Welcome to CSC667/867

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Welcome to CSC667/867

• Internet Application Design and Development
• Dr. Ilmi Yoon

NOTE Course note courtesy to Ellis Horowits (USC
CS571) and PrenticeHall (Deitel Associates).
The materials are modified to fit to CSc667/867
with permissions from authors.
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Topics what you will learn

• Web Application Architecture
• Principles, Protocols and Practices
• Understanding of core technology, not platform
  specific knowledge
• Pre-WWW, Internet, TCP/IP
• Web Server, Browser, HTTP
• Client side technologies
• Server side technologies
• E-commerce system DB connections
• Web application development Deployment
• XML and its applications
• Emerging technologies
• Web services, Mobile Application, Semantic Web,
  Data exploration, 3Ds on the WWW, Security and
  more

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Course Overview (1/2)

• Mechanism and various technologies of Internet
  applications through projects
• Develop your own web server (using JAVA)
• 2 people team project
• Client-Server Architecture
• HTTP protocols
• MultiThread
• Proj 2 (2 people team project)
• Experiment JavaScript/Python CGI project
• Python or PHP
• AJAX?
• Extra Credit
• Design for deBugger Game Web site
• Design for Hydrodynamics Computation Web site

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Course Overview (2/2)

• Advanced Topic Presentation
• Decide Topic
• Submit the report and slides
• Selected ones will be presented in class
• Various Reports
• Proof of Self Study
• Important topics that can not be covered in depth
  in class will be given as reading assignments.
• Term Project
• Develop and Deploy an Internet application
• 4 people team project
• Most of all, not only knowledge, you will learn
  the experience of building large application,
  team work, presentation skills, searching for
  necessary information from given large resources,
  and learning by yourself!

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PHP vs. JSP vs. ASP

• http//www.wrensoft.com/zoom/benchmarks.html

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From Job posting sites
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Announcements

• TA Manori Thaker
• Start to think of term project as early as
  possible!!!
• Make a team and get started
• Topic will be given, but you may propose your
  own.
• Assignment 1 is now available on the course web
  site (will be updated by 1/31)

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• Any Questions?
• Then, lets get started jump to Project 1!!!
• Rest of the slides are very informative, so
  please read bring questions to the next class!

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• Right before jumping into Technology, use a few
  moments about Principles Usability
• What made Web App become so important?

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Defining the World Wide Web

• A wide-area hypertext, multimedia information
  retrieval system that provides access to a large
  universe of documents
• A uniform way of accessing and viewing some
  information on the Internet
• The WWW
• creates a world in which information has a
  reference by which it can be accessed
• subsumes the capabilities of ftp, gopher, wais
  and news

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History of the World Wide Web

• WWW
• Allows computer users to locate and view
  multimedia-based documents
• Introduced in 1990 by Tim Berners-Lee for
  astrophysicist to share documents
• Internet today
• Mixes computing and communications technologies
• Makes information constantly and instantly
  available to anyone with a connection

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The Internet and the WWW are Different

• The Internet is a global digital infrastructure
  that connects millions of computers and tens of
  millions of people
• The World Wide Web is a mechanism that unifies
  the retrieval and display of a subset of data on
  the Internet
• An intranet is a local/global information
  structure that connects an organization internally

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Major Technology Components

• Client/server architecture
• where client programs interact with web servers
• Network protocol
• HTTP, Hypertext Transfer Protocol, is the
  language understood by browsers and web servers
• designed to move quickly from document to
  document
• Addressing system (Uniform Resource Locators)
• http//domain/directory/file.html
• Markup Language
• every web server understands and every browser
  displays
• includes support for Hypertext and multimedia

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Client/Server Architecture Model
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The WWW Server

• Web browsers and Web servers communicate
  according to a protocol known as HTTP (HyperText
  Transfer Protocol)
• The current HTTP protocol is version 1.1
• The Web server is a software system running on a
  machine often called the Web server, dont
  confuse them
• A web server can
• receive and reply to HTTP requests
• retrieve documents from specified directories
• run programs in specified directories
• handle limited forms of security
• A web server does not
• know about the contents of a document, links in a
  document, images in a document or whether a
  particular file, e.g. a .gif file, is in the
  correct format

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Markup Languages

• HTML - hypertext markup language, specifies
  document layout and the specification of
  hypertext links to text, graphics and other types
  of objects
• browsers display text and graphics using the
  markup as guidance
• You need to read HTML1 2 Self study slides!!
• However, HTML is not like a word processing
  program, e.g. Microsoft Word or WordPerfect, and
  not like a page description languages, e.g.
  postscript
• as a result, translation into HTML can produce a
  result that does not look exactly like the
  original
• XML (extensible markup language)

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Uniform Resource Locator

• A mechanism whereby an Internet resource can be
  specified in a single line of ASCII text
• 1. Scheme followed by a colon http,ftp,gopher,n
  ews,mailto,wais,telnet
• file//pub/xt.ps (a PostScript file in
  directory pub on your local machine)
  ftp//cs.sfsu.edu/docs/sweng.txt (a file
  sweng.txt in directory docs on cs.sfsu.edu, an
  anonymous ftp) http//nunki.usc.edu/mydocs/book.do
  c (a file in directory mydocs on machine
  nunki.usc.edu)
• 2. Double slash (only for http, ftp, gopher,
  wais) //
• 3. Internet domain name e.g., cs.sfsu.edu
• 4. Port number (this field is optional e.g.,
  pollux.usc.edu8081)
• -- Standard or default port numbers
• --- ftp is 21 gopher is 70
• --- telnet is 23 http is 80
• --- smtp is 25 nntp is 119
• 5. Path e.g., /pub/docs

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Download Install Apache
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Total Sites Across All Domains August 1995 -
January 2010
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Market Share for Top Servers Across All Domains
August 1995 - January 2010
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Basic Internet Terminology Definitions

• http//www.pierobon.org/iis/ by Pierobon
• Simple definitions for LAN, WAN, Internet, WWW,
  Hypertext, Intranet, Extranet, Protocol, TCP/IP,
  UDP, Address, Domain, Domain Name, Plug-in, URL,
  URI, socket and a short quiz!

