprise, but it's more of a one-time thing. Once you know about it, you can lift it and be done with it forever, if you choose.

(2) is also configurable.

(3) is known, but there are boilerplate ways to work around this. The StockTrader code for example, demonstrates a proven pattern. You can re-use the code in your own app. Not sure if this is fixed in WCF for .NET 4.0. I know it was an open request.

(4) The config is a beast. This is a concern for a lot of people. The problem here is that WCF is so flexible, and config of all of that flexibility is exposed through xml files. It can be overwhelming. An approach that seems to work is to take it in small bites, as you need it.

(5) I don't understand.