Submission Manager

SubmissionManager.swift

import UIKit

class SubmissionManager: NSObject {
    
    static let sharedManager = SubmissionManager()
    
    var serverURLComponents : NSURLComponents = NSURLComponents()
    
    private let keyDefaultsServerAddress : String = "com.company.serverURL"
    
    private override init() {
        super.init()
        
        NSUserDefaults.standardUserDefaults().registerDefaults([
            keyDefaultsServerAddress : [
                "scheme" : "http",
                "host" : "192.168.1.5",
                "port" : NSNumber(int: 8000),
                "path" : "/api/submit/"
            ]
            ])
        
        if let components = self.loadURLComponents() {
            self.serverURLComponents = components
        }
    }
    
    // MARK: - Server URL Settings
    
    /**
    
    Loads the most recent server URL from the defaults store.
    
    */
    
    func loadURLComponents() -> NSURLComponents? {
        
        var returnComponents : NSURLComponents? = nil
        
        if let serverComponentsDictionary : [String : AnyObject] = NSUserDefaults.standardUserDefaults().dictionaryForKey(keyDefaultsServerAddress) {
            
            let components : NSURLComponents = NSURLComponents()
            
            components.scheme = serverComponentsDictionary["scheme"] as? String
            components.host = serverComponentsDictionary["host"] as? String
            components.port = serverComponentsDictionary["port"] as? NSNumber
            components.path = serverComponentsDictionary["path"] as? String
            
            returnComponents = components
        }
        
        return returnComponents
    }
    
    /**
     
     Saves the components to NSUserDefaults.
     
     - parameter components: The URL components to save.
     
     */
    
    func saveURLComponents(urlComponents components: NSURLComponents) {
        
        var componentsToSave : [String : AnyObject] = [:]
        
        if let scheme = components.scheme, let host = components.host, let port = components.port, let path = components.path  {
            
            componentsToSave["scheme"] = scheme
            componentsToSave["host"] = host
            componentsToSave["port"] = port
            componentsToSave["path"] = path
        }
        
        NSUserDefaults.standardUserDefaults().setObject(componentsToSave, forKey: keyDefaultsServerAddress)
        self.serverURLComponents = components
    }
    
    // MARK: - Uploading a Submission
    
    /**
    
    Uploads a PDF to the server.
    
    */
    
    func uploadPDF(pdf data: NSData, withName name: String, andHandler handler: (response : NSURLResponse?, error : NSError?) -> Void) {
        
        guard let payload = self.payload(withData: data, andName: name) else {
            let error = NSError(domain: "com.company.product", code: -3, userInfo: ["reason" : "Failed to convert data into payload."])
            handler(response: nil, error: error)
            return
        }
        
        self.uploadData(payload, withName: name, andHandler: handler)
    }
    
    /**
     
     Uploads a Dictionary to the server.
     
     */
    
    func uploadJSON(submission : NSDictionary, withName name: String, andHandler handler: (response : NSURLResponse?, error : NSError?) -> Void) {
        
        print("(Product) : JSON Submission started...")
        
        // Step 1. Prepare the data for upload.
        guard let payload = self.payload(withDictionary: submission, andName:name) else {
            let error = NSError(domain: "com.company.product", code: -2, userInfo: ["reason" : "Failed to convert dictionary into payload."])
            handler(response: nil, error: error)
            return
        }
        
        self.uploadData(payload, withName: name, andHandler: handler)
    }
    
    /**
     
     Uploads a prepared payload to the server.
     
     */
    
    private func uploadData(payload : NSData, withName name: String, andHandler handler: (response : NSURLResponse?, error : NSError?) -> Void) {
        
        print("(Product) : Payload prepared (\(payload.length) bytes).")
        
        // Step 2. Prepare the URL
        
        guard let url = self.serverURLComponents.URL else {
            print("(Product) : URL generation failed.")
            handler(response: nil, error: NSError(domain: "com.company.product", code: -1, userInfo: ["reason" : "Failed to create url from components."]))
            return
        }
        
        print("(Product) : URL generated, preparing request.")
        
