Transcript ppt
CSE 190: Internet E-Commerce Lecture 5 Exam Material • Lectures 1-4 (Presentation Tier) – 3-tier architecture – HTML – Style sheets – Javascript – DOM – HTTP – Web servers Exam: 3-Tier Architecture • What are the three tiers? • Presentation: purpose of – – – – – Firewall Cache Load balancing server Web server How to recover from failure? • Application Tier – How to recover from failure? • Data Tier – Why can’t this be combined with application tier? Exam: HTML • • • • Purpose; difference with other doc formats Structure of an HTML document General tag syntax Familiar with tags: html, head, body, H#, A, UL, OL, form, input, table, tr, td, br, img, center, frame, script • Components of URL • URL encoding ( url?arg1=ab+cd&arg2=ef%20 ) • Difference between relative and absolute URL Exam: Stylesheets • • • • Purpose What is meant by cascading? General CSS syntax Applying style to: – All tags of type X – All elements of class X • Specify an external stylesheet, internal stylesheet, and inline style Exam: Javascript • • • • • • • • Purpose How to include in a page Writing text to HTML page Declaring variables Declaring functions Returning a value Displaying an alert When the script executes Exam: HTTP • • • • • Status codes, classes of Purpose of: GET, POST, HEAD Syntax of: GET, POST Request fields: Host, Content-Length Response fields: Content-Type Exam: Web Servers • Purpose of • Apache multi-client model • Apache configuration: Purpose of – – – – • • • • Port DocumentRoot ServerName User HTTP authentication SSL Virtual Hosts CGI Example Exam Questions • (2 pts) Draw & explain the relationship between a load balancer and a cluster of web servers. • (3 pts) Show the URL that represents a GET request for domain ucsd.edu and document /student/ski/home.asp with two arguments, task with value open and the second shibboleth with “ali baba” (no quotes). • (3 pts) Explain two advantages of stylesheets over plain HTML. Write an HTML file that applies an internal style to all DIV tags such that the attribute font-size is 18. Example Exam (cot’d) • (3 pts) Write an HTML page that contains a form taking username and password and submits it to ucsd.edu/form.cgi using HTTPS. Onlookers may not view the password. • (3 pts) Write HTML code that uses Javascript to write “Hello World!” to the browser window. • (2 pts) Write a Javascript function that takes two numbers and returns their sum. • (2 pts) Using Javascript to access the DOM, access the second form on the page and assign it to a variable. Example Exam (cot’d) • (3 pts) Show an HTTP/1.0 client send a request for a document hello.gif from an HTTP 1.1 server. Show both request and response headers. Indicate when the connection closes. • (2 pts) What is the purpose of DocumentRoot in Apache’s configuration file (httpd.conf)? • (2 pts) What happens to your web server if a hostile user crashes a child process? How does the parent recover? Are pages still served?