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Web Programming in PHP

Web Programming in PHP. Dr. Hsiang-Fu Yu National Taipei University of Education Original by James Bowen. Reference Sites. http://www.php.net http://www.php.net/manual http://www.zend.com http://www.zend.com/manual. PHP History. PHP originally stood for “ Personal Home Page ”

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Web Programming in PHP

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  1. Web Programming in PHP Dr. Hsiang-Fu Yu National Taipei University of Education Original by James Bowen

  2. Reference Sites • http://www.php.net • http://www.php.net/manual • http://www.zend.com • http://www.zend.com/manual

  3. PHP History • PHP originally stood for “Personal Home Page” • It started out, in 1994, as a simple preprocessor of HTML files • built by Rasmus Lerdorf (born in Greenland, grew up in Denmark and Canada, graduated from University of Waterloo in 1993, now prominent member of Open Source movement) • original purpose was to log people who viewed his on-line resume • Name now supposed to stand for “Hypertext Pre-Processor”

  4. PHP History (cont.) • Initially, PHP comprised a simple parser plus a library of C functions • Scan a HTML file looking for instances of a new non-standard tag • Then replace the contents of these tag instances with the result of executing some functions in the C library • Thus, much PHP syntax looks like C • Other parts of it, however, have a Perl flavour

  5. Enable PHP in HTTP (Web) Servers • PHP is available in Windows and all types of Unix environments • It is supported by Apache, AOLServer, Roxen and IIS • Here, we assume that the httpd recognizes a file who name has the suffix .php as a PHP file

  6. A first PHP file <html> <head> <title>PHP Test</title> </head> <body> <?phpecho “<p>Hello World</p>";?> </body> </html>

  7. How PHP files Are Processed • The httpd demon simply copies regular HTML content in the .php file to the message body that will be sent to a client which requests the .php file • The new non-standard tag is of the form <?php …?> • The text inside the tag is PHP code <?php echo “<p>Hello World</p>"; ?> • The httpd demon executes this PHP code and copies the output text, generated by this PHP code, to the message body that will be sent to the client • Thus, the client would see only <p>Hello World</p>

  8. Suppose That We Request This File C:\> telnet 80 Trying Connected to Escape character is '^]'. GET /index.php <html> <head> <title>PHP Test</title> </head> <body> <p>Hello World</p> </body> </html> Connection closed by foreign host.

  9. PHP Files Are Not Special • PHP files do not have to be executable • They can be regarded as simply HTML files with some new tags

  10. PHP Tags • In the example just seen, the PHP tag was <?php … ?> • This is the best PHP tag to use – it is the one which works best if we are also using XML, because it avoids conflicts with XML Processing Instructions • The following tags are also used • <? … ?> • <% … %> • <script language=“php”> … </script>

  11. Variables in PHP • Variables in PHP are denoted by a dollar sign followed by the name of the variable • $a, $b • A variable name is case-sensitive, like C • A valid variable name starts with a letter or underscore, followed by any number of letters, numbers, or underscores, like C again

  12. Example of Variables <html> <head> <title>Greetings</title> </head> <body> <h1>Greetings</h1> <p> <?php $person = "Tom"; $Person = "Dick"; echo "Hello $person and $Person"; ?> </p> </body> </html>

  13. Example of Variables (cont.)

  14. Automatic Variables in PHP • One of the main benefits of PHP is that it provides lots of variables automatically • Consider, for example, the .php file on the next slide, $_SERVER[‘HTTP_USER_AGENT’] • It produces the output on the following two slides when viewed by MSIE 6.0 and Netscape 2.0

  15. Example of Automatic PHP Variable <html> <head> <title>Your browser</title> </head> <body> <h1>Your Browser</h1> <p> You are using <?phpecho $_SERVER[‘HTTP_USER_AGENT’];?> to view this page. </p> </body> </html>

  16. Example of Automatic PHP Variable (cont.)

  17. Example of Automatic PHP Variable (cont.)

  18. Data Types in PHP • PHP supports eight primitive data types • There are four scalar types • boolean • integer • floating-point number • string • There are two structured types • array • object • There are two special data types • resource • NULL

