Call Routing with Twilio and Force.com

Connector.page

<?xml version="1.0" encoding="UTF-8" ?>
<apex:page sidebar="false" 
           showHeader="false" 
           controller="ConnectorController" 
           contentType="application/xml">
  <Response>
    <Say>Hello {!callerName}. Connecting you with {!rep.Name}.</Say>
    <Pause/>
    <Dial>{!rep.Phone}</Dial>
  </Response>
</apex:page>

ConnectorController.cls

public class ConnectorController {
    public User rep {get; set;}
    public String callerName {get; set;}
    
    public ConnectorController() {
        // Check the incoming params!
        String accountSid = System.currentPageReference().getParameters().get('AccountSid');        
        if (accountSid != TwilioAPI.getDefaultAccount().getSid()) {
            throw new TwilioRestException('Account SID mismatch',1);
        }
        
        String callSid = System.currentPageReference().getParameters().get('CallSid');
        TwilioRestClient client = TwilioAPI.getDefaultClient();
        TwilioCall call = new TwilioCall(client, callSid);
        call.setRequestAccountSid(TwilioAPI.getDefaultAccount().getSid());
        if (call.getStatus() != 'ringing') {
            throw new TwilioRestException('Call SID mismatch',1);
        }
        
        // Look up contact from incoming caller id
        String fromNumber = System.currentPageReference().getParameters().get('From');
        List<Contact> callers = (fromNumber == null) 
            ? null 
            : [SELECT Name, OwnerId 
               FROM Contact 
               WHERE Phone = :fromNumber OR MobilePhone = :fromNumber];
        Contact caller = (callers != null && callers.size() == 1) 
            ? callers[0]
            : null;
        callerName = caller.Name;
        
        // Look up rep from contact
        List<User> reps = (caller == null) 
            ? null 
            : [SELECT Name, Phone 
               FROM User 
               WHERE Id = :caller.OwnerId];
        
        // If we don't have a unique rep, connect with switchboard
        rep = (reps != null && reps.size() == 1) 
            ? reps[0] 
            : [SELECT Name, Phone 
               FROM User 
               WHERE LastName = 'Switchboard'];
    }
}