PHP implementation of CAPTCHA Verification code class instance, CAPTCHA verification Code _php Tutorial

PHP implementation of CAPTCHA Verification code class instance, CAPTCHA verification code

This paper describes the PHP implementation of the CAPTCHA verification code class, in the PHP program design has a very wide range of applications. Share to everyone for your reference. Here's how:

The Verification code class file is as follows:

<?php/** Captcha Verification Code class * date:2011-02-19* author:fdipzone*/class captcha{//class start private $sname = "; Ction __construct ($sname = ") {//$sname CAPTCHA session name $this->sname = $sname = ="? ' M_captcha ': $sname; }/** generate captcha picture * @param int $length captcha length * @param Array $param parameters * @return IMG */Public Function Create ($length =4, $param  =array ()) {Header ("Content-type:image/png"), $authnum = $this->random ($length);//generate CAPTCHA characters. $width = Isset ($param [' width '])? $param [' width ']: 13; Text width $height = isset ($param [' height '])? $param [' Height ']: 18; Text Height $pnum = isset ($param [' pnum '])? $param [' Pnum ']: 100; Number of interfering pixels $lnum = isset ($param [' lnum '])? $param [' Lnum ']: 2;  Number of interfering lines $this->captcha_session ($this->sname, $authnum); Writes a random number to the session $PW = $width * $length +10;   $PH = $height +6;   $im = Imagecreate ($PW, $ph); Imagecreate () Creates a new image with a blank image of size x_size and y_size. $black = Imagecolorallocate ($im, 238,238,238); Set the background color $values = Array (mt_rand (0, $PW), Mt_rand (0, $ph), Mt_rand (0, $PW), Mt_rand (0, $ph), Mt_rand (0, $PW), Mt_rand (0, $ph), Mt_rand (0, $PW), Mt_rand (0, $ph), Mt_rand (0, $PW), Mt_ra nd (0, $ph), Mt_rand (0, $PW), Mt_rand (0, $ph)); Imagefilledpolygon ($im, $values, 6, Imagecolorallocate ($im, Mt_rand (170,255), Mt_rand (200,255), Mt_rand (210,255))); Set the noise polygon basemap/* text */for ($i = 0; $i < strlen ($authnum); $i + +) {$font = Imagecolorallocate ($im, Mt_rand (0,50), Mt_rand (0,150), Mt_rand (0,200));//Set text color $x = $i/$length * $PW + rand (1, 6);   Sets the random x-coordinate $y = rand (1, $PH/3);  Set the random y-coordinate imagestring ($im, Mt_rand (4,6), $x, $y, substr ($authnum, $i, 1), $font); }/* Add interference pixels */for ($i =0; $i < $pnum; $i + +) {$dist = Imagecolorallocate ($im, Mt_rand (0,255), Mt_rand (0,255), Mt_rand (0,255 ));  Set the dot color Imagesetpixel ($im, Mt_rand (0, $PW), Mt_rand (0, $ph), $dist); }/* Add interference Line */for ($i =0; $i < $lnum; $i + +) {$dist = Imagecolorallocate ($im, Mt_rand (50,255), Mt_rand (150,255), Mt_rand (200 , 255)); Set Line Color Imageline ($im, Mt_rand (0, $PW), Mt_rand (0, $ph), Mt_rand (0, $PW), Mt_rand (0, $PH), $DIST); } imagepng ($im); Output images to a browser or file Imagedestroy ($im) in PNG format; Destroy an image}/** check Verification code * @param String $captcha captcha * @param int $flag verified successfully 0: Do not clear session 1: Clear Session * @return Boolean */P ublic function Check ($captcha, $flag =1) {if (empty ($captcha)) {return false;} else{if (strtoupper ($captcha) = = $this->captcha_session ($this->sname)) {//Detect Verification code if ($flag ==1) {$this  Captcha_session ($this->sname, ");  } return true;  }else{return false;  }}}/* Generates a random number function * @param int $length The string to be randomly generated * @return String */Private function random ($length) {$hash = '; $chars = ' ABCDEFGHIJKLMNPQRSTUVWXYZ23456789 '; $max = strlen ($chars)-1; for ($i = 0; $i < $length; $i + +) {$hash. = $chars [Mt_rand (0, $max)];} return $hash; }/** validation code session processing method * @param string $name captcha Session name * @param string $value * @return String */Private Functio  N Captcha_session ($name, $value =null) {if (Isset ($value)) {if ($value!== ") {$_session[$name] = $value;  }else{unset ($_session[$name]); }}else{return isset ($_session[$name])? $_session[$name]: ';} }}//Class end?>

The Demo sample program is as follows:

<?php   session_start ();   Require_once (' Captcha.class.php ');    $obj = new Captcha ($sname);   # Create Captcha Class object                   # $sname to save the CAPTCHA session name, leave it blank and leave it as ' M_captcha '    $obj->create ($length, $param);  #创建Captcha并输出图片                   # $length is captcha length, can be left blank, default is 4                   /* $param = Array (                       ' width ' =    captcha character Widths                       ') Height ' = ' +    captcha character altitude                       ' pnum ' = number    of interference points                      ' lnum ' and 2     interference lines                       can be left blank                   *   /$obj->check ($captcha, $flag); # Check that the user entered the correct verification code, true or False                   # $captcha the user entered the verification code, required                   # $ Flag can be left blank, default is 1                    #    1: Automatically clears captcha session                   # 0 When validation is successful    : block validation does not clear Captcha session, for Ajax check?>

It is believed that this article has some reference value to the study of PHP program design.

Which one gives an example of a zend_captcha to generate a verification code OH-PHP Framework Development

Do not understand why the default verification code Zend so difficult to recognize, people are quickly recognized.

PHP Registration page CAPTCHA Verification Code code is as follows:

You have to judge, judge you to fill in the verification code is not the same as your previous verification code saved

if ($_post["Captcha"]!=$_session["Captcha"])
{
echo "Verification code error";
}

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