BIT 4444 EXAM1 (Lecture 1)

What does URL stand for?

Uniform Resource Locator

Instantiation

Use of object classes

Sub-class

Inheritance

What does this indicate? "HTTP/1.1 200 OK"

It indicates success

Code reuse

software library?

Web 1.0

(CRAWL) - Mostly read only, company focus, home pages, owning content, web forms, directories, page views, banner advertising, Britannica online HTML portals etc

Web 2.0

(WALK) - Wildly read-write, community focused, blogs/ wikis, sharing content, web application, tagging, cost per click, interactive advertising, wikipedia, SML/RSS

Components of URL: http://www.deitel.com/books/downloads.html What is the hostname?

(www.deitel.com) the name of the web - server computer on which the resources reside

Limitations of server- side scripting

- Consume resources on the server - Less efficient than client- side script - Increases internet traffic

Client - side scripting limitations

- browser dependency - Restricted from arbitrarily accessing the local hardware and file system for security reasons. - Source code an be viewed by the client. - Sensitive information should not be on the client side. - Operations on the client can open web applications to security issues.

Web 2.0: Going social

2.0 was used as a platform to create collaborative, community based sites (ex- social networking sites)

How does GET request work?

A GET request appends data to the URL, e.g., www.google.com/search?q=deitel. }In this case searchis the name of Google's server-side form handler, qis the nameof a variable in Google's search form and deitelis the search term. }The ?in the preceding URL separates the query stringfrom the rest of the URL in a request. }A name/valuepair is passed to the server with the nameand the valueseparated by an equals sign (=). }If more than one name/valuepair is submitted, each pair is separated by an ampersand (&). }The server uses data passed in a query string to retrieve an appropriate resource from the server. }The server then sends a response to the client. A GET request may be initiated by submitting an HTML form whose methodattribute is set to "GET", or by typing the URL (possibly containing a query string) directly into the browser's address bar.

Internet

A global system of inter-connected computer networks (network of network)

Property

A named value of an object

What happens when the user clicks the hyper link?

A web request is sent to a web server, which locates the requested web page and sends it back to the user's web browser

Polymorphism

Ability to process objects different depending on their data type or class

Portable

Allows to design web pages and applications that run across all internet enabled devices

Method

An action that an object is able to perform.

Examples of popular web server

Apache's HTTP server and Microsoft's Internet Information Services

Why is computer referred to as the host?

Because it houses and maintains resources

Encapsulation

Binds together the data and functions that manipulate the date (data hiding)

Client side caching

Browsers often cache (save on disk) recently viewed web pages for quick reloading.

Client - side scripting

Can be used to validate user input, to interact with browser, to enhance web pages, and to add client / server communication between a browser and a web server

What is the name of bottom tier and what does it do?

Data tier or the information tier. - Maintains the application's data, typically in a relational database management system (RDBMS)

What happens if the hyperlink's URL is in the form of mailto: emailAddress

Default e-mail programs loads up and message window pops up

What does business logic do?

Enforces business rules and ensures that data is reliable before the application updates a database or presents data to users

Internet = Web ( True or False)

False

Programmers have more flexibility with client- side scripts. (True or false)

False

Two most common HTTP request types (request methods) are

GET and POST

Current W3C recommendation include

HTML5, cascading style sheets 3 (CSS) and extensive markup language (XML)

Server- side scripting

Has a wider range of programming capabilities than their client - side equivalents

What does Ajax do?

Helps internet- based applications perform desktop applications- (very difficult task)

What does HTML stand for?

HyperText Markup Language (externsion .html or .htm)

What does URI do

Identifies resources on the internet

What does URL contain

Information that directs a browser to the resource that the user wishes to access

What does the word "GET" indicate

It indicates that the client wishes to obtain a resource from the server

What does this indicate? "HTTP/1.1 404 Not found"

It indicates that web browser could not locate the requested resource

What does controller logic do?

It processes client requests and retrieves data from the database

What does HTTP headers do

It provides additional information about the data that will be sent

What does text/html specify?

It specifies the Multipurpose Internet Mail Extensions (MIME) type of the content that the server is transmitting to the browser.

The MIME standard specifies data formats which programs can use to interpret data correctly. Give some examples

MIME type text/ plain indiciates the sent information is a text. MIME type image/ jpeg indiciates the content is a JPEG image.

What does an internet Domain Name System (DNS) server do?

Maintain a database of hostnames and their corresponding IP addresses and performs the translations automatically

Event

Occurs when an object sends a signal that an action g as taken place

Web

One of the services communicated via the internet

Object

Particular instance of a class. Contains real values

What does POST do?

Posts or sends data to a server (ex- forms, documents etc.)

What does presentation logic do?

Processes data from the information tier and presents the content to the client

Web 3.0

RUN

What are web technologies standardized by the W3C called?

Recommendations

What does GET do?

Retrieves information from a server (ex- HTML document, search results etc.)

What does URI stand for?

Uniform Resource Identifiers

Class

Template. Where objects are created

Web applications are often multitier applications (sometimes refereed to as n- tier applications)

That divides functionality into separate tiers ( i.e logical groupings of functionality)

Server- side programming

The applications that respond to requests fro client- side web applications. Ex- searching the internet

Kernel

The software that contains the core components of the operating systems

What is one of the primary goals of W3C?

To make the web universally accessible- regardless of disability, language or culture

Both images and texts may be hyperlinked?

True

Browsers typically do not cache the server's response to a POST request, because the next POST might not return the same result. (True or False)

True

Client- side scripting uses computing resource of the client

True

Server- side scripts often generate custom responses for clients. (True or False)

True

Similarly, there's also the "not modified" HTTP response, indicating that the file content has not changed since it was last requested (which is information that's send in the request). (True or false)

True

The hostname (www.deitel.com) gets translated to IP (Internet Protocol) address

True

The user can type the address of a web page into the browser's address field and press Enter to view the specified page. True or False

True

URIs that start with http:// are called URL. (True or False)

True

Client- side programming

Web pages and applications that are run on user's browser

What else can hyperlink reference?

Web pages, email addresses and files etc

What does W3C stand for?

World wide web consortium (1994)

World wide web

a collection of interlinked multimedia documents that are stored on the internet. They are accessed using HTTP protocol

Example of 3- tier architecture

databse (bottom tier | data tier ) <--> web server (middle tier) --> Browser (top tier | UI tier)

How does POST request work?

message, not as part of the URL. }A GET request typically limits the query string (i.e., everything to the right of the ?) to a specific number of characters, so it's often necessary to send large amounts of information using the post method.}The POST method is also sometimes preferred because it hides the submitted data from the user by embedding it in an HTTP message. }If a form submits several hidden input values along with user-submitted data, the POST method might generate a URL like www.searchengine.com/search. }The form data still reaches the server and is processed in a similar fashion to a GET request, but the user does not see the exact information sent.

Ajax

premier web 2.0 software technologies

Operating systems

provide services that allow each application to execute safely, efficiently and concurrently with other applications