Webben är en framgångssaga. Men vilka tekniska egenskaper gör den framgångsrik?Dr. Roy Fielding identifierade dess stora fördelar och vilka arkitektoniskarestriktioner som främjar dessa. REpresentational State Transfer, ellerREST, är en arkitektonisk stil som samlar dessa restriktioner under en akronym.REST kan användas för att ge webbens positiva egenskaper till webbservicessom konsumeras av automatiserade klienter. Uppdraget har varit att implementeraett Application Programming Interface (API) på ett befintligt system föravtalshantering. API:et ska vara RESTful. Vad detta egentligen innebär verkarinte helt solklart. En stor del av arbetet har legat i att studera Fieldings avhandlingoch reda ut begreppen. Det centrala i REST är det enhetliga interfacet, sominnebär att system, oberoende av varandra ska kunna förstå de meddelandensom hanteras. Det utvecklade systemet har utvärderats mot definitionen avREST och systemet saknar den essentiella delen Hypertext As The Engine OfApplication State (HATEOAS). Denna del är också vad som verkar vara denmest missförstådda, eller till och med helt ignorerade delen av REST. HATEOASinnebär att servern genom länkar, dynamiskt serverar klienten med de vägarklienten kan navigera API:et. Detta leder till att ny funktionalitet kan läggas tillutan att skapa inkompatibilitet med klienten. Klienten kan välja att ignorera länkarmed relationer den inte känner igen. För att REST ska vara användbart såmåste klienten förstå relationerna i API:ets länkar och representationen av dessdata. / The World Wide Web is a success. But, what technical properties made it whatit is today? Dr. Roy Fielding identified the web´s great advantages and a set ofarchitectural restrictions to guard the advantages. REpresentational State Transfer,or REST, is an architectural style gathering these restrictions under oneacronym. REST can be used to give the web´s properties to web services to beconsumed by automated clients. The mission has been to implement an ApplicationProgramming Interface (API) on top of a system for contract handling.The API should be RESTful. What RESTful actually means seems unclear. Themajor part of the work has been to study Fieldings dissertation, sorting out thecharacteristics. The central part of REST, is the uniform interface. It allows intermediarynodes to understand the meaning of a message without knowinganything else about the sender. The system developed has been evaluatedagainst Fieldings definition of REST, still the system lacks Hypertext As TheEngine Of Application State (HATEOAS). This part seems to be the mostwidely misunderstood part of REST, often completely ignored. HATEOASgives the server the power of steering the client through the API, by always providinglinks to the available steps. This leads to the ability to add functionalityto the API without breaking the client. The client can just ignore the links that itdoes not know how to handle. For REST to be useful by automated clients, theclient needs to understand the link relations and the data representations of theAPI.

RESTful services are becoming increasingly popular. This work, that was carried out at Scania IT, investigates how a RESTful service should be designed and specified so that it meets the demands of an enterprise environment. In particular, this report will focus on documentation and validation of RESTful services, i.e. specifications. These are important aspects in an enterprise environment. The investigation consists of a comparative case study of four specification formats and Hypermedia As The Engine Of Application State (HATEOAS). The results show that the most commonly used specification formats have flaws. They also suggest that Swagger and RAML (RESTful API Modeling Language) are the two most mature formats. The results also show that HATEOAS, which is a more dynamic approach, can be useful in an enterprise environment but that it requires careful design. / REST-tjänster blir alltmer populära. Detta arbete, som utfördes på Scania IT, undersöker hur en REST-tjänst bör designas och specifieras för att möta de krav som finns i en enterprise-miljö. Specifikt kommer denna rapport att fokusera på dokumentation och validering av REST-tjänster, med andra ord specifikationer. Dessa är viktiga aspekter i en enterprise-miljö. Undersökningen består av en jämförande fallstudie med fyra specifikationsformat samt Hypermedia As The Engine Of Application State (HATEOAS). Resultaten visar att de mest vanligt förekommande specifikationsformaten har brister. De antyder också att Swagger och RAML (RESTful API Modeling Language) är de två mest mogna formaten. Resultaten visar också att HATEOAS, som är ett mer dynamiskt angreppssätt, kan vara användbart i en enterprise-miljö men att det kräver omsorgsfull design.

