Flex Data Communications

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Flex Data Communications

• Nick Kwiatkowski, Michigan State University

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Data Communications

• Why communicate?
• Your Flex applications most likely want to have
  fresh data from a database or other webservice
• You may need to send current data to your
  end-users
• Three-Tiered applications
• Data -gt View -gt Controller
• Your data tier doesn't have to be local!

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Data Communication Basics

• Flex currently supports three types of data
  communications with external sources
• XML via HTTP Requests
• SOAP Web-Services
• AMF / Remote Objects
• With this combination, you can virtually talk to
  any back-end server

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HTTPService

• The HTTPService MXML tag allows for the most
  basic communication level between you and a web
  server
• Mostly used for legacy middleware applications
  and static XML documents
• Any application that can generate proper XML on
  the fly can talk to your Flex app using this tag

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HTTPService

• How it is used
• Place the HTTPService tag at the application or
  component level (root level) of your current MXML
  document.

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HTTPService

• Common Parameters
• id Used to name the component
• url The full URL to the component
• result The event function that will be fired
  when the result came back successfully
• The XML document will be stored in the
  event.result object
• fault The event function that will be fired
  when the result did not come back correctly.

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Web-Services

• SOAP or Web-Services can easily be called using
  the ltmxWebServicegt component.
• Web Services allow you to communicate data back
  to the web-server, and retrieve typed objects
  (strings, numbers, arrays, queries)
• Because it is based on XML, it is very verbose,
  and often slow for large sets of data.

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Web-Services

• How it is used
• Place the ltmxWebServicegt tag at the root level
  of the document (application or component) that
  you are working on.

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Web-Services

• Common Parameters
• id Used to name the object
• wsdl Points to the WSDL (Web Service
  Descriptor) file. This file is different for
  each language
• showBusyCursor Changes the current pointer to a
  rotating clock to let the user know something is
  happening

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Web-Services

• Passing parameters
• You can pass parameters to web-services by naming
  operations (methods or functions).
• The operation tag allows for result or fault
  functions

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Web-Services

• Passing Parameters
• You CAN use binding statements within your
  parameters (to bind to users input, for example)
• Webservices are Case Sensitive, so make sure that
  your parameters match case
• Some application servers, such as ColdFusion
  dont care about case-sensitivity
• Watch out with ColdFusion, because it transforms
  all cases to Uppercase when transmitting data!

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AMF

• AMF, or Remote Objects are the most efficient way
  to transmit data between your application server
  and your Flex Application
• Data is transmitted in Binary, so it is fairly
  compressed
• Objects will stay in their native form when
  transmitted
• Very easy to use

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AMF

• So, why NOT use AMF?
• Only ColdFusion, ActionScript and Java are
  supported by Adobe.
• PHP has an open source solution, however.
• Fairly hard to setup your environment
• Requires files to be copied down from your
  development / deployment environment
• Makes a lot of assumptions that can hurt you your
  first time through.

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AMF

• What your need
• You need to get a copy of services-config.xml
  from your environment.
• ColdFusion this is your ltwebrootgt/WEB-INF/flex/
• JRun this is ltwebrootgt/ltear filegt/WEB-INF/flex/
• If you do not develop your applications locally,
  you need to modify this file.
• Copy the ColdFusion destination section and
  my-cfamf sections to meet your needs.

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AMF

• Services-Config?
• This file is compiled into your project and will
  convert the destination portion of your
  RemoteObject call to the tcp/ip hostname and port
  numbers
• Depending on how this file looks, your
  application can be very portable, or not portable
  at all.

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AMF

• How it is used
• Just the same as WebService, but instead of the
  WSDL parameter, you use the destination and
  source parameters
• Destination Destination from the
  services-config.xml file
• Source If using ColdFusion, this the path to
  the CFC, in dot notation

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Advanced Communication

• By customizing the services-config.xml file, you
  can also enable some advanced communication
• By using the ltmxProducergt and ltmxConsumergt
  tags, you can produce content to other
  applications or Coldfusion Event Gateways.
• This allows for Many-to-One or Many-To-Many
  applications with little or no work.

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ColdFusion Demo

• What is it, and how is it used with Flex.

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ASP.NET Demo

• What is it, and how is it used with Flex?

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PHP Demo

• What is it, and how is it used with Flex?

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ColdFusion and Flex

• When using ColdFusion with Flex Builder, there
  are certain wizards available to the developer
  which helps make data communications quicker.
• These need to be installed manually with Flex
  Builder follow the directions in the readme.
• You also need to configure the Data Sources
  within ColdFusion before you can begin.

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ColdFusion and Flex

• Within the Preferences dialog box, go to the RDS
  configuration to setup your connection with
  ColdFusion
• Context Root and User Name are un-used unless you
  are using the Multi-Server version of ColdFusion

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ColdFusion and Flex

• Open the RDS Dataview tab by going to Window -gt
  Show View -gt Other -gt Coldfusion -gt RDS Dataview
• You will then be shown all the Data Sources
  available to Coldfusion. You can browse the
  data, too!
• Double-Click to launch thequery browser.

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ColdFusion and Flex

• Right click on a table to template out CFCs for
  your Flex apps
• Demo!

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Where to find more info

• AMF-PHP Project
• http//www.amfphp.org
• Adobe DevNet
• http//www.adobe.com/devnet/flex/
• Adobe LiveDocs
• http//livedocs.adobe.com/flex/2/
• Community Flex Project
• http//www.cflex.net

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Where to find more info

• Adobe Flex 2 Training from the source
• Jeff Tapper, et al

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Questions?