BMIS 289: Spring 2003 Gonzaga University

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BMIS 289 Spring 2003Gonzaga University

• Class 1Course ASP Introduction

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Course Introduction

• Syllabus
• Programs
• Quizzes
• Exams
• Final Project
• Time Requirements
• Web/Email
• Check daily

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Programming Models

• Linear Programming
• Command line driven input/output (IO)
• Linear execution path
• GUI Programming
• Graphical user interface
• Event driven
• Internet Programming
• Client/Server model
• Not platform-dependent

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Linear Programming Example

• Code is executed synchronously - one line at a
  time.
• User inputs one line at time.
• Often run on mainframes.
• The user interface is strictly two-dimensional

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GUI Programming Example

• Code executes asynchronously multiple lines can
  execute at the same time.
• Code is written to respond to events
• A button is clicked, a window is opened, a time
  has been reached, etc.
• Visual user interface

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Internet Programming

• A melding of linear and GUI programming.
• The core logic and data of the program resides on
  a centralized server.
• Users access the program via a rich GUI interface
  (Web) on a personal computer.

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The Internet The Web

• The Internet is a collection of numerous
  networking protocols and applications designed to
  work on a global scale.
• The World Wide Web, or the Web, is one of those
  applications.
• The Web was designed to give the Internet a more
  user friendly interface, similar to how the
  Windows and Macintosh interfaces were designed to
  make PCs more user friendly.

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Basic Web Architecture

• The web is made up of two basic elements
  computer hardware and software.
• Hardware
• Servers computers that deliver the content (in
  the form of web pages) to the users.
• Clients computers that receive information from
  the server and display it to the user. Like a PC.
• Software
• Protocols computer communication rules used to
  deliver the information (TCP/IP, HTTP)
• Browsers computer programs that display and
  interact with the information received via the
  protocols (Internet Explorer, Netscape).

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Web Pages

• Most people view the web via web pages.
• These pages are the interface to a web site.
• They contain text, images, sounds, and video for
  displaying data.
• They contain input mechanisms such as text boxes,
  check boxes, and buttons for obtaining input.
• The majority of web pages are static and written
  purely with HTML.

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Static Web Pages

• HTML Hypertext Markup Language
• HTML is the computer language used to write a web
  page. It is NOT A PROGRAMMING LANGUAGE.
• HTML describes how data looks and is presented,
  it does not actually do anything with the data.
• For example, you could not do arithmetic with
  HTML.
• Because HTML is not a programming language the
  data it presents cannot change unless some person
  physically edits the HTML file, hence HTML files
  are static.

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A Simple HTML Example

• A simple page of HTML code might look like this

lthtmlgt ltheadgt lttitlegtTestlt/titlegt lt/headgt ltbodygt lt
h1gtHello!lt/h1gt lt/bodygt lt/htmlgt
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The Client/Server Model

• Static web pages are delivered based on the
  client/server model of networking.
• The static web pages are stored on a host
  computer called a server.
• Another computer, called a client, contacts that
  server and request the page.

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How A Static Page Is Served

• Developer writes HTML page and places it on the
  server (ex via FTP).
• Browser (client) requests the HTML page from the
  server.
• Server receives request and locates HTML file on
  its hard drive.
• The HTML pages contents are sent to the client
  over the network (LAN, Internet, etc).
• Browser process received HTML and displays it.

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Basic Request/Response (Fig. 1)
Developer creates HTML page and then stores it on
the server
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Server
2
Client Requests Web Page
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Web Page Sent To Client
3
5
Client renders web page
Server locates web page on its hard drive
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How Do Protocols Figure In?

• Lets consider the previous diagram and see where
  the protocols we discussed earlier (TCP/IP, HTTP)
  fit in.
• TCP/IP provides the rules that govern how the
  browser and server communicate with each other on
  the Internet and how data gets from one end to
  the other.
• HTTP provides the rules for how data is
  transferred between the client and server (and
  vice/versa) on the Web.

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Protocols Sending From Server To Client (Fig. 2)
The client and server connect via the TCP/IP
protocol
TCP/IP
Server
HTTP
Static HTML page
Data is sent via the HTTP protocol
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Advantages Of Static HTML

• Easy to learn, use, and understand.
• Even non-programmers can use HTML to create web
  pages.
• With the use of WYSIWYG editors development can
  be simplified even further, to the point where it
  is similar to word processing.
• HTML and HTTP do what they are intended to do
  very well
• The language and protocol was designed to present
  information quickly in an appealing and organized
  manner.

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Disadvantages of Static HTML

• Its static. The files content does not change
  unless a person physically edits the file.
• Often this process involves retrieving the file
  through FTP, editing it, and then uploading back
  to the server with FTP again.
• HTML cannot actually process data. In other
  words, it cannot execute code by itself.
• Cumbersome. The more information you need to
  present the more pages you have to write.

