ISCOD / LSTI Ambient(Compu-ng(...

Ambient(Compu-ng(/(Web(of(Things(/(

ENS(Mines(Saint/E-enne(

Andrei(Ciortea(

“Web(Intelligence”(Master(–(December(2013(

[email protected](

2(

Andrei'Ciortea'PhD(Student(

ISCOD / LSTI

The White City of R’Landri

"Web(Intelligence"(Master,(December(2013(

3("Web(Intelligence"(Master,(December(2013(

M.(Weiser.(The(Computer(for(the(21st(Century,(1991(

Xerox(PARC,(1991'



Xerox(PARC,(1991'



Xerox(PARC,(1991'

•  tabs(•  pads(•  boards(



Xerox(PARC,(1991'

ubiquitous'compu5ng'(ubicomp)'

•  tabs(•  pads(•  boards(

“The(most(profound(technologies(are(those(that(disappear.(They(weave(themselves(into(the(fabric(of(everyday(life(un-l(they(are(indis-nguishable(from(it.”(

"Web(Intelligence"(Master,(December(2013( 7(

Fast/forward(to(2013…(


(Good'Night'Lamp,'2013)'h\p://www.vimeo.com/56586373(


Fast/forward(to(2013…(


Integra5ng(func-onality(across(smart&things:(


(Philips,(2012)(

An(augmented'reality(app(for(shaving(app(



(Philips,(2012)(

Smart(things(already(provide(interes-ng(func-onality(by(themselves…(




(Philips,(2012)(

Smart(things(already(provide(interes-ng(func-onality(by(themselves…(

…(but(integra-ng(func-onality(across(smart(things(opens(up(a(world(of(new(possibili-es!(




(Ericsson,'The'Social'Web'of'Things,'2011)'h\p://www.vimeo.com/22022800(

Challenge:((


How(to(create(a(loosely'coupled(ecosystem(of(services(for(smart&things?(

Challenge:((


How(can(the(Web(help?(

How(to(create(a(loosely'coupled(ecosystem(of(services(for(smart&things?(

•  Introduc-on(•  Web(Services(

– WS/*(Web(Services(– RESTful(Web(Services(

•  RESTifying(Things(•  Service(Integra-on(in(the(WoT(•  The(Social(Web(of(Things(

17(

Outline(

"Web(Intelligence"(Master,(December(2013( "Web(Intelligence"(Master,(December(2013( 18(

WWW(Virtual(Library,(h\p://www.vlib.us(

Key(Takeaways(

•  What(is(the(WoT(•  What(is(REST(•  How(to(RESTify(things(•  Current(challenges(in(the(WoT(


•  Introduc5on'•  Web(Services(



20(

Outline(


Introduc-on(Internet'of'Things'(IoT)'–(one(term,(many(visions(


L.(Atzori,(A.(Iera,(and(G.(Morabito.(The(Internet(of(Things:(A(Survey,(2010.(



“Things(have(iden--es(and(virtual(personali-es(opera-ng(in(smart(spaces(using(intelligent(interfaces(to(connect(and(communicate(within(social,(environmental,(and(user(contexts.”(

INFSO(D.4(Networked(Enterprise(&(RFID(INFSO(G.2(Micro(&(Nanosystems,(Working(Group(RFID(of(the(ETP(EPOSS.(Internet(of(Things(in(2020,(Roadmap(for(the(Future,(2008.(






(“The(Internet(of(Things(allows(people(and(things(to(be(connected(Any-me,(Anyplace,(with(Anything(and(Anyone,(ideally(using(Any(path/network(and(Any(service.”(

P.(Guillemin(and(P.(Friess.(Internet(of(Things(strategic(research(roadmap,(2009.(






(“The(Internet(of(Things(allows(people(and(things(to(be(connected(Any-me,(Anyplace,(with(Anything(and(Anyone,(ideally(using(Any(path/network(and(Any(service.”(

P.(Guillemin(and(P.(Friess.(Internet(of(Things(strategic(research(roadmap,(2009.((“The(IoT(integrates(a(large(number(of(technologies(and(envisions(a(variety(of(things(or(objects(around(us(that,(through(unique(addressing(schemes(and(standard(communica-on(protocols,(are(able(to(interact(with(each(other(and(cooperate(with(their(neighbors(to(reach(common(goals.”(

L.(Atzori,(A.(Iera,(G.(Morabito,(and(M.(Nim.(The(Social(Internet(of(Things(–(When(social(networks(meet(the(Internet(of(Things:(Concept,(architecture(and(network(characteriza-on,(2012.(


Introduc-on(


“The(IoT(does(not(revolu-onize(our(lives(or(the(field(of(compu-ng.(It(is(another(step(in(the(evolu-on(of(the(Internet(we(already(have.”(

C.(Petera,(A.(Zaslavsky,(P.(Christen,(and(D.(Georgakopoulous.(Context(Aware(Compu-ng(for(the(Internet(of(Things:(A(Survey,(2013.(

