CSC 385 Chapter 29, Fall 2003

V. Sawma, Internet Computing 1 Chapter 29 - PHP Outline 29.1 Introduction 29.2 PHP 29.3 String Processing and Regular Expressions 29.4 Viewing Client/Server Environment Variables 29.5 Form Processing and Business Logic 29.6 Verifying a Username and Password 29.7 Connecting to a Database 29.8 Cookies 29.9 Operator Precedence 29.10 Internet and World Wide Web Resources Outline 2 Data.html 1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 2 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3 4 <!-- Fig. 29.18: data.html --> 5 <!-- Querying a MySQL Database --> 6 7 <html xmlns = "http://www.w3.org/1999/xhtml"> 8 <head> 9 <title>Sample Database Query</title> 10 </head> 11 12 <body style = "background-color: #F0E68C"> 13 <h2 style = "font-family: arial color: blue"> 14 Querying a MySQL database. 15 </h2> 16 17 <form method = "post" action = "database.php"> 18 <p>Select a field to display: 19 20 <!-- add a select box containing options --> 21 <!-- for SELECT query --> 22 <select name = "select"> 23 <option selected = "selected">*</option> 24 <option>ID</option> 25 <option>Title</option> 26 <option>Category</option> 27 <option>ISBN</option> 28 </select> 29 </p> 30 Select box containing options for a SELECT query. Outline 3 Data.html Program Output 31 <input type = "submit" value = "Send Query" 32 style = "background-color: blue; 33 color: yellow; font-weight: bold" /> 34 </form> 35 </body> 36 </html> Outline 4 Database.php 1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 2 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3 4 <!-- Fig. 29.19: database.php --> 5 <!-- Program to query a database and --> 6 <!-- send results to the client. --> 7 8 <html xmlns = "http://www.w3.org/1999/xhtml"> 9 <head> 10 <title>Search Results</title> 11 </head> 12 13 <body style = "font-family: arial, sans-serif" 14 style = "background-color: #F0E68C"> 15 <?php 16 17 // build SELECT query 18 $query = "SELECT " . $select . " FROM Books"; 19 20 // Connect to MySQL 21 if ( !( $database = mysql_connect( "localhost", 22 "httpd", "" ) ) ) 23 die( "Could not connect to database" ); 24 25 // open Products database 26 if ( !mysql_select_db( "Products", $database ) ) 27 die( "Could not open Products database" ); 28 29 // query Products database 30 if ( !( $result = mysql_query( $query, $database ) ) ) { 31 print( "Could not execute query! <br />" ); 32 die( mysql_error() ); 33 } 34 ?> 35 Build the select query and assign the string to variable $query. Function mysql_connect returns a database handle which represents PHP’s connection to a database. If this connection is not made, function die is called to terminate script execution. Function mysql_select_db is called to specify the database to be queried. Function mysql_query returns an object containing the result set of the query, which we assign to variable $result. Outline 5 Database.php 36 <h3 style = "color: blue"> 37 Search Results</h3> 38 39 <table border = "1" cellpadding = "3" cellspacing = "2" 40 style = "background-color: #ADD8E6"> 41 42 <?php 43 44 // fetch each record in result set 45 for ( $counter = 0; 46 $row = mysql_fetch_row( $result ); 47 $counter++ ){ 48 49 // build table to display results 50 print( "<tr>" ); 51 52 foreach ( $row as $key => $value ) 53 print( "<td>$value</td>" ); 54 55 print( "</tr>" ); 56 } 57 58 mysql_close( $database ); 59 ?> 60 61 </table> 62 63 <br />Your search yielded <strong> 64 <?php print( "$counter" ) ?> results.<br /><br /></strong> 65 66 <h5>Please email comments to 67 <a href = "mailto:deitel@deitel.com"> 68 Deitel and Associates, Inc. 69 </a> 70 </h5> The for loop iterates through each record in the result set while constructing an XHTML table from the results. Variable $counter is incremented by one for each row retrieved. Function mysql_fetch_row returns an array containing the elements of each row in the result set of our query ($result). The foreach loop iterates through the array containing the elements of each row and prints out each element in an individual table cell. The total number of results are printed to the client. Outline 6 Database.php Program Output 71 72 </body> 73 </html> Outline 7 Cookies.html 1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 2 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3 4 <!-- Fig. 29.20: cookies.html --> 5 <!-- Writing a Cookie --> 6 7 <html xmlns = "http://www.w3.org/1999/xhtml"> 8 <head> 9 <title>Writing a cookie to the client computer</title> 10 </head> 11 12 <body style = "font-family: arial, sans-serif; 13 background-color: #99CCFF"> 14 15 <h2>Click Write Cookie to save your cookie data.