Nicholas Allen's Indigo Blog

Inside the Standard Bindings: BasicHttp

Since there isn't a lot of documentation about how the standard bindings are put together, I decided to start a series going over each of the bindings and looking at their component pieces. I'm not going to dive into all of the binding elements so that the presentation goes a little bit faster. I'll probably get back to that some time this summer and do another series that focuses on individual binding elements.

The BasicHttp binding is going to be one of the more popular out-of-the-box choices for communicating over the Internet. The primary pivot for what goes in your channel stack is going to be the method you choose for securing messages. The choices you have with BasicHttp are no security, HTTPS security, SOAP security, and HTTPS security with SOAP credentials. This is set by the Security.Mode property on the binding. Let's look at each of those in turn.

I've cut down on the number of properties presented by eliminating duplicates between the binding settings and binding element settings. For instance, the XML reader quotas can be set on either the binding or the message encoder binding element, but I'm only going to show them on the message encoder. I've also omitted most of the security credential settings because they're very messy and you hopefully won't need to change them much.

When security is None, there are two elements in the channel stack.

1. System.ServiceModel.Channels.TextMessageEncodingBindingElement

   AddressingVersion: Addressing10 (http://www.w3.org/2005/08/addressing)
   MaxReadPoolSize: 64
   MaxWritePoolSize: 16
   ReaderQuotas: 
     MaxArrayLength: 16384
     MaxBytesPerRead: 4096
     MaxDepth: 32
     MaxNameTableCharCount: 16384
     MaxStringContentLength: 8192
   

2. System.ServiceModel.Channels.HttpTransportBindingElement

   AllowCookies: False
   AuthenticationScheme: Anonymous
   BypassProxyOnLocal: False
   HostNameComparisonMode: StrongWildcard
   ManualAddressing: False
   MappingMode: Soap
   MaxBufferPoolSize: 524288
   MaxBufferSize: 65536
   MaxReceivedMessageSize: 65536
   ProxyAddress: 
   ProxyAuthenticationScheme: Anonymous
   Realm: 
   Scheme: http
   TransferMode: Buffered
   UnsafeConnectionNtlmAuthentication: False
   UseDefaultWebProxy: True
   

And there are a number of loose settings on the binding not otherwise covered by these elements.

CloseTimeout: 00:01:00
EnvelopeVersion: Soap11 (http://schemas.xmlsoap.org/soap/envelope/)
Namespace: http://tempuri.org/
OpenTimeout: 00:01:00
ReceiveTimeout: 00:01:00
SendTimeout: 00:01:00
TextEncoding: System.Text.UTF8Encoding

These are the baseline settings and all of the variations are very similar so I'm not going to repeat the properties unless they're new or different.

By switching over to Transport security, you just replace the HTTP transport with an HTTPS transport.

1. System.ServiceModel.Channels.TextMessageEncodingBindingElement
2. System.ServiceModel.Channels.HttpsTransportBindingElement

   RequireClientCertificate: False
   Scheme: https
   

With Message security, you're going to have a layered channel providing security at the SOAP level but then an unsecure HTTP transport at the bottom of your channel stack. SOAP security does not protect HTTP-level information, such as headers, so those should not be considered trustworthy.

1. System.ServiceModel.Channels.AsymmetricSecurityBindingElement
2. System.ServiceModel.Channels.TextMessageEncodingBindingElement
3. System.ServiceModel.Channels.HttpTransportBindingElement

The last security mode, which is TransportWithMessageCredentials security, is also called mixed-mode security. Mixed-mode security does most of the heavy lifting through transport security. You then get the minimal SOAP security on top to provide credentials at the message level.

1. System.ServiceModel.Channels.TransportSecurityBindingElement
2. System.ServiceModel.Channels.TextMessageEncodingBindingElement
3. System.ServiceModel.Channels.HttpsTransportBindingElement

   RequireClientCertificate: False
   Scheme: https
   

Finally, you can also change the message encoder by setting the MessageEncoding property on the binding. The only other choice you have besides the default of text is MTOM. That just changes the message encoder binding element in your stack.

1. System.ServiceModel.Channels.MtomMessageEncodingBindingElement
2. System.ServiceModel.Channels.HttpTransportBindingElement

You'd have to build your own binding if you wanted to use any of the other message encoders.

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