How to Implement Custom configSection in your Configuration

Introduction

Here, I will provide the details about how to implement custom configSection in your application.

Suppose you want to create a configSection for your custom membership implementation as below:

<memberships>
  <member username="test" password="testpassword" role="client" />
  <member username="hostuser" password="private" role="client,host" />
</memberships>

For this, you need to create the required classes as below.

MembershipElement.cs

public class MembershipElement : ConfigurationElement
{
    [ConfigurationProperty("username", IsRequired = true, IsKey = true)]
    public string Username
    {
        get { return base["username"] as string; }
        set { base["username"] = value; }
    }

    [ConfigurationProperty("password", IsRequired = true, IsKey = false)]
    public string Password
    {
        get { return base["password"] as string; }
        set { base["password"] = value; }
    }

    [ConfigurationProperty("role")]
    public string Role
    {
        get { return base["role"] as string; }
        set { base["role"] = value; }
    }
}

MembershipCollection.cs

public class MembershipCollection : ConfigurationElementCollection
{
    protected override ConfigurationElement CreateNewElement()
    {
        return new MembershipElement();
    }

    protected override object GetElementKey(ConfigurationElement element)
    {
        return ((MembershipElement)element).Username;
    }

    protected override string ElementName
    {
        get
        {
            return "member";
        }
    }

    protected override bool IsElementName(string elementName)
    {
        return !String.IsNullOrEmpty(elementName) && elementName == "member";
    }

    public override ConfigurationElementCollectionType CollectionType
    {
        get
        {
            return ConfigurationElementCollectionType.BasicMap;
        }
    }

    public MembershipElement this[int index]
    {
        get
        {
            return base.BaseGet(index) as MembershipElement;
        }
    }

    public MembershipElement this[string key]
    {
        get
        {
            return base.BaseGet(key) as MembershipElement;
        }
    }

}

MembershipConfigurationHandler.cs

public class MembershipConfigurationHandler : ConfigurationSection
{
    [ConfigurationProperty("", IsDefaultCollection = true, IsKey = false, IsRequired = true)]
    public MembershipCollection Members
    {
        get
        {
            return base[""] as MembershipCollection;
        }

        set
        {
            base[""] = value;
        }
    }
}

Now you are ready to use your custom configSection in your application. Your application’s config file will have the elements as below:

<configSections>
  <section name="memberships" type="Authentication.Configuration.MembershipConfigurationHandler, Authentication"/>
</configSections>

<memberships>
  <member username="test" password="testpassword" role="client" />
  <member username="hostuser" password="private" role="client,host" />
</memberships>

I have a created a helper class to access the member details with ease.

MembershipProvider.cs

public static class MembershipProvider
{
    public static MembershipElement GetMember(string userName)
    {
        var memberships = ConfigurationManager.GetSection("memberships") as MembershipConfigurationHandler;

        if(memberships == null || memberships.Members == null || memberships.Members.Count < 1)
            return null;

        return memberships.Members[userName];
    }

    public static MembershipElement ValidateUser(string userName, string password)
    {
        var member = GetMember(userName);
        if (member != null && member.Password.Equals(password))
            return member;
        return null;
    }
}

You can use this provider to validate the member or get the member details. I have used this provider in my application to authenticate the member and set the roles in current thread.

CustomUsernamePasswordValidator.cs

public class CustomUsernamePasswordValidator : UserNamePasswordValidator
{
    public override void Validate(string userName, string password)
    {
        var member = MembershipProvider.ValidateUser(userName, password);

        if(member == null)
            throw new FaultException<SecurityTokenException>
            (new SecurityTokenException("Authentication failed"),
            "Unknown Username or Password");

        Thread.CurrentPrincipal = new GenericPrincipal(new GenericIdentity(userName),
        member.Role.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries));
    }
}

I have used this validator in WCF service application to validate using custom username and password. I will explain that in other post.

Appreciate your query and suggestions.

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