I have a WCF-based REST service and I'm planning to add hypermedia support to it. Currently I'm relying on WCF to build the service response by serializing my data contracts. With hypermedia in the picture now, I need a way to instruct WCF to insert hypermedia links in the XML response that it builds. My question is, how do I do that?
One way could be that I modify my data contracts to include the said links as data members. Then WCF can automatically serialize them. But is that the best practice? Or is it better to intercept WCF's serialization process and add these links at that time? Or is there any other more suitable alternative?
You need to construct the hypermedia yourself. If you choose Atom there are some helpers. Basically you create a SyndicationFeed and add SyndicationItem items to it and use an Atom10FeedFormatter to turn the whole feed into an Atom document.
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Before embarking on API development, looking to choose the right foundation.
So...OData permits queryability over models. Great!
...but REST apis can be decorated with the [Queryable] ...
So... what is the remaining advantage of OData over such Queryable APIs?
Maybe the following are true?
OData routing relies primarily on convention based routing, so not sure one can craft if ever needed to (e.g.: to avoid legacy routes one has to implement?)
Suspect one cannot query REST APIs based on child entities?
Anything else that would come into play?
Thank you!
OData is a specific and standardized implementation of REST. If you make your standard API endpoint's queryable then those specific endpoints will follow most of the OData v4 response conventions but it is up to you to document this for the consumers.
When you choose to start from OData, you are choosing to implement the OData conventional standards for all of the controllers and Entities that you choose to include in the OData Entity Model. This in turn will generate the $metadata document that describes the model and the supported functions and actions.
You can add custom types, functions and actions to an OData controller if you follow the conventions correctly. You can also directly host standard API controller endpoints if you want to, but unless you register them with the OData model, they will not be included in the $metadata document.
You could choose to replicate or implement the entire OData specification in your API from first principals if you want to, including producing your own $metadata document... But if you were going to go to all that trouble then it would have been far easier to just use the ODataController and implement OData properly.
Making the decision to use OData over standard Web API is usually driven by your chosen documentation method and if you can accept the general OData query conventions and if the consumers of the API can understand OData. OData standards are clearly defined so that you don't have to worry as much about educating consumers on how to use your API and can focus more on the implementation itself.
Was planning to use Service Routing (on WCF/REST) to do some common tasks before a request hits the actual service. Now that I read more about it, looks like REST is not supported yet on RoutingService and the suggested method is to use System.Web.Routing or ARR.
What needs to happen in the router is a key validation, a header value extraction and versioning.
ARR doesn't look right for this as it just routes and there is no "handler" we have access to. System.Web.Routing looks like a lot of custom implementation which might undermine the efficiency of WCF.
An old school alternative am thinking of is to have the common functionalities in one chain-of-responsibilities implementation and just compose it in every service. This has the disadvantage of being referenced in N number of places for N services. But this increasingly looks like the only alternative if I don't want to mess with the WCF handling of endpoints.
Am looking for advice on a right way to do this, and any samples.
Didn't try, but maybe writing a custom service behavior can solve your problem. Take a look here : Extending WCF with Custom Behaviors.
The idea is to extend the WCF engine with a custom behavior, then attaching your service with this behaviors. This is transparent for the services.
Take a look at HttpMessageHandlers in the new WCF Web Api project htttp://wcf.codeplex.com This mechanisms allows you to do something similar to Rack or WSGI. I have a couple of examples of what you can do with them on my blog http://www.bizcoder.com/index.php/2011/05/22/how-to-get-ahead-with-messagehandlers/
I have a existing WCF in .NET which is consumed through wsdl and proxy classes. Soon, there will be multiple consumers and the load on the WCF will be pretty high. I was asked to develop a new WCF with REST which can be beneficial interms of performance. I don't have much knowledge on REST, hence can you please let me know whether implementing a RESTFUL WCF will improve the performance drastically? Please provide me any links to implement the same.
Thanks in advance,
Vinoth Khanna.S
You can also use WCF Data Services to easily offer a REST interface to your data.
