Transcript Classnotes2 - Marymount University Master Suydam

Advanced Web Development
IT225
Spring Term 2016
Marymount University
School of Business
Administration
Professor Suydam
Week 2
HTML Review,
Summary of Chapters 1 & 2,
Establishing a Web Presence
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Review of HTML
Summary of Chapters 1 & 2
Preparation for In-Class Exercise in Week 3
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Distinguish between the Internet and the World Wide Web (WWW) (W3) and
provide a very brief history of each
Explain client-server architectures, as illustrated by web browsers and web servers
Discuss how web browsers and web servers communicate
Take a brief look at a real-world e-commerce website
Outline the technologies we will discuss in this text and mention some of the
competing technologies
Explain what an Internet Service Provider (ISP) is and what services you can expect
from one
Discuss what web development tools you need to get started
Create a simple text-only web page
Test a web page “offline” before going “online”
Put a web page “online” by “uploading” it
Discuss MIME (Multipurpose Internet Mail Extension) types and how browsers use
them to determine the kind of document they are being asked to process
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The Internet
 Think hardware (“connected” computers/devices)
 Originated with ARPANET (late 1960s)
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The World Wide Web (WWW) (W3)
 Think software (users communicating over the Internet via software
applications)
 Originated with Tim Berners-Lee and HTML, and took off with the first GUI
browser, Mosaic
Client-Server Architectures
 A “client” makes a request to a “server”
 The server’s response may be
• Compliance with the request, then breaks connection
• An error message indicating a problem
 Example
• A user’s browser requests a web page for display from a particular web site
• The web server at that site sends the web page or an error message (like a
page-not-found error)
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The term “server” may refer to a program or the machine it runs on
Current popular servers are Apache and Microsoft’s Internet Information Services
(IIS)
Every browser is a program that can act as the client in a client-server relationship
Current popular browsers include: Chrome, Internet Explorer (Edge?), Firefox,
Safari and Opera
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Source: W3C Counter
Chrome on Windows
Sarfari on Mac
Safari for Windows no longer available
Firefox on Windows
Internet Explorer 11 on Windows
Opera on Windows
If you design a page, test it with all browsers to ensure it renders the same.
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 Person-to-person telephone
• Telephone rings
• Callee answers and says “Hello”
• Caller self-identifies and states reason for call
• Callee responds appropriately
• Caller and callee exchange information
• Caller (or callee) says “Good-bye”, and the other responds likewise
• Both caller and callee hang up
 Browser and Server via the Internet
• User types address of web page into browser’s address bar and
presses “Go” button
• Browser sends an HTTP request message to the server identified by
the web address
• Server receives the request and sends back an HTTP response message
• If there was no error, the browser displays the content part of the
response message
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Request
 An HTTP request from a browser contains
 A request line, with a request method (often GET or POST), the URI of
the desired resource, and the version of HTTP in use
 Some header lines, indicating such things as language in use, encoding
scheme, and so on
 A (very important) blank line
 An optional message body
Response
 An HTTP response from a server contains
 A status line, indicating everything is OK or a number indicating that
an error has occurred (404 not found, for example)
 Some header lines, providing information about the response,
especially its content type
 A (very important) blank line
 The content of the returned web page or other resource
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TCP/IP is the fundamental protocol for most communication on the web
UDP is fast and can be used if there is a lot of data and you don’t mind
losing a few bits
FTP is a file transfer standard
TELNET provides a non-secure way to login to a remote computer
SSH can be thought of as a “secure telnet”
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Every device connected to the Internet must have a unique IP address:
 IPv4 is 32 bits: a.b.c.d with a, b, c, d in 0..255
 IPv6 is 128 bits, allowing for many more addresses
Computers understand IP addresses much better than humans,
who prefer FQDNs
 FQDN = Fully Qualified Domain Name
 FQDN cs.smu.ca has IP address 140.184.133.99
 A Domain Name Server (DNS) translates between an IP address and
the corresponding FQDN
A Uniform Resource Locator (URL) is the actual location of a resource on the
web
A Uniform Resource Name (URN) has the same form as a URL but may not
refer to an actual resource
The term Uniform Resource Identifier (URI) is a generalization of the above
two terms and may refer to either one.
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Internet Service Provider (ISP)
 A business or organization that provides you with an Internet
connection
 You may have to pay, or it may be free
 The connection may be wired, or wireless
 Different ISPs provide different levels of service
Wired Connection Options
 Dialup over regular phone lines via a modem
 Cable modem (usually from your TV provider)
 Integrated Service Digital Network (ISDN)
 Asymmetric Digital Subscriber Line (ADSL)
 Fiber-to-the-Premises (FTTP)
Wireless Connection Options
 WiFi (at home and at downtown “hot spots”)
 Code Division Multiple Access (CDMA) allows bandwidth sharing of
different frequencies
 Global System for Mobile (GSM), very popular for mobile telephone
systems
 Worldwide interoperability for Microwave Access (WiMAX) for fixed
and mobile Internet access
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E-mail (often several e-mail addresses)
Network data storage
A URL for a personal or business website, but
 Server-side technologies like scripting and database access may or may
not be provided
 Available bandwidth (upload and download speeds may vary
considerably)
 Cost will vary from one ISP to another
 Bottom line: Be sure to check out the options available and “shop
around” before signing up
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Basic Tools
 A text editor for creating files
 A browser for displaying locally those files as they would appear on
the web
 A file transfer program for uploading your files to your website on the
server at your ISP
“Gotchas” to Avoid
 Be sure to use a text editor, not a word processor, to create your files
 Don’t get wedded to a single browser, and always view your web
pages in more than one
 Use a file transfer program that understands that end-of-line markers
in text files are different on different platforms and deals with this
“transparently” (most do so nowadays)
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Welcome to the Website of
Nature's Source
This is our first foray onto the World Wide Web.
We are a small company dedicated to the health
of our customers through natural remedies.
We have a wide range of products that include:
- books, and multimedia documents that help you get
healthy and stay healthy
- herbal medicines
- equipment for injury free body toning exercises
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Once you have a file ready to go “online”, you need to place it in the correct
location on your ISP’s server (your ISP will tell you where):
• One way: If you have created it on your PC, use a file transfer program to
“upload” it to your ISP’s server – we will use WinSCP
• Another way: It may also be possible to create files directly on the server if
you have an account there.
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