Using CouchDB from Air applications with CouchDB Flex

Andrea Franz — Tue, 03 Nov 2009 14:31:37 +0000

In the last weeks I played a lot with CouchDB and I love it. I always used it from ruby but yesterday I tried to use it with flex. I started a new Actionscript project called CouchDB Flex, you can browse the source from github. The implementation is inspired by couchrest, but it’s asynchronous because I use URLLoader internally. Since the flash player doesn’t support the PUT and DELETE HTTP methods, you must create an AIR project if you want to try the library. You can find a compiled swc here, put it in your libs folder and you are ready to go. Here a small example, but it’s still in development, and a lot of functionality are not implemented yet.

CouchdbFlexExample.mxml: the main mxml file, it’s just a window with a textarea that will display the data loaded from CouchDB.

xml version="1.0" encoding="utf-8"?>
<c:App xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" xmlns:c="com.gravityblast.couchdbflexexample.*">
  <s:TextArea id="textarea" width="100%" height="100%" text="{log}"/>			
c:App>

com/gravityblast/couchdbflexexample/Contact.as: the model I’ll save on CouchDB. By default the model has a name and an email, but I can add more properties since it’s a dynamic class.

package com.gravityblast.couchdbflexexample
{
  import com.gravityblast.couchdb.Document;
 
  public dynamic class Contact extends Document
  {		
    public var name:String;
    public var email:String;
 
    public function Contact()
    {
      super();
    }
  }
}

com/gravityblast/couchdbflexexample/App.as: the main application, where I create a new Contact Document, and I load all the contacts using a view created with the Design and View classes.

package com.gravityblast.couchdbflexexample
{
  import com.gravityblast.couchdb.CouchDb;
  import com.gravityblast.couchdb.Database;
  import com.gravityblast.couchdb.Design;
  import com.gravityblast.couchdb.View;
  import com.gravityblast.couchdb.events.CouchRestEvent;
  import com.gravityblast.couchdb.events.DocumentEvent;
  import com.gravityblast.couchdb.events.ViewEvent;
 
  import mx.events.FlexEvent;
 
  import spark.components.TextArea;
  import spark.components.WindowedApplication;
 
  public class App extends WindowedApplication
  {		
    private var couchdb:CouchDb;
    private var database:Database;
 
    [Bindable]
    public 	var log:String;
    public 	var textarea:TextArea;
 
    public function App()
    {			
      this.couchdb = new CouchDb();
      this.database = this.couchdb.database("couchdb-flex-example");
      this.log = "";
      this.addEventListener(FlexEvent.CREATION_COMPLETE, this.creationCompleteHandler);
      super();
    }
 
    private function creationCompleteHandler(event:FlexEvent):void
    {			
      this.database.create(this.databaseCreateHandler);	
    }
 
    private function databaseCreateHandler(event:CouchRestEvent):void
    {
      trace(event.data);
      if (event.json.ok || event.json.error.toString() == "file_exists")
      {
        var map:String = "function(doc) {if (doc['couchdb-flex-type'] == 'com.gravityblast.couchdbflexexample::Contact') emit(null, doc);}";
        var view:View = new View("all", map);
        var design:Design = new Design("contacts");
        design.addView(view);
        design.save(this.designSaveHandler);	
      }
    }
 
    private function designSaveHandler(event:DocumentEvent):void
    {
      trace(event.data);									
      if (event.json.ok || event.json.error == "conflict")			
        this.createContacts();
      else
        trace("Error saving design document: " + event.data)			
    }
 
    private function createContacts():void
    {
      var contact:Contact = new Contact();
      contact.name    = "jack";
      contact.email   = "jack@example.com";
      contact.address = "Jack Street";
      contact.save(this.contactSaveHandler);			
    }
 
    private function contactSaveHandler(event:DocumentEvent):void
    {			
      trace(event.data);
      var contact:Contact = event.document as Contact;
      contact.address = "Jack Street updated at " + (new Date()).toString();
      contact.save(this.contactUpdateHandler);			
    }
 
    private function contactUpdateHandler(event:DocumentEvent):void
    {			
      trace(event.data);
      View.load("contacts", "all", {}, this.contactsLoadHandler);
    }
 
    private function contactsLoadHandler(event:ViewEvent):void
    {					
      for each (var contact:Contact in event.documents)
      {
        for (var property:String in contact.attributes)
        {
          this.log += property + ": " + contact[property] + "\n";	
        }
        this.log += "-------------\n";
      }
    }
  }
}

I’ll write more about the library as soon as it’s more stable.

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Using CouchDB from Air applications with CouchDB Flex