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CCaptchaAction

Package	system.web.widgets.captcha
Inheritance	class CCaptchaAction » CAction » CComponent
Implements	IAction
Since	1.0
Source Code	framework/web/widgets/captcha/CCaptchaAction.php

CCaptchaAction renders a CAPTCHA image.

CCaptchaAction is used together with CCaptcha and CCaptchaValidator to provide the CAPTCHA feature.

You must configure properties of CCaptchaAction to customize the appearance of the generated image.

Note, CCaptchaAction requires PHP GD2 extension.

Using CAPTCHA involves the following steps:

Override CController::actions() and register an action of class CCaptchaAction with ID 'captcha'.
In the form model, declare an attribute to store user-entered verification code, and declare the attribute to be validated by the 'captcha' validator.
In the controller view, insert a CCaptcha widget in the form.

Public Properties

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Property	Type	Description	Defined By
backColor	integer	the background color.	CCaptchaAction
backend	string	the graphic extension that will be used to draw CAPTCHA image.	CCaptchaAction
controller	CController	the controller who owns this action.	CAction
fixedVerifyCode	string	the fixed verification code.	CCaptchaAction
fontFile	string	the TrueType font file.	CCaptchaAction
foreColor	integer	the font color.	CCaptchaAction
height	integer	the height of the generated CAPTCHA image.	CCaptchaAction
id	string	id of this action	CAction
maxLength	integer	the maximum length for randomly generated word.	CCaptchaAction
minLength	integer	the minimum length for randomly generated word.	CCaptchaAction
offset	integer	the offset between characters.	CCaptchaAction
padding	integer	padding around the text.	CCaptchaAction
testLimit	integer	how many times should the same CAPTCHA be displayed.	CCaptchaAction
transparent	boolean	whether to use transparent background.	CCaptchaAction
verifyCode	string	Gets the verification code.	CCaptchaAction
width	integer	the width of the generated CAPTCHA image.	CCaptchaAction

Protected Properties

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Property	Type	Description	Defined By
sessionKey	string	Returns the session variable name used to store verification code.	CCaptchaAction

Public Methods

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Method	Description	Defined By
__call()	Calls the named method which is not a class method.	CComponent
__construct()	Constructor.	CAction
__get()	Returns a property value, an event handler list or a behavior based on its name.	CComponent
__isset()	Checks if a property value is null.	CComponent
__set()	Sets value of a component property.	CComponent
__unset()	Sets a component property to be null.	CComponent
asa()	Returns the named behavior object.	CComponent
attachBehavior()	Attaches a behavior to this component.	CComponent
attachBehaviors()	Attaches a list of behaviors to the component.	CComponent
attachEventHandler()	Attaches an event handler to an event.	CComponent
canGetProperty()	Determines whether a property can be read.	CComponent
canSetProperty()	Determines whether a property can be set.	CComponent
detachBehavior()	Detaches a behavior from the component.	CComponent
detachBehaviors()	Detaches all behaviors from the component.	CComponent
detachEventHandler()	Detaches an existing event handler.	CComponent
disableBehavior()	Disables an attached behavior.	CComponent
disableBehaviors()	Disables all behaviors attached to this component.	CComponent
enableBehavior()	Enables an attached behavior.	CComponent
enableBehaviors()	Enables all behaviors attached to this component.	CComponent
evaluateExpression()	Evaluates a PHP expression or callback under the context of this component.	CComponent
generateValidationHash()	Generates a hash code that can be used for client side validation.	CCaptchaAction
getController()	Returns the controller who owns this action.	CAction
getEventHandlers()	Returns the list of attached event handlers for an event.	CComponent
getId()	Returns id of this action	CAction
getVerifyCode()	Gets the verification code.	CCaptchaAction
hasEvent()	Determines whether an event is defined.	CComponent
hasEventHandler()	Checks whether the named event has attached handlers.	CComponent
hasProperty()	Determines whether a property is defined.	CComponent
raiseEvent()	Raises an event.	CComponent
run()	Runs the action.	CCaptchaAction
runWithParams()	Runs the action with the supplied request parameters.	CAction
validate()	Validates the input to see if it matches the generated code.	CCaptchaAction

