1. Web Server Design Assignment #3: Transfer Encoding & Content Negotiation Due: 03/24/2010 Old Dominion University Department of Computer Science CS 495/595 Spring 2010 Martin Klein

2. Grading To be done by an automated program that will test most (all?) combinations –assignment is listed under the day it is to be demoed in class –each group will give a 3-4 minute status report the week before an assignment is due! If you have a question: –email the class list –mimic the behavior of a well known Apache server (e.g., www.cs.odu.edu)

3. Methods to Support Same as assignments 1 & 2

4. Status Codes to Support Same as assignments 1 & 2, plus: –300 Multiple Choice use if there are > 1 possible representations provide html list for a user to pick from –406 Not Acceptable use if there are no possible representations that match the requested q values

5. Request Headers Same as assignments 1 & 2 and add: –Accept –Accept-Charset –Accept-Encoding –Accept-Language –User-Agent –Referer –Negotiate

6. Response Headers Same as assignments 1 & 2, but add: –Vary –Content-Language –Content-Location –Content-Encoding –“Transfer-Encoding: chunked” –Alternates –TCN Modified –Content-type add charset after type if not ISO-8859-1 (ASCII) –see week 8 slides for examples

7. MIME Types Same as assignment #1

8. Encoding Types compress, gzip, deflate, identity, chunked –(see week 7 lecture)

9. Further Guidance Use “chunked” transfer encoding for any dynamically generated server response –i.e., directory listings and 3xx, 4xx, 5xx html snippets –use 2 lines as the “chunk” Use these language encodings –en, es, de, ja, ko, ru Use these non-ASCII charset encodings –“.jis” -> “iso-2022-jp” –“koi8-r” -> “koi8-r” –“euc-kr” -> “euc-kr”

10. Further Guidance Build “Vary” response header as: Vary: negotiate, header1, header2, …, headerN use the “Vary” header only if content negotiation has been performed No “default” q values in content negotiation –remember: content negotiation only happens if the request would have generated a 404 without content negotiation Generate structured ETags on selected representation as per RFC-2295 (section 9.2)

11. Status Code Definition Generate a 200: –if there is only a single representation as a result of Accept headers and q values Generate a 300: –if there are multiple representations that “tie” in q values OR the client sends a “Negotiate: 1.0” request header –generate an HTML list showing possible options Generate a 406: –if no representations are suitable given Accept headers and q values –generate an HTML list showing closest options

12. 302 Redirection # # Incoming RE302 URI # (this overwrites the redirection from A2) # ^(.*)/galaxie(.*)$1/fairlane$2

13. Keep in mind: Status report in 2 weeks!

14. START NOW!!!