PowerSchoolWrapper.swift

extension String {
    func Base64Encode() -> String? {
        let asciiString = self.dataUsingEncoding(NSASCIIStringEncoding, allowLossyConversion: true)
        guard let base64String = asciiString?.base64EncodedStringWithOptions(NSDataBase64EncodingOptions()) else { return nil }
        return base64String
    }
}

public class PowerSchoolServiceWrapper {
    static let sharedInstance = PowerSchoolServiceWrapper()
    private init() { }
    
    let clientID = “yourclientid”
    let secret = “yoursecret”
    let authURL = "https://psserver.com/oauth/access_token/"

    let studentSearchURL = "https://psserver.com/ws/schema/query/com.companyName.product.students.student_search"
    
    func getBearerToken(completion:(bearerToken: String) -> ()) {
        guard let baseEncodedString = "\(clientID):\(secret)".Base64Encode() else { return }
        let request = NSMutableURLRequest(URL: NSURL(string: authURL)!)
        request.HTTPMethod = "POST"
        request.addValue("Basic " + baseEncodedString, forHTTPHeaderField: "Authorization")
        request.addValue("application/x-www-form-urlencoded;charset=UTF-8", forHTTPHeaderField: "Content-Type")
        let grantType = "grant_type=client_credentials"
        request.HTTPBody = grantType.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: true)
        
        let task = NSURLSession.sharedSession().dataTaskWithRequest(request) { (data, response, error) -> Void in
            do {
                let results = try NSJSONSerialization.JSONObjectWithData(data!, options: .AllowFragments) as? [String:AnyObject]
                results
                if let token = results!["access_token"] as? String {
                    completion(bearerToken: token)
                }
            } catch {
                print("error")
            }
        }
        
        task.resume()
    }
    
    func getResponse(url:String, payload:String, parser:(data: NSData, response: NSURLResponse, error: NSError?) -> ()) {
        getBearerToken { (bearerToken) -> () in
            let request = NSMutableURLRequest(URL: NSURL(string: url)!)
            request.HTTPMethod = "POST"
            let token = "Bearer " + bearerToken
            request.addValue(token, forHTTPHeaderField: "Authorization")
            request.addValue("application/json", forHTTPHeaderField: "Content-Type")
            request.HTTPBody = payload.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: true)
            
            let task = NSURLSession.sharedSession().dataTaskWithRequest(request, completionHandler: { (data, response, error) -> Void in
                guard let theData = data, let theResponse = response else { return }
                parser(data: theData, response: theResponse, error: error)
            })
            
            task.resume()
        }
    }
}