Hateoas APIs are about relationships

HATEOAS APISMatt Bishop, Product Architect at Elastic Path

@MattBishopL3

Growth of APIs, How Exciting!

www.elasticpath.com @MattBishopL3

http://www.elasticpath.com/

Actually, it’s more like 14,000

1 minute per API = 6 weeks end-to-end



REST beats SOAP, How Exciting!



Growth of Internet Hostnames



What happened in the 90s?

1989 HTML invented (thanks Tim!) 1992 First browsers built 1994 Netscape launched 1995 Internet Explorer in Win95, IIS

bundled in NT, Apache, PHP released



Internet Host Names In A Line



Make a Website, 1995-style

Web sites were coded in:• Java• C / C++• Perl• ColdFusion• Python



Templates Blew the Doors off the Internet

Late 90s Microsoft ASP, Apache JSP, DreamWeaver, Velocity, etc.

Templates opened internet development to the common man

Templates made data BROWSABLE



Templates made data browsable

Made linking easy <asp:HyperLink … <a href=“<%= getLink

(somedata) %>

Easy linking means easy browsability

Drives the Network Effect



APIs are stuck in the 80s

…1987, to be exact (28,174 hosts)

APIs must be browsable before they can be adopted by 100m organizations

100m organizations == your sister’s dress store, my mom’s knitting club



Comfortably Numb

We can stay stuck here if we don’t link our resources together



Links are about Relationships Relationships are hard



Relationships are not hard after all

• Relationships are a fundamental part of being an animal



Relationships make Versionless APIs possible

Relationships are very stable The resources themselves move, but

their relationships do not GET /profiles/id• “addresses”: “/profiles/id/addresses”

? Hmm maybe addresses should be their own resource ?GET /profiles/id• “addresses”: “/addresses”



Relationships make APIs browsable

Browsable APIs == Browsable data == mass adoption

First step is to make it easy to link



Cortex API Engine

Elastic Path’s API endeavors have failed four times 2010 drank the HATEOAS Kool-Aid, reset our API

effort Found no frameworks to help past URI-to-method

mapping and ser/deser We built an engine using some existing

technology (Jax-RS, Spring, Shiro) and our own work

Cortex is an API engine that happens to run commerce



Cortex Design Philosophy

• Small, simple resources written by BAs• Small, simple state changes via controls

• Form• Selector

• “Secret Admirer” rule• All Operations are identified

• REST is the Gestalt, HTTP is a transport



Technology

Hateoas APIs are about relationships