Internet'of'Things'(IoT)'–(one(term,(many(visions(

Introduc-on(


“The(IoT(does(not(revolu-onize(our(lives(or(the(field(of(compu-ng.(It(is(another(step(in(the(evolu-on(of(the(Internet(we(already(have.”(

C.(Petera,(A.(Zaslavsky,(P.(Christen,(and(D.(Georgakopoulous.(Context(Aware(Compu-ng(for(the(Internet(of(Things:(A(Survey,(2013.(

Internet'of'Things'(IoT)'–(one(term,(many(visions(

Introduc-on(


(Philips,(2012)(

•  InternetIenabled(programmable'mirror,(capable(of(displaying(data(in(a(given(format.(

•  InternetIenabled(programmable'electric'razor,(capable(of(collec-ng(usage(data.(

•  Task:(Build(an(augmented(reality(shaving(applica-on(that(displays(on(the(mirror(some(data(collected(by(the(electric(razor.(

Introduc-on(


(Philips,(2012)(




PlaMormIindependence:(what(if(there(are(several(manufacturers?(

Introduc-on(


(Philips,(2012)(




PlaMormIindependence:(what(if(there(are(several(manufacturers?(

Rapid'prototyping:(do(I(need(to(get(familiar(with(each(plaqorm?(

Introduc-on(RealIworld'case'study(–(developing(Glassware:(




•  Web/based(apps,(using(the(Mirror'API'


h\p://developers.google.com/glass/develop/(









•  Web/based(apps,(using(the(Mirror'API:(•  Plaqorm(independence(•  Common(infrastructure(•  Easy(integra-on(with(exis-ng(Web(apps(•  Low(entry(barrier(for(developers(




•  na-ve(apps,(using(the(GDK((Glass(Development(Kit):(•  Real/-me(user(interac-on(•  Offline(func-onality(•  Access(to(hardware(•  Solid(background(in(Android(is(required(




•  na-ve(apps,(using(the(GDK((Glass(Development(Kit):(•  Real/-me(user(interac-on(•  Offline(func-onality(•  Access(to(hardware(•  Solid(background(in(Android(is(required(

•  or(using(both.(

Introduc-on(


Challenge:(( How(to(create(a(loosely'coupled(ecosystem(of(

services(for(smart&things?(

Introduc-on(


We(need(a(protocol(that(is(simple,(lightweight,(looselyIcoupled,(scalable,(flexible(and((hopefully)(standard.(



Material(adapted(from:(V.(Trifa(and(D.(Guinard.(Web(of(Things(–(Connec-ng(People(and(Objects(on(the(Web,(SXSW,(2010.(

Introduc-on(


We(need(a(protocol(that(is(simple,(lightweight,(looselyIcoupled,(scalable,(flexible(and((hopefully)(standard.(



How(about(the(Web?(

Material(adapted(from:(V.(Trifa(and(D.(Guinard.(Web(of(Things(–(Connec-ng(People(and(Objects(on(the(Web,(SXSW,(2010.(

Introduc-on(


Web'of'Things'(WoT)(Ubiquitous(Web,(Dave(Ragge\,(2007(

Introduc-on(


Web'of'Things'(WoT)(

“The(emerging(Web(of(Things(is(a(concrete(implementa-on(of(the(Internet(of(Things(vision(that(focuses(on(establishing(applica-on/level(connec-vity(between(heterogeneous(devices.”((

S.(Mayer(and(G.(Basler.(Seman-c(metadata(to(support(device(interac-on(in(smart(environments,(2013.(

Ubiquitous(Web,(Dave(Ragge\,(2007(

Introduc-on(



“In(the(Web(of(Things,(we(are(considering(smart(things(as(first/class(ci-zens(of(the(Web(and(posi-on(the(WoT(as(a(refinement(of(the(IoT(by(integra-ng(smart(things(not(only(into(the(Internet((the(network),(but(into(the(Web((the(applica-on(layer).”(



D.(Guinard.(A(Web(of(Things(Applica-on(Architecture(–(Integra-ng(the(Real/World(into(the(Web,(2011.(


Introduc-on(




Using(the(Web(as(an(applica-on(architecture,(and(not(as(a(transporta-on(layer.(





Introduc-on(


Two(types(of(Web(services(stand(out(as(poten-al(candidates:(

•  WS/*(Web(services(•  RESTful(Web(services(

D.(Guinard,(I.(Ion,(and(S.(Mayer.(In(search(of(an(Internet(of(Things(Service(Architecture:(REST(or(WS/*?(A(developers’(perspec-ve,(2012.(



•  Introduc-on(•  Web'Services'

– WSI*'Web'Services'– RESTful(Web(Services(


47(

Outline(


WS/*(Web(Services(

A(serviceIoriented'architecture(–  An(endpoint(is(an(ac-on,(in(the(form(of(a(service'call:(

•  e.g.,(h\p://emse.fr/room104/getTemperature(


WS/*(Web(Services(

A(serviceIoriented'architecture(–  An(endpoint(is(an(ac-on,(in(the(form(of(a(service'call:(

•  e.g.,(h\p://emse.fr/room104/getTemperature(

(What(is(the(WSI*'stack?(

–  WS/Addressing,(WS/Discovery,(WS/Federa-on,(etc.(

"Web(Intelligence"(Master,(December(2013( 49( "Web(Intelligence"(Master,(December(2013( 50(

h\p://www1.innoq.com/resources/ws/standards/poster/(

WS/*(Web(Services(

•  SOAP((used(to(be(Simple&Object&Access&Protocol)(–  a(protocol(for(accessing(Web(services((service(access).(

•  WSDL((Web(Services(Descrip-on(Language)(–  a(language(for(describing(Web(services(and(how(to(access(them(

(service(descrip-on).'

