WCF credentials

This time it is not a sitecore post but I had to search a long time to find how to put my WCF service authentication in the web.config file.
To pass the service credentials in the code it is easy:

myServiceClient.ClientCredentials.Windows.ClientCredential = new System.Net.NetworkCredential("myUsername", "myPassword", "myDomain");

But to put those credentials into the web.config it is a bit more complex.

1. Create this class:

   using System;
   using System.Collections.Generic;
   using System.Configuration;
   using System.Linq;
   using System.ServiceModel.Configuration;
   using System.ServiceModel.Description;
   using System.Text;
   
   namespace MyNamespace
   {
       public class UserNameClientCredentialsElement : ClientCredentialsElement
       {
           private ConfigurationPropertyCollection properties;
   
           public override Type BehaviorType
           {
               get { return typeof(ClientCredentials); }
           }
   
           /// <summary>
           /// Username (required)
           /// </summary>
           public string UserName
           {
               get { return (string)base["userName"]; }
               set { base["userName"] = value; }
           }
   
           /// <summary>
           /// Password (optional)
           /// </summary>
           public string Password
           {
               get { return (string)base["password"]; }
               set { base["password"] = value; }
           }
   
           protected override ConfigurationPropertyCollection Properties
           {
               get
               {
                   if (properties == null)
                   {
                       ConfigurationPropertyCollection baseProps = base.Properties;
                       baseProps.Add(new ConfigurationProperty(
                                         "userName",
                                         typeof(String),
                                         null,
                                         null,
                                         new StringValidator(1),
                                         ConfigurationPropertyOptions.IsRequired));
                       baseProps.Add(new ConfigurationProperty(
                                         "password",
                                         typeof(String),
                                         ""));
                       properties = baseProps;
                   }
                   return properties;
               }
           }
   
           protected override object CreateBehavior()
           {
               var creds = (ClientCredentials)base.CreateBehavior();
               if(creds != null)
                   creds.Windows.ClientCredential = new NetworkCredential(UserName, Password);            
               return creds;
           }
       }
   }

2. Register the behaviorExtension
3. Use your new extension

Now your web.config should look like:

<system.serviceModel>
  <client><!--(3)-->
    <endpoint ...YourEndpointConfig... behaviorConfiguration="UserNamePasswordBehavior" />
  </client>
  <behaviors><!--(2)-->
    <endpointBehaviors>
      <behavior name="UserNamePasswordBehavior">
        <userNameClientCredentials userName="skroob" password="12345" />
        <!--Visual Studio will give you warning squiggly on <userNameClientCredentials>
            saying that "The element 'behavior' has invalid child element" 
            but will work at runtime.-->
      </behavior>
    </endpointBehaviors>
  </behaviors>
  <extensions><!--(1)-->
    <behaviorExtensions>
      <add name="userNameClientCredentials" type="MyNamespace.UserNameClientCredentialsElement, MyAssembly, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" />
    </behaviorExtensions>
  </extensions>
  ...
</system.serviceModel>

Thanks a lot to Patrick Paquet to post this answer on this topic