The easiest way is to build an Entity Framework model of your data and then to expose that model as a WCF Data Service. This then exposes all data using the OData protocol, which is REST + AtomPub.
And Kiran is of course right, REST by itself does not increase performance. I assume that you want your UI to access the REST service directly rather than go through a web service which contains hand-written methods to read and write data. In that case, there may be some performance gain, but I wouldn't count on it much.
See also:
http://msdn.microsoft.com/en-us/library/cc668794.aspx
and
http://en.wikipedia.org/wiki/WCF_Data_Services
If you want to return results as JSON, the easiest way to get that to work is by adding the WCF Data Services Toolkit:
http://wcfdstoolkit.codeplex.com/
As far as I know REST is not for performance enhancement, it makes your webmethods URL accessible and make those URL's more predictable and logical. I would start with this video http://channel9.msdn.com/Events/PDC/PDC08/TL35 then with WCF REST Starter Kit http://www.asp.net/downloads/starter-kits/wcf-rest
Assume a situation where a data will never be queried directly. AKA, there will always be some filtering logic and/or business logic that must occur.
When is a good reason to use data services outside of ajax/js?
Please don't site this page http://msdn.microsoft.com/en-us/data/bb931106.aspx
Your essentially asking what layer of abstraction should I use, WCF Data Services is built on top of WCF and aims to simplify the process of creating a REST based service that is consumable by anything on the web. It takes away a lot of the plumbing and configuration required to do this with a standard WCF service. The querying feature is another big plus and something that is difficult to get right with standard WCF.
So in short:
If you want to quickly build a loosely typed service that wraps an existing data model and enables querying support give WCF Data Services a go.
If you want full control over the service contract or the flexibility of exposing the service over any protocol, stick with plain old WCF.
I am bit confused about ADO.Net Data Services.
Is it just meant for creating RESTful web services? I know WCF started in the SOAP world but now I hear it has good support for REST. Same goes for ADO.Net data services where you can make it work in an RPC model if you cannot look at everything from a resource oriented view.
At least from the demos I saw recently, it looks like ADO.Net Data Services is built on WCF stack on the server. Please correct me if I am wrong.
I am not intending to start a REST vs SOAP debate but I guess things are not that crystal clear anymore.
Any suggestions or guidelines on what to use where?
In my view ADO.Net data services is for creating restful services that are closely aligned with your domain model, that is the models themselves are published rather then say some form of DTO etc.
Using it for RPC style services seems like a bad fit, though unfortunately even some very basic features like being able to perform a filtered counts etc. aren't available which often means you'll end up using some RPC just to meet the requirements of your customers i.e. so you can display a paged grid etc.
WCF 3.5 pre-SP1 was a fairly weak RESTful platform, with SP1 things have improved in both Uri templates and with the availability of ATOMPub support, such that it's becoming more capable, but they don't really provide any elegant solution for supporting say JSON, XML, ATOM or even something more esoteric like payload like CSV simultaneously, short of having to make use of URL rewriting and different extension, method name munging etc. - rather then just selecting a serializer/deserializer based on the headers of the request.
With WCF it's still difficult to create services that work in a more a natural restful manor i.e. where resources include urls, and you can transition state by navigating through them - it's a little clunky - ADO.Net data services does this quite well with it's AtomPub support though.
My recommendation would be use web services where they're naturally are services and strong service boundaries being enforced, use ADO.Net Data services for rich web-style clients (websites, ajax, silverlight) where the composability of the url queries can save a lot of plumbing and your domain model is pretty basic... and roll your own REST layer (perhaps using an MVC framework as a starting point) if you need complete control over the information i.e. if you're publishing an API for other developers to consume on a social platform etc.
My 2ΓΈ worth!
Using WCF's rest binding is very valid when working with code that doesn't interact with a database at all. The HTTP verbs don't always have to go against a data provider.
Actually, there are options to filter and skip to get the page like feature among others.
See here: