rest - representational state transfer (emc brdc internal tech talk)

Representational State

Transfer

Rodrigo D. A. Senra EMC BRDC TechTalk

Overview• Roy Fielding’s Vision

• ReST = URI + HTTP + Hypermedia

• API Design

• Success Stories

• Q & A

ReST for a minuteWhat: Representational State Transfer (REST) architectural style

Who: Roy Thomas Fielding

When: 2000

Where: Chapter 5, Ph.D. dissertation: “Architectural Styles and the Design of Network-based Software Architectures”

Why: need for blueprints to guide the design and development of the architecture for the modern Web

• scalable component interactions• general and uniform interfaces• self-descriptive representations• independent deployable components• reduced interaction latency • enforced security• able to encapsulate legacy systems

How: HTTP + URI + (Client Pull - Resolver - [Cache] - Stateless [Tunnel] - Server ) = ULCODC$SS

Patterns• (Uniform) Pipe and Filters

• Replicated Repository

• Cache$

• Client Server

• Layered Systems

• Remote Session

• Remote Data Access

• Mobile Code Styles

• Virtual Machine

• Remote Evaluation

• Code on Demand

• Mobile Agent

• Event-based Integration

• (Brokered) Distributed Objects

from Roy Fielding’s Dissertation

Evaluation Criteria

• modifiability• evolvability• extensibility• customizability• configurability• reusability

• simplicity • scalability• portability• reliability• visibility

Connectors != Componentsfrom A Guide to REST and API Design

Solve problems

in unique ways

public and standardized


from A Guide to REST and API Design

Data StructureData Element Examples

resource conceptual target of a hypertext reference

resource identifier URI (URN or URL)

resource metadata source link, alternates, vary, …

representation HTML, XML, JSON, JPG,…

representation metadata media-type, last-modified,…

control data if-modified-since, cache-control,…

$ curl -i -X HEAD http://stackoverflow.com/questions/4913343/what-is-the-difference-between-uri-url-and-urn

HTTP/1.1 200 OK

Cache-Control: public, no-cache="Set-Cookie", max-age=60

Content-Length: 92646

Content-Type: text/html; charset=utf-8

Expires: Thu, 12 Mar 2015 23:42:26 GMT

Last-Modified: Thu, 12 Mar 2015 23:41:26 GMT

Vary: *

X-Frame-Options: SAMEORIGIN

X-Request-Guid: 8f94e452-513b-43fb-958d-5de2aa67a557

Set-Cookie: prov=aa08df12-afe7-4073-928f-a09504693cc5; domain=.stackoverflow.com;

http://stackoverflow.com

7 Steps to API design1.List all data elements clients might need

2.Draw state diagrams (actions)

3.Reconcile Magic Strings (schema.org, DC, FOAF,…)

4.Select Media-types (html, xml, json, csv, hdf5,…)

5.Create a semantic profile (WSDL, WADL, APP, RAML, Swagger,/ALPS,Json-LD, Json-Schema Hydra)

6. Write the code

7.Publish the API

from A Web API Design Methodology - Mike Amundsen

http://schema.org

Some RESTful APIs• Amazon S3

• Google DoubleClick Ad Exchange Buyer

• Google YouTube

• Twitter

• Twilio Voice and SMS

• Netflix API (2014/11)

• Facebook Graph

• EMC Isilon OneFS

Isilon REST API ExampleThe following request creates an access point named 'accesspoint1' on the namespace.

