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web technologies----------------

some historical detailsTCP : handles conversion between messages and streams packetsIP : handles addressing of packets across networksTCP/IP : enables packets to be sent across multiple networks using multiple standardsTelnet : one of the earliest standards for exchanging transmission, directly connect accounts on different systems.SMTP : specifies another way of direct connection : email applicationMIME : Extension to the SMTP protocol which supports the exchange of richer data files such as audio, video and images dataFTP : (1973) supports file transfer between internet sites and allow a system to publish a set of files by hosting an FTP server. innovation => permits anonymous users to transfer filesArchie : late 1980's distributed file system based on FTPGopher : first simple system, providing GUI.

core web technologiesHTTP (Hypertext transfer Protocol)- generic, stateless protocol- governs the transfer of files across a network- developed at CERN (Central European Research Network), they also came up with

the name WWW, later W3C- support access to SMTP, FTP and other protocols- was designed to support hypertext.

HTTPuser - common application (browser) directly send the request to the web server- web server search - after get the information send it back to browser and display it to the user

core web technologies- exchanged information, can be static or dinamic- every resource, accessible over the web has URL (uniform resource locator)- HTTP mechanism is based on client

- limitation of http version 1.1 requires servers to suppert persistent connections, to minimize- http is stateless

- no suitable for transactions: does not provide storing of informationbetween requests

- no indication of any relationship between two different requests-> cookies, small data structures that a web server requests the HTTP client tostore on the local machine, are used to maintain state informatione.g. cookies store recently view items on a web shop

clienta client is thre requesting program in a client/server relationship

servercomputer program that provde services to other information

web browserapplication use by client

htmltagging language used to compose documents

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web pagea mixture of text, graphics, sound and animation in the HTML format, to make information accessible in a easy to understand format using the internet

web site:a collection of web pages connected (linked) by hypertext clickable links

web site storage/hostingafter a web site is desined it must be stored on a computer that can be accessed through the internet and the world-widde web.

URL (uniform resource locator):the URL is a "standard" way of easily expressing the location and data type of a resource

- unique address for a resource on the internet- scheme://hostname[:port]/path/filename

scheme:- http: hypertext transfer protocol- ftp: file transfer protocol- malito: send email- news: newsnet news

DNS (domain name services):DNS refers to a network service that associates host names (alphanumeric) with their equivalent TCP/IP address.

XML no focus to display the content but focus to compose the document

main tecnological components that make up moden web pages* HTML - hypertext markup language* CSS* javascript

Javascript

what javascript isn't- java (object-oriented programming language)- a "programmers-only" language

what javascript is- extension to HTML (support depends on browser)- an accessible, object-based scripting language

what javascript is forinteractivity with the user:- input (user provides data to application)- processing (application manipulates data)- output (application provides results to user)

implementing javascript

- direct insertion into page (immediate)- direct insertion into page (deffered)

web based applicationB2C (business to consumer)- conventional 3-tier architectures are designed to operate within a single company -> data exchanges occur within the safe boundaries of the company

- in principles there are no reasons why the system could not be openedto other users if the need arises

ATM (automatic teller machines are an excellent example of the advantage

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s if doing so)

B2C- client /server system- a pc with a network connection to the information services of the bank- gives customers easier access to their accounts without the bank incurring- a significant part of manual work disappears- more efficient

B2C limitations- customer must travel to the nearest ATM, would not be necessary, access to their bank accounts any time, helps extend its functionality.

problem- users wanting to take advantages of this opportunity would need to have specialized clients for every company they want to interact with- complexity would grow enormous -> administration.

solution- one of the biggest contributions of the web -> providing a universal client for such extensions

- nowadayas such architectures are implemented by letting the remote computer use a web browser as a client

- since web browsers are standards tools, no application specific client

 has to be installed.

application servers- equivalent to middleware platforms

- main difference -> intercorporation of the web as a key access channel to the services implemented using the middleware -> several important implications

- the presentation layer acquires a much more relevant role- direct consequence of how HTTP and the web work.

application servers - short overviewrealized by merging the presentation layer related to the web with the applicati

on layer of the middleeware platformreason -> to allow the efficient delivery of content through the web as well asto simplify the management of the web applications

CGI (common gateway interface)

applet = html + javaservlet = java to generate to html

TUGAS DISCUSSION----------------selo@ugm.ac.idsubject: TEI630

1. WHAT IS WEB SERVER? NAME ANY THREE WEB SERVERS2. WHAT IS HYPERTEXT PROTOCOL? EXPLAIN THE REQUEST PHASE AND RESPONSE PHASE IN DETAIL3. GIVE A DEFINITION AND EXPLAIN STANDARD xhtml DOCUMENT STRUCTURE4. WHARE ARE CSS STYLE SHEETS? WHAT IS ADVANTAGE OF DOCUMENT-E

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