Introduction to HTTP 1.1

A brief introduction to HTTP for web and mobile developers.

Transcript

1. Introduction to HTTP 1.1 By Zaki Shaheen
2. “There is no sense in being precise if you do not know what you are talking about.”
 
 John von Neumann
3. Prerequisites Understanding of computer networks Understanding of OSI and TCP/IP Model Understanding of network applications (client, server, connection, persistent/nonpersistent connection, etc.)
4. The OSI Layer Model (Charles Bachmann, Honeywell, 1983 - ISO 7498)
8. What is HTTP? HTTP = HyperText Transfer Protocol Application-level protocol for distributed, collaborative hypermedia systems. Mother of All Demos (D. Englebart - 1968)
9. HyperText HyperText = Contains links to other Vennevar Bush, 1930-1945 - “As we may think” Ted Nelson, 1965
10. Foundational technology of the WorldWideWeb. 
 Generic and stateless. 
 Can be used for almost any kind of information exchange in a distributed environment. 
 Focus on “negotiation” to transfer any kind of data.
11. Brief History of HTTP v0.9 - 1991
 v1.0 - 1996 (Tim Berners-Lee RFC1945)
 v1.1 - 1999 (The internet society - RFC2616)
 
 Other related things: URIs (RFC 5785)
12. 2014 update to HTTP Message syntax and routing (RFC 7230)
 Semantics and content (RFC 7231)
 Conditional Requests (RFC 7232) Range Requests (RFC 7233)
 Caching (RFC 7234)
 Authentication (RFC 7235)
 Authentication Registration (RFC 7236) ...
13. Skipping URIs but...
14. Remember... connection packet, frame, message, request, response resource, entity, representation client, user agent, server
15. Pop Quiz How is a request transmitted from your browser to the server and back?
18. HTTP message header entity | message Entity entity-header response-header general-header entity-header request-header general-header Entity
19. Header fields general-header request-header | response-header entity-header message body can be any content but must be specified what kind of content it is.
20. general-header cache-control connection date transfer-encoding (chunked?)
21. request-header Accept, Accept-charset, Accept-Encoding, Accept-Language, Authorization, Expect, From, Host, If- Match, If-Modified-Since, User-Agent…
22. response-header accept-ranges, age, e-Tag, location (201, created), proxy-authentication, retry-after, server, vary, www- authenticate...
23. entity-header
24. message
25. Pop-Quiz How many HTTP request methods?
26. 8 methods GET POST OPTIONS HEAD
 PUT DELETE
 TRACE CONNECT
27. GET and HEAD Normal GET
 Partial GET (Range headers) Conditional GET (If-Modified-Since)
 
 Head only returns the header, not the entity itself.
28. POST The POST method is used to request that the origin server accept the entity enclosed in the request as a new subordinate of the resource identified by the Request-URI in the Request-Line.
29. PUT and DELETE Add or update. Client specifies the URI. 
 If new Entity is created - respond with 201. 
 If existing entity is updated - respond with 200.
 
 
 Delete deletes the entity specified.
30. TRACE Reflect my message back to me!
31. Pop- Quiz: How many status messages?
32. 41 Status codes Informational: 100-101 Successful: 200 - 206 Redirection: 300 - 307
 Client error: 400 - 417
 Server error: 500 - 505
33. 100 - continue 101 - switching protocols 200 - OK 201 - Created 202 - Accepted 203 - non-authoritative information 204 - no content
34. 205 - reset content 206 - partial content …
 400 - bad request 401 - unauthorized 403 - forbidden 404 - not found
35. Advanced topics Authentication and authorisation Caching Advanced header fields
36. Resources Read the HTTP and related RFCs TutsPlus articles on HTTP
 Read The Innovators for a beautiful history of computing.