{"id":113,"date":"2006-05-03T17:46:29","date_gmt":"2006-05-04T00:46:29","guid":{"rendered":"http:\/\/kennyw.com\/indigo\/113"},"modified":"2006-05-03T17:46:29","modified_gmt":"2006-05-04T00:46:29","slug":"exposing-capabilities-on-your-binding","status":"publish","type":"post","link":"https:\/\/kennyw.com\/?p=113","title":{"rendered":"Exposing Capabilities on your Binding"},"content":{"rendered":"

Bindings<\/a> represent a wide variety of functionality. Everything from different transports, to different security mechanisms, delivery mechanisms, transactions, and custom protocols. Nonetheless, there are times where you want to make a decision based on a binding’s capabilities.<\/p>\n

For example: “Does this binding support ordered delivery?”
\nOr: “Does this binding support both client and server authentication?”<\/p>\n

WCF has a polymorphic way of making such inquiries of a Binding, though there are a few subtleties involved.<\/p>\n

The first pivot point is to decide whether the capability is a property of the actual Binding, or a property exposed by the stack of Binding Elements. For example, supporting client authentication is a property of the underlying stack. It can be added at different layers (e.g. transport, WS-Security, etc), and can even be removed by some layers. These capabilities are accessed though a method on the Binding:<\/p>\n

T GetProperty<T>()<\/code><\/div>\n

As in: <\/p>\n

ISecurityCapabilities<\/code> s = binding.GetProperty<ISecurityCapabilities<\/code>>();<\/div>\n

GetProperty<T> simply constructs a Binding Context representing the stack of Binding Elements, and queries them through:<\/p>\n

T GetProperty<T>(<\/code>BindingContext<\/code> context)<\/div>\n

Each individual Binding Element can handle the inquiry itself, delegate the inquiry, or a combination of the two. GetProperty is also supported by the runtime objects (IChannelFactory, IChannelListener, IChannel, etc).<\/p>\n

Conversely, if a Binding claims to support Basic Profile 1.0<\/a>, that is a claim about a particular coordination and configuration of binding elements. Therefore, this is not a feature to expose through T GetProperty<T>()<\/code>. The Binding should instead implement the capability directly. For example:<\/p>\n

public class<\/code> MyBasicProfileBinding : IBasicProfile10Binding<\/code><\/div>\n

Where IBasicProfile10Binding<\/code> is an agreed upon interface. It is queried as “if<\/code> (binding<\/code> is<\/code> IBasicProfile10Binding<\/code>)<\/code>”<\/p>\n

Lastly, there are a handful of cases where a particular property is applicable to all<\/strong> bindings. In that case, we use the traditional approach of a strongly typed property on our base class. For example:<\/p>\n

\npublic abstract string<\/code> Scheme {<\/code> get<\/code>; }<\/code>\n<\/div>\n

To re-cap: for polymorphic properties, use GetProperty<T>. For capabilities of the binding element stack, and interface implementation for composite capabilities provided by the concrete binding.<\/p>\n","protected":false},"excerpt":{"rendered":"

Bindings represent a wide variety of functionality. Everything from different transports, to different security mechanisms, delivery mechanisms, transactions, and custom protocols. Nonetheless, there are times where you want to make a decision based on a binding’s capabilities. For example: “Does this binding support ordered delivery?” Or: “Does this binding support both client and server authentication?” […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11],"tags":[],"class_list":["post-113","post","type-post","status-publish","format-standard","hentry","category-indigo"],"_links":{"self":[{"href":"https:\/\/kennyw.com\/index.php?rest_route=\/wp\/v2\/posts\/113","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kennyw.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kennyw.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kennyw.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/kennyw.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=113"}],"version-history":[{"count":0,"href":"https:\/\/kennyw.com\/index.php?rest_route=\/wp\/v2\/posts\/113\/revisions"}],"wp:attachment":[{"href":"https:\/\/kennyw.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=113"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kennyw.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=113"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kennyw.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=113"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}