abhisharma7674

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PHP( Hypertext Preprocessor)

• INTRODUCE - TO SERVER SLIDE PROGRAMING
• Online E-commerce Solutions System with Source
  Code
• REQUEST TO STATIC SITE'S
• 1 The server must respond dynamically if it needs
  to provide different client-side code depending
  on the situation
• Date and time Specifics of the users request
  Database contents - SYSTEM
  forms and authentication
  SERVER
• 
  
• HTML, CSS, JAVASCRIPIT,AJAX
• PROCESSING
• PHP (Hypertext Preprocessor)

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What is php

• PHP PHP Hypertext Preprocessor Server-side
  scripting language that may be embedded into HTML
  Ultimate goal is to get PHP files to generate
  client side code must end up with HTML, CSS,
  JavaScript, other client .
• 
  

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SIDE BY SIDE

• PHP FILE
  HTML FILE
  OUTPUT
• ltheadgt
  ltHeadgt
  
  
• ltTitle introducing php lt /Titlegt
  lttitle introducing phplt
  /titlegt
• ltBodygt
  ltbody
• lt?php
  HELLO WORLD
• ECHO HELLO WORLD
  lt/bodygt
• ?gt
  Print(output)
• lt/Bodygt
  HELLO WORLD
• 
  

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Introducing php

• 
  PHP TAGS
• Single line
  comment (//)
• Multiple line
  comment (/ and /)
• The echo command

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VIEWING PHP FILE

• PHP files executed on the
  web server
• _ Therefore we cannot save them anywhere and
  view them, as with HTML files
• _ Must save .php files in subdirectory of web
  server
• var/www/ on many Linux configurations
• _ www directory of your user directory on Athena
• _ Make call to web server via domain name
  (google.com), IP address (127.0.0.1), or
  localhost
• if on your own computer

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PHP

• 
  Syntax Variables,
• Operators, and
  Strings

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VARIABLE'S

• Store values for future reference, use variable
  name to refer to the value stored in it PHP is a
  loosely-typed language Do not need to declare the
  type of a variable
• Type can change
  throughout the program x 42 //
• store the value 42 in x echo x // prints 42
  echo x1 // prints 43, value of x is still 42
  x hello! // type of x can change

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OPRATER'S

• 
  Arithmetic operators
• ,-,/,
  (modulus - remainder after division) Logical AND
  (), OR (), NOT (!)
• Assignment operators Shorthand for assignment
  operators x y equivalent to x x y
  Also works with subtraction, multiplication,
  division, modulus, and string concatenation

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VERSUS

• Two equality operator tests for
  equality in value but not necessarily
• type tests for identity in value AND type
  ignores the distinction between Integers,
  floating point numbers, and strings containing
  the same numerical value Nonzero numbers
  and boolean TRUE
• Zero and boolean FALSE

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STRING'S

• A sequence of characters Single and double
  quotes suppose str 42
• echo With single quotes, str is str 7
  output
• With single quotes, str is str echo With
  double quotes, str is str
• output With double quotes, str is 42

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STRING'S

• Col icatenation of rings - the . operator
  String aie ictions 7 Length strlen() Position
  of substring strpos()
• _ More on string functions http//www.w3schools.c
  om/php/php_ref_string.asp a hello pb wor
  rid echo a.. b.! // prints hello
  world!

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CONDITIONAL STATEMENTS

• if (condition / boolean expression)
  statements
• else if (another
  condition) statements
• // there may be more than
  one else if block else statements
• x 5 if(Sx5) echo The
  variable x has value 5!

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THE WHILE LOOP

• while
  (condition) statements x lt 1000) echo
  x. n //is newline character
• x x x

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THE DO WHILE LOOP

• The code within the loop is executed at least
  once, regardless of ae condition is true O
  statements while (condition) equivalent to
  statements while (condition) statements

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CONDITIONAL STATEMENTS

• if (condition / boolean expression) statements
• else if (another condition) statements
• // there may be more than one else if block
• else statements
• 5 a )
• echo The variable x has value 5!

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THE WHILE LOOP

• while (condition) statements j x lt 1000) echo
  x.n //newline character
• x x x

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THE DO WHILE LOOP

• The code within the loop is executed at least
  once, regardless of whether the condition is true
  do statements while (condition) equivalent
  to statements while (condition)
  statements

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THE FOR LOOP

• for (init condition increment)
• ie Cae equivalent to init while (condition)
  statements
• increment
• Prints the first 10 positive integers and their
  squares
• f i 1 i lt 10 i a ae i) ir)
• Defining your fucation
• function function_name (arg1, arg2) function
  code return var //optional True funcation
• Example a simple multiply function
• function Re x y
• echo echo multiply(5, 1.2) 2 prints 6 a5
  Sip.
• error a, b) 7 prints O (?!)

