Sync It Up

Sean Voisen 2008. Licensed under Creative Commons Attribution No-Derivatives 3.0 license.

ME: SEAN VOISENTHIS: SYNC IT UPSynchronizing Desktop Data with AIR and SQLite@ FITC, Toronto on April 21, 2008

•YOU KNOW SOME AS3

•YOU’VE TRIED AIR DEVELOPMENT

•YOU KNOW A LITTLE SQL

A FEW ASSUMPTIONS ...


1. WHY SYNCHRONIZE?

2. SYNCHRONIZATION STRATEGIES.

3. DESIGN PATTERNS.

4. SQLITE IN AIR.

5. CONNECTION DETECTION IN AIR.

6. AS3 PROGRAMMING STRATEGIES.


WHY SYNCHRONIZE?When it’s not always good to have your head in the “cloud.”


•OFFLINE DATA ACCESS

•LARGE DATA SETS

•FASTER START UP TIME

•STORE EPHEMERAL DATA

•EXPORT DATA EASILY


SYNCHRONIZATION STRATEGIES.Keeping your data fresh.


•USER MAKES CHANGES WHILE OFFLINE

•DATA IS CHANGED ON SERVER BY THIRD PARTIES

•DATA IS CHANGED LOCALLY BY THIRD PARTIES (RSS FEEDS)


•REQUIRES USER TO PUSH A BUTTON

•GOOD FOR SHORT SYNC TIMES OR SMALL AMOUNTS OF DATA

•EASIEST TO IMPLEMENT

•BUT ... USER MAY FORGET

MANUAL SYNC


BACKGROUND SYNC

•WORKS “BEHIND THE SCENES” WITHOUT INTERVENTION

•USE TIMER OR TRIGGERING EVENTS (PROBABLY BOTH)

•SERVER CAN PUSH DATA (LIVECYCLE DATA SERVICES)


•TIMESTAMPS

•“DIRTY” BITS

•DIRECT DATA COMPARISON

•COLLISIONS: CLIENT OVERRIDES SERVER, SERVER OVERRIDES CLIENT

WHAT TO SYNC


DESIGN PATTERNSMake it beautiful and usable.


•PATTERN: AN APPROPRIATE AND SUCCESSFUL APPROACH TO A PROBLEM.

BRETT RAMPATA

•ACCOMODATES BOTH MANUAL AND BACKGROUND SYNCHRONIZATION

•UNOBTRUSIVE

•CONNECTION AVAILABILITY AND SYNC ARE VISUALLY LINKED

DEMO: PAYPAL DESKTOP.A combined project of Adobe XD and PayPal, with a little help from yours truly.


SQLite in AIR.What you need to know to get your feet wet.


•EMBEDDED SQL DATABASE ENGINE

•NO SETUP, NO SERVER

•DATABASE IS STORED AS A SINGLE FILE

•MOST OF SQL92 SUPPORTED

•INCLUDING THE ADVANCED STUFF LIKE VIEWS, TRANSACTIONS AND TRIGGERS!


DATA TYPES in SQLite

•SQLite USES TYPE AFFINITIES

•TYPE “AFFINITY” = RECOMMENDED, BUT NOT REQUIRED

•THE NORMAL SQLite AFFINITIES:

•NULL, INTEGER, REAL, TEXT, BLOB


•ADDITIONAL TYPE AFFINITIES AVAILABLE FOR AIR:

•TEXT, NUMERIC, INTEGER, REAL, BOOLEAN, DATE, XML, XMLList, OBJECT, NONE


1. CREATE A File REFERENCE FOR THE DB

2. CREATE A SQLConnection INSTANCE

3. OPEN SQLConnection ON FILE

4. CREATE A QUERY USING SQLStatement

5. EXECUTE THE QUERY

THE BASICS

var db:File = File.applicationStorageDirectory.resolvePath("filename.db");

var connection:SQLConnection = new SQLConnection();connection.openAsync(db, SQLMode.CREATE);

var stmt:SQLStatement = new SQLStatement();stmt.sqlConnection = connection;stmt.text = "SELECT * FROM mytable";stmt.addEventListener( SQLEvent.RESULT, onResult );stmt.execute();


•SQLConnection SUPPORTS BOTH SYNCHRONOUS AND ASYNCHRONOUS CONNECTIONS

•SYNC: APP INTERACTIVITY BLOCKED UNTIL COMPLETE (LIKE FILE I/O API)

