1. Sarge Sr. Technical Support Engineer Adobe Systems
Building High-performing Applications using Asynchronous Gateways - 201
Sarge
Sr. Technical Support Engineer
Adobe Systems
CFUNITED – The premier ColdFusion conference

2. Introduction Sarge (sarge@adobe.com)
“The Man, The Myth, The Legend”
Native Son
Started with Allaire in March 2000
Allaire Consulting
Macromedia Product Support
Currently Adobe Gold Support
CF Experience
Started with 2.0
Build global CF site for integration with DOD PKI
Contributed to a couple books and magazines
June 28th – July 1st 2006

3. Agenda What’s covered (and what’s not) What is Asynchrony?
Event Gateway Primer
CF Asynchronous Gateway
Examples
Damon Cooper’s Threading
Case Studies
June 28th – July 1st 2006

4. What’s Covered (and what’s not)
Asynchronous programming in CF
CF Event Gateway Primer
CF Asynchronous gateway
Not Covered
Ajax, CFAjax, etc.
Flex, Flash Remoting, etc.
.NET Asynchronous Programming Models
June 28th – July 1st 2006

5. What is Asynchrony? State of being unsynchronized
Non-blocking, parallel requests
Requests run simultaneously
“Concurrent multi-tasking”
June 28th – July 1st 2006

6. What is Asynchrony? (cont’d)
Benefits: Increased application response
Does not always mean “no refresh”
Performing multiple tasks within the same interface
Better scaling applications
Drawback: Programming shift
Gets away from traditional request/response paradigm
Requires additional threads
Not suitable for all occasions/circumstances
June 28th – July 1st 2006

7. Asynchronous Programming
Most applications are synchronous
Procedural and object oriented designs
Multiple tasks are performed sequentially
Each task has to wait for running task to complete
Easier to maintain state/connection
Tasks can provide feedback within the request
Asynchronous applications can perform multiple tasks within a single request, concurrently
Tasks are performed in parallel
Tasks are autonomous
Asynchronous tasks may provide feedback to originating requests
June 28th – July 1st 2006

8. Synchronous Example: threadsynch_serial.cfm
Damon Cooper’s code that creates 100 copies of a file
Loops over <cffile>
Includes 200ms sleep time
Demonstrates typical synchronous application logic
Multiple tasks in single template request
Tasks execute/complete sequentially
~26 sec execution time
June 28th – July 1st 2006

9. Sandals.com: Asynchronous Lookups
Travel site featuring Sandals resort + travel booking
Internal web service (CF) for air and land travel availability
Synchronous Model
User submits form
CF calls land web service (~4 secs) then calls air web service (~12-20 secs)
Typically +30 secs avg response time
Simultaneous Request hog!
Asynchronous Model
User submits form
Java polling services (5 secs) queries both land and air web services and saves results as WDDX in single DB row
~15 sec total response time
Separating functionality increases stability and responsiveness
June 28th – July 1st 2006

10. Event Gateway Primer
Available with ColdFusion MX 7 Enterprise (and Developer*)
Allows non-HTTP communication with CF
Written in Java
Extensible API
Ships with several types
Asynchronous CFML, SMS, SAMETIME, and XMPP
Example types: Directory Watcher, JMS, TCP Sockets, etc.
Third-party gateways available (e.g.
June 28th – July 1st 2006

11. Event Gateway Primer (cont’d)
Configurable via CF Administrator
Register gateway types
Start and stop gateway instances
Configure thread and queue sizes
June 28th – July 1st 2006

12. Event Gateway Primer (cont’d)
CF Event Gateway Architecture
Event Gateway Subsystem
Threads, queue, logging, etc.
Configuration files
Listener CFCs
All the power of ColdFusion Components
Specific methods for gateway types – e.g. onIncomingMessage, onAddBuddyRequest
CFEvent structure
Properties: gatewayID, data, originator, gatewayType
Application types:
Initiator/Generator
Responder
June 28th – July 1st 2006

13. Event Gateway Architecture
Message
Generator/Receiver
SMSC Server
IM Provider
Etc.
Listener
CFC CF
Event
Gateway
Services
Event
CFEvent
CFEvent
Listener
CFC or
CFM Page
Event
CFEvent
Message
<CFML>
June 28th – July 1st 2006

