Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Hypertext Transfer Protocol

  • Login to see the comments

Hypertext Transfer Protocol

  1. 1. Hypertext Transfer Protocol Internet Engineering Task Force (IETF) and the World Wide Web Consortium (W3C)
  2. 2. Topics What is HTTP Why HTTP HTTP 1.0 vs. HTTP 1.1 Request/Response formats and header HTTP methods HTTP Status Codes Session maintenance What is HTTPS SSL Handshake
  3. 3. • Foundation of data communication for the World Wide Web Defines how messages are formatted and transmitted What actions web servers and browsers should take in response to various commands Ted Nelson Vannevar Bush's-memex Tim Berners-Lee- CERN
  4. 4. Why Http?  To transfer hypertext(linked) data over WWW  Request/response stateless protocol that can be used widely.
  5. 5. HTTP?  Functions as a request-response protocol in the client-server computing model.  Application layer protocol.  Stateless protocol.  TCP connection.  Uses URL addressing  Method request  Response codes  Uses Caching and conditional get  Session maintenance
  6. 6. HTTP versions 1.0 vs 1.1  Persistent Connections  Pipelining  State management(cookies)  Compression  Range requests  Caching
  7. 7. HTTP versions 1.0 vs 1.1  Persistent Connections : TCP connection to send and receive multiple HTTP requests/responses as opposed to opening a new connection for every single request/response pair  Pipelining
  8. 8. HTTP versions 1.0 vs 1.1  State management(cookies):  Netscape introduced cookies  Compression:  compression could save almost 40% of the bytes sent via HTTP  content-coding or as a transfer-coding  Accept-Encoding header  Range requests: A client may need only part of a resource range requests allow a client to request portions of a resource  To complete a response transfer that was interrupted (either by the user or by a network failure)
  9. 9. HTTP versions 1.0 vs 1.1  Caching: to store locally for faster access Caching in HTTP/1.0  Check validity by conditional request ( If-Modified-Since) Replying 304 (Not Modified) or 200 (OK)  No Cache control (incorrect caching and failure to cache) Caching in HTTP/1.1  Opaque cache validator string- Entity tag(caching errors either because of clock synchronization errors, or because of lack of resolution)  New conditional request-headers: If-None-Match, If-Unmodified- Since and If-Match  Cache-Control header : public, private, no-store, no-cache
  10. 10. HTTP request and response HTTP Response format HTTP Request format
  11. 11. HTTP Methods  Methods are commands to server for request or command
  12. 12. Method classified as:  Safe Methods: Do not modify resources- retrieval only  Idempotent Method: Can be called many times , same outcome
  13. 13. Get, Put and Post  Get: GET method means retrieve whatever information is identified by the Request-URI.  Conditional Get : If-Modified-Since, If-Unmodified-Since, If-Match, If-None- Match  Partial Get : Range header field. **Response to GET request is cacheable  PUT: PUT method requests that the enclosed entity be stored under the supplied Request-URI  If a new resource is created server responsed 201 (Created).  Responses to PUT method are not cacheable
  14. 14.  POST: POST method requests that a web server accepts and stores/processes the data enclosed in the body of the request message.  Function of POST method is determined by the server and is dependent on the Request-URI ** GET requests data from a specified resource POST submits data to be processed to a specified resource **PUT is like a file upload. A put to a URI affects exactly that URI. A POST to a URI could have any effect at all.
  15. 15. HTTP Status Codes • This class of status code indicates a provisional response
  16. 16. Cookies  Sessions are used for maintaining user specific state and authenticated user identities, among many interactions  privacy and security implications
  17. 17. HTTPS  HTTP over SSL  port 443  HTTPS is authentication web server and to protect the privacy and integrity of the exchanged data.
  18. 18. SSL/TSL  TCP & SSL: provides a reliable & secure end-to-end service.  Uses Public private key to encrypt  Asymmetric then symmetric  Key exchange(Deffie-hellman), Cipher (AES), Hash(MD5), Version, random number  Ensures confidentiality, Message intergrity and key Authentication. SSL originally developed by Netscape

×