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Dynamic Web Pages

• Writing a large web application that needed to
  process user inputs and output meaningful
  results, like Amazon.com, would require thousands
  of static HTML pages and scores of people to
  constantly update them.
• A more efficient solution is a dynamic web page
  a page that changes its appearance, output, etc.
  based on user inputs and does not require
  constant manual updating.

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Dynamic Web Pages

• A dynamic web page is a mixture of HTML and code.
• The code manipulates the HTML and the information
  contained within it.
• Example
• User inputs their birthday, via a browser, into
  an HTML form.
• The dynamic web page calculates the number of
  days that have passed since the inputted date.
• The resulting value is output as normal HTML in
  the users browser.

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How Dynamic Web Pages Work

• Client browser requests page
• Web server processes the server-side code in the
  requested page.
• Inputs are read in, values are calculated, data
  is retrieved from (or added to) databases, etc.
• The results of the processed code are then
  combined with the HTML in the file.
• The results are sent back to the client as a
  normal HTTP stream of data (just like a static
  HTML page)

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Dynamic Web Pages (Fig. 3)
TCP/IP
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2
Server ProcessesServer-Side Code
Static HTML returned
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3
Results combined with HTML and one page is created
HTTP
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Example Dynamic Web Page

• lthtmlgt
• ltheadgt
• lttitlegtTestlt/titlegt
• lt/headgt
• ltbodygt
• lt
• Hours GetCurrentHours
• if Hours lt 12 then
• print ltH1gtGood Morninglt/H1gt
• elseif Hours gt12 and Hours lt 17 then
• print ltH1gtGood Afternoonlt/H1gt
• else
• print ltH1gtGood Eveninglt/H1gt
• end if
• gt
• lt/bodygtlt/htmlgt

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Advantages of Dynamic Pages

• Because code is actually run in response to a web
  page request, a dynamic page can perform almost
  any action a normal linear or GUI program could
  perform.
• The number of pages that needs to be maintained
  for a given web site/application is greatly
  reduced.
• The code behind the web page can take advantage
  of other technologies like databases, security
  software, etc. to aide it in presenting
  meaningful and correct output to the user.
• Platform independence because all the code is
  run on a remote server, if the clients understand
  HTTP and HTML they can use the application.

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Disadvantages of Dynamic Pages

• More complex than simplistic, static HTML
  pages.
• Programming knowledge required
• Server/Database administration
• More resource-intensive
• Server must process code in addition to sending
  HTML back to the client.
• Security Concerns
• Instead of strictly viewing static content, users
  are now interacting with the servers resources
  and data.
• Anyone with access to the network where the web
  application resides could conceivably gain access
  to it and its resources.

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Applications of Dynamic Pages

• E-Commerce
• Amazon.com, etc.
• E-Business
• Business to Business
• Intranets
• Internal HR systems, etc.
• Thin Clients
• Ticketing systems
• Cheap network PCs, powerful servers.
• Web Services
• Application Service Providers (CRMs, Data
  Processing, etc.)

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ASP (Active Server Pages)

• ASP is a dynamic web page technology created by
  Microsoft.
• It runs primarily on Microsoft platforms (Windows
  98, NT 4, 2000, XP).
• It utilizes several different programming
  languages (VbScript, Jscript, PerlScript).

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ASP IIS

• ASP requires a Microsoft server product called
  IIS in order to run.
• IIS Internet Information Server.
• IIS is freely included with all Microsoft server
  operating systems (NT, 2000, XP).
• It is freely downloadable in the form of Personal
  Web Server for running on workstation operating
  systems (98, NT 4 Workstation).
• IIS and ASP are different programs, but ASP must
  have IIS (or a derivate of it) in order to
  function.

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Alternatives To ASP

• CGI (Common Gateway Interface) Perl.
• PHP Pre-HTML Processor, Linux.
• JSP Java-Server Pages.
• Cold Fusion
• Strict JavaScript (Client-Side only)

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ASP.Net

• Microsoft recently released its next version of
  ASP called ASP.Net.
• The ASP we are using is now, generally, referred
  to as Classic ASP or ASP 3.0.
• ASP.Net has several features that make it more
  powerful and developer friendly than its
  predecessor.
• ASP.Net is not widely in use yet, and most
  existing ASP applications are written in classic
  ASP.

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Class Topics

• Up to the midterm
• Programming fundamentals and their corresponding
  constructs in ASP.
• Web programming fundamentals
• ASP object model
• HTTP, Cookies, Sessions
• After the midterm
• ASP and Data Access
• Advanced ASP topics
• Security
• Final Project

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Next Class

• Send and email to cfukai_at_gonzaga.edu with this
  information

• Name
• School/Major (ex School Of Business/MIS)
• Email Address
• Have you had previous programming experience? If
  yes, what languages?
• What would you most like to learn in this course?

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