REST or SOAP Which style of Service is “best” for building the Web of Science? Duncan Hull Web Services Workshop 2007-09-20

Looks like we’ll be developing some WS-* What are Web Services? A vague term, but in practice it usually means either SOAP-based or HTTP-based machine-to-machine communication: SOAP style description Demonstrate simpler REST style with examples Introduce some pros and cons of each Conclusions What should we be doing in dbkgroup and why?

What are Web Services? A vague term, but in practice it usually means either SOAP-based or HTTP-based machine-to-machine communication:

SOAP style description

Demonstrate simpler REST style with examples

Introduce some pros and cons of each

Conclusions

What should we be doing in dbkgroup and why?

WS-* are interesting because they transform the web into… --Harry Halpin and Henry Thompson, University of Edinburgh “One document to bind them: combining XML, web services, and the semantic web”, Proceedings of WWW2006 conference, see http://www.nodalpoint.org/2006/05/24/dub_dub_dub_06 image above via http://lipmagazine.org one open-ended, vast, decentralised computer

--Harry Halpin and Henry Thompson, University of Edinburgh “One document to bind them: combining XML, web services, and the semantic web”, Proceedings of WWW2006 conference, see http://www.nodalpoint.org/2006/05/24/dub_dub_dub_06 image above via http://lipmagazine.org

Creating a bioinformatics nation? A Web services model will allow biological data to be fully exploited… --Lincoln Stein, Cold Spring Harbor Laboratory Nature 2002, 417(6885):119-20 http://view.ncbi.nlm.nih.gov/pubmed/12000935 e.g. “jimome” browser at http://jimwatsonsequence.cshl.edu/

A Web services model will allow biological data to be fully exploited…

More than 1 600 000 job submissions were processed using Web Services during 2006, accounting for around 30% of all jobs run at the EBI during that period. --Alberto Labarga et al in Nucleic Acids Research European Bioinformatics Institute (EBI), see http://www.cs.man.ac.uk/~hulld/q2007-06-28.html

More than 1 600 000 job submissions were processed using Web Services during 2006, accounting for around 30% of all jobs run at the EBI during that period.

If you hit the Amazon.com gateway page, the application calls more than 100 [web] services to collect data and construct the page for you . --Werner Vogels, Chief Technology Officer (CTO) Amazon.com, interviewed in ACM Queue, 2006 see, http://www.cs.man.ac.uk/~hulld/q2006-09-27.html

If you hit the Amazon.com gateway page, the application calls more than 100 [web] services to collect data and construct the page for you .

WS-heaven or WS-hell? Users / clients Internet or Web (Interweb)?! http://en.wikipedia.org/wiki/Interweb Service providers: INPUT OUTPUT etc… workflow

SOAP and WSDL walkthrough Registry WSDL / UDDI Search / Browse SOAP (xml) HTTP INPUT / OUTPUT http://www.w3.org/TR/soap/ http://www.w3.org/TR/wsdl/ Ugly, heavyweight and complicated, seems like overkill? “ layers of complexity that aren’t needed”?

No matter how hard I try, I still think the WS-* stack is bloated, opaque, and insanely complex. I think it's going to be hard to understand, hard to implement, hard to interoperate, and hard to secure. --Tim Bray, Director of Web technology at Sun Microsystems Inc., “Loyal opposition to Web Services” (2004) http://www.cs.man.ac.uk/~hulld/q2004-11-02.html

Web service goodness The problem is most of today's “web services” have nothing to do with the Web.... Today's “web service” architectures reinvent or ignore every feature that makes the Web successful. --Leonard Richardson & Sam Ruby (IBM) “ RESTful Web Services ” (2007) book, see http://www.cs.man.ac.uk/~hulld/q2007-06-30.html

H.T.T.P. is just C.R.U.D…Create, Read, Update, Delete H.T.T.P. is K.I.S.S. too ( K eep I t S imple S tupid) DELETE (delete an existing resource) D ELETE PUT (modify or overwrite an existing resource) U PDATE GET (Retrieve a representation of a resource) R EAD POST (create a new resource) C REATE HTTP request method CRUD

REST example: EBI services OR OR etc.

REST style No SOAP, Simpler ( don’t have to use SOAP ) and “dirtier” too! No standard way (yet) of creating a registry of services though many different options exist XML is optional, our resources can be anything we want There is a lot more to REST than this, it’s an architectural style for building web applications

No SOAP, Simpler ( don’t have to use SOAP ) and “dirtier” too!