•  UDDI((Universal(Descrip-on,(Discovery(and(Integra-on)(–  a(plaqorm/independent,(XML/based,(distributed(repository((service(

discovery).(


WS/*(Web(Services(


Material(adapted(from:(S.(Mayer.(Service(integra-on(in(the(Web(of(Things,(École(d’Éte(Web(Intelligence(2013(–(Web(des(Objets,(2013.(

SOAP(


•  SOAP((used(to(be(Simple&Object&Access&Protocol)(–  is(an(XML(language(that(defines(a(format(for(messages;(–  is(plaqorm(and(language(independent;(–  mul-ple(transport(protocols:(HTTP,(SMTP,(TCP,(etc.(

SOAP(


SOAP(envelope(

header((op-onal)(

body(

fault((op-onal)(

Applica-on/specific(informa-on((e.g.,(the(context(of(a(transac-on)(

Error(messages(

•  SOAP((used(to(be(Simple&Object&Access&Protocol)(–  is(an(XML(language(that(defines(a(format(for(messages;(–  is(plaqorm(and(language(independent;(–  mul-ple(transport(protocols:(HTTP,(SMTP,(TCP,(etc.(

SOAP:(A(Sample(Request(


POST /InStock HTTP/1.1 Host: www.example.org Content-Type: application/soap+xml; charset=utf-8 Content-Length: nnn <?xml version="1.0"?> <soap:Envelope xmlns:soap="http://www.w3.org/2001/12/soap-envelope" soap:encodingStyle="http://www.w3.org/2001/12/soap-encoding"> <soap:Body xmlns:m="http://www.example.org/stock"> <m:GetStockPrice> <m:StockName>IBM</m:StockName> </m:GetStockPrice> </soap:Body> </soap:Envelope>

h\p://www.w3schools.com/webservices/ws_soap_body.asp(













SOAP:(A(Sample(Response(


HTTP/1.1 200 OK Content-Type: application/soap+xml; charset=utf-8 Content-Length: nnn <?xml version="1.0"?> <soap:Envelope xmlns:soap="http://www.w3.org/2001/12/soap-envelope" soap:encodingStyle="http://www.w3.org/2001/12/soap-encoding"> <soap:Body xmlns:m="http://www.example.org/stock"> <m:GetStockPriceResponse> <m:Price>34.5</m:Price> </m:GetStockPriceResponse> </soap:Body> </soap:Envelope>


WSDL(

•  WSDL((Web(Services(Descrip-on(Language)(–  is(an(XML(language(for(describing(interfaces(syntac-cally:(

•  func-on(signatures;(•  service(binding((URL(and(protocol).(

– WSDL(documents(are(stored(in(repositories((e.g.,(UDDI).(


WSDL(


WSDL(defini-on(

types(

portType(

binding(

service(

•  WSDL((Web(Services(Descrip-on(Language)(

messages(

What(does(the(exchanged(data(look(like?(

What(are(messages(composed(of?(

What(do(the(opera-ons(look(like?(

Which(protocol(to(use?(

Structure/Bundling(of(opera-ons.(


WSDL:(HelloService(<defini-ons(name="HelloService"((((targetNamespace="h\p://www.examples.com/wsdl/HelloService.wsdl"((((xmlns="h\p://schemas.xmlsoap.org/wsdl/"((((xmlns:soap="h\p://schemas.xmlsoap.org/wsdl/soap/"((((xmlns:tns="h\p://www.examples.com/wsdl/HelloService.wsdl"((((xmlns:xsd="h\p://www.w3.org/2001/XMLSchema">((((((<message(name="SayHelloRequest">(((((((<part(name="firstName"(type="xsd:string"/>((((</message>((((<message(name="SayHelloResponse">(((((((<part(name="gree-ng"(type="xsd:string"/>((((</message>(((((<portType(name="Hello_PortType">(((((((<opera-on(name="sayHello">((((((((((<input(message="tns:SayHelloRequest"/>((((((((((<output(message="tns:SayHelloResponse"/>(((((((</opera-on>((((</portType>(((((<binding(name="Hello_Binding"(type="tns:Hello_PortType">((((<soap:binding(style="rpc"(((((((transport="h\p://schemas.xmlsoap.org/soap/h\p"/>(

