Give It A Rest(ful) web service

www.opencredo.com

Give it a REST(ful web service)

Russ Miles

Monday, 25 January 2010

© 2009 Open Credo Ltd www.opencredo.com

Agenda

• What do we want from an integration approach?

• A trip through history...• What’s REST?• Why REST?• That’s gotta be difficult to implement...• Summary



First a BIG PLUG!

RESTful Web Services by O’ReillyGo buy this book, now! (Ok, or borrow it off of me)


http://www.opencredo.com



Who the heck is Russ Miles?

• Author and Technical Editor– AspectJ Cookbook– Learning UML 2.0– Head First Software Development

• OpenCredo– CEO– Consultant

• And in other lives...– Search– Mobile– Defence– Open Source





Who the heck is Russ Miles?

• Author and Technical Editor– AspectJ Cookbook– Learning UML 2.0– Head First Software Development

• OpenCredo– MD– Consultant

• And in other lives...

–Search– Mobile– Defence

–Open Source





What do we want from an integration approach?





Some of the things we’ve been promised

• Platform/language/framework agnostic• Scaleable• Evolvable• Secure• Simple (or as simple as possible)• Open Standards



A short (and painful) trip through integration technologies...





IPC

“Look ma! It’s all just pipes...”




mailto:[email protected]



RPC

“Look ma! It’s all just objects!”







IPC/RPC... sucks (between apps/systems)

• Cannot easily evolve• Doesn’t scale to the ‘new’ integration

challenge• Is brittle

– (Stateless? Scalable? I think not...)• Is ‘interesting’ when it comes to multiple

languages/frameworks...• Tries to solve the WRONG problem



Web Services to save the day...

“It’s time to reinvent that wheel boy!”







RPC Web Services sucked

• Framework and Language nuances• Encouraged worst practices• RPC is the essential problem here!



Contract First Web Services?

“Still reinventing...”







Contract First, Document Literal, Web Services tried to help

• XML is the lingua franca!• Transport agnostic• Contract first!• SOAP and WSDL• WS-Addressing• WS-Policy• WS-Security• Ummm WS-WhateverYouLike!



And the vendors got fat...





But all was not well in WS-ville...





And then came Roy Fielding...





Representational State Transfer

• Think in ‘things’• Things have addresses• Things have representations you can GET• Things can be PUT back differently• Things can be DELETEd• Things can be, umm, POSTed to create

them• Does anyone see this as anything new...?



Haven’t we seen something like this before?

WWWMonday, 25 January 2010




Web apps are Web services (done right)





The key components of REST

• Resources• URIs• Uniform interface• Stateless• Representations



But WHY?!

• Simple to implement• Systems are naturally broken down into

Resources...• Naturally HTTP, not abusing HTTP...• Scales like a western man on 40

hamburgers a day!



And now an apology...

• Not all systems that claim RESTfulness, are actually RESTful...

• XML over HTTP isn’t the same– unless you mean the same as web services...

• The URL matters (dammit!)• The mime type matters• The HTTP method (really) matters!



You need to think about REST

• Decide on resources• Decide on URIs• Decide on methods you’ll support• Decide on how resources will relate

(hypermedia, WADL, both?)• Decide on representations you’re going to

support



Finally, some code!

Aren’t RESTful services hard to develop...?







Summary

• RESTful services are ubiquitous• REST is actually very simple• Think about resources up front• Keep things stateless• The uniform interface unlocks the power of

the web for your internal services• Implementation is simple



Some of the things we’ve been promised




Some of the things that REST delivers




Thanks and Any Questions?

[email protected]

http://www.russmiles.com








Give It A Rest(ful) web service

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Transcript of Give It A Rest(ful) web service