Transcript Powerpoint - 405kb - The Michigan Flex Users Group

Flex Data Communications
Nick Kwiatkowski, Michigan State
University
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 -> View -> Controller
– Your data tier doesn't have to be local!
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
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
HTTPService
• How it is used:
– Place the HTTPService tag at the application
or component level (root level) of your current
MXML document.
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.
Web-Services
• SOAP or Web-Services can easily be
called using the <mx:WebService>
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.
Web-Services
• How it is used:
– Place the <mx:WebService> tag at the root
level of the document (application or
component) that you are working on.
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
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
Web-Services
• Passing Parameters:
– You CAN use binding statements within your
parameters (to bind to user’s input, for
example)
– Webservices are Case Sensitive, so make
sure that your parameters match case
• Some application servers, such as ColdFusion
don’t care about case-sensitivity
• Watch out with ColdFusion, because it transforms
all cases to Uppercase when transmitting data!
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**
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.
AMF
• What your need:
– You need to get a copy of services-config.xml
from your environment.
• ColdFusion this is your <webroot>/WEB-INF/flex/
• JRun this is <webroot>/<ear file>/WEB-INF/flex/
– If you do not develop your applications locally,
you need to modify this file.
• Copy the ColdFusion destination section and mycfamf sections to meet your needs.
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.
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 servicesconfig.xml file
• Source = If using ColdFusion, this the path to the
CFC, in dot notation
Advanced Communication
• By customizing the services-config.xml
file, you can also enable some advanced
communication
– By using the <mx:Producer> and
<mx:Consumer> 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.
ColdFusion Demo
What is it, and how is it used with
Flex.
ASP.NET Demo
What is it, and how is it used with
Flex?
PHP Demo
What is it, and how is it used with
Flex?
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.
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 unused unless you are
using the Multi-Server
version of ColdFusion
ColdFusion and Flex
• Open the “RDS Dataview” tab by going to
Window -> Show View -> Other ->
Coldfusion -> RDS Dataview
• You will then be shown all the Data
Sources available to Coldfusion. You can
browse the data, too!
• Double-Click to launch the
query browser.
ColdFusion and Flex
• Right click on a table to template out CFCs
for your Flex apps
• Demo!
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
Where to find more info
• Adobe Flex 2: Training from the source
– Jeff Tapper, et al
Questions?