(((<opera-on(name="sayHello">(((((((<soap:opera-on(soapAc-on="sayHello"/>(((((((<input>((((((((((<soap:body(((((((((((((encodingStyle="h\p://schemas.xmlsoap.org/soap/encoding/"(((((((((((((namespace="urn:examples:helloservice"(((((((((((((use="encoded"/>(((((((</input>(((((((<output>((((((((((<soap:body(((((((((((((encodingStyle="h\p://schemas.xmlsoap.org/soap/encoding/"(((((((((((((namespace="urn:examples:helloservice"(((((((((((((use="encoded"/>(((((((</output>((((</opera-on>((((</binding>(((((<service(name="Hello_Service">(((((((<documenta-on>WSDL(File(for(HelloService</documenta-on>(((((((<port(binding="tns:Hello_Binding"(name="Hello_Port">((((((((((<soap:address(((((((((((((loca-on="h\p://www.examples.com/SayHello/">(((((((</port>((((</service>(</defini-ons>(

"Web(Intelligence"(Master,(December(2013( 62(h\p://www.tutorialspoint.com/wsdl/wsdl_example.htm(

WS/*(in(Prac-ce(

•  Stubs(handle(communica-on(issues,(such(as(message'packing'and'unpacking'(“marshalling”)'

•  The(server(stub(is(also(responsible(for(publishing(the(WSDL'document'

•  Crea-ng(stubs:(–  Bo\om/up((code/first):(stub'from'implementa5on(

(JAX/WS)(–  Top/down((contract/first):(stub'from'WSDL'



WS/*(Discussion(

•  Extremely(powerful(and(lots(of(available(tools(–  Huge(complexity(

•  WSDL(is(quite(verbose(for(simple(func-onality(

•  SOAP(over(HTTP(uses(only(POST(–  Therefore,(no(HTTP/based(caching(is(possible(




– WS/*(Web(Services(– RESTful'Web'Services'


65(

Outline(


RESTful(Web(Services(•  REST'(REpresenta-onal(State(Transfer)(

–  was(coined(by(Roy'Fielding(in(his(PhD(thesis((2000).(–  is(an(architectural(style(for(distributed(hypermedia(systems.(





a(named,(coordinated(set(of(architectural(constraints(





non/linear(medium(of(informa-on((first(used(in(1965(by(Ted(Nelson)(





non/linear(medium(of(informa-on((first(used(in(1965(by(Ted(Nelson)(

“REST(emphasizes(scalability(of(component(interac-ons,(generality(of(interfaces,(the(independent(deployment(of(components(as(well(as(intermediary(components(to(reduce(interac-on(latency,(enforce(security,(and(encapsulate(legacy(systems.”(

R.(Fielding.(Architectural(Styles(and(the(Design(of(Network/based(So|ware(Architectures,(2000(






–  is(a(dis7lla7on(of(the(Web(and(was(applied(to(design(HTTP(1.1(and(Uniform(Resource(Iden-fiers((URI).(





–  is(independent(of(the(Web.(





–  is(independent(of(the(Web.(•  An(applica-on(conforming(to(the(REST(constraints(is(

characterized(as(being(RESTful.(





–  is(independent(of(the(Web.(•  An(applica-on(conforming(to(the(REST(constraints(is(

characterized(as(being(RESTful.(•  REST'is'simple,'but'full'of'subtle5es!'


REST(in(a(Nutshell(A(resourceIoriented(architecture(

•  Everything(is(a(resource,(iden-fied(through(a(URI.(–  An(endpoint(is(a(resource,(e.g.(h\p://emse.fr/room104/temperature(

•  Everything(has(a(uniform(interface,(with(well(defined(interac-on(seman-cs.(

•  Messages(are(self/descrip-ve.(•  Hypermedia(drives(the(applica-on(state.(

–  HATEOAS((Hypermedia(As(The(Engine(Of(Applica-on(State)(

•  Interac-ons(are(stateless.(–  No(client(state(can(be(stored(on(a(server(between(interac-ons.(


R.(Fielding.(Architectural(Styles(and(the(Design(of(Network/based(So|ware(Architectures,(2000(For(an(interes-ng(summariza-on(of(Roy’s(thesis,(check(out:(h\p://wwatson.me/2011/10/01/rest/disserta-on/overview/part/1/(

(please(note:(it(might(be(the(personal(interpreta-on(of(the(blogger)(

Deriving(REST(

•  Two(common(perspec-ves(on(the(process(of(architectural(design:(–  start(from(scratch(and(build/up(an(architecture(from(familiar(

components(un-l(it(sa-sfies(the(needs(of(the(intended(system;(–  start(with(the(system(needs(as(a(whole,(without(constraints,(and(then(

incrementally(iden-fy(and(apply(constraints(to(elements(of(the(system.(



Deriving(REST(






Deriving(REST(





WWW(

Null(style(R.(Fielding.(Architectural(Styles(and(the(Design(of(Network/based(So|ware(Architectures,(2000(

Deriving(REST(

•  REST(constraints:(– Client/Server(– Stateless(– Cacheable(– Uniform(Interface(– Layered(System(– Code/On/Demand((op-onal)(