Submitted by Alison Vanceto (alison-vanceto@hotmail.com) on 2017-01-16T10:24:44Z No. of bitstreams: 1 DissARG.pdf: 3218861 bytes, checksum: 52a9961c02ff8f02866be4a0e7c3462a (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2017-01-17T12:59:21Z (GMT) No. of bitstreams: 1 DissARG.pdf: 3218861 bytes, checksum: 52a9961c02ff8f02866be4a0e7c3462a (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2017-01-17T12:59:28Z (GMT) No. of bitstreams: 1 DissARG.pdf: 3218861 bytes, checksum: 52a9961c02ff8f02866be4a0e7c3462a (MD5) / Made available in DSpace on 2017-01-17T12:59:35Z (GMT). No. of bitstreams: 1 DissARG.pdf: 3218861 bytes, checksum: 52a9961c02ff8f02866be4a0e7c3462a (MD5) Previous issue date: 2016-09-14 / Não recebi financiamento / One of the Software Engineering challenges is the development of applications that can adapt to the heterogeneous needs of users. Technical Dynamic Composition of Services Driven by User is a solution for developing applications capable of overcoming these challenges. This type of application which will call User-Driven Service Composition Application (UDSCA) allows to compose services during its execution, thus meeting the needs of users. But the lack of guidance on how to develop UDCAs can make it difficult or even impossible to build these applications, because it may aggregate unknown solutions by developers. Looking supply this lack, this work presents an approach to guide developers during the development of this kind of application. To develop the approach, it has been defined which activities should be undertaken during the development as well as the concepts, techniques, artifacts, technologies and tools needed to perform these activities. To evaluate the approach one conducted a case study in which a UDSCA was developed in the field of building maintenance services. The resulting application of the approach was shown to be able to adapt to the heterogeneous needs of the user, also the approach provided artifacts that promoted reuse. In conclusion, the approach guides the developer during the UDSCAs development and provides artifacts that reduce efforts for development. / Um dos desafios da Engenharia de Software é o desenvolvimento de aplicações capazes de adaptar-se às diferentes necessidades dos usuários. A técnica de Composição Dinâmica de Serviços Dirigida pelo Usuário é uma solução para desenvolver aplicações capazes de superar esses desafios. Esse tipo de aplicação, a qual denominaremos User-Driven Service Composition Application (UDSCA), permite compor serviços durante sua execução, satisfazendo assim às necessidades dos usuários. Porém a falta de orientação em como desenvolver UDSCAs pode dificultar ou mesmo impossibilitar a construção dessas aplicações, pelo fato de agregar soluções que possam ser desconhecidas pelos desenvolvedores. Procurando suprir essa falta, este trabalho apresenta uma abordagem capaz de orientar os desenvolvedores durante o desenvolvimento deste tipo de aplicação. Na abordagem foram definidas quais as atividades devem ser realizadas durante o desenvolvimento deste tipo de aplicação, assim como os conceitos, técnicas, artefatos, tecnologias e ferramentas necessárias para realizar essas atividades. Para avaliar a abordagem foi realizado um estudo de caso que compreende o desenvolvimento de uma UDSCA no domínio de serviços urbanos. A aplicação resultante da abordagem mostrou-se capaz de adaptar-se às necessidades heterogêneas dos usuários. Além disso, a abordagem forneceu artefatos que promoveram o reuso. Concluiu-se assim que a abordagem orienta os desenvolvedores durante o desenvolvimento de UDSCAs e fornece artefatos que reduzem esforços durante esse desenvolvimento.