REST vs SOAP for Web Services Applications and Services in Internet Benjamin Hilaire – 81747L

TKK, Application and Services on Internet 2 Summary 1- Introduction 2- Differents approachs 3- Simple Object Access Protocol (SOAP) 4- Represational State Transfer (REST) 5- Web Services in practice 6- Conclusion

TKK, Application and Services on Internet 3 Introduction Computer changes Hardware was central mainframe is many specialized server Software was specific is re-usable Network was local (LAN) is global (Internet) New principles Modularity Interoperability Normalized protocols

TKK, Application and Services on Internet 4 ”A web service is a network accessible interface to application functuonnality, built using standard Internet technologies” (Programming Web Services with SOAP, James Snell, O’Reilly, 2001) Internet-oriented services Most famous : Google Search REST : SOAP More complex : Google Documents Online office service using only the browser Non Internet-oriented service Replace Electronic Data Interfaces (EDI) New remote interface Light client (ie Website) Heavy client (ie Software) What is a Web Service ? POST search/beta2 HTTP/1.1 Host: api.google.com Content-Type: application/soap+xml SOAPAction: urn:GoogleSearchAction web+services...

TKK, Application and Services on Internet 5 2 standards from 2 fields Software Need for distributed system Remote Call Procedure (1988) XML+RPC -> XML-RPC (1998) SOAP (2000) SOAP standard W3C (2003) Network Building the World Wide Web HTTP (1996) XML (1998) REST as the Web architecture (2000) Rest for Web Services (>2002) Why 2 standards ?

TKK, Application and Services on Internet 6 SOAP Use of object remotely by message sending Proposed by Microsoft and IBM Supported by the Web Services Interoperability Organization (WS-I) Standard packaging protocol for Web Services XML enveloppe Header How process the message Body XML message Calling methods from to a distant object Embedded in transports messages SOAP – Principles (1/2)

TKK, Application and Services on Internet 7 Web Services Technology Stack (WS-*) UDDI : Universal Description Discovery Integration WSDL : Web Service Description Language SOAP : Simple Object Access Protocol SOAP – Principles (2/2)

TKK, Application and Services on Internet 8 Well know architecture Remote object call (ie like Java Message Service) Standard object programmation WSDL  interfaces Network used can be transparent Statefull Transaction-state persistent All objects can be considered as locals Message rejection Detect network error (don’t trust the WWW) Security OASIS (company consortium) built standards protocols All kind of web cryptography protocols (Key exchange, signature, certifications, secure transport,...) SOAP - Properties

TKK, Application and Services on Internet 9 Origin Architecture descripted by Roy Thomas Fielding in 2000 Same architecture as the WWW REST  rest on the WWW HTTP TCP/IP No upper layer URI Universal Ressource Identifier  URL for web pages HTTP Methods as interface GET (get a ressource) PUT (set a ressource) POST (modify a ressource) DELETE (delete a ressource) REST - Principles

TKK, Application and Services on Internet 10 Main objectives Simplicity Scaleability Stateless Server don’t keep track on previous request Cache Possibility to cache the response to earn time Uniform Interface 4 known-methods per ressource Security Secure transport method (SSL/HTTPS) Main issue REST - Properties

TKK, Application and Services on Internet 11 2 philosophies SOAP RESTfull (all properties respected) Not RESTfull Hybrid New architecture – new protocols SOAP close to usual programming style RPC via internet Created/supported by company REST close to Internet concepts Simple - Efficient Open-source community New frameworks (exemples) Microsoft.NET Ruby On Rails Web Services in practice (1/3)

TKK, Application and Services on Internet 12 Main visibles differences Messages sizes REST use HTTP only SOAP use HTTP+XML enveloppe Number of methods (4 vs N) Stateless or statefull Storing transaction improve performance and easiest architecture Stateless mean complex architecture and redondant information sent but performance Transparency – Intuitivness REST is user-friendly : can be used without noticing SOAP needs WSDL and UDDI to be used Security SOAP is well-known since 8 years : knows how use it in secure way REST is brand-new and mostly use transport security Web Services in practice (2/3)

TKK, Application and Services on Internet 13 What approach for what application Technical choice Internet-oriented or not User-oriented or machine-oriented Quality’s needed Practical choice Developping team knowledge’s Server/Languages used ”Marketing” choice REST is new, fresh, fashion, nice SOAP is old, reliable, secure, serious Hybrid method Read-only Approach (ROA) REST for GET SOAP for other methods Web Services in practice (3/3)

TKK, Application and Services on Internet 14 REST vs SOAP for Web Services 2 different approachs, phylosophies Choice according different criteria Hybridation possible Future of Web Service More and more Web Services everywhere On Internet Remember the milk iGoogle On Computer Gadget/Widgets layers On ”big” systems New interfaces Google Gears Cloud computing Conclusion

TKK, Application and Services on Internet 15 Questions ? Thanks !