InSync: Automatic Offline Data Synchronization in AIR using LCDS 2.6

LCDS 2.6 allows you to build AIR applications with automatic offline data synchronization. This feature leverages the SQLite relational database system embedded in the AIR runtime, but the advantage is that the data synchronization process is entirely automatic: you don’t have to write SQL statements or synchronization logic to keep your local database in sync with your central database.

I have been getting a number of questions related to this feature, so I decided to build a sample application that demonstrates how it works.

In this application the synchronization process is implicit. When you are online, the cache (a SQLite database) is automatically updated along with the server database to make sure the user can go offline with the latest data without explicitly triggering a synchronization process. When you are offline, the changes are saved in the local cache. If the network becomes available while working in the application, the application will detect the network status change and automatically synchronize data (send your offline changes to the server, and get changes made by other users while you were offline).

Installation Instructions

  1. If you haven’t already done so, install LCDS 2.6.
  2. Unzip insync.zip
  3. Copy the content of the sampledb folder in the sampledb folder of your existing LCDS directory
  4. Copy the content of the tomcat folder in the tomcat folder of your existing LCDS directory
  5. Add the following destination to data-management-config.xml

    <destination id="insync">
        <adapter ref="java-dao" />
        <properties>
            <source>lcds.samples.contact.ContactAssembler</source>
            <scope>application</scope>
            <metadata>
                <identity property="contactId" undefined-value="0"/>
            </metadata>
        </properties>
    </destination>
    

  6. Restart the sample database: run sampledb.bat (Windows) or sampledb.sh (Unix) in the sampledb directory
  7. Restart your application server

Quick Tour

  1. Install and run the AIR application. Notice the green light in the status bar indicating that the application is in online mode.

    [airbadge]sqliteadmin, http://coenraets.org/apps/insync/insync.air, v1.0, http://coenraets.org/apps/insync/insync1.png[/airbadge]

  2. Double click a contact to view the contact details.
  3. Modify the data in a few fields and click Save. Your server console indicates that the contact has been updated.
  4. Click the + button in the application title bar. Enter a first name, last name, etc and click Save. Your server console indicates that the contact has been updated.
  5. Shut down the server
  6. Notice that the green light turns grey to indicate that the application is now working in offline mode.
  7. Repeat steps 2 to 4 above: changes are saved locally. Notice that the offline status (not modified, created, or updated is displayed in the contact form (bottom left corner)
  8. Restart the server.
  9. The green light appears in that status bar as soon as the server is up and running. Notice that LCDS automatically detects the offline changes and sends them to the server.

, , ,

  • In case data of the same item changes in both offline cache & online database.
    which data is taken?

  • Forrest

    it seems great,may i use BlazeDS instead of using LiveCycle ?

  • christophe

    Forrest, Offline sync is a feature of Data Management Services which is part of LCDS. Note that there is a free version of LCDS currently called LCDS Express.
    Christophe

  • christophe

    @Rosenthal Ido: if you go back online and try to apply a change to an item that someone else has already changed in the central database, you will have a conflict. There is a conflict resolution API that you use to resolve this situation.

  • I was just talking with a friend the other and we were brainstorming on how to accomplish this very task. Auto Sync of a local database with a server database is a very nice feature to have.

    Thanks!

  • Pingback: 17 Pens » links for 2008-05-20()

  • Pingback: Ryan Stewart - Rich Internet Application Mountaineer » Online/Offline Synchronization with Adobe AIR()

  • Pingback: LCDS Makes AIR Offline Sync Easy (…and Why You’ll Care) | 网络赚钱网摘()

  • Pingback: LCDS Makes AIR Offline Sync Easy (…and Why You’ll Care)()

  • That’s great – I have been waiting for something like that!

    Thank you!

