SlideShare verwendet Cookies, um die Funktionalität und Leistungsfähigkeit der Webseite zu verbessern und Ihnen relevante Werbung bereitzustellen. Wenn Sie diese Webseite weiter besuchen, erklären Sie sich mit der Verwendung von Cookies auf dieser Seite einverstanden. Lesen Sie bitte unsere Nutzervereinbarung und die Datenschutzrichtlinie.
SlideShare verwendet Cookies, um die Funktionalität und Leistungsfähigkeit der Webseite zu verbessern und Ihnen relevante Werbung bereitzustellen. Wenn Sie diese Webseite weiter besuchen, erklären Sie sich mit der Verwendung von Cookies auf dieser Seite einverstanden. Lesen Sie bitte unsere unsere Datenschutzrichtlinie und die Nutzervereinbarung.
Part1:~ Api$ Evolution_
• Compile time libraries for a specific language
• Language independent, platform specific, run-time local libraries (e.g. DLL’s
• Platform independent, language independent, run-time, non-local libraries
• HTTP-REST, everything on the internet can connect, language independent,
run-time, internet libraries
Same name for many things.
Part1:~ Api$ What are REST-API’s?_
• Strictly spoken a REST-API is just an interface, a specification: it hides ‘an
implementation’ and standardizes its usage and connectivity
• Pragmatically spoken a REST-API is a library (of functionality) connected
• They are the servers in a client-server model
• These libraries can be built in every programming language
• These libraries can contain any type of functionality: financial services, mail-
service, math, AI, sensor/attenuator, etc.
REST-API’s are the building blocks of the IoT.
REST-API’s can contain (encapsulate) any type of technology.
• Software programs
• Human operators etc.
• Connections to other API’s or systems
Part1:~ Api$ Implementation_
What is inside? How are they implemented?
Everything on the internet can connect to a REST-API:
• Other API’s
• Server applications
• Web applications and web front ends (built with frameworks like AngularJS,
• Mobile app’s, applications etc.
Part1:~ Api$ Users_
What is connected? Who are the run-time users?
Part1:~ Api$ API catalogs_
There is an API for everything.
Part2:~ Enterprise$ Business perspective_
• The REST-API unlocks new markets and types of customers (machines)
• The REST-API enables new business models
• The right REST-API can transform the enterprise into a IoT platform, the
realm of exponential growth
• It is the universal channel upon which all other channels can be built
What use is a REST-API to the business? It is Product!
Part2:~ Enterprise$ Architects perspective_
• Primary enabler of the digital enterprise
• The REST-API is (should be) the primary unit of modularity of the
enterprise, internally as well as to external clients
• REST-API’s are building blocks that are integrated/combined into business
processes with tools like BPM and apps
• REST-API’s promote autonomy of underlying systems. They also separates
UI/process from basic data manipulation
What is a REST-API to the architect? Modularity!
Part2:~ Enterprise$ Programmers perspective_
• For the programmer that uses an REST-API, it’s just another code-library.
Most API’s come with a language specific ‘wrapper’ that hides the API itself.
To this programmer it no longer makes a difference whether it is REST or
SOAP, or JSON or XML etc.
What is an API to the consuming programmer?
Part2:~ Enterprise$ Programmers perspective_
• The programmer that creates an API needs a suitable framework. Typically
NOT the same frameworks that are used for traditional web-design.
• API-design is NOT web-design, it’s ‘traditional’ application-design.
• The API-developer does not need visual design or visual UI skills.
• He does need good ‘interface designer’ skills, which means he needs to be
able to switch from his role as an API-creator into that of an API-user.
What is an API to the producing programmer? Deliverable!
Part2:~ Enterprise$ Team perspective_
• Ideally teams are formed around API’s, the operation of the API is their
‘deliverable’, not the API itself.
• Ideally (agile) teams are multidisciplinary: BizDevOps they not only
develop but also run and support the API
• Ideally all teams have an API / interface designer role
• Teams MUST have autonomy in managing their API’s
What is a REST-API’s to the team? Tool!