Client/Server(•  A(client(component(that(sends(requests,(and(a(server(that(receives(

requests(and(may(also(issue(a(response(to(the(client.(

•  Design(principle:(separa5on'of'concerns.(•  Induced(proper-es:(

–  portability,(e.g.,(separa-ng(the(user(interface(concerns((client)(from(the(data(storage(concerns((server);(

–  scalability,(server(components(are(simplified;(

–  components(can(evolve(independently((developed,(replaced,(etc.).(










WWW(

Null(style(R.(Fielding.(Architectural(Styles(and(the(Design(of(Network/based(So|ware(Architectures,(2000(








Client/Server(R.(Fielding.(Architectural(Styles(and(the(Design(of(Network/based(So|ware(Architectures,(2000(

Stateless(

•  The(client/server(interac-on(is(selfIcontained.(



Stateless(


(



no(contextual(informa-on(is(needed(for(interpre-ng(the(request((e.g.(no(sessions(or(transac-ons)(

Stateless(


(

–  Session(state(is(held(in(the(client.(




Stateless(


(

–  Session(state(is(held(in(the(client.(–  There(may(be(state(involved(and(the(server(can(transfer(the(session(

state(to(a(different(service((e.g.(a(database,(for(persis-ng(a(state(over(a(period(of(-me),(but(the(client/server(interac-on(itself(is(stateless.(




Stateless(




Stateless(



•  The(client/server(interac-on(is(selfIcontained.(•  Induced(proper-es:(

–  visibility,(a(monitoring(system(does(not(have(to(look(beyond(a(single(request(to(understand(the(request;(

–  reliability,(easier(to(recover(interac-on(from(par-al(failures;(

–  scalability,(servers(don’t(have(to(manage(resources(across(requests.(

•  Tradeoff:(–  decrease(in(network(performance((repe--ve(data(across(requests);(–  the(server(does(not(have(direct(control(on(the(applica-on(behavior.(

Stateless(



Client/Server(

Stateless(



Client/Stateless/Server(

Cacheable(

•  Data(within(a(response(to(a(request(must(be(implicitly(or(explicitly(labeled(as(cacheable.(

•  Induced(proper-es:(–  improved(efficiency,(scalability(and(userIperceived'performance,(through(par-ally(or(completely(elimina-ng(some(interac-ons((reduced(average(latency(for(a(series(of(interac-ons).(

•  Tradeoff:(–  reliability(may(be(decreased(due(to(stale(data.(



Cacheable(



Client/Stateless/Server(

Cacheable(



Client/Cache/Stateless/Server(

Cacheable(




The(early(Web(architecture((prior(to(1994).(

Cacheable(




The(early(Web(architecture((prior(to(1994).(•  no(consistent(set(of(seman-cs(for(all(resources,(just(CERN(libwww.(

Uniform(Interface(

•  Central(to(REST,(decouples(the(architecture.(



Uniform(Interface(

•  Central(to(REST,(decouples(the(architecture.(•  Design(principle:(generality.(



Uniform(Interface(




remember(the(Y2K(bug?(


h\p://en.wikipedia.org/wiki/Year_2000_problem(

Uniform(Interface(




Uniform(Interface(

•  Central(to(REST,(decouples(the(architecture.(•  Design(principle:(generality.(•  Induced(proper-es:(

–  increased(evolvability,(simplicity,(visibility.(•  Tradeoff:(

–  degraded(efficiency,(informa-on(being(transferred(in(a(standard(form,(and(not(in(an(applica-on/specific(form.(



Uniform(Interface(


Iden-fica-on(of(resources(

Manipula-on(of(resources((through(representa-ons(

Self/descrip-ve(messages(

HATEOAS(


4(interface(constraints:(

Uniform(Interface(





HATEOAS(



What(is(a(resource?(

Uniform(Interface(





HATEOAS(




Any(informa-on(that(can(be(named(is(a(resource.(

Uniform(Interface(





HATEOAS(




Any(informa-on(that(can(be(named(is(a(resource.(

A(representa5on(is(a(sequence(of(bytes(and(the(descrip-on(of(those(bytes((e.g.,(HTML,(XML,(JSON).(

Uniform(Interface(





HATEOAS(


A(resource(has(a((resource'iden5fier((e.g.,(URI).((

The(naming'authority(that(assigns(a(resource(iden-fier(is(responsible(for(maintaining(the(seman-c(validity(of(the(mapping(over(-me.(


Uniform(Interface(





HATEOAS(


A(client(does(not(have(access(to(a(resource(directly.(It(can(only(send(and(receive(representa-ons(to(and(from(a(server.(


Uniform(Interface(





HATEOAS(


A(message(must(include(metadata(describing(its(meaning.((Methods(used(to(invoke(the(message(must(be(standard(and(agreeable(between(the(client,(the(server,(and(intermediaries(in(between.(