14. CFUNITED: Event Gateway Sessions
Event Gateways in CFMX 7 – Jeff Tapper
June 28th – July 1st 2006

15. Asynchronous CFML Gateway
CF Event Gateway type that provides asynchronous calls to CFC methods
Allows your code to call CFC methods and continue processing without waiting for them to complete or return (data/error)
Useful for tasks not requiring user interaction
Batch processing ( ers, site maintenance, report generation, etc.)
Logging
Verity Indexing (be very careful)
Can be combined with any other Gateway type
Provides flexibility and fosters innovation
Does not return feedback to calling thread
sendGatewayMessage() actually returns a queued status message – True | False
See Sean Corfield’s blog posting on Concurrency:
June 28th – July 1st 2006

16. Calling the Asynch CFML Gateway
Create CFC with onIncomingMessage method
Required: CFEvent argument that accepts a struct
Register CFC as a CFML gateway type
Provide a unique ID, the path to the CFC, and a startup mode.
Configuration file is not needed
Start the gateway instance
Remember to do this step!
June 28th – July 1st 2006

17. Calling the Asynch CFML Gateway
Code CFML to call the gateway instance
Use sendGatewayMessage(gatewayID, data) to pass message structure to the CFC’s CFEvent argument
gatewayID – Gateway ID registered in CF Admin
data – structure containing the message
Optional fields in data structure: cfcpath, method, originatorID, and timeout
June 28th – July 1st 2006

18. Asynchronous Example: threadsynch.cfm
Damon Cooper’s code that creates 100 copies of a file
Loops over sendGatewayMessage() call
doWork.cfc does the file copy
Includes 200ms sleep time
Demonstrates power of asynchronous programming
Multiple tasks in single template request
Tasks execute/complete in parallel
Processing returns to requested template while tasks complete
Tasks queue while waiting for available thread to run
~2sec execution time
June 28th – July 1st 2006

19. Asynch CFML vs. Scheduled Tasks
Asynchronous CFML
Called via CF Event Gateway
Utilizes CF Event Gateway thread pool
Requires sendGatewayMessage()
Does not provide user feedback
Hard to debug
Use <cflog> and eventgateway.log
Truly asynchronous
Returns processing to running template
Scheduled Tasks
Schedule in CF Admin or CFML
Uses Simultaneous Requests
Requires no user interaction
Does not provide user feedback
Easier to debug
Can fire Asynch CFML calls
Pseudo-asynchronous
June 28th – July 1st 2006

20. Interactive Sites: Batch Processing
Builds premier sites for hotel industry (e.g. The Golden Nugget)
HotelBook.com
Features advanced caching mechanism to increase responsiveness
Custom API for generating/populating cache of hotels
Synchronous Model
Loop over individual hotels adding properties to cache
Single hotel per iteration
Verifies hotel’s existence in cache
Single request thread model typically taking +6 hours on live site
Asynchronous Model
Uses CF Asynch Gateway to simultaneously cache multiple hotels
Typically takes 45 minutes on live site
Decreased available Event Gateway Threads for stability
June 28th – July 1st 2006

21. Sports MatchMaker: Logging
SportsMatchmaker.org (in Beta)
Premier sports match making site
Converted from CF 5.0 to CFMX 7/Flex 2
Synchronous Model
Error messages logged to file using cffile and to DB
Uses custom IM and system to notify admins
Can quickly lock up site if underlying systems fail (file system, , DB, etc.)
Asynchronous Model
Uses sendGatewayMessage() to send cfcatch struct
Now uses structured error handling – including <cflog>
Integrates with other Event Gateway types for admin notification (e.g. XMPP and er)
June 28th – July 1st 2006

22. Asynchronous Programming: Advantages/Disadvantages
Allows tasks to run concurrently within a single request
Tasks run autonomously
Long running requests no longer cause increased response times
Disadvantages
Not suitable for all applications
High user interactivity
Security models
Hard to debug
Overuse can cause server bottleneck
June 28th – July 1st 2006

23. Resources Tom Jordahl Damon Cooper
Taking Advantage of ColdFusion MX 7 Event Gateways
Writing and Using Event Gateways in ColdFusion MX 7
Damon Cooper
Matt Woodward (
“The Asynchronous CFML Gateway”
LiveDocs:
Thanks to Sandles, Interactive Sites, and SMM
June 28th – July 1st 2006

24. June 28th – July 1st 2006