<?php
/*
Changelog
:: Fri Apr 24, 2009
I have updated the documentation and the GenerateCaptcha function
so the session checking is done before generating the captcha image.
*/
/**
* class AbsCaptcha
*
* The AbsCaptcha is a very simple, fully configurable and easy to
* implement class that you can use to generate captcha images.
* While you can change the background color, the text color, the
* width and the height of the image, you cannot change the size of the text.
* It requires the GD library installed and a session started so the
* code from the image can be stored in a session variable.
* This class will regenerate the captcha image for each page request.
*
* Disclaimer:
* This class might not completely stop bots but will definitely
* give them a hard time ;)
*
* @package AbsCaptcha
* @category Captcha
* @author Costin Trifan <costintrifan@yahoo.com>
* @copyright 2009 Costin Trifan
* @licence http://en.wikipedia.org/wiki/MIT_License MIT License
* @version 1.0
*
* Copyright (c) 2009 Costin Trifan <http://june-js.com/>
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
final class AbsCaptcha
{
private function __clone(){}
# PRIVATE PROPERTIES
#==================================
private
$sess_name = 'X_CAPTCHA_CODE', # The name of the session variable that will hold the captcha's generated code
$save_dir = 'captcha', # The path to the directory where to store the created captchas(temporary)
$image_name = 'code_img', # The name of the captcha image
$width = 100, # The width, in pixels, of the captcha image
$height = 50, # The height, in pixels, of the captcha image
$code_length = 6, # The number of digits and letters to display in the captcha image
$bgColor = array(0, 0, 0), # The background color of the captcha image. (r,g,b)
$fgColor = array(255, 255, 0); # The image's text color. (r,g,b)
# PUBLIC METHODS
#==================================
/**
* Constructor
*
* @param string $captcha_session_name The name of the session variable that will hold the captcha's generated code. It's important not to use the default assigned name!
* @param string $save_dir The path to the directory where to store the created images.
* @param string $image_name The name of the image. The image's extension is not required.
* @param array $image_bg_color The image's background color.
* @param array $image_fg_color The image's text color.
* @param string $code_length The number of digits and letters to display in the image.
* @param string $width The width, in pixels, of the captcha image.
* @param string $height The height, in pixels, of the captcha image.
*/
public function __construct( $captcha_session_name='', $save_dir='', $image_name='', $image_bg_color=array(), $image_fg_color=array(), $code_length=NULL, $width=NULL, $height=NULL )
{
// GD Library is a MUST !
if ( !extension_loaded('gd') or !function_exists('gd_info'))
exit('The <strong>'.__CLASS__.'</strong> class requires the <strong>GD Library</strong> to be able to generate the captcha images!') ;
$this->SetSessionName($captcha_session_name);
$this->SetDirectory($save_dir);
$this->SetImageName($image_name);
$this->SetImageBgColor($image_bg_color);
$this->SetImageFgColor($image_fg_color);
$this->SetCodeLength($code_length);
$this->SetImageWidth($width);
$this->SetImageHeight($height);
}
/**
* Create the captcha image.
* @return boolean
*/
public function GenerateCaptcha()
{
// update: Fri Apr 24, 2009
// Makes no sense to generate the image before checking for if the session has been started. (my bad)
// If the session hasn't been started, the captcha won't work.
if ( ! isset($_SESSION) )
exit('Error: The session was not started! The <strong>'.__CLASS__.'</strong> class requires a session to be started in order to function properly!');
// Create the captcha image
$captcha = $this->_create_captcha($this->save_dir, $this->image_name, $this->bgColor, $this->width, $this->height);
// Set the background color for lines
$line1 = @imagecolorallocate($captcha,233,239,239);
$line2 = @imagecolorallocate($captcha, 125, 255, 033);
$line3 = @imagecolorallocate($captcha, 105, 155, 200);
$line4 = @imagecolorallocate($captcha, 200, 30, 120);
$line_yellow = @imagecolorallocate($captcha,255,255,0);
$line_gray = @imagecolorallocate($captcha, 128, 128, 128);
$forecolor = @imagecolorallocate($captcha, $this->fgColor[0], $this->fgColor[1], $this->fgColor[2]);
// Draw some lines.