No standard way (yet) of creating a registry of services

though many different options exist

XML is optional, our resources can be anything we want

There is a lot more to REST than this, it’s an architectural style for building web applications

REST criticism Foolish to model everything as HTTP GET, POST, PUT and DELETE operations? How to do Atomic transactions (all actions must be completed or none) Reliable messaging? Security (HTTP Authentication leaves a lot to be desired) Too simple No toolkits for REST (a criticism from software vendors who want to sell you bloat-ware)

Foolish to model everything as HTTP GET, POST, PUT and DELETE operations?

How to do

Atomic transactions (all actions must be completed or none)

Reliable messaging?

Security (HTTP Authentication leaves a lot to be desired)

Too simple

No toolkits for REST

(a criticism from software vendors who want to sell you bloat-ware)

Conclusions 1: Gartner’s Hype cycle --Eric Newcomer IONA, see http://www.cs.man.ac.uk/~hulld/q2007-04-26.html Web services are now past the peak of inflated expectations, through the trough of disillusionment, on the way toward mainstream adoption. 2000 2002 2004 2006 2008 You are here (probably) SOAP WSDL

--Eric Newcomer IONA, see http://www.cs.man.ac.uk/~hulld/q2007-04-26.html

Conclusions 2: Who can you trust? Be wary of the opinions of people working for technology companies. Especially if they have long hair, beards or hats (Hull, 2007) … but you knew that already Reality of (bio- / chemo- / whatevero-) informatics on the Web is we have a legacy of both, and this will probably continue. So we need to understand and use both styles… myGrid Taverna handles BOTH styles and hides some of the SOAP and WSDL nastiness but they are difficult to sweep under the carpet When we’re developing NEW services, I advocate REST-style services which are simpler and probably safer for most of the things we’ll need them for Only use SOAP if really you have to… Said only a little about WHY in a 7 minute talk but… … can provide more details if you buy me a beer Don’t trust ANYONE about Web Services (including me!)

Be wary of the opinions of people working for technology companies.

Especially if they have long hair, beards or hats (Hull, 2007)

… but you knew that already

Reality of (bio- / chemo- / whatevero-) informatics on the Web is we have a legacy of both, and this will probably continue. So we need to understand and use both styles…

myGrid Taverna handles BOTH styles and hides some of the SOAP and WSDL nastiness

but they are difficult to sweep under the carpet

When we’re developing NEW services, I advocate REST-style services which are simpler and probably safer for most of the things we’ll need them for

Only use SOAP if really you have to…

Said only a little about WHY in a 7 minute talk but…

… can provide more details if you buy me a beer

Acknowledgements / References Thanks to everyone I robbed stuff off : Homer Simpson, Michael Parkin, Sam Ruby, Paul Downey, Tim Bray, Werner Vogels, Carole Goble, Stian Soiland, Tom Oinn and myGrid team, Leonard Richardson, Tim O’Reilly, Timo Hannay, Lincoln Stein, Roy Fielding, Greg Tyrelle, Harry Halpin, Henry Thompson, Hugo Haas, Roger Costello, John Cowan, Eric Newcomer, Steve Vinoski, Richard Apodaca and Douglas Kell These slides are also available at http://www. slideshare .net/dullhunk See Also: “ REST tutorial” by Roger Costello at http://www.xfront.com/REST.htm “ Reconciling REST and Web Services” by Hugo Haas at http://www.w3.org/2005/Talks/1115-hh-k-ecows/ “ If Web Services are the Answer, What is the Question?” by Michael Parkin http://www.archive.org/details/IfWebServicesAreTheAnswerWhatsTheQuestion “ RESTful Web Services” by John Cowan http://home.ccil.org/~cowan/restws.pdf Questions?

Thanks to everyone I robbed stuff off :

Homer Simpson, Michael Parkin, Sam Ruby, Paul Downey, Tim Bray, Werner Vogels, Carole Goble, Stian Soiland, Tom Oinn and myGrid team, Leonard Richardson, Tim O’Reilly, Timo Hannay, Lincoln Stein, Roy Fielding, Greg Tyrelle, Harry Halpin, Henry Thompson, Hugo Haas, Roger Costello, John Cowan, Eric Newcomer, Steve Vinoski, Richard Apodaca and Douglas Kell

These slides are also available at http://www. slideshare .net/dullhunk

See Also:

“ REST tutorial” by Roger Costello at http://www.xfront.com/REST.htm

“ Reconciling REST and Web Services” by Hugo Haas at http://www.w3.org/2005/Talks/1115-hh-k-ecows/

“ If Web Services are the Answer, What is the Question?” by Michael Parkin http://www.archive.org/details/IfWebServicesAreTheAnswerWhatsTheQuestion

“ RESTful Web Services” by John Cowan http://home.ccil.org/~cowan/restws.pdf

Questions?