Example – Create audience criteria

(Thanks to Ted and Gustaf for this example.)

One usage scenario could be to check for a cookie that says the visitor has previously completed a purchase on the website and is a returning customer.

The example uses the following steps:

1. Creating the settings and criterion classes
2. Implementing the settings class
3. Implementing the criterion class
4. Testing the criterion

Create the settings and criterion classes

Audience criteria require a settings class and a criterion class. The settings class is used to persist any settings available to editors when creating an audience. The criterion class contains the logic to determine whether or not a visitor belongs to the audience.

You should create the two classes in a suitable folder structure:

Implement the settings class

The only setting required for this audience criterion is the cookie name you should look for.

1. First, make the CookieExistsCriterionSettings class inherit the CriterionModelBase class:

   C#

   public class CookieExistsCriterionSettings : CriterionModelBase

2. Add a public property to let editors specify the cookie name:

   C#

   [Required]
   public string CookieName {
     get;
     set;
   }

3. If you need custom validation logic when a criterion is saved, you can make your settings class implement the IValidateCriterionModel interface (this is optional). By implementing that interface’s Validate method, you can customize how settings are validated before saving a criterion for an audience.

   The abstract CriterionModelBase class requires you to implement the Copy() method. Because you are not using complex reference types, you can implement it by returning a shallow copy as shown (see Create custom audience criteria):

public override ICriterionModel Copy() {
  return ShallowCopy();
}

This is the complete CookieExistsCriterionSettings class:

public class CookieExistsCriterionSettings: CriterionModelBase {
  [Required]
  public string CookieName {
    get;
    set;
  }
  public override ICriterionModel Copy() {
    return ShallowCopy();
  }
}

Implement the criterion class

1. Make the CookieExistsCriterion class inherit the abstract CriterionBase class with the settings class as the type parameter:

   C#

   public class CookieExistsCriterion : CriterionBase<CookieExistsCriterionSettings>

2. Add a VisitorGroupCriterion attribute to set the category, name, and description of the criterion (for more available VisitorGroupCriterion properties, see Create custom audience criteria:

   C#

   [VisitorGroupCriterion(   
     Category = "Technical",
     DisplayName = "Cookie Exists",
     Description = "Checks if a specific cookie exists")]

3. The abstract CriterionBase class requires you to implement an IsMatch() method, which determines whether the current user matches this audience criterion. You should check if a specific cookie exists based on the criterion settings:

   C#

   public override bool IsMatch(IPrincipal principal, HttpContextBase httpContext) {
     return httpContext.Request.Cookies[Model.CookieName] != null;
   }

   The criterion class appears as follows:

   C#

   [VisitorGroupCriterion(
     Category = "Technical",
     DisplayName = "Cookie Exists",
     Description = "Checks if a specific cookie exists")]
   
   public class CookieExistsCriterion: CriterionBase<CookieExistsCriterionSettings> {
     public override bool IsMatch(IPrincipal principal, HttpContextBase httpContext) {
       return httpContext.Request.Cookies[Model.CookieName] != null;
     }
   }

📘

Note

You access the criterion settings instance through the Model property.

Test the criterion

To test the criterion, create an audience using the cookie criterion.

1. Set the cookie name to .EPiServerLogin, the name of the cookie created when a user logs in to Episerver:
   

   If you are on CMS version 10 or 11, it will look like this:
   

2. Select some content in the editor that should only be displayed to users currently logged in to Episerver.
   

3. Click Personalized Content and select the  Episerver User audience.
   

   This content is now only displayed to users logged into Episerver:

   

   After publishing the page, you see this:

   

   However, if you log out of Episerver, you no longer see the personalized content.