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?