Uniform(Interface(





HATEOAS(


Applica-on(states(are(reachable(only(through(hypermedia.(


Hypermedia(As(The(Engine(Of(Applica-on(State(

Uniform(Interface(




Uniform(Interface(



Uniform/Client/Cache/Stateless/Server(

Layered(System(

•  The(architecture(may(be(composed(of(hierarchical(layers(of(components,(restric-ng(knowledge(of(the(system(to(a(single(layer.(–  A(client(cannot(tell(if(it(is(communica-ng(with(an(end(server(or(an(

intermediary.(

•  Induced(proper-es:(–  Intermediary(servers(may(improve(system(scalability(through(load/

balancing(and(shared(caches.(

•  Tradeoff:(–  may(reduce(user/received(performance(due(to(having(several(levels(of(

indirec-on.(



Layered(System(



Uniform/Layered/Client/Cache/Stateless/Server(

Code/On/Demand(

•  The(func-onality(of(the(client(can(be(extended(by(downloading(and(execu-ng(code((e.g.,(applets,(scripts).(

•  An(op-onal(constraint.(•  Induced(proper-es:(

–  simplifies(clients;(

–  improves(scalability,(off/loading(work(onto(clients.(•  Tradeoff:(

–  reduced(visibility.(



A(RESTful(Architecture(



REST(

REST(and(HTTP(

•  REST(is(not(the(HTTP(verbs.(

•  REST(is(a(set(of(constraints(that(guided(the(design(of(HTTP(1.1,(by(iden-fying(problems(and(providing(solu-ons(to(those(problems(wrt(the(requirements(of(the(Web.(

•  HTTP(was(designed(specifically(to(manipulate(resources(via(representa5on'transfer.(

•  There(are(some(mismatches(between(HTTP(1.1(and(REST.(–  e.g.,(cookies(promote(sessions(on(the(server.(



WS/*(and(REST(

•  WS/*(uses(HTTP(as(a(transport(protocol(– SOAP(uses(only(POST(

•  HTTP/based(caching(not(possible(•  The(opera-on(itself(is(pushed(in(the(SOAP(message(

– Applica-ons(remain(outside'of'the'Web'

•  REST(uses(HTTP(as(an(applica5on(protocol(– Applica-ons(are(part'of'the'Web'


C.(Pautasso,(O.(Zimmermann,(and(F.(Leymann:(RESTful(Web(Services(vs.(“Big”(Web(Services.(Making(the(Right(Architectural(Decision,(2008.(

WS/*(and(REST(



Using(the(Web(as(an(applica-on(architecture,(and(not(as(a(transporta-on(layer.(




WoT'Defini5ons'Revisited'

WS/*(and(REST(

•  REST(vs.(SOAP(on(resource/constrained(devices(


D.(Yazar(and(A.(Dunkels:(Efficient(Applica-on(Integra-on(in(IP/based(Sensor(Networks,(2009.(


WS/*(and(REST(•  A(developer’s(perspec-ve(

–  ETH(Zurich(–  69(computer(science(students((3rd(or(4th(year(of(Bachelor(studies)(


D.(Guinard,(I.(Ion,(and(S.(Mayer.(REST(or(WS/*?(A(developers’(perspec-ve,(2011.(

REST:(•  very(easy(to(understand,(learn(and(

implement(•  More(lightweight(and(scalable'

WSI*:(•  WSDL(enables(service'contracts'•  Be\er(security(features(•  Be\er(level(of(abstrac5on'(

Ease(of(learning( Speed(of(learning(


WS/*(and(REST(

•  REST(is(well(suited(for(“Do/It/Yourself”,(ad/hoc(integra-on(over(the(Web((mashups)(

•  WS/*(is(well(suited(in(enterprise(applica-ons(with(advanced(QoS(requirements(–  However,(REST(gains(more(adop-on(here(as(well(


C.(Pautasso,(O.(Zimmermann,(and(F.(Leymann:(RESTful(Web(Services(vs.(“Big”(Web(Services.(Making(the(Right(Architectural(Decision,(2008.(

WS/*(and(REST(•  UDDI(discon5nued(by(IBM,(Microso|,(SAP(in(2006(

–  Func-onality(removed(from(Windows(Server(in(2010(

•  WS/*(APIs(discon5nued(by(Google(in(2011((

Google(Trends,(2004/2013(





•  RESTifying'Things'•  Service(Integra-on(in(the(WoT(•  The(Social(Web(of(Things(

123(

Outline(


RESTifying(Things(



Resource(Design(

Representa-on(Design(

Implementa-on(Strategy(

Interface(Design(

RESTifying(Things(


Resource(Design(



Interface(Design(

Resource:(any(component(of(an(applica-on(that(is(worth(being(uniquely(iden-fied(and(linked(to.(


RESTifying(Things(


Resource(Design(



Interface(Design(


M.(Kovatsch,(S.(Mayer,(and(B.(Ostermaier.(Towards(the(thin(server(architecture(for(the(Internet(of(Things,(2012.(

RESTifying(Things(



Resource(Design(



Interface(Design(


h\p://<DOMAIN>:<PORT>/genericNodes/node1/sensors/light(

RESTifying(Things(



Resource(Design(



Interface(Design(



Guidelines(for(resource'iden5fiers((i.e.(URIs):(•  Use(descrip-ve(names.(•  Use(the(plural(form(for(aggregate(resources.(