  19. Data Types in PHP (cont.) • The programmer does not need to specify the type of a variable • a variable’s type is determined from the context of its usage

  20. Booleans • The boolean data type admits two values • true (case-insensitive) • false (case-insensitive) • Example $itIsRainingToday = true; $thePrinterIsBusy = True; $theQueueIsEmpty = FALSE;

  21. Integers • Integers can be specified in decimal, hexadecimal or octal notation, optionally preceded by a sign • In octal notation, the number must have a leading0 • In hexadecimal notation, the number must have a leading 0x. • Examples $a = 1234;# decimal number $a = 0123;# octal number (i.e., 83 decimal) $a = -123;# a negative number $a = 0x1B;# hexadecimal number (i.e., 27 decimal)

  22. Integers (cont.) • The maximum size of an integer is platform-dependent, but usually it’s 32 bits signed– about 2,000,000,000 • PHP does not supportunsigned integers.

  23. Floating Point Numbers • Specified using any of these forms $a = 1.234; $a = 1.2e3; $a = 7E-10; • The maximum size of a float is platform-dependent, although most support a maximum of about 1.8e308 with a precision of roughly 14 decimal digits

  24. Strings • Specified in three different ways • single quoted • double quoted • heredoc syntax

  25. Single-quoted Strings • In single-quoted strings, single-quotes and backslashes must be escaped with a preceding backslash echo 'this is a simple string'; echo 'You can embed newlines in strings, just like this.'; echo ‘Douglas MacArthur said "I\'ll be back” when leaving the Phillipines'; echo 'Are you sure you want to delete C:\\*.*?';

  26. Double-quoted Strings • In double-quoted strings, • variables are interpreted to their values, and • various characters can be escaped • \n linefeed • \r carriage return • \t horizontal tab • \\ backslash • \$ dollar sign • \” double quote • \[0-7]{1,3} a character in octal notation • \x[0-9A-Fa-f]{1,2} a character in hexadecimal notation

  27. Heredoc Strings • Heredoc strings are like double-quoted strings without the double quotes • A heredoc string is delimited as follows • The string is preceded by <<< followed by a label • The string followed by a 2nd occurrence of the same label • Note: the second label must be put in the first position without any space or other characters • Example $str = <<<EOD Example of string spanning multiple lines using heredoc syntax. EOD;

  28. Functions for Strings • addcslashes • Quote string with slashes in a C style • addslashes • Quote string with slashes • bin2hex • Convert binary data into hexadecimal representation • chop • Alias of rtrim() • chr • Return a specific character

  29. Functions for Strings (cont.) • chunk_split • Split a string into smaller chunks • convert_cyr_string • Convert from one Cyrillic character set to another • count_chars • Return information about characters used in a string • crc32 • Calculates the crc32 polynomial of a string • crypt • One-way string encryption (hashing)

  30. Functions for Strings (cont.) • echo • Output one or more strings • explode • Split a string by string • get_html_translation_table • Returns the translation table used by htmlspecialchars() and htmlentities() • get_meta_tags • Extracts all meta tag content attributes from a file and returns an array

  31. Functions for Strings (cont.) • hebrev • Convert logical Hebrew text to visual text • hebrevc • Convert logical Hebrew text to visual text with newline conversion • htmlentities • Convert all applicable characters to HTML entities • htmlspecialchars • Convert special characters to HTML entities • implode • Join array elements with a string

  32. Functions for Strings (cont.) • join • Join array elements with a string • levenshtein • Calculate Levenshtein distance between two strings • localeconv • Get numeric formatting information • ltrim • Strip whitespace from the beginning of a string

  33. Functions for Strings (cont.) • md5 • Calculate the md5 hash of a string • md5_file • Calculates the md5 hash of a given filename • metaphone • Calculate the metaphone key of a string • nl2br • Inserts HTML line breaks before all newlines in a string • ord • Return ASCII value of character

  34. Functions for Strings (cont.) • parse_str • Parses the string into variables • print • Output a string • printf • Output a formatted string • quoted_printable_decode • Convert a quoted-printable string to an 8 bit string • quotemeta • Quote meta characters