Part2:~ Enterprise$ Technology landscape_
• HTTP. The basic communication protocol of the web and thus the
• CORBA. Distributed objects, synchronous inter-process communication
(legacy, deprecated). ‘The enterprise as one big application’
• MQ. Message Queue. Asynchronous, loosely coupled, event-driven inter-
process communication based on message-broadcasts and message-loops
• ESB. Enterprise Service Bus, client-server model, SOA-architecture,
facilitates REST, SOAP -> ‘the enterprise as one big collection of services’
• BPM and MDM. Bussiness process and master data management. Tools
that integrate services into processes
• Streaming data. Simple queueing service, ‘fast data’, real-time, scalable.
• Gateway. ‘The switch board’. Does filtering, authentication, integration,
scaling etc. mostly used in combination / integrated with an ESB
• Web API. An HTTP library, RPC-like, point-to-point. The server in a client-
Gluing an enterprise together.
Part2:~ Enterprise$ REST-API’s and functions_
REST-API’s generally map/represent functions, as in a functional decomposition.
• REST-API’s are designed outside-in, based on client perspective (clients
can be internal)
• Ideally REST-API’s are designed before they are implemented and endpoint
tests should be coded before the REST-API is implemented (test-driven
• REST-API implementations are not based on extensive architectures,
patterns or layering, as integration is typically done in clients (BPM tools,
apps, etc.) REST-API’s are typically very simple internally
• Consider implementing a REST-API as a (set of) microservices
• The goal should be to have only open REST-API’s / every REST-API should
Part2:~ Enterprise$ Implementation_
Some design and implementation guidelines
Part2:~ Enterprise$ Connecting_
• API gateway is the central hub (routing, authentication, translation, etc.)
• Ideally all internal clients consume API’s (also the external API’s)
through the API gateway
• Customer API’s are exposed only through the API-gateway
• API management is the publication and administration tool for teams
• Internal vs. external / customer facing
• Lifecycle management
• Integration and remixing of API’s
• Access management
• API keys / customer tracking
Part2:~ Enterprise$ Api management_
REST-API’s are more than just deliverable
REST is HTTP/1.1. It is the native protocol of the web. Advantages are:
• Every tool that can handle HTTP, can handle REST as native ‘content’. For
instance gateways, web-servers and browsers can effectively cache, route,
verify, manipulate REST requests or responses.
• In short the whole web supports REST by nature
• It is simple and elegant
• Less diversity in technology, you already use HTTP
See also the dissertation of Roy Fielding:
Part3:~ Rest$ WHY REST?_
REST ís HTTP. It is the same protocol. Created by the same designer: Roy Fielding.
Part3:~ Rest$ SOAP vs REST_
• REST is URL-based, SOAP is procedure-based
• REST is not only a protocol, it is also an architectural style (HTTP is the
• REST is much simpler, less strict, can use any data format, any
• REST is transport-bound (HTTP), SOAP can be used with any transport
protocol (even SMTP for instance, or REST)
• REST is more scalable, more efficient, client-side cacheable, etc.
See also: https://www.quora.com/What-is-the-difference-between-a-SOAP-
Part3:~ Rest$ PROTOCOL_
HTTP is a plain text conversation between
a client and a server. The conversation is
based on actions performed on resources
which are addressed by URL’s.
Part3:~ Rest$ ENDPOINTS_
The REST protocol is based on ‘endpoints’, which are
operations on resources addressed by URL’s.
Endpoints can be bundled to form an API.
GET https://animal.api/1/lions (returns collection)
GET https://email@example.com (returns single lion)
POST https://animal.api/1/lions (create new element)
PUT https://firstname.lastname@example.org (updates element)
PATCH https://email@example.com (partial update)
DELETE https://animal.api/1/lions (deletes collection)
DELETE https://firstname.lastname@example.org (deletes single element)
GET https://animal.api/1/lions?id=100&id=103&id=107 (array)
Part3:~ Rest$ ACTION + RESOURCE_
An endpoint has a very strict URL structure. This is key to
‘REST’. Map your functional application resources onto the WWW
and allow them to be manipulated.
Part1:~ Api$ Maslov’s API_
Good API, bad API, first things first!