Protected Methods

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Method	Description	Defined By
generateVerifyCode()	Generates a new verification code.	CCaptchaAction
getSessionKey()	Returns the session variable name used to store verification code.	CCaptchaAction
renderImage()	Renders the CAPTCHA image based on the code using library specified in the $backend property.	CCaptchaAction
renderImageGD()	Renders the CAPTCHA image based on the code using GD library.	CCaptchaAction
renderImageImagick()	Renders the CAPTCHA image based on the code using ImageMagick library.	CCaptchaAction
runWithParamsInternal()	Executes a method of an object with the supplied named parameters.	CAction

Property Details

backColor property

public integer $backColor;

the background color. For example, 0x55FF00. Defaults to 0xFFFFFF, meaning white color.

backend property (available since v1.1.13)

public string $backend;

the graphic extension that will be used to draw CAPTCHA image. Possible values are 'gd', 'imagick' and null. Null value means that fallback mode will be used: ImageMagick is preferred over GD. Default value is null.

fixedVerifyCode property (available since v1.1.4)

public string $fixedVerifyCode;

the fixed verification code. When this is property is set, getVerifyCode will always return this value. This is mainly used in automated tests where we want to be able to reproduce the same verification code each time we run the tests. Defaults to null, meaning the verification code will be randomly generated.

fontFile property

public string $fontFile;

the TrueType font file. Defaults to SpicyRice.ttf which is provided with the Yii release. Note that non-free Duality.ttf has been changed to open/free SpicyRice.ttf since 1.1.14.

foreColor property

public integer $foreColor;

the font color. For example, 0x55FF00. Defaults to 0x2040A0 (blue color).

height property

public integer $height;

the height of the generated CAPTCHA image. Defaults to 50.

maxLength property

public integer $maxLength;

the maximum length for randomly generated word. Defaults to 7.

minLength property

public integer $minLength;

the minimum length for randomly generated word. Defaults to 6.

offset property (available since v1.1.7)

public integer $offset;

the offset between characters. Defaults to -2. You can adjust this property in order to decrease or increase the readability of the captcha.

padding property

public integer $padding;

padding around the text. Defaults to 2.

sessionKey property read-only

protected string getSessionKey()

Returns the session variable name used to store verification code.

testLimit property

public integer $testLimit;

how many times should the same CAPTCHA be displayed. Defaults to 3. A value less than or equal to 0 means the test is unlimited (available since version 1.1.2).

transparent property

public boolean $transparent;

whether to use transparent background. Defaults to false.

verifyCode property read-only

public string getVerifyCode(boolean $regenerate=false)

Gets the verification code.

width property

public integer $width;

the width of the generated CAPTCHA image. Defaults to 120.

Method Details

generateValidationHash() method (available since v1.1.7)

public string generateValidationHash(string $code)
$code	string	the CAPTCHA code
{return}	string	a hash code generated from the CAPTCHA code

Source Code: framework/web/widgets/captcha/CCaptchaAction.php#140 (show)


public function generateValidationHash($code)
{
    for($h=0,$i=strlen($code)-1;$i>=0;--$i)
        $h+=ord($code[$i]);
    return $h;
}

Generates a hash code that can be used for client side validation.

generateVerifyCode() method

protected string generateVerifyCode()
{return}	string	the generated verification code

Source Code: framework/web/widgets/captcha/CCaptchaAction.php#191 (show)


protected function generateVerifyCode()
{
    if($this->minLength > $this->maxLength)
        $this->maxLength = $this->minLength;
    if($this->minLength < 3)
        $this->minLength = 3;
    if($this->maxLength > 20)
        $this->maxLength = 20;
    $length = mt_rand($this->minLength,$this->maxLength);