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RETURN VALUE'S

• A function can return a value after it is done
• _ Use this value in future computation, use like
  a variable, assign value to a variable
• A modified multiply function
• function multiply(x, y)
• return x y
• j
• multiply(2,3) 3 prints nothing! returns value,
  but we dont store anywhere echo multiply(2,3)
  prints 6
• a multiply(2,3) 0 assigns the value 6 to the
  variable a
• b multiply(multiply(2,3), multiply(3,4))
  assigns the value 72 to the variable b

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RETURN VALUE'S

• puecten can return at
  most once, and it can only return one value
• If it does not return anything, assignments
  will result in NULL _ A function ends after it
  returns, even if there is code following the
  return statement
• function do_stuff(x)
• if (x 2 0) //if even
• return x/2 // exits function at this point
• // this is ONLY executed if x is odd x 5
• if (x lt 10)
• x 3

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MAKING FUNCATION CALL

• Code inside of a function is not executed unless
  the function is called. Code outside of
  functions is executed whenever the program is
  executed. lt2PHP
• .. // some code function1() // makes function
  call to functioni(), which /finturn calls
  function3() function function1() .. // some
  code
• function3() // makes function call to
  function3()
• function functiona() // this function is never
  called! . // some code
• function function3() i some code

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Arry as alist of elements

• Use arrays to keep track of a list of elements
  using the same variable name, identifying each
  element by its index, starting with O
• colors array(red, blue, green, black,
  yellow To add an element to the array
• colors purple
• Toremove an element from the array
  unset(colors2) colors) Recap arrays
• print_r(array_name) function lets you easily

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RECAPARRAY

• View the contents of an array
• PHP arrays as alist PHP arrays as a map
  favorite_colors array(Joe gt blue, Elena
  gt green, Mark gt brown, Adrian gt
  black, Charles gt red) colorsAdrian)
  colors array(red, blue, green, black,
  yellow colors1) colors) All

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All arrays are
associative

• Each element in an array will have a
  unique key,
• whether you specify it or not.
• EXAMPLE colors array(red, blue, green,
  black, yellow)
• print_ pacolers gives Array( 3 gtred gt blue tae
  reen gt black 4 gt yellow

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For each loop

• The for-each loops allow for easy iteration over
  all elements of an array.
• foreach (array_name as value) code here
• foreach (array_name as key gt value) code
  here
• foreach (colors as color) echo color //
  simply prints each color
• foreach (colors as number gt color)
• echo number gt color // prints color with
  index // to change an element
• // number new_color

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When to use get vs._post

• 1.GET requests are sent via the URL, and can
  thus be
• cached, bookmarked, shared, etc
• 2.GET requests are limited by the length of
  the URL
• 3. POST requests are not exposed in the URL
  and should be used for sensitive data
• 4. There is no limit to the amount
  of information
• passed via _POST

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FORMSSERVER-SIDE

• A simple PHP file that displays what was entered
  into the form
• Can do many other things server-side depending on
  the situation
• Note the use of _POST

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COOKIES AND SESSIONS

• HTTP is stateless it does not keep track of the
  client between requests
• But sometimes we need to keep track of this
  information
• Shopping cart Remember me on login sites 2
  solutions to this issue Cookies - small file
  stored client-side _ Sessions - relevant data
  stored on the server

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EXAMPLE OF COOKIES USAGE

• Main disadvantages of cookies
• _ Limited in size by browser
• _ Stored client-side can be tampered with
• _ Sessions store user data on the server
• _ Limited only by server space
• - Cannot be modified by users
• _ A potential downside to sessions is that they
  expire
• when the browser Is closed
• _ Sessions are identified by a session Id often
  a small cookie! But the rest of the data is still
  stored on the server. Using session

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Using session

• Call session_start() at top of every page to
  start session U Sets a cookie on the client must
  follow same rules as cookies (before any HTML,
  CSS, JS, echo or print statements)
• 0 Access data using the _ SESSION superglobal,
  just like COOKIE, _GET, or _POST

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Using session

• lt?php
  
• Session start ()
  session count1
• If(isset(session (count)))
  echo you visited once
• 
  
• session count1
  ?gt
• Echo visited here
• Else

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Indore Institute of Computer Education (IICE)

• http//www.iiceducation.in/
• IICE (Indore Institute of Computer Education) is
  the leading training institute in Indore, India.
  We have developed ourselves into a well-known
  brand in the education sector of the country. We
  offer a wide range of courses that are designed
  to provide a well-rounded education to the
  students so that they can gain a competitive edge
  in the current job markets.