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On the #epidayuk event I demonstrated how to create a custom visitor group criterion with a custom Dojo widget and a MVC controller. Since the entire day had a social theme I could not miss the chance to get into Facebook development. On the day, the code was explained to the tech session attendees and download can be enabled by joining a Facebook event. It is totally understandable that some may not want to expose their Facebook credentials, let alone to authorise some Facebook app that was created by a guy they only met once. So as promised in the seminar, and for the general public who may think this is useful, a Facebook Event Attendance Criterion.
The name says it all – A visitor group can be defined to include this criterion, where the marketer can select the event to attend. See screenshot:
An editor will be able to create a block of personalised content just visible to this visitor group. See screenshot:
If site visitors are attending/have attended a specified event published on Facebook, they belong to the visitor group and personalised content will be displayed. They will need to authorise your website to access their event attendance information on their Facebook profiles. See screenshots:
Step 1 – Authorise Facebook App
Step 2 - No personalised content yet
Step 3 - Join the event
Step 4 – personalised content is visible
The development is formed of two parts – to create a widget for the criteria in the visitor group UI, and to implement the IsMatch method that will be evaluated when a personalised page is visited.
Again, a picture equals a thousand words:
IsMatch() is the only method to override. In this case, check if the user has authorised the Facebook App and has attended the selected Facebook event (which is accessible through the Model object).
The model class, inheriting from EPiServer.Personalization.VisitorGroups.CriterionModelBase. It contains a public property “EventName” (string) that can be selected from a dropdown list when creating a visitor group. The selected value will then be passed to the IsMatch method in the main criterion class.
By default, EPiServer will use a text box for a string property when using the criteria to create visitor groups. In this case, we want to use a dropdown list instead, which means the EventName property needs some annotation using EPiServer.Personalization.VisitorGroups.DojoWidgetAttribute.
e.g. [DojoWidget(WidgetType = "dijit.form.FilteringSelect", …)]
This drop down needs to have some options, which is why the FacebookEventCriterion class has used ScriptUrl in its VisitorGroupCriterionAttribute.
This is a page that you only need to run once to get a “permanent” (or long standing) access token for your Facebook App to get the Facebook user’s profile events information. We want to get a long standing token because this is likely to be a Facebook user created by the same marketing department that is responsible for the web site. So there isn’t any trust issue here, and this Facebook user is unlikely to change, and the password of this Facebook user is unlikely to change, either. However if any of situation changes, you will need to regenerate the access token. We want to allow this by using an AppSettings section in the web.config.
In order to generate an access token, you firstly need a Facebook App. That topic, together with the source code download, deployment and configuration, will come in Part II of this article.