HTTP - Stateless Protocol

책을 읽다 보니 stateless라는 이야기가 나왔다
분명 예전에는 명확히 알고 있던 내용이었는데 설명을 해보려니 가물가물 해서 다시 정리해 보았다

HTTP - Stateless Protocol
Stateless?
def.
In computing, a stateless protocol is a communications protocol that treats each request as an independent transaction that is unrelated to any previous request so that the communication consists of independent pairs of requests and responses. A stateless protocol does not require the server to retain session information or status about each communications partner for the duration of multiple requests.

Advantages and Disadvantages
The stateless design simplifies the server design because there is no need to dynamically allocate storage to deal with conversations in progress. If a client dies in mid-transaction, no part of the system needs to be responsible for cleaning the present state of the server.

A disadvantage of statelessness is that it may be necessary to include additional information in every request, and this extra information will need to be interpreted by the server.

e.g.
An example of a stateless protocol is HTTP.^[1] The protocol provides no means of storing a user's data between requests. As a work-around, HTTP Servers implement various session management methods,^[2] typically utilizing a unique identifier in a cookie or parameter that allows the server to track requests originating from the same client.

Contrast this with a traditional FTP server that conducts an interactive session with the user. During the session, a user is provided a means to be authenticated and set various variables (working directory, transfer mode), all stored on the server as part of the user's state.

정말 간결하다 역시 위키쨔응...고맙습니다


state를 사용한다면 client와 server 사이의 state 동기화를 검증하는 복잡한 메커니즘이 요구됨
물론 state는 필요함 하지만 http의 용도를 생각해 볼 때 프로토콜단에서 해줄 필요는 없다 이런 내용인듯


출처 :
http://en.wikipedia.org/wiki/Stateless_protocol
http://www.ibm.com/developerworks/kr/library/wa-state/index.html    - 한글 그런데 번역투라 읽기 힘듬
http://www.ibm.com/developerworks/web/library/wa-state/   - 영문