RESTifying(Things(



Resource(Design(



Interface(Design(



Guidelines(for(resource'iden5fiers((i.e.(URIs):(•  Use(descrip-ve(names.(•  Use(the(plural(form(for(aggregate(resources.(

(HATEOAS)(A(resource(should(link(to(its(parent,(children(and(other(related(resources.(

RESTifying(Things(



Resource(Design(



Interface(Design(

Resources(are(abstract(en--es,(they(can(have(mul-ple(representa-ons(in(different(formats((e.g.,(HTML,(JSON,(XML).(

Recommenda-ons:(•  human/to/machine(interac-on:(HTML.(•  machine/to/machine(interac-on:(JSON.(

RESTifying(Things(



Resource(Design(



Interface(Design(

Resources(are(abstract(en--es,(they(can(have(mul-ple(representa-ons(in(different(formats((e.g.,(HTML,(JSON,(XML).(

Recommenda-ons:(•  human/to/machine(interac-on:(HTML.(•  machine/to/machine(interac-on:(JSON.(

RESTifying(Things(



Resource(Design(



Interface(Design(

Opera5ons((HTTP(verbs):(•  GET:(retrieve(the(resource(

•  e.g.,(GET /genericNodes/node1/sensors/temperature •  PUT:(update(the(value(of(a(resource(

•  e.g.,(PUT /genericNodes/node1/actuators/leds/led1 {“status”:“on”} •  POST:(create(a(new(resource(

•  e.g.,(POST /genericNodes/node1/sensors/temperature/rules {“threshold”:42} •  DELETE:(delete(the(resource(

•  e.g.,(DELETE /genericNodes/node1/sensors/temperature/rules/1(•  OPTIONS:(retrieve(allowed(opera-ons(

•  e.g.,(OPTIONS /genericNodes/node1/sensors/temperature/rules/(

RESTifying(Things(


Resource(Design(



Interface(Design(

Opera5ons((HTTP(verbs):(•  GET:(retrieve(the(resource(•  PUT:(update(the(value(of(a(resource(•  POST:(create(a(new(resource(•  DELETE:(delete(the(resource(•  OPTIONS:(retrieve(allowed(opera-ons(


RESTifying(Things(


Resource(Design(



Interface(Design(

Opera5ons((HTTP(verbs):(•  GET:(retrieve(the(resource(•  PUT:(update(the(value(of(a(resource(•  POST:(create(a(new(resource(•  DELETE:(delete(the(resource(•  OPTIONS:(retrieve(allowed(opera-ons(ContentInego5a5on'

•  HTTP(Header,(e.g.(Accept •  Recommenda-on:(support(content(nego-a-on(in(the(URI(as(well(•  e.g.,(GET /genericNodes/node1/sensors/temperature.json(


RESTifying(Things(


Resource(Design(



Interface(Design(

Opera5ons((HTTP(verbs):(•  GET:(retrieve(the(resource(•  PUT:(update(the(value(of(a(resource(•  POST:(create(a(new(resource(•  DELETE:(delete(the(resource(•  OPTIONS:(retrieve(allowed(opera-ons(ContentInego5a5on'

•  HTTP(Header,(e.g.(Accept •  Recommenda-on:(support(content(nego-a-on(in(the(URI(as(well(•  e.g.,(GET /genericNodes/node1/sensors/temperature.json(

Status'codes'•  ( e.g.,(HTTP/1.1 405 Method Not Allowed


RESTifying(Things(


h\p://dev.evrythng.com/documenta-on/api(

h\p://www.evrythng.com(

Resource(Design(



Interface(Design(

RESTifying(Things(




Resource(Design(



Interface(Design(

RESTifying(Things(




Resource(Design(



Interface(Design(

RESTifying(Things(




Resource(Design(



Interface(Design(

RESTifying(Things(


Resource(Design(



Interface(Design(




•  RESTifying(Things(•  Service'Integra5on'in'the'WoT'•  The(Social(Web(of(Things(

141(

Outline(

"Web(Intelligence"(Master,(December(2013( "Web(Intelligence"(Master,(December(2013( 142(

Jean(Claude,(a(WoT(enthusiast(


Jean(Claude,(a(WoT(enthusiast(

known( unknown(

Service(Integra-on(in(the(WoT(

'Challenges(in(service(integra-on(•  Arrive/and/Operate:(Service(Discovery(and(Look/up(•  Physical(Mashups(•  Automa-c(Service(Composi-on(



Arrive/and/Operate(

Service(Discovery:(–  Adver-sing(services(that(are(provided(by(devices(within(a(smart(environment,(e.g.,(DiscoWoT(

(

Service(Look/up:(–  It’s(not'sta5c'text(documents(anymore!(

•  e.g.,(“Empty(rooms(that(have(a(temperature'of'23°C”(•  Possible(to(use(Google(for(this?(

– Which(aeributes?(Keywords,(Device(Type,(Reviews…(–  Search(engines(for(the(WoT,(e.g.,(Dyser,(InfraWoT(