  35. Functions for Strings (cont.) • str_rot13 • Perform the rot13 transform on a string • rtrim • Strip whitespace from the end of a string • sscanf • Parses input from a string according to a format • setlocale • Set locale information • similar_text • Calculate the similarity between two strings

  36. Functions for Strings (cont.) • soundex • Calculate the soundex key of a string • sprintf • Return a formatted string • strncasecmp • Binary safe case-insensitive string comparison of the first n characters • strcasecmp • Binary safe case-insensitive string comparison • strchr • Find the first occurrence of a character

  37. Functions for Strings (cont.) • strcmp • Binary safe string comparison • strcoll • Locale based string comparison • strcspn • Find length of initial segment not matching mask • strip_tags • Strip HTML and PHP tags from a string • stripcslashes • Un-quote string quoted with addcslashes()

  38. Functions for Strings (cont.) • stripslashes • Un-quote string quoted with addslashes() • stristr • Case-insensitive strstr() • strlen • Get string length • strnatcmp • String comparisons using a "natural order" algorithm

  39. Functions for Strings (cont.) • strnatcasecmp • Case insensitive string comparisons using a "natural order" algorithm • strncmp • Binary safe string comparison of the first n characters • str_pad • Pad a string to a certain length with another string • strpos • Find position of first occurrence of a string

  40. Functions for Strings (cont.) • strrchr • Find the last occurrence of a character in a string • str_repeat • Repeat a string • strrev • Reverse a string • strrpos • Find position of last occurrence of a char in a string • strspn • Find length of initial segment matching mask

  41. Functions for Strings (cont.) • strstr • Find first occurrence of a string • strtok • Tokenize string • strtolower • Make a string lowercase • strtoupper • Make a string uppercase • str_replace • Replace all occurrences of the search string with the replacement string

  42. Functions for Strings (cont.) • strtr • Translate certain characters • substr • Return part of a string • substr_count • Count the number of substring occurrences • substr_replace • Replace text within a portion of a string • trim • Strip whitespace from the beginning and end of a string

  43. Functions for Strings (cont.) • ucfirst • Make a string's first character uppercase • ucwords • Uppercase the first character of each word in a string • vprintf • Output a formatted string • vsprintf • Return a formatted string

  44. Functions for Strings (cont.) • wordwrap • Wraps a string to a given number of characters using a string break character. • nl_langinfo • Query language and locale information

  45. Arrays • An array in PHP is a structure which maps keys to values • The keys can specified explicitly or they can be omitted • If keys are omited, integers starting with 0 are keys • The value mapped to a key can, itself, be an array, so we can have nested arrays

  46. Create An Array • A special function is used to specify arrays • array() • Format of Usage array([key =>] value, …) • A key is either a string or a non-negative integer • A value can be anything

  47. Create An Array (cont.) • Format of array creation • array( [key =>] value, ... ) • A hash array $mothers = array (“tom"=>“mary", “mick"=>“ann", “bill"=>“orla"); • Implicit indices are integers, starting at 0 $places = array (“Cork”, “Dublin”, “Galway”);

  48. Create An Array (cont.) • If an explicit integer index is followed by implicit indices, they follow on from the highest previous index • Here is an array indexed by integers 1, 2, 3 $places = array (1 => “Cork”, “Dublin”, “Galway”); • Here is an array indexed by integers 1, 5, 6 $places = array (5=> “Cork”, 1 => “Dublin”, “Galway”);

  49. Create An Array (cont.) • A two-dimensional hash array $parents = array (“tom” => array (“father” => “bill”, “mother”=> “mary”), “dave” => array(“father” => “tom”, “mother” => orla”)); • A two-dimensional ordinary array $heights = array (array (10,20), array(100,200));

  50. Array Example 1 <html> <head><title>Array Demo</title></head> <body> <h1>Array Demo</h1> <p> <?php $capital = array ('France'=>'Paris','Ireland'=>'Dublin'); echo 'The capital of Ireland is '; echo $capital['Ireland']; ?> </p> </body> </html>

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