        // Required for successful submission.
        let boundary : String = "----------SwIfTeRhTtPrEqUeStBoUnDaRy"
        
        let request : NSMutableURLRequest = NSMutableURLRequest(URL: url)
        request.HTTPMethod = "POST"
        request.HTTPBody = payload
        request.setValue("multipart/form-data; boundary=\(boundary)", forHTTPHeaderField: "Content-Type")
        request.setValue("\(payload.length)", forHTTPHeaderField: "Content-Length")
        
        let session = NSURLSession.sharedSession()
        
        let uploadTask = session.uploadTaskWithRequest(request, fromData: payload, completionHandler: { (responseData: NSData?, response : NSURLResponse?, error : NSError?) -> Void in
            
            print("(Product) : Upload completed, processing response...")
            
            handler(response: response, error: error)
            
            if let data = responseData {
                
                do {
                    let responseDictionary = try NSJSONSerialization.JSONObjectWithData(data, options: [])
                    
                    print("(Product) Response: \(responseDictionary)")
                }
                catch let e as NSError
                {
                    print("(Product) Error unwrapping response : \(e)")
                    print("\(NSString(data: data, encoding: NSUTF8StringEncoding))")
                }
                
            }
            else
            {
                print("(Product) : Didn't receive a response. \(error)")
            }
            
            print("(Product) Done.")
        })
        
        print("(Product) : Task prepared.")
        
        uploadTask.resume()
        
    }
    
    // MARK: - Test Server Connection
    
    func testServerConnection() {
        
        if let task = self.testTask() {
            task.resume()
        }
    }
    
    func testTask() -> NSURLSessionDataTask? {
        
        let components = NSURLComponents()
        components.scheme = self.serverURLComponents.scheme
        components.host = self.serverURLComponents.host
        components.port = self.serverURLComponents.port
        components.path = "/"
        
        guard let url = components.URL else {
            print("Failed to build URL from components. \(components)")
            return nil
        }
        
        let request = NSURLRequest(URL: url)
        
        let task = NSURLSession(configuration: NSURLSessionConfiguration.defaultSessionConfiguration()).dataTaskWithRequest(request, completionHandler: { (data : NSData?, response : NSURLResponse?, error : NSError?) -> Void in
            
            var success : Bool = false
            
            if let data = data {
                
                if let responseString : NSString = NSString(data: data, encoding: NSUTF8StringEncoding) {
                    
                    if responseString == "Hello world." {
                        
                        success = true
                    }
                }
            }
            
            var results : String
            
            if success {
                results = "Successfully connected to server at '\(url)'."
            }
            else
            {
                results = "Connection failed to server at '\(url)'."
            }
            
            let alert : UIAlertController = UIAlertController(title: "", message: "\(results)", preferredStyle: UIAlertControllerStyle.Alert)
            
            let cancel = UIAlertAction(title: "OK", style: .Cancel, handler: { (action : UIAlertAction) -> Void in
                if let rootViewController = UIApplication.sharedApplication().keyWindow?.rootViewController {
                    rootViewController.dismissViewControllerAnimated(true, completion: nil)
                }
            })
            
            alert.addAction(cancel)
            
            dispatch_async(dispatch_get_main_queue(), { () -> Void in
                if let rootViewController = UIApplication.sharedApplication().keyWindow?.rootViewController {
                    rootViewController.presentViewController(alert, animated: true, completion: { () -> Void in
                    })
                }
            })
        })
        
        return task
    }
    
    
    // MARK: - Converting a submission dictionary into data.
    
    /**
    
    Converts a submission into a data payload for upload to server.
    
    */
    
    func payload(withDictionary dictionary : NSDictionary, andName name:String) -> NSData? {
        
        var returnData : NSData? = nil
        do {
            guard let data : NSData = try NSJSONSerialization.dataWithJSONObject(dictionary, options: .PrettyPrinted) else {
                return nil
            }
            
            returnData = self.payload(withData: data, andName: name)
        }
        catch let e as NSError {
            print("Error converting dictionary to data:\(e)")
        }
        
        return returnData
    }
    
    func payload(withData data : NSData, andName name:String) -> NSData? {
        
        var returnData : NSData? = nil
        
        let boundary : String = "----------SwIfTeRhTtPrEqUeStBoUnDaRy"
        let contentDisposition : String = "Content-Disposition: form-data; name=\"\(name)\"; filename=\"\(name)\"\r\n"
        let contentType : String = "Content-Type: application/octet-stream\r\n\r\n"
        let payload : NSMutableData = NSMutableData()
        
        if let encodedBoundary = ("--\(boundary)\r\n").dataUsingEncoding(NSUTF8StringEncoding),
            let metadata1 = contentDisposition.dataUsingEncoding(NSUTF8StringEncoding),
            let metadata2 = contentType.dataUsingEncoding(NSUTF8StringEncoding),
            let trailingNewlineData = "\r\n\r\n".dataUsingEncoding(NSUTF8StringEncoding)
        {
            payload.appendData(encodedBoundary)
            payload.appendData(metadata1)
            payload.appendData(metadata2)
            payload.appendData(data)
            payload.appendData(trailingNewlineData)
            payload.appendData(encodedBoundary)
        }
        
        returnData = payload
        
        return returnData
    }
}