    $letters = 'bcdfghjklmnpqrstvwxyz';
    $vowels = 'aeiou';
    $code = '';
    for($i = 0; $i < $length; ++$i)
    {
        if($i % 2 && mt_rand(0,10) > 2 || !($i % 2) && mt_rand(0,10) > 9)
            $code.=$vowels[mt_rand(0,4)];
        else
            $code.=$letters[mt_rand(0,20)];
    }

    return $code;
}

Generates a new verification code.

getSessionKey() method

protected string getSessionKey()
{return}	string	the session variable name

Source Code: framework/web/widgets/captcha/CCaptchaAction.php#219 (show)


protected function getSessionKey()
{
    return self::SESSION_VAR_PREFIX . Yii::app()->getId() . '.' . $this->getController()->getUniqueId() . '.' . $this->getId();
}

Returns the session variable name used to store verification code.

getVerifyCode() method

public string getVerifyCode(boolean $regenerate=false)
$regenerate	boolean	whether the verification code should be regenerated.
{return}	string	the verification code.

Source Code: framework/web/widgets/captcha/CCaptchaAction.php#152 (show)


public function getVerifyCode($regenerate=false)
{
    if($this->fixedVerifyCode !== null)
        return $this->fixedVerifyCode;

    $session = Yii::app()->session;
    $session->open();
    $name = $this->getSessionKey();
    if($session[$name] === null || $regenerate)
    {
        $session[$name] = $this->generateVerifyCode();
        $session[$name . 'count'] = 1;
    }
    return $session[$name];
}

Gets the verification code.

renderImage() method

protected void renderImage(string $code)
$code	string	the verification code

Source Code: framework/web/widgets/captcha/CCaptchaAction.php#228 (show)


protected function renderImage($code)
{
    if($this->backend===null && CCaptcha::checkRequirements('imagick') || $this->backend==='imagick')
        $this->renderImageImagick($code);
    else if($this->backend===null && CCaptcha::checkRequirements('gd') || $this->backend==='gd')
        $this->renderImageGD($code);
}

Renders the CAPTCHA image based on the code using library specified in the $backend property.

renderImageGD() method (available since v1.1.13)

protected void renderImageGD(string $code)
$code	string	the verification code

Source Code: framework/web/widgets/captcha/CCaptchaAction.php#241 (show)


protected function renderImageGD($code)
{
    $image = imagecreatetruecolor($this->width,$this->height);

    $backColor = imagecolorallocate($image,
            (int)($this->backColor % 0x1000000 / 0x10000),
            (int)($this->backColor % 0x10000 / 0x100),
            $this->backColor % 0x100);
    imagefilledrectangle($image,0,0,$this->width,$this->height,$backColor);
    imagecolordeallocate($image,$backColor);

    if($this->transparent)
        imagecolortransparent($image,$backColor);

    $foreColor = imagecolorallocate($image,
            (int)($this->foreColor % 0x1000000 / 0x10000),
            (int)($this->foreColor % 0x10000 / 0x100),
            $this->foreColor % 0x100);

    if($this->fontFile === null)
        $this->fontFile = dirname(__FILE__).DIRECTORY_SEPARATOR.'SpicyRice.ttf';

    $length = strlen($code);
    $box = imagettfbbox(30,0,$this->fontFile,$code);
    $w = $box[4] - $box[0] + $this->offset * ($length - 1);
    $h = $box[1] - $box[5];
    $scale = min(($this->width - $this->padding * 2) / $w,($this->height - $this->padding * 2) / $h);
    $x = 10;
    $y = round($this->height * 27 / 40);
    for($i = 0; $i < $length; ++$i)
    {
        $fontSize = (int)(rand(26,32) * $scale * 0.8);
        $angle = rand(-10,10);
        $letter = $code[$i];
        $box = imagettftext($image,$fontSize,$angle,$x,$y,$foreColor,$this->fontFile,$letter);
        $x = $box[2] + $this->offset;
    }

    imagecolordeallocate($image,$foreColor);

    header('Pragma: public');
    header('Expires: 0');
    header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
    header('Content-Transfer-Encoding: binary');
    header("Content-Type: image/png");
    imagepng($image);
    imagedestroy($image);
}