•ASYNC: USES EVENT LISTENERS AND QUERIES ARE QUEUED


var stmt:SQLStatement = new SQLStatement();stmt.text = "SELECT * FROM mytable WHERE id = :id";stmt.parameters[":id"] = 5;stmt.execute();

•CACHES QUERY FOR FASTER EXECUTION

•PREVENTS INJECTION VULNERABILITY

ABOUT PARAMETERS


ABOUT RESULT PAGING

•SQLStatement SUPPORTS PAGING

•LIMITS NUMBER OF ROWS RETURNEDvar statement:SQLStatement = new SQLStatement();statement.sqlConnection = mySQLConnection;statement.text = "SELECT * FROM contacts";statement.execute( 10 );

statement.next();


ABOUT TRANSACTIONS

•MULTIPLE STATEMENTS (USING LOOPS) IN ONE WRITE OPERATION

•ALLOWS ROLLBACKS ON ERRORvar stmt:SQLStatement = new SQLStatement();stmt.sqlConnection = connection;stmt.text = "INSERT INTO tasks VALUES(:task)";connection.begin();for each( var task:String in tasks ) {

stmt.parameters[":task"] = task;stmt.execute();

}connection.commit();


CONNECTION DETECTION in AIR.Is this thing on?


•NATIVENativeApplication.nativeApplication.addEventListener( Event.NETWORK_CHANGE, onNetworkChange );

•ONLY DETECTS A CHANGE!

•SERVICE MONITOR FRAMEWORK

•URLMonitorvar m:URLMonitor = new URLMonitor(

new URLRequest('http://myurl.com') );m.addEventListener( StatusEvent.STATUS, onStatus );m.start();

•SocketMonitor

http://myurl.com

http://myurl.com


AS3 PROGRAMMING STRATEGIESA few tips to make your life easier.


CREATE DAOs

•DAO = DATA ACCESS OBJECT

•SINGLETON or STATIC CLASS

•ABSTRACTS SQL MANIPULATION, HANDLES CRUD OPERATIONS

•ONE PLACE FOR DB ACCESS and HANDLING DB ERRORS

public class ContactsDAO {private static var instance:ContactsDAO;public function ContactsDAO() {

if( ContactsDAO.instance != null ) {throw new Error("Singleton!");

}}

public static function getInstance():ContactsDAO {if( ContactsDAO.instance == null ) {

ContactsDAO.instance = new ContactsDAO();}return ContactsDAO.instance;

}

public function getAllContacts( resultHandler:Function, faultHandler:Function ):void {

var statement:SQLStatement = new SQLStatement(); statement.sqlConnection = mySQLConnection; statement.text = "SELECT * FROM contacts"; statement.execute( -1, new Responder(

function( result:SQLResult ):void {resultHandler.call( this, result.data );

}, faultHandler ));

}}


USE “IF NOT EXISTS”

•CREATE TABLES WHEN DB IS OPENED IF THEY DON’T EXISTvar statement:SQLStatement = new SQLStatement();statement.sqlConnection = mySQLConnection;statement.text = "CREATE TABLE IF NOT EXISTS mytable (" +

"id INTEGER PRIMARY KEY AUTOINCREMENT," +"first_name TEXT," +"last_name TEXT)";

statement.addEventListener( SQLEvent.RESULT, onResult );statement.execute();


WATCH FOR MEMORY LEAKS•DATA QUERIED FROM SQL STORED IN

Array/ArrayCollection

•DATA CAN’T BE USED DIRECTLY FROM DB IN GRIDS, CHARTS, ETC.

•RELOAD ALL DATA IN ARRAYS? OR INDIVIDUAL ITEMS?

•USE FLEX 3 PROFILER

DEMO: LibrarianFree sample code to be posted on voisen.org


USE SQLiteAdmin

•USED TO HANDY TOOLS LIKE PHPMyAdmin? Try:

http://coenraets.org/blog/2008/02/sqlite-admin-for-air-10/





DEMO: SQLite Admin.By Christophe Coenraets.


RESOURCES•CHRISTOPHE COENRAETS: coenraets.org -

SQLite Admin for AIR

•PETER ELST: peterelst.com - SQLite Wrapper Classes

•PAUL ROBERTSON: probertson.com - Insider info on AIR SQLite

•ADOBE XD: xd.adobe.com


QUESTIONS?Web: http://voisen.orgE-mail: [email protected]

http://voisen.org

http://voisen.org

mailto:[email protected]

mailto:[email protected]

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Sync It Up