Api chaining(tm)

RestFest 2017
orubel@gmail.comOwen Rubel
API Chaining™
& API Abstraction

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What is API Chaining™?
“ API Chaining is a monad allowing a series of api
calls to be passed and processed using one
REQUEST/RESPONSE.”

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• Abstraction of Communication Logic/Data from Biz Logic
• Internal Redirect Handling in API Service
• Separated Communication Data from Communication Logic
Requirements for API Chaining™

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Understanding API Abstraction

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“ An API is Standardized Input/Output (I/O) to/from
a Separation of Concern (usually being Business
Logic).”
In Short :
What Is An API? (1 OF 2)

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What Is An API? (2 OF 2)
owenr@uw.edu

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What Is Separation of Concern? (2 of 2)
Bound Secondary
Concern
(Communication
Logic)
Primary
Concern
(Business Logic)

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“ In computer science, separation of concerns (SoC) is a
design principle for separating a computer program
into distinct sections, such that each section addresses
a separate concern. A concern is a set of information that
affects the code of a computer program” (ex HTML, CSS,
JS)
- Source : Separation Of Concern, Wikipedia
What Is Separation of Concern?

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API Pattern in Distributed Architecture

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“Cross-cutting concerns can be directly responsible for tangling,
or system inter-dependencies, within a program. Because
procedural and functional language constructs consist entirely of
procedure calling, there is no semantic through where two
goals (the capability to be implemented and the related cross-
cutting concern) can be addressed simultaneously.[3] As a
result, the code addressing the cross-cutting concern must be
scattered, or duplicated, across the various related locations,
resulting in a loss of modularity.[2]”
- Source : Cross Cutting Concern, Wikipedia
What is a Cross Cutting Concern?

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• Synchronization
• Real-time constraints
• Error detection and correction
• Product features
• Memory management
• Data validation
• Persistence
• Transaction processing
• Internationalization and localization which includes
Language localisation
• Information security
• Caching
• Logging
• Monitoring
• Business rules
• Code mobility
• Domain-speciﬁc optimizations
Issues of a Cross Cutting Concern

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This is The API Patterns Brick Wall
Brick Wall

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So How Do We Fix?

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Old API Pattern in MVC
redirect/response

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New API Pattern in MVC

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Shared I/O State In Distributed Architecture

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This handles the Redirect and allows
communication to take place internally when
needed…

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This allows:
• Central Piece of architecture (where REQUEST AND RESPONSE
are handled) to be ‘Single Version of Truth’ (SOV) called ‘IO State’
• All services can sync data from SOV
• Failure of SOV DOES NOT affect synchronization of data
• Reload state on the ﬂy at SOV and update ALL subscribed services
Shared IO State

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So What Is IO State?

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What is IO State?
• Caches Communications Data
• Synchronizes Architectural Props (distribute rules of communication)
• Handles API Authorizations (access for communication)
• Api Docs Deﬁnitions (how to communicate)
I/O State is data directly related to a request/response, normally
separated from functionality. Handles all data associated with
communication and communication access

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What Does IO State Contain
•Data specifically related to I/O (request/response); not data related to
function (ie, errors, how to process, etc).all the data contained in
annotations act as rules associated with the URI endpoint (not URL or
the FQDN)
•by containing all those rules in one file and caching that data, we can
share it with the other architectural components (and abstract data from
functionality)
•this enables us to change it on the fly and reload without having to
restart any services allowing subscribed services to get changes
pushed to them through web hooks

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I/O State : Communications Properties
Shared I/O State is ‘IO State’ data unbound from
functionality so that it can be shared across architectural
components. This is the approach used by distributed
architectures.
Bound I/O State is ‘I/O State’ data bound to functionality
which cannot be shared or synchronized with additional
architectural components creating an ‘architectural cross
cutting concern’. This is commonly found in centralized
architectures.

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Shared I/O State
• DOESN’T bind to the application
• DOESN’T bind to functionality
• DOESN’T bind to a resource

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What Does It Look Like?
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https://gist.github.com/orubel/7c4d0290c7b8896667a3

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• RAML, OpenAPI, Swagger, API BluePrint
• not role based; endpoints need to be checked via token roles
• limited to CRUD-based REST of 4 calls per class
• duplicitous; lack of separation
• Confuses API data with functionality

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• Dramatic Code reduction By Reducing Duplication
• Automation of nearly all aspects of API
• 0% downtime for changes to endpoint data and rules
• New API Patterns (ie API Chaining (tm) )
What Does It Improve?

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Code Reduction (1 of 2)
Controller : Mixed Concerns (Duplication)
@Secured(['ROLE_ADMIN', ‘ROLE_USER'])
@RequestMapping(value="/create", method=RequestMethod.POST)
@ResponseBody
public ModelAndView createAddress(){
List authorities = springSecurityService.getPrincipal().getAuthorities()
User user
if(authorities.contains(‘ROLE_ADMIN’)){
if(params.id){
user = User.get(params.id.toLong())
}else{
render(status:HttpServletResponse.SC_BAD_REQUEST)
}
}else if(authorities.contains(‘ROLE_USER’)){
user = User.get(principal.id)
}
Address address = new Address(params)
…
address.user = user
…

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Code Reduction (2 of 2)
Controller : Single Concern
public ModelAndView createAddress(){
User user= (params.id)?User.get(params.id.toLong()): User.get(principal.id)
Address address = new Address(params)
address.user = user
…
}

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This allows for new Patterns like
API Chaining™…

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• Post Chain
• GET > GET > (PUT/POST/DELETE)
• Pre Chain
• (PUT/POST/DELETE) > GET > GET
• Blank Chain
• GET > GET > GET
Three types of Chains

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What data is sent for a chain
API Chain Data
{
<put/post data (if applicable)>,
chain:{
key:dept_id,
combine:'false',
type:'postchain',
order:{dept/show:company_id,company/update:return}
}
}

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Chain Examples
GET Chain Example
PUT Chain Example
curl -v -i -H "Content-Type: application/json" -H "Authorization: Bearer <token>" --request
PUT -d "
{'testdata':'testamundo','chain':{'key':'sectionId','combine':'false','type':'postchain','order':
{'section/get':'id','section/update':'return'}}}" "http://localhost:8080/c0.1/post/show/1"
curl -v -i -H "Content-Type: application/json" -H "Authorization: Bearer <token>" --request
GET -d "
{'chain':{'key':'Id','combine':'false','type':'blankchain','order':{'postTopic/
showByTopic':'postId','post/show':'return'}}}" "http://localhost:8080/c0.1/topic/show/1"

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More documentation on API Chaining
API Chaining™ Documentation
http://orubel.github.io/Beapi-API-Framework/chain.html

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DEMO

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Questions?
(please contact for business opportunities or hiring)

Api chaining(tm)

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