@RestResource(urlMapping='/textlead/*')
global with sharing class TextLeadRestfulReceiver {

    @HttpGet
    global static String init() {
        String payload = ' -d "grant_type=password"' +
            ' -d "client_id=ID"' +
            ' -d "client_secret=secret"' +
            ' -d "username=here@there.com.staging"' +
            ' -d "password=whateverTOKEN"';

        HttpRequest req = new HttpRequest();
        req.setMethod('GET');
        req.setEndpoint('https://login.salesforce.com/services/oauth2/token');
        req.setHeader('Content-Type','application/x-www-form-urlencoded');
        req.setHeader('Content-Length', String.valueOf(payload.length()));
        req.setHeader('X-PrettyPrint', '1');
        req.setBody(payload);

        Http binding = new Http();
        HttpResponse res = binding.send(req);

        System.debug(String.valueOf(res));

        return String.valueOf(res);
    }

    global static String saveText() {
        String ACCOUNT_SID = 'what';
        String AUTH_TOKEN  = 'ever';

        TwilioRestClient client = new TwilioRestClient(ACCOUNT_SID, AUTH_TOKEN);

        RestRequest request = RestContext.request;
        request.addHeader('Authorization', 'Bearer');
        String body         = 'Nada.';
        String leadNumber   = request.requestURI.substring(request.requestURI.lastIndexOf('/') + 1);
        List<Lead> result   = [SELECT Id, FirstName, MobilePhone
                               FROM Lead WHERE MobilePhone=:leadNumber];

        for (TwilioMessage message: client.getAccount().getMessages().getPageData()) {
            body = message.getBody();
        }

        for (Lead l: result) {
            Task task = new Task(WhoId = l.Id, OwnerId = l.OwnerId, Description = body, ActivityDate = Date.today(),
                                 Subject = 'Text received from ' + l.FirstName + ' on ' + leadNumber);
            insert task;
        }
        return body;
    }
}

String ACCOUNT_SID = 'AXXXXXXXXXXXXXXXXX';
String AUTH_TOKEN = 'YYYYYYYYYYYYYYYYYY';
TwilioRestClient client = new TwilioRestClient(ACCOUNT_SID, AUTH_TOKEN);

for (TwilioSms message : client.getAccount().getSmsMessages().getPageData()) {
    System.debug(message.getBody());
}