@imageline($captcha, 0,0,104,129,$line1);
@imageline($captcha, 10,0,164,129,$line1);
@imageline($captcha, 50,0,9,139,$line2);
@imageline($captcha, 70,130,32,32,$line3);
@imageline($captcha, 80,0,52,52,$line4);
@imageline($captcha, 90,0,72,72,$line3);
@imageline($captcha, 84,20,12,72,$line_gray);
@imageline($captcha, 84,22,13,73,$line_gray);
@imageline($captcha, 30,0,120,72,$line1);
@imageline($captcha, 100,122,130,73,$line_gray);
// Generate a random string
$code = md5(uniqid(rand(), true));
// cut string to the length of the digits set to be displayed in the image
$string = strtoupper(substr($code,0,$this->GetCodeLength()));
// Write the string into the image
@imagestring($captcha, 7, 25, 17, $string, $forecolor);
// Save the new image
@imagepng($captcha, $this->save_dir.$this->image_name, 9, PNG_ALL_FILTERS);
// Store the code in the SESSION
//if (isset($_SESSION)) $_SESSION[$this->sess_name] = $string;
//exit('Error: The session was not started! The <strong>'.__CLASS__.'</strong> class requires a session to be started in order to function properly!');
// Store the code in the SESSION
$_SESSION[$this->sess_name] = $string;
return TRUE;
}
# ACCESSOR/MUTATOR METHODS
#==================================
/**
* Set the the name of the session variable that will hold the generated code
*
* @param string $sess_name The name of the session variable that will hold the captcha's generated code
* @return void
*/
public function SetSessionName( $sess_name = '' )
{
if ( (strlen(trim($sess_name)) > 0) and !isset($_SESSION[$sess_name]))
$this->sess_name = $sess_name;
}
/**
* Get the the name of the session variable that holds the generated code
* @return string
*/
public function GetSessionName()
{
return $this->sess_name;
}
/**
* Set the background color of the image
*
* @param array $image_bg_color The list of colors(r,g,b) to use to fill the image
* @return void
*/
public function SetImageBgColor( $image_bg_color = array() )
{
if (count($image_bg_color) < 1) return;
if (isset($image_bg_color[0]) and $image_bg_color[0] >= 0)
$this->bgColor[0] = $image_bg_color[0];
if (isset($image_bg_color[1]) and $image_bg_color[1] >= 0)
$this->bgColor[1] = $image_bg_color[1];
if (isset($image_bg_color[2]) and $image_bg_color[2] >= 0)
$this->bgColor[2] = $image_bg_color[2];
}
/**
* Set the color of the text that will be displayed in the image
*
* @param array $image_fg_color The list of colors(r,g,b) to use for the text
* @return void
*/
public function SetImageFgColor( $image_fg_color = array() )
{
if (count($image_fg_color) < 1) return;
if (isset($image_fg_color[0]) and $image_fg_color[0] >= 0)
$this->fgColor[0] = $image_fg_color[0];
if (isset($image_fg_color[1]) and $image_fg_color[1] >= 0)
$this->fgColor[1] = $image_fg_color[1];
if (isset($image_fg_color[2]) and $image_fg_color[2] >= 0)
$this->fgColor[2] = $image_fg_color[2];
}
/**
* Set the image's code length
*
* @param string $length The number of digits and letters to display in the captcha image
* @return void
*/
public function SetCodeLength( $length )
{
if ( !is_null($length) and $length > 0)
$this->code_length = $length;
}
/**
* Get the image's code length
* @return number
*/
public function GetCodeLength()
{
return $this->code_length;
}
/**
* Set the path to the directory where to save the captcha images
*
* @param string $save_dir The path to the directory where to store the created captchas(temporary)
* @return void
*/
public function SetDirectory( $save_dir = '' )
{
if ( ! empty($save_dir))
{
if (is_dir($save_dir)) $this->save_dir = $save_dir;
else {
if (@mkdir($save_dir)) // try to create the directory
$this->save_dir = $save_dir;
else exit('Error: The directory where to store the generated captchas could not be found nor created. Please create it manually!');
}
}
}
/**
* Get the path to the directory where to save the captcha image
* @return string
*/
public function GetDirectory()
{
return $this->save_dir;
}
/**
* Get the captcha's code stored in the session
* @return string
*/
public function GetCaptchaCode()
{
$code = 0;
if ( isset($_SESSION) and isset($_SESSION[$this->sess_name]))
$code = $_SESSION[$this->sess_name];
return $code;
}
/**
* Set the the name and extension of the image
*
* @param string $image_name The name of the captcha image
* @return void
*/
public function SetImageName( $image_name = '' )
{
if (strlen(trim($image_name)) > 0)
$this->image_name = $image_name.'.png';
else $this->image_name .= '.png';
}
/**
* Get the the name and extension of the image
* @return string
*/
public function GetImageName()
{
return $this->image_name;
}
/**
* Set the width of the image
*
* @param string $width In pixels, the width of the captcha image
* @return void
*/
public function SetImageWidth( $width )
{
if ( !is_null($width) and $width > 0)
$this->width = $width;
}
/**
* Get the width of the image
* @return number
*/
public function GetImageWidth()
{
return $this->width;
}
/**
* Set the the height of the image
*
* @param string $height In pixels, the height of the captcha image
* @return void
*/
public function SetImageHeight( $height )
{
if ( !is_null($height) and $height > 0)
$this->height = $height;
}
/**
* Get the the height of the image
* @return number
*/
public function GetImageHeight()
{
return $this->height;
}
# PRIVATE (INTERNAL) METHODS
#==================================
/**
* Convenient function to create the background support image for captchas
* @access: internal
* @return resource An empty image
*/
private function _create_captcha( $save_dir, $image_name, array $bgColor, $width, $height )
{
// Create image
$image = @imagecreatetruecolor($width, $height);
// Set background color
$color_background = @imagecolorallocate($image, $bgColor[0], $bgColor[1], $bgColor[2]);
// Fill the image
@imagefill($image, 0, 0, $color_background);
return $image;
}
}
// >> END
?>
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