PUT /namespace/accesspoint1 HTTP/1.1 Host my_cluster:8080 Date: Fri, 15 Mar 2013 21:51:50 GMT Content-Type: text/xml

{ "path": “/ifs/home/" } Example response

HTTP/1.1 200 OK Date: Fri, 15 Mar 2013 21:51:50 GMT Server: Apache/2.2.21 (FreeBSD) mod_ssl/2.2.21 OpenSSL/0.9.8x Allow: DELETE, GET, HEAD, POST, PUT, OPTIONS x-isi-ifs-spec-version: 1.0 Vary: Accept-Encoding Content-Encoding: gzip Keep-Alive: timeout=15, max=335 Connection: Keep-Alive Transfer-Encoding: chunked Content-Type: text/plain

Facebook Graph API - https://developers.facebook.com/tools/explorer

The Graph API is the primary way to get data in and out of Facebook's platform. It's a low-level HTTP-based API that you can use to query data, post new stories, manage ads, upload photos and a variety of other tasks that an app might need to do

Brainiak is …

• 100% Python• API RESTful • Hypermedia (HATEOAS)

• Json-schema ☜☞ RDF

Architecture

Legacy Virtuosos

Solr

Bus

Replicator

Authentication & AuthorizationBackstage

Eureka VoceDaNota A-Z Sitemaps CMAaS

Brainiak

ElasticSearch

Architecture

Query SPARQL

select ?id ?nomefrom esportes:where {

?id rdf:type esportes:Equipe . ?id rdfs:label ?nome .}

/esportes/Equipe

Brainiak API

GET

Response{ "items": [ { "title": "Atlético-MG", "@id": "http://semantica.globo.com/esportes/equipe/282", "class_prefix": "esportes", "resource_id": "282" }, { "title": "Bahia de Feira", "@id": "http://semantica.globo.com/esportes/equipe/2590", "class_prefix": "esportes", "resource_id": "2590" }[ ], "@id": "esportes:Equipe"}

Schema{ "links": [ { "href": "/esportes/Equipe/_schema?class_prefix=http://semantica.globo.com/esportes/", "method": "GET", "rel": "class" }, { "href": "/esportes/Equipe?class_prefix=http://semantica.globo.com/esportes/", "method": "POST", "rel": "create", "schema": {"$ref": "{+_base_url}"} }, { "href": "/_/_/_?instance_uri={value}", "method": "GET", "rel": "relatedInstance" },…

/esportes/Equipe/_schema

Hyper-map

Business Perspective

from eMag Web APIs from Start to Finish

"As a result of Data Enabled Disruption, many of Amazon’s former competitors are now dead. By utilizing APIs at all points of the data lifecycle, Amazon is able to continuously improve the accuracy, applicability, and accessibility of its data. "

Jeff BezosAs Yegge's recalls that one day Jeff Bezos issued a mandate, sometime back around 2002 (give or take a year):

All teams will henceforth expose their data and functionality through service interfaces. Teams must communicate with each other through these interfaces. There will be no other form of inter-process communication allowed: no direct linking, no direct reads of another team’s data store, no shared-memory model, no back-doors whatsoever.

The only communication allowed is via service interface calls over the network.

It doesn’t matter what technology they use.

All service interfaces, without exception, must be designed from the ground up to be externalizable. That is to say, the team must plan and design to be able to expose the interface to developers in the outside world. No exceptions.

Anyone who doesn’t do this will be fired. Thank you; have a nice day!

from http://apievangelist.com/2012/01/12/the-secret-to-amazons-success-internal-apis/

http://apievangelist.com/2012/01/12/the-secret-to-amazons-success-internal-apis/

References

REST API Design Rulebook Mark Masse (2011)

RESTful Web APIs Leonard Richardson and Mike Amundsen (2013)

REST APIs must be hypertext- driven Roy T. Fielding: Untangled (2008)

RESTful Web Services Leonard Richardson and Sam Ruby (2008)

HTTP Developer’s Handbook Chris Shiflett (2003)

RESTful Web Services Cookbook Subbu Allamaraju (2010)

Building Hypermedia APIs with HTML5 and NodeMike Amundsen (2011)

Thank you.

Rodrigo Dias Arruda Senra

[email protected]

http://rodrigo.senra.nom.br @rodsenra

mailto:[email protected]

http://rodrigo.senra.nom.br

rest - representational state transfer (emc brdc internal tech talk)

Technology