  • WE need to vote again :) https://bugs.adobe.com/jira/browse/FP-247

    I realy hope we can have USB communication in AIR and Flash Player :)

    I can imagine many different type of applications which can communicate with different devices connected over USB, atleast my phone (over bluetooth or cable)…

    It would be great if AIR and Flash player can have USB API for those things, so that we (developers) are not forced to write socket-servers and take care of installation etc..

  • Tristan

    Any chance you’ll be releasing the source behind your AIR app?

    Very cool btw.

  • Tristan, the source code for the AIR app is actually available in insync.zip.
    Christophe

  • Pingback: FlexLive.net » Flex Developer Update - May 23, 2008()

  • Can I use this progoram with my MySQL database? If so, how can I set it? Thank you so much anyone. This is a super cool program.

  • Alberto

    Hi Christophe,

    Very useful and clean tutorial as usual. I had to change a couple of things ( most of them related to my eclipse developing environment ) to have this working but, finally, everything works fine now.

    Congratulations again for your work.

    Alberto

  • Charly

    Hi Christophe,

    I know it’s not really the right place to ask this, but… :-)

    Is it possible (or if not is it planned) to have the Air runtime and application installers localized…?

    Thx.

  • Martin Karlsson

    Really exited about this because currently we’re having to maintain a SQLlite db “manually” on a big project.

    Started testing this and got a run-time error… all I’m doing is creating a new DataService and setting the cacheID=”users”;

    userDataService = new DataService(“UserService”);
    userDataService.cacheID = “users”;

    ReferenceError: Error #1065: Variable mx.data::LocalStoreFactory is not defined.
    at mx.data::DataStore/get localStore()[C:\depot\flex\branches\enterprise_corfu_b2\frameworks\projects\data\src\mx\data\DataStore.as:2670]
    at mx.data::DataStore/set cacheID()[C:\depot\flex\branches\enterprise_corfu_b2\frameworks\projects\data\src\mx\data\DataStore.as:317]
    at mx.data::ConcreteDataService/set cacheID()[C:\depot\flex\branches\enterprise_corfu_b2\frameworks\projects\data\src\mx\data\ConcreteDataService.as:231]
    at mx.data::DataService/set cacheID()[C:\depot\flex\branches\enterprise_corfu_b2\frameworks\projects\data\src\mx\data\DataService.as:428]
    at LCDSX/init()[C:\Documents and Settings\Karlsson\My Documents\Flex 3\LCDSX\src\LCDSX.mxml:14]

    Any pointers?

    Thanks

  • Martin Karlsson

    Nevermind – adding the airfds.swc to the project helps :)

  • Martin Karlsson

    Anyone have problems with going back online after a network disconnection [using authentication]? I’m the client is always successful in sending data [like dataService.deleteItem] but ~60% of the time it’s not receiving updates from the server [although it fill()’s just fine].

    Any pointers would be greatly appreciated. / Thanks

  • Martin Karlsson

    Found that if I disconnect using “ipconfig /release” I get the 60% failure – but if I disconnect the ehternet cable and then reconnect it something is cleared up automatically and it works fine.

    I’m trying to simulate a rather unique network environment :) – is there a way to “manually reset” or “clear” the RTMPChannel/ChannelSet/DataService such that it gets into the same state as it was before starting to use it [other than restarting the app]?

  • Subhadip Chakraborty

    If I add delete and update lots of data while offline and then come to online while running the application its gets synchronized fine.

    But if i close the application after making changes and again start it in offline status if goes failed and show s the alert “Cannot Fill”……

    It is going fine if i add only the first name or change the phone number…..

    but if i add a full details of a person and do the said process it fails….

    please help…. and how to improve it?

  • florence kolberg

    hi,

    I have installed LCDS 2.6 and started the server, after I started the sample database.
    When I run the inSync app. I get an green online button, but I also get a “cannot fill” message popping.
    Could anyone help me solving that issue? it looks like the contactdb.script is not run or something.