</h2> 16 17 <form method = "post" action = "cookies.php" 18 style = "font-size: 10pt"> 19 <strong>Name:</strong><br /> 20 <input type = "text" name = "NAME" /><br /> 21 22 <strong>Height:</strong><br /> 23 <input type = "text" name = "HEIGHT" /><br /> 24 25 <strong>Favorite Color:</strong><br /> 26 <input type = "text" name = "COLOR" /><br /> 27 28 <input type = "submit" value = "Write Cookie" 29 style = "background-color: #F0E86C; color: navy; 30 font-weight: bold" /></p> 31 </form> 32 </body> 33 </html> Form data is posted to cookies.php. Outline 8 Program Output Outline 9 Cookies.php 1 <?php 2 // Fig. 29.21: cookies.php 3 // Program to write a cookie to a client's machine 4 5 // write each form field’s value to a cookie and set the 6 // cookie’s expiration date 7 setcookie( "Name", $NAME, time() + 60 * 60 * 24 * 5 ); 8 setcookie( "Height", $HEIGHT, time() + 60 * 60 * 24 * 5 ); 9 setcookie( "Color", $COLOR, time() + 60 * 60 * 24 * 5 ); 10 ?> 11 12 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 13 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 14 15 <html xmlns = "http://www.w3.org/1999/xhtml"> 16 <head> 17 <title>Cookie Saved</title> 18 </head> 19 20 <body style = "font-family: arial, sans-serif"> 21 <p>The cookie has been set with the following data:</p> 22 23 <!-- print each form field’s value --> 24 <br /><span style = "color: blue">Name:</span> 25 <?php print( $NAME ) ?><br /> 26 27 <span style = "color: blue">Height:</span> 28 <?php print( $HEIGHT ) ?><br /> 29 30 <span style = "color: blue">Favorite Color:</span> 31 Function setcookie takes the name of the cookie to be set as the first argument, followed by the value to be stored in the cookie. The optional third argument specifies the expiration date of the cookie. Each form field’s value is printed to confirm the data that has been set as a cookie with the user. Outline 10 Cookies.php Program Output 32 <span style = "color: <?php print( "$COLOR\">$COLOR" ) ?> 33 </span><br /> 34 <p>Click <a href = "readCookies.php">here</a> 35 to read the saved cookie.</p> 36 </body> 37 </html> Hyperlink to readCookies.php. V. Sawma, Internet Computing 11 29.8 Cookies Fig. 29.22 Cookies directory before a cookie is written. Fig. 29.23 Cookies directory after a cookie is written. Outline 12 ReadCookies.php 1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 2 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3 4 <!-- Fig. 29.24: readCookies.php --> 5 <!-- Program to read cookies from the client's computer --> 6 7 <html xmlns = "http://www.w3.org/1999/xhtml"> 8 <head><title>Read Cookies</title></head> 9 10 <body style = "font-family: arial, sans-serif"> 11 12 <p> 13 <strong> 14 The following data is saved in a cookie on your 15 computer. 16 </strong> 17 </p> 18 19 <table border = "5" cellspacing = "0" cellpadding = "10"> 20 <?php 21 22 // iterate through array $HTTP_COOKIE_VARS and print 23 // name and value of each cookie 24 foreach ( $HTTP_COOKIE_VARS as $key => $value ) 25 print( "<tr> 26 <td bgcolor=\"#F0E68C\">$key</td> 27 <td bgcolor=\"#FFA500\">$value</td> 28 </tr>" ); 29 ?> 30 31 </table> 32 </body> 33 </html> PHP creates array $HTTP_COOKIE_VARS which contains all cookie values indexed by their names. The foreach loop iterates through the $HTTP_COOKIE_VARS array and prints the name and value of each cookie in an XHTML table. Outline 13 Program Output V. Sawma, Internet Computing 14 29.9 Operator Precedence Operator Type Associativity new constructor none [] Subscript right to left ~ ! ++ -- - @ (double) (integer) (string) (array) (object) bitwise not not increment decrement unary negative error control double type cast integer type cast string type cast array type cast object type cast right to left * / % multiplication division modulus left to right + - . Addition subtraction concatenation left to right << >> bitwise shift left bitwise shift right left to right < > <= >= less than greater than less than or equal greater than or equal None Fig. 29.25 PHP operator precedence and associativity. V. Sawma, Internet Computing 15 29.9 Operator Precedence Operator Type Associativity == != === !== equal not equal identical not identical none & bitwise AND left to right ^ bitwise XOR left to right | bitwise OR left to right && logical AND left to right || logical OR left to right = += -= *= /= &= |= ^= .= <<= >>= assignment addition assignment subtraction assignment multiplication assignment division assignment bitwise AND assignment bitwise OR assignment bitwise exclusive OR assignment concatenation assignment bitwise shift left assignment bitwise shift right assignment left to right Fig. 29.25 PHP operator precedence and associativity. V. Sawma, Internet Computing 16 29.9 Operator Precedence Operator Type Associativity and logical AND left to right xor exclusive OR left to right or logical OR left to right , list left to right Fig. 29.25 PHP operator precedence and associativity.