CODEWITHSUNDEEP
wcf
user738383
user738383

Reputation: 607

Validation exceptions from a WCF service

I'd like some help with this one.

I want to return some kind of validation exception from my WCF service if the given entity data doesn't pass the business logic, but I'm not sure the best way to return muliple things from a WCF Service (for example a validation error and a list of entities).

This one might be really simple, but even so, I'd appreciate a little help.

Upvotes: 0

Views: 952

Answers (1)

chris.house.00
chris.house.00

Reputation: 3301

I would suggest you take a look at the Enterprise Library Validation Block:

http://msdn.microsoft.com/en-us/library/ff648951.aspx

http://msdn.microsoft.com/en-us/library/ff648939.aspx (note this is for EntLib 3.1, which is a bit dated, but even in EntLib 5, WCF integration works similarly)

I've used this approach a number of times for WCF validation and it works out quite well. You'll end up decorating your data contracts with validation attributes that are part of EntLib. This defines what your validation rules are. Then you configure your service to use Enterprise Library's WCF extensibility. This is an endpoint behavior, so essentially this intercepts any incoming messages for your serivce, checks that all the defined validation attributes pass and then sends the message on to your service option. If the rules specified by your validation attributes don't pass then the endpoint behavior returns a fault message that contains the details about all validation failures. So, if one attribute didn't pass, there would be one message. If three attributes didn't pass, you'd have three messages and so on. Each validation failure message references what property didn't pass validation. The nice thing about the EntLib validation WCF integration is that the fault messages used for validation failures are strongly types and available in your service's WSDL. This means that your clients can easily consume these faults and act upon them appropriately.

If you feel like Enterprise Library is a little too heavy for your needs then you could certainly roll your own validation. You'd probably want the data contracts returned by your service operations to include something like a List that cotains validation messages.

Upvotes: 2

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