    Thanks,
    Florence

  • florence kolberg

    Hi,

    I have been debugging the insync application – it still does not work on my computer for some reasons – and I get the following error message:

    Error: Unable to initialize destinations on server: [“insync”]
    at ()[C:\depot\flex\branche\enterprise_corfu_rc\frameworks\projects\data\src\mx\data\DataStore.as:2347]
    at ()[C:\depot\flex\branches\enterprise_corfu_rc\frameworks\projects\data\src\mx\data\DataStore.as:2363]
    at flash.events::EventDispatcher/dispatchEventFunction()
    at flash.events::EventDispatcher/dispatchEvent()
    at mx.data::SQLDBCache/dispatchStatusEvent()[C:\depot\flex\branches\enterprise_corfu_rc\frameworks\projects\airfds\src\mx\data\SQLDBCache.as:540]
    at Function/http://adobe.com/AS3/2006/builtin::apply()
    at mx.rpc::AsyncDispatcher/timerEventHandler()[E:\dev\3.0.x\frameworks\projects\rpc\src\mx\rpc\AsyncDispatcher.as:50]
    at flash.utils::Timer/_timerDispatch()
    at flash.utils::Timer/tick()

    If anyone has a pointer to how I can solve that problem, I gladly take it.

    thanks
    Florence

  • Güzel bilgiler..Teşekkürler…

  • Joe

    I’m having the same issue as Florence…. can’t seem to quite figure this one out. Could really use the help on this one if someone knows what’s going on.

    thanks,

    Joe

  • Greatest AIR app interface designer ever

  • Güzel bilgiler..Teşekkürler…

  • Damian Vuckovich

    Yah i’m getting the same problem as Florence and can’t figure it out myself. Any pointers would be useful. The debug statements kept on saying the server producer was disconnecting right before i’d see the error message.

  • Pingback: pocker game holdem texas hold em()

  • Pingback: Ryan Stewart - Rich Internet Application Mountaineer » Blog Archive » Online/Offline Synchronization with Adobe AIR, ColdFusion and LCDS()

  • nimesh nanda

    Hi,

    please help me how to synchronize online and offline data in Flex (AIR) and Ruby on Rails ..

    Regrads,
    Nimesh nanda

  • Sky

    I’m currently having the same problem as “Martin Karlsson” (from June 27th, 2008 1:23 pm). I added the airfds.swc to the compilation line… and it doesn’t work. :( It did work for a while, but then I had to change my DSN source in CF8 to point to a different DB. I don’t think that should change anything…

    Any ideas?

  • Pingback: Life As An Evangelist » Online/Offline Synchronization with Adobe AIR, ColdFusion and LCDS()

  • Pingback: Cornel Creanga » Blog Archive » LiveCycle Data Services 2.6 – new features (4)()

  • kauser

    Hi,
    I am working on a simple application using flex and air as the presentation layer, java as the back end and the data base which i am using is ms access. Can you tell me how to use LCDS with an application whose back end is written in java. Thanks in advance.

  • Jin Lei

    To make the installation instruction more clear,

    5. Add the following destination to data-management-config.xml

    actually, add the following destination to

    tomcat folder, \webapps\lcds-samples\WEB-INF\flex\management-config.xml

  • kauser

    Hi,
    I went through the sample lcds application for data synchronization and created a similar application. I am getting the following errors:
    1. Unable to initialize destinations on server.
    2. No destination with id ‘[my id]’ is registered with any service.
    Can you tell me what could be the possible cause of this error. Thanks.

  • ED

    Is this possible using Coldfusion 8 alone (From what I understand LiveCycle Data Services is integrated in Coldfusion 8) ? Thanks in advance.

  • Souvik Mukherjee

    I am developing an application and I am in a position where I can push messages to one or many AIR applications and the selection of AIR application will be decided by LCDS server. Here I am making use of JMS along with JMS adapter. I need a way to receive an acknowledgement to LCDS server when the message is delivered.
    I have found few application where JMS subscriber is sending acknowledgement to JMS producer, but I need a way where JMS producer is getting acknowledgement from each Flex client.