S.(Mayer,(D.(Guinard,(and(V.(Trifa.(Searching(in(a(Web/based(Infrastructure(for(Smart(Things,(2012.(B.(Ostermaier,(K.(Römer,(F.(Ma\ern,(M.(Fahrmair,(and(W.(Kellerer.(A(Real/Time(Search(Engine(for(the(Web(of(Things,(2010.(

S.(Mayer,(D.(Guinard.(An(Extensible(Discovery(Service(for(Smart(Things,(2011.(


Physical(Mashups(

Composite(WoT(applica-ons,(involving(smart(things(and(virtual(services.(

–  Inspired(by(Web(2.0(mashups.((

Physical(mashup(development:(–  Manual(mashup(development(–  Widget/based(mashup(development(–  End/user(mashup(development(



Automa-c(Service(Composi-on(

•  Embed(informa-on(about(what(smart(things(can(do:(–  Syntac5c(level((e.g.,(data(types,(measurement(units)(–  Seman5c(level((data(meaning)(


Example(from(S.(Mayer(and(G.(Basler.(Seman-c(metadata(to(support(device(interac-on(in(smart(environments,(2013.(



•  RESTifying(Things(•  Service(Integra-on(in(the(WoT(•  The'Social'Web'of'Things'

148(

Outline(


The(Social(Web(of(Things(


A.(Ciortea,(O.(Boissier,(A.(Zimmermann,(and(A.(Florea.(Reconsidering(the(Social(Web(of(Things:(Posi-on(Paper,(2013.(
















•  Web(technologies(enabled(users(to(be(proac5ve(on(the(Web.(•  Exci-ng(-mes(ahead:(seman-c(Web(technologies,(Linked(Data(Plaqorm,(

Push(API,(CoAP,(etc.(

•  Can(we(enable(things(to(be(proac-ve?(


Problem:((Placing(autonomous(and(proac-ve(things(on(the(Web.(

(

Where(to(start?((Socio/technical(networks(

(

Mo-va-on:(•  Providing(a(good(experience(for(the(WoT(user(•  Extending(the(percep-on(of(things(•  Providing(a(framework(for(the(development(of(complex(WoT(

applica-ons.(






Applica-on(

Norma-ve(

Social(

Agency(

RESTful(WoT(API(




Applica-on(

Norma-ve(

Social(

Agency(

RESTful(WoT(API(

Agents(as(individuals(

•  Connec-vity:(at(the(level(of(the(SNS(•  Rela-onship(management:(hardcoded(in(the(agent(•  Decision/making:(Based(on(agent’s(knowledge(•  Coordina-on(mechanisms:(hardcoded(in(the(agent(•  Control(of(autonomy:(applica-on/level(




Applica-on(

Norma-ve(

Social(

Agency(

RESTful(WoT(API(

Agents(in(social(structures(

•  Connec-vity:(open'set'of'social'networks'•  Rela-onship(management:(hardcoded(in(the(agent(•  Decision/making:(Based(on(collec5ve(knowledge(•  Coordina-on(mechanisms:(hardcoded(in(the(agent(•  Control(of(autonomy:(applica-on/level(




Applica-on(

Norma-ve(

Social(

Agency(

RESTful(WoT(API(

Agents(in(organiza-ons(

Enabling:(•  Structural'control:(encourage(of(discourage(

connec-ons(among(things;(•  Communica5on'control:(placing(informa-on(

in(the(appropriate(context;(•  Func5onal'control:(coordina-on(mechanisms(

through(top/down(specifica-ons(of(organiza-onal(processes.(




Applica-on(

Norma-ve(

Social(

Agency(

RESTful(WoT(API(

Agents(in(organiza-ons(

•  Connec-vity:(open(set(of(social(networks(•  Rela-onship(management:(can'be'enforced'•  Decision/making:(Based(on(collec-ve(and'

organiza5onal(knowledge(•  Coordina-on(mechanisms:(organiza5onal'

processes'•  Control(of(autonomy:(organiza5onIlevel'




161(

Outline(


Conclusions(

The(Web'of'Things(is(about(enabling(smart'things(as(firstIclass'ci5zens'of'the'Web.(

(

Mo-va-on:(Create(a(loosely'coupled(ecosystem(

of(services(for(smart(things.((

Lower(the(entry'barrier(for(WoT(applica-on(developers.(


Conclusions(

The(REST'architectural'style(induces(proper-es(that(are(useful(for(smart(environments.(

(

The(Web(is(RESTful,(so(the(WoT(should(be(RESTful.(

(

There(is(a(lot(of(exci5ng,'uncharted'territory.(


Conclusions(

Some(of(the(new(cool(kids(on(the(block:((((The(Web(of(Things(Community:(

–  Community(blog:(h\p://www.webo|hings.org(–  Web(of(Things(Workshop(Series(

•  WoT(2010(@(PerCom,(Mannheim(•  WoT(2011(@(Pervasive,(San(Francisco(•  WoT(2012(@(Pervasive,(Newcastle(•  WoT(2013(@(UbiComp,(Zurich(


Thank(you!(


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