Once I was asked to personalize Sitecore component depending on custom URL query string parameter, to identify users coming by a promo campaign in order to display them slightly modified component reflecting campaign presentation. Easy, I thought, but in next couple minutes struggled to find that condition in Rules Engine. It is not in Sitecore, what a surprise!..
So, let's go through and see what conditions are in Sitecore and how you can create any custom condition you would ever imagine.
First of all, all stuff for Rules Engine is specified as Sitecore items underneath /sitecore/system/Settings/Rules folder. So let's create an item named Query String Value Presents of /sitecore/templates/System/Rules/Condition template within /sitecore/system/Settings/Rules/Conditional Renderings/Conditions/URL Query String Conditions folder. There are just two important fields we are going to set. Type field, as it is very common to Sitecore, specifies fully qualified class and assembly names, where business logic is implemented. Another, Text field, is more interesting on that stage - it shows wordings that would be presented to user when using his condition with Rules Engine. Here is what we set there:
Where the User [QueryStringName,,,QueryString Name] has a value that [operatorid,StringOperator,,compares to] [QueryStringValue,,,QueryString Value].
Pay attention to parameters in square brackets - they would be replaced by Rules Enging to selectors.
Now let's look at the code. Fom the item we ahave referenced the class.
public class QueryStringCondition<T> : StringOperatorCondition<T> where T : RuleContext
All derived condition classes should have same definition and derive from base StringOperatorCondition class. As the absolute minimal, we are to override just one Execute(T ruleContext) method. Additionally we must create public string properties named exactly the same as in parameters above from Text field from condition definition item in Sitecore.
public string QueryStringName { get; set; }
public string QueryStringValue { get; set; }
protected override bool Execute(T ruleContext)
{
// process QueryStringName and QueryStringValue properties here
// return true if personlization parameters falls within the condition
}
QueryStringName and QueryStringValue would be auto-populated by Rules Engine.
With our next example we are trying to display an additional promo component when user access our website by URL with sourceId=campaign as parameters.
Full implementation of QueryStringCondition<T> class can be found on GitHub by this link.
Hope you find this helpful!