  • So I spent three days on this, and I think I solved or at least identified a work around for the problem that several guys including florence were having above. I tried to write down all the steps I took to get this demo running in three parts. Part three is here and has the fix of compiling in your services to fix the dreaded Error: Unable to initialize destinations on server: [“insync”]

    Hope it helps

    http://somehardwareguy.blogspot.com/2009/03/part-3-lcds-insync-example-it-works-and.html

  • Sam

    Hi Christophe,

    Is there any limitation on the amount of datasets you can cache offline? I am working on a rather large AIR/LCDS/Flex/ColdFusion application and the offline caching seems to work fine when using one dataset but if I enable the others I get one of two errors…

    Error 1:

    Database must be connected to perform this operation

    Error 2:

    Nested transactions are not supported

    The application runs fine and super-fast when I disable saveToCache on my DataService objects but fails when I enable it.

    ANY help would be greatly appreciated.

  • Pingback: Solution Hacker » Adobe Air with SQLite database()

  • Is this possible using Coldfusion 8 alone (From what I understand LiveCycle Data Services is integrated in Coldfusion 8) ? Thanks in advance

  • This is realy. The application runs fine and super-fast when I disable saveToCache on my DataService objects but fails when I enable it.

  • There’s good info here. I did a search on the topic and found most people will agree with your blog. Keep up the good work mate!

  • how are you baby melisa

  • that is a awesome tool

  • that is a awesome tool

  • that is a awesome tool, thank you.

  • good post admin, thank you very much

  • Can I use this progoram with my MySQL database? If so, how can I set it? Thank you so much anyone. This is a super cool program.

    I would also like to know.

  • Is there any way to do similar application without write any server side Java code? Thank you for your entry.

  • Abhishek D.V.

    Mr. Coenraets,

    I am thinking of implementing your application, but I don’t have LiveCycle DS 2.6. Instead, I am using LCDS 2.5. Will this pose any problem? That is, will I have to make any modifications to the code and/or settings or will the application work fine with LCDS 2.5?

  • I am thinking of implementing your application, but I don’t have LiveCycle DS 2.6. Instead, I am using LCDS 2.5. Will this pose any problem? That is, will I have to make any modifications to the code and/or settings or will the application work fine with LCDS 2.5?

  • that is a awesome tool.

  • Top Sehr Gut…………..

  • Well done and good luck with your very great work thanks

  • thanks for information

  • very good contributing very helpful thank you.

  • thanx so much

  • thanx so much

  • mohsin

    is it possible using lcds can we store the data to mysql

  • Thank you, I´ve tried Piwik and it worked very good!

  • Thank you, I´
    ve tried Piwik and it worked very good! super dancke

  • güzel bilgiler.

  • Auto Trader compares over 400 car insurance prices
    to find you the right policy.

  • A farm is a place of growing, nurturing, life, hope and peace. and A farm can be a destination location, a place of sharing and learning for those wishing to experience a touch yesteryear in the rural whether it be for an hour or two, or an entire day

  • The Debian Free Software Guidelines

  • Thank You for the Automatic Offline Data Synchronization Quick Tour.

  • Paylasdigin icin tesekkürler ederim !

  • As an independent financial adviser, broker or agent, you want to ensure that your clients are getting the best international private medical insurance to suit their needs.

  • very good, thanx

  • Whoa that is strange. I merely wrote an really extensive comment but when i pressed send my thoughts did not show up. Nevermind I am certainly not writing that all over again. Anyhow, I only wanted to speak about your wonderful site!

  • Pingback: Integration with two database – Transfer of data between two database » free icons download()

  • Pingback: Article: AIR Data Synchronization via LiveCycle Data Services ES 2.6 | John C. Bland II()

  • Samba Siva Reddy

    Can any one help me providing full set of LCDS Data Sync Example!..

  • raf

    Hey Chris, this is definitely a great idea!

  • kaliteli,seri üretim ve uygun fiyatlarda burda.

css.php