Server Database Cloud
Is the cloud a mystery?
“Until recently, we mainly used our computers to run software programs (Microsoft Word, Quicken) installed on our hard drives. Now, we use them mainly to connect to the vast databases of the Internet — to "the cloud," as the geeks say.”
Nicholas Carr, NPR.org “The New Republic: The Day The PC Died”, January 28, 2010
URL
Uniform Resource Locator
Typically,
http://www.example.com
.com (and others - like .org, .edu) are Top
Level Domains
“example” is the Second Level Domain
Sub domains (Second Level, etc.) exist too.
http://myblog.example.com
HTML
A way to display content on a web page
System is based on tags and attributes
<p><font color=“blue” size=“2”>Hello</font></p>
Links on a web page work a similar way
<a href=“http://www.cnn.com”>CNN</a>
Title text
<a href=“http://www.cnn.com” title=“CNN”>CNN</a>
Rel attribute
<a href=” http://www.cnn.com rel="nofollow">sign in</a>
Fonts, colors, styles, tables, etc are all handled this
Other useful tags
UL
OL
img
form
body
head
Cascading Style Sheets
Separation of content and presentation
p {
font-family:Verdana, Arial, Helvetica, sans-serif; font-size:10pt; text-align:left; font-style:normal; font-weight:normal; color:#333333; }
<p>Hello</p>
Try it<div>
The div element is often used with CSS to layout a
web page
<div class="category">
<a href="http://www.truthdig.com/arts_culture/category/book_reviews/">Book Review</a> </div>
.category {
font-family: Arial, Helvetica, sans-serif; font-size: 115%;
line-height: 82%; }
API
“Application Programming Interface”
It's a way to get information and pass information to trusted
partners.
You need a “key”
Send & receive “requests” - if you have key - good
If not, it kicks you out
Allows you to engage with their data in a way the
way the partner wants
<breakfast_menu> − <food> <name>Belgian Waffles</name> <price>$5.95</price> − <description>
two of our famous Belgian Waffles with plenty of real maple syrup </description>
<calories>650</calories> </food>
−
<food>
<name>Strawberry Belgian Waffles</name> <price>$7.95</price>
−
<description>
light Belgian waffles covered with strawberries and whipped cream </description>
<calories>900</calories> </food>
−
</breakfast_menu>
XML - sharing information on the web
A Breakfast menu
First item is Belgian Waflles, at $5.95, 650 calories, etc.
Fundation Elements
Log Files
Record of every “transaction” on the server
Find, read, send
This means everything – images, files, spiders,
etc. 2006-01-21 00:01:01 72.3.191.179 GET /preview.asp file=/3/stroll6.asp 80 - 193.227.174.73 Mozilla/4.0+(compatible;+MSIE+6.0;+Windows +NT+5.1) 302 0 0 ~120 bytes of data
What it Means
2006-01-21 00:01:01 72.3.191.179 GET /preview.asp?file=/3/stroll6.asp 80 - 193.227.174.73 Mozilla/4.0+(compatible;+MSIE+6.0;+Windows+NT +5.1) 302 0 0 Date Time Server’s IP address Requester’s IP address File requestedUsed in web analytics, for example
More Information Behind the Scenes
When making a request to the server, you
send along a lot of information
Values from any form you fill out
Querystring information
Client Certificate information
Cookie information
Server Variables (contained in the nature of the
QueryString
What is it?
Key=Value pairs that come after a question-mark (?) in a
URL
Multiple pairs joined by an ampersand (&)
What does it look like?
http://www.google.com/search?hl=en&q=what+is+a+querystring
What can you do with this information?
Capture it, and …..?
Can you get this information some other way?
Referrer
What is it?
the referer or referring page is the URL of the
previous webpage from which a link was followed. It is sent by the request.
Let’s see this in action
Example of referrers and querystrings
Cookies
What is it?
A packet of information sent by a server to a browser and
then sent back by the browser each time it accesses that server.
Cookies are always sent back to the site that originated them
What does it look like?
cookie
ID6925457
www.petsmart.com/
1536234352704029706260151645934429633036*
What can you do with this information?
Cookies are mostly used for authentication, tracking, and
maintaining user-specific information (preferences, electronic shopping cart, etc.)
Session (Variables)
What is it?
When a user first accesses a web site, they start a
session. Any information stored at this level is
called a Session variable. Sessions last until you close your browser or some time limit of
non-activity (e.g., 20 minutes)
What can you do with this information?
tracking, and maintaining user-specific information
Other Useful Terms
Page View
Actual visitor views, regardless of the number of images,
etc used to create that view.
Convoluted by reloads, caching, frames, file type
Visitor or Unique Visitor
Unique depends on the person, the person/day, etc.
Loyalty, Frequency, Recency
Number of times, how often, & time since last visit
Bounce Rate
Percent of uses who leave the first page they see on your
Javascript
Programming language often used for “client
side” web programming
Interacts with the web page, not the operating
system
Useful for all sort of cool actions to enhance
a users experience
site navigation, animation, browser identification,
Other Uses of Javascript
Pull information and code from other web
sites
Ad servers, web analytics, etc.
<script src="http://www.google-analytics.com/urchin.js" type="text/ javascript"> </script> <script type="text/javascript"> _uacct = "UA-348254-2"; urchinTracker(); </script>
Screen scraping
Using programming to transfer html from one
site to another
Used before “web services” to get information
For example, get sports scores from ESPN on
your site.
Here’s an example:
www.insightla.org - a buddhist web site
Ajax
What some think will be hot in 2011
The Tablet
Geo
Realtime Search
Chrome OS
HTML 5 - no plugins, drag-drop, offline storage
Mobile Video
Augmented Reality
Mobile Transactions
Android
Blogging software
Acts as a content management system
(CMS)
Brought down barriers to content entry to
zero
Main players: Wordpress, Typepad
Extended to social networking software, with
players like BuddyPress, Drupal, Joomla,
Ning, etc.
WIFI
“The main difference between the white space spectrum and the
spectrum used for Wi-Fi is that white spaces are at a lower frequency, which means they travel much longer distances and penetrate
obstacles, such as walls, much more easily than higher frequency spectrum used for Wi-Fi.”
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