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(No Transcript)
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Network Basics

• A host is a computer that is enabled to function
  on a network
• any set of hosts connected in such a way that any
  two hosts can send and receive messages is called
  a network
• a protocol is the method by which two computers
  agree to communicate
• an address space is the set of names of computers
  that can be referenced

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Internet Protocol (IP)

• delivering distinguished protocol datagrams
  (packets) from the source host to the destination
  host solely based on their addresses.
• Unreliable or best effort delivery.
• No data checksum.
• Physically transmits to next link after resolving
  network address.
• Routing algorithms decide what physical link to
  send on.

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Transmission Control Protocol (TCP)

• Provides reliable end-to-end connection
• Reordering of messages.
• Flow control (sliding window protocol)
• Resending of lost messages.
• Abstraction of a stream of bytes.
• Connection oriented a connection is established
  before messages are sent.
• Uses IP as the underlying transport mechanism.
• Assumes one process is the client and one is the
  server in establishing a connection
• Destination address is characterized by an IP
  address and a 16-bit port number.

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User Datagram Protocol (UDP)

• Characteristics
• Connectionless, Datagram, Unreliable
• Adds only application multiplexing/demultiplexing
  and checksumming to IP
• Good for Streaming Media, Real-time Multiplayer
  Networked Games, VoIP

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Example of a Layered Communication

• Arranging an appointment between two CEOs

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Conceptual layering of protocol software
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Layered Communication Concepts

• Layer n provides a service for layer n1
• API C - header files, Java - interfaces
• Protocol language spoken between two instances
  of a layer

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Sockets and Ports

• Sockets provide endpoints for communication
  between processes.
• A socket must be bound to a local port.
• Socket pair - (local IP address, local port,
  foreign IP address, foreign port) uniquely
  identifies a communication.

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TCP Server (Java)
import java.io. import java.net. public
class Server public static void
main(String args) try
ServerSocket ding null Socket dong
null BufferedReader in
String str try //
ServerSocket, Socket are availalbe Java classes.
ding new ServerSocket(9099)
System.out.println("Opened socket "
9099) while (true) //
keeps listening for new clients, one at a time
try dong ding.accept()
// waits for client here
System.out.println("Wow, something came
in!!!")
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in new BufferedReader(
new InputStreamReader(
dong.getInputStream())) int i
0 str in.readLine()
System.out.println("\n" i "" str)
while (in.ready()) str
in.readLine() System.out.println("\n"
i "" str) i
BufferedOutputStream out new BufferedOutputStrea
m(dong.getOutputStream()) PrintWriter
writer new PrintWriter( out, true )
writer.println("HTTP/1.1 200 OK")
writer.println("Date Thu, 18 Sep 1997 193418
GMT") writer.println("Server
Apache/1.1.3") writer.println("Content-Ty
pe text/html") writer.println("\n")
writer.println("ltHTMLgtltbodygtWow, this simple
server works!! lt/bodygtlt/HTMLgt")
dong.close() catch (IOException e)
System.out.println("Error reading from
socket") System.exit(1) //
there should be more catch blocks to match with
try. And then close the main and class.
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TCP Server (C)
// Creating the socket struct sockaddr_in sa int
sock sock socket(AF_INET,
SOCK_STREAM, 0) if (sock lt 0) // Error int on
1 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
(char ) on, sizeof(on)) // Binding the
socket to an address memset(sa, sizeof(sa),
0) sa.sin_port htons(9090) sa.sin_addr.s_addr
htonl(INADDR_ANY) sa.sin_family AF_INET if
(bind (sock, (struct sockaddr) sa, sizeof(sa))
lt 0) error("bind") listen(sock, 1) // Wait for
a client int rsock accept(sock, 0, 0) if
(rsock lt 0) // Error
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TCP Client (C)
// Create a socket int sock socket(AF_INET,
SOCK_STREAM, 0) if (sock lt 0) // Error //
Associate remote address with socket struct
hostent hp struct sockaddr_in sin hp
gethostbyname(argv1) if (!hp) // Error
memset((char) sin, 0, sizeof(sin)) memcpy((cha
r) (sin.sin_addr), hp-gth_addr,
hp-gth_length) sin.sin_family
hp-gth_addrtype sin.sin_port htons(9090) //
Connect to the remote server if (connect(sock,
(struct sockaddr ) sin, sizeof(sin)) lt 0)
// Error
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API Java C / Unix C / Window
Initialization - - WSAStartup()
Create a socket ServerSocket / Socket socket() socket()
Bind address ServerSocket / Socket bind() bind()
Accept connection ServerSocket.accept() accept() accept()
Make a connection - connect() connect()
Receive data InputStream.read() read() recv()
Send data OutputStream.write() write() send()
Close socket Socket.close() close() close()