Renders the CAPTCHA image based on the code using GD library.

renderImageImagick() method (available since v1.1.13)

protected void renderImageImagick(string $code)
$code	string	the verification code

Source Code: framework/web/widgets/captcha/CCaptchaAction.php#295 (show)


protected function renderImageImagick($code)
{
    $backColor=$this->transparent ? new ImagickPixel('transparent') : new ImagickPixel(sprintf('#%06x',$this->backColor));
    $foreColor=new ImagickPixel(sprintf('#%06x',$this->foreColor));

    $image=new Imagick();
    $image->newImage($this->width,$this->height,$backColor);

    if($this->fontFile===null)
        $this->fontFile=dirname(__FILE__).DIRECTORY_SEPARATOR.'SpicyRice.ttf';

    $draw=new ImagickDraw();
    $draw->setFont($this->fontFile);
    $draw->setFontSize(30);
    $fontMetrics=$image->queryFontMetrics($draw,$code);

    $length=strlen($code);
    $w=(int)($fontMetrics['textWidth'])-8+$this->offset*($length-1);
    $h=(int)($fontMetrics['textHeight'])-8;
    $scale=min(($this->width-$this->padding*2)/$w,($this->height-$this->padding*2)/$h);
    $x=10;
    $y=round($this->height*27/40);
    for($i=0; $i<$length; ++$i)
    {
        $draw=new ImagickDraw();
        $draw->setFont($this->fontFile);
        $draw->setFontSize((int)(rand(26,32)*$scale*0.8));
        $draw->setFillColor($foreColor);
        $image->annotateImage($draw,$x,$y,rand(-10,10),$code[$i]);
        $fontMetrics=$image->queryFontMetrics($draw,$code[$i]);
        $x+=(int)($fontMetrics['textWidth'])+$this->offset;
    }

    header('Pragma: public');
    header('Expires: 0');
    header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
    header('Content-Transfer-Encoding: binary');
    header("Content-Type: image/png");
    $image->setImageFormat('png');
    echo $image->getImageBlob();
}

Renders the CAPTCHA image based on the code using ImageMagick library.

run() method

public void run()

Source Code: framework/web/widgets/captcha/CCaptchaAction.php#116 (show)


public function run()
{
    if(isset($_GET[self::REFRESH_GET_VAR]))  // AJAX request for regenerating code
    {
        $code=$this->getVerifyCode(true);
        echo CJSON::encode(array(
            'hash1'=>$this->generateValidationHash($code),
            'hash2'=>$this->generateValidationHash(strtolower($code)),
            // we add a random 'v' parameter so that FireFox can refresh the image
            // when src attribute of image tag is changed
            'url'=>$this->getController()->createUrl($this->getId(),array('v' => uniqid())),
        ));
    }
    else
        $this->renderImage($this->getVerifyCode());
    Yii::app()->end();
}

Runs the action.

validate() method

public boolean validate(string $input, boolean $caseSensitive)
$input	string	user input
$caseSensitive	boolean	whether the comparison should be case-sensitive
{return}	boolean	whether the input is valid

Source Code: framework/web/widgets/captcha/CCaptchaAction.php#174 (show)


public function validate($input,$caseSensitive)
{
    $code = $this->getVerifyCode();
    $valid = $caseSensitive ? ($input === $code) : strcasecmp($input,$code)===0;
    $session = Yii::app()->session;
    $session->open();
    $name = $this->getSessionKey() . 'count';
    $session[$name] = $session[$name] + 1;
    if($session[$name] > $this->testLimit && $this->testLimit > 0)
        $this->getVerifyCode(true);
    return $valid;
}

Validates the input to see if it matches the generated code.