1. RESTful Web Service 2014 년 12 월 한연희 yhhan@koreatech.ac.kr http://link.koreatech.ac.kr

2. REST – Definition and Motivation  REST (Representational State Transfer) – 웹을 기반으로 하는 대규모 네트워크 시스템 설계 및 구현을 위한 일종의 원칙들의 모음 –2000 년 Roy Fielding 의 박사 학위 논문에서 처음 제안. 제목 : Architectural Styles and the Design of Network-based Software Architectures http://www.ics.uci.edu/~fielding/pubs/dissertation/top.htm  최근 REST 에 대한 인식 변화 – 기존 방식인 SOAP, XML-RPC 등을 대치하는 웹 서비스 (Web Service) 구현 방식 2

3. Why is it called “Representational State Transfer?” 3  “Web” is a REST system! State n State n+1 google GET http://www.google.com State n+1 GET https://www.google.co.kr/search?q=IoT Representation html/xml/json Representation html/xml/json facebook State n+2 GET https://www.facebook.com/nest Representation html/xml/json a link selection

4. REST is Not a Standard!  REST is not a standard –You will not see the W3C REST specification.  REST is just a design pattern –You can design your Web services according to its rules.  REST uses standards: –HTTP –URL –XML/HTML/JSON/RSS/GIF/JPEG/etc. (Resource Representations) –text/xml, text/html, image/gif, image/jpeg, etc. (Resource Types, MIME Types) 4

5. REST’s Key Abstraction: Resources  Any information that can be named can be a resource –Document, Image, Service ( e.g. Today's weather in NY) and so on…  Identified by URI –http://weather.com/nyhttp://weather.com/ny  Represented by a standard format –html –xml –json –rss –… 5 Resource http://weather.com/ny 31.5 NY’s Weather [URI] [HTML]

6. REST Generic Interface  CRUD/HTTP – 전체 시스템은 단지 다음 4 개의 명령을 사용해서만 동작 6 GET http://wisefree.com/employee 전체 직원 명단을 얻어 온다.http://wisefree.com/employee POST http://wisefree.com/employee/603045 특정 직원의 자세한 정보를 생성한다. GET http://wisefree.com/employee/603045 특정 직원의 자세한 정보를 얻어온다.http://wisefree.com/employee/603045 PUT http://wisefree.com/employee/603045 특정 직원의 해당 정보를 갱신한다.http://wisefree.com/employee/603045 DELETE http://wisefree.com/employee/603045 특정 직원의 해당 정보를 삭제한다.http://wisefree.com/employee/603045 애플리케이션 작업 HTTP 명령 Create ( 생성 ) POST Read ( 읽기 ) GET Update ( 갱신 ) PUT Delete ( 삭제 ) DELETE [Note] http://wisefree.com/employee?id=603045 – (X)http://wisefree.com/employee?id=603045

7. REST Web Service Design  Resources – 제공하려고 하는 자원 ( 리소스, Resource) 은 무엇인가 ?  Representation – 지원할 Content-type 은 어떤 것들이 있는가 ? XML, JSON, RSS, …  Operation – 지원할 연산은 어떤 것들이 있는가 ? GET/POST/PUT/DELETE  Description – 별도의 웹 페이지 (?) –RSDL (RESTful Service Description Language) 7

8. REST vs. RPC (Remote Procedure Call) style  REST vs RPC-style (Java RMI, CORBA, DCOM, SOAP…) 8

9. REST Design Example  Airline Reservation Service: Approach 1 –“Press 1 for Premier, Press 2 for…“ 9 Premier Members Frequent Flyer Members Regular Members Airline Reservations Answering Machine Premier Customer Representative F.F. Customer Representative Regular Customer Representative

10. REST Design Example  Airline Reservation Service: Approach 2 –“Telephone Numbers are Cheap! Use Them!” 10 Premier Customer Representative F.F. Customer Representative Regular Customer Representative Premier Members Frequent Flyer Members 1-800-Premier 1-800-Frequent 1-800-Reservation Regular Members

11. Web Design – Axiom 0 11 Premier Members Frequent Flyer Members Regular Members client http://www.kings-air/reservations/premier http://www.kings-air/reservations/frequent-flyer http://www.kings-air/reservations/regular Premier Member Reservation Service Frequent Flyer Reservation Service Regular Member Reservation Service

12. REST Design - Advantages 12  The different URLs are discoverable by search engines.  Easy to understand what each service does –simply by examining the URL.  No need to introduce rules. –Just CRUD is all of rules –"What you see is what you get.“  Consistent with Axiom 0.

13. RESTful Open API Example 13  Twitter –Retrieving “Follower Information” using HTTP GET https://api.twitter.com/1.1/followers/ids.json?cursor=- 1&screen_name=sitestreams&count=5000  {11221722, 23428412, …}

14. RESTful Open API Example 14  Facebook (https://developers.facebook.com/tools/explorer)

15. RESTful Open API Example 15  NAVER –Retrieving “ 벤허 영화 정보 ” using HTTP GET http://openapi.naver.com/search?key=test&query= 벤허 &display=10&start=1&target=movie

16. Government 2.0 & Open API 16  서울 열린 데이터 광장 (http://data.seoul.go.kr/)http://data.seoul.go.kr/

17. Government 2.0 & Open API 17  서울 열린 데이터 광장 (http://data.seoul.go.kr/)http://data.seoul.go.kr/

18. Government 2.0 & Open API 18  일반 시민들이 직접 공공데이터를 활용해 만든 앱들

19. Open API Statistics 19 Source (2012): Blog - Innotribe (http://petervan.files.wordpress.com/2012/07/apibillionaires.png)http://petervan.files.wordpress.com/2012/07/apibillionaires.png

20. 20 Resources (  Things) URLs Generic Operations

21. 21 인식의 발전

22. Basic GET Request and IoT 22

23. Advanced GET Request and IoT 23 Subscribe & Notify (Push)

24. 웹 ( 인터넷 )+IoT 기술 발전방향 24 “ 웹은 기술적이라기 보다는 사회적인 창조에 가깝다. 나는 기술적인 장난감이 아니라 사람들이 함께 일함에 도움을 주는 것 같은 사회적인 효과를 위해 웹을 디자인했다. 웹의 궁극적인 목적은 우리의 거미줄 같은 생활을 지원하고 향상시키는 데 있다.” – Tim Berners-Lee