Introduction: Install the Live HTTP Headers (Add-ons for Firefox). Carry out the following activities to study more about HTTP headers.
Activity One: Server
- Find the web server used (name and version) for the following websites
- www.ouhk.edu.hk
- ole.ouhk.edu.hk
- www.microsoft.com.hk
Activity Two: count HTTP Requests
- Find the total number of HTTP requests sent when you access the following webpages:
- www.gov.hk
- www.ouhk.edu.hk
Activity Three: WWW-Authenticate and Authorization
- Access the following webpage: plbpc013.ouhk.edu.hk/pma/, input username and password, and then click cancel.
- Why does your browser know that it is a password-protected webpage?
- What does your browser send when it tries to access the webpage with the username and password?
Activity Four: Cache Mechanism
- Access the following webpage: www.findaway.hk/images/primaryschool/ps199.jpg
- Reload the page, and study the HTTP headers.
- What does your browser send to allow the use of cached content it has got previously?
- Now, press down the shift key and click the refresh button of your browser. Then study the change of the HTTP headers.
- What does your browser send to enforce that no cache will be used?
- What is the Etag value of the above resources? When does it will be changed?
Activity Five: Referer
- Access the following webpage: www.ouhk.edu.hk. Study the HTTP headers.
- What is the referer when your browser retrieve the resource: www.ouhk.edu.hk/images/2008_11/web_main_2_r1_c1.jpg
- Now, access the above image by directly inputting the URL: www.ouhk.edu.hk/images/2008_11/web_main_2_r1_c1.jpg.
- What is the referer now?
Activity Six: Referer from search engines
- Go to a search engine and input some search term.
- Study the HTTP headers when you click one of the search results.
- What is the referer when your browser retrieve the result webpage?
Activity Seven: Cookie
- Access the following website: hk.dictionary.yahoo.com. Input some terms for the dictionary. Study the HTTP headers.
- How does the server remember the words you have inputted before?
Activity Eight: HTTP POST
Activity Nine: Redirect
- Access the following website: ole.ouhk.edu.hk
- What is the redirect page?
Activity Ten: Forbidden
- Access the following webpage: paper.wenweipo.com/2010/01/18/. Study the HTTP headers.
- What is the difference between 403 Forbidden and 404 Not Found?
Submission
- Please submit your work to Steven by email.
- Email: sochoy@ouhk.edu.hk
- Email title: NP Tutorial 12 Submission -SXXXXXXX
