This presentation provides an introduction to API Facade pattern. It describes what the problem is, how the pattern solves the problem and how such a pattern can be utilized in real deployments.

1. API Façade Pattern
Prepared by @nabeelxy
9/2/2014

2. Furniture showroom - warehouse
Facade

3. Façade Patten in OOP
(Source:
http://en.wikipedia.org/wiki/Facade_pattern)

4. API Façade Pattern
 It provides a simple interface to a complex system
 Most enterprise software/services are stable and
provide a dependable service, but they are
difficult to expose to web using protocols such as
HTTP.
 More and more apps are relying on such
enterprise services
 This pattern allows to expose such enterprise
services as APIs to app developers
 Still confused what it does for you? Next few
slides illustrate the pattern.

5. Problem
 Imagine that you are an app developer. You are
writing personalized weather app, called
MyWeather, where you automatically get the
location from Google maps (service 1), feed it to
weather channel service (service 2) and maintain
a profile for user at another third-party service
called myprofile (service 3). How do you about
designing and implementing your app?
MyWeath
er
Service 2
Service 1
End users Service 3

6. Direct Connection to Complex
Systems
do_op() do_op()
Client 1 Client 2
(1) op1
(2) op2 (3) op3
System 1 System 2 System 3

7. Direct Connection to Complex
Systems
 Clients needs to deal with
 Multiple network connections
 Initialization of multiple security/API contexts
 Different message formats from each system
 How can we avoid multiple connections from
clients and make the client app development less
painful?

8. API Façade Pattern
Client 1 Client 2
do_op() do_op()
(1) op1
API Layer
(2) op2
(3) op3
System 1 System 2 System 3

9. API Façade Pattern
 One connection, one security/API context, one
message format for client
 Further:
 Allows to perform centralized validation
 Allows to control message content and flow
 Ability to provide value added services such as
monitoring, logging, throttling, etc.

10. Three Step Process
(1) Design API
(2) Implement the design with data stubs (Façade)
(3) Mediation between Façade and
legacy/complex systems

11. A Practical Solution
Client 1 Client 2
API Gateway
Enterprise Service Bus
System 1 System 2 System 3

12. References
 eBook: API Façade Pattern, Brian Mulloy
 http://en.wikipedia.org/wiki/Facade_pattern
 My blog:
http://mohamednabeel.blogspot.com/2014/09/api-facade-
pattern.html