framework/captcha/CaptchaAction.php
<?php
/**
* @link https://www.yiiframework.com/
* @copyright Copyright (c) 2008 Yii Software LLC
* @license https://www.yiiframework.com/license/
*/
namespace yii\captcha;
use Yii;
use yii\base\Action;
use yii\base\InvalidConfigException;
use yii\helpers\Url;
use yii\web\Response;
/**
* CaptchaAction renders a CAPTCHA image.
*
* CaptchaAction is used together with [[Captcha]] and [[\yii\captcha\CaptchaValidator]]
* to provide the [CAPTCHA](https://en.wikipedia.org/wiki/CAPTCHA) feature.
*
* By configuring the properties of CaptchaAction, you may customize the appearance of
* the generated CAPTCHA images, such as the font color, the background color, etc.
*
* Note that CaptchaAction requires either GD2 extension or ImageMagick PHP extension.
*
* Using CAPTCHA involves the following steps:
*
* 1. Override [[\yii\web\Controller::actions()]] and register an action of class CaptchaAction with ID 'captcha'
* 2. In the form model, declare an attribute to store user-entered verification code, and declare the attribute
* to be validated by the 'captcha' validator.
* 3. In the controller view, insert a [[Captcha]] widget in the form.
*
* @property-read string $verifyCode The verification code.
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @since 2.0
*/
class CaptchaAction extends Action
{
/**
* The name of the GET parameter indicating whether the CAPTCHA image should be regenerated.
*/
const REFRESH_GET_VAR = 'refresh';
/**
* @var int 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).
*/
public $testLimit = 3;
/**
* @var int the width of the generated CAPTCHA image. Defaults to 120.
*/
public $width = 120;
/**
* @var int the height of the generated CAPTCHA image. Defaults to 50.
*/
public $height = 50;
/**
* @var int padding around the text. Defaults to 2.
*/
public $padding = 2;
/**
* @var int the background color. For example, 0x55FF00.
* Defaults to 0xFFFFFF, meaning white color.
*/
public $backColor = 0xFFFFFF;
/**
* @var int the font color. For example, 0x55FF00. Defaults to 0x2040A0 (blue color).
*/
public $foreColor = 0x2040A0;
/**
* @var bool whether to use transparent background. Defaults to false.
*/
public $transparent = false;
/**
* @var int the minimum length for randomly generated word. Defaults to 6.
*/
public $minLength = 6;
/**
* @var int the maximum length for randomly generated word. Defaults to 7.
*/
public $maxLength = 7;
/**
* @var int the offset between characters. Defaults to -2. You can adjust this property
* in order to decrease or increase the readability of the captcha.
*/
public $offset = -2;
/**
* @var string the TrueType font file. This can be either a file path or [path alias](guide:concept-aliases).
*/
public $fontFile = '@yii/captcha/SpicyRice.ttf';
/**
* @var string|null the fixed verification code. When this property is set,
* [[getVerifyCode()]] will always return the value of this property.
* 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.
* If not set, it means the verification code will be randomly generated.
*/
public $fixedVerifyCode;
/**
* @var string|null the rendering library to use. Currently supported only 'gd' and 'imagick'.
* If not set, library will be determined automatically.
* @since 2.0.7
*/
public $imageLibrary;
/**
* Initializes the action.
* @throws InvalidConfigException if the font file does not exist.
*/
public function init()
{
$this->fontFile = Yii::getAlias($this->fontFile);
if (!is_file($this->fontFile)) {
throw new InvalidConfigException("The font file does not exist: {$this->fontFile}");
}
}
/**
* Runs the action.
*/
public function run()
{
if (Yii::$app->request->getQueryParam(self::REFRESH_GET_VAR) !== null) {
// AJAX request for regenerating code
$code = $this->getVerifyCode(true);
Yii::$app->response->format = Response::FORMAT_JSON;
return [
'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' => Url::to([$this->id, 'v' => uniqid('', true)]),
];
}
$this->setHttpHeaders();
Yii::$app->response->format = Response::FORMAT_RAW;
return $this->renderImage($this->getVerifyCode());
}
/**
* Generates a hash code that can be used for client-side validation.
* @param string $code the CAPTCHA code
* @return string a hash code generated from the CAPTCHA code
*/
public function generateValidationHash($code)
{
for ($h = 0, $i = strlen($code) - 1; $i >= 0; --$i) {
$h += ord($code[$i]) << $i;
}
return $h;
}
/**
* Gets the verification code.
* @param bool $regenerate whether the verification code should be regenerated.
* @return string the verification code.
*/
public function getVerifyCode($regenerate = false)
{
if ($this->fixedVerifyCode !== null) {
return $this->fixedVerifyCode;
}
$session = Yii::$app->getSession();
$session->open();
$name = $this->getSessionKey();
if ($session[$name] === null || $regenerate) {
$session[$name] = $this->generateVerifyCode();
$session[$name . 'count'] = 1;
}
return $session[$name];
}
/**
* Validates the input to see if it matches the generated code.
* @param string $input user input
* @param bool $caseSensitive whether the comparison should be case-sensitive
* @return bool whether the input is valid
*/
public function validate($input, $caseSensitive)
{
$code = $this->getVerifyCode();
$valid = $caseSensitive ? ($input === $code) : strcasecmp($input, $code) === 0;
$session = Yii::$app->getSession();
$session->open();
$name = $this->getSessionKey() . 'count';
$session[$name] += 1;
if ($valid || $session[$name] > $this->testLimit && $this->testLimit > 0) {
$this->getVerifyCode(true);
}
return $valid;
}
/**
* Generates a new verification code.
* @return string the generated verification code
*/
protected function generateVerifyCode()
{
if ($this->minLength > $this->maxLength) {
$this->maxLength = $this->minLength;
}
if ($this->minLength < 3) {
$this->minLength = 3;
}
if ($this->maxLength > 20) {
$this->maxLength = 20;
}
$length = random_int($this->minLength, $this->maxLength);
$letters = 'bcdfghjklmnpqrstvwxyz';
$vowels = 'aeiou';
$code = '';
for ($i = 0; $i < $length; ++$i) {
if ($i % 2 && random_int(0, 10) > 2 || !($i % 2) && random_int(0, 10) > 9) {
$code .= $vowels[random_int(0, 4)];
} else {
$code .= $letters[random_int(0, 20)];
}
}
return $code;
}
/**
* Returns the session variable name used to store verification code.
* @return string the session variable name
*/
protected function getSessionKey()
{
return '__captcha/' . $this->getUniqueId();
}
/**
* Renders the CAPTCHA image.
* @param string $code the verification code
* @return string image contents
* @throws InvalidConfigException if imageLibrary is not supported
*/
protected function renderImage($code)
{
if (isset($this->imageLibrary)) {
$imageLibrary = $this->imageLibrary;
} else {
$imageLibrary = Captcha::checkRequirements();
}
if ($imageLibrary === 'gd') {
return $this->renderImageByGD($code);
} elseif ($imageLibrary === 'imagick') {
return $this->renderImageByImagick($code);
}
throw new InvalidConfigException("Defined library '{$imageLibrary}' is not supported");
}
/**
* Renders the CAPTCHA image based on the code using GD library.
* @param string $code the verification code
* @return string image contents in PNG format.
*/
protected function renderImageByGD($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 - 1, $this->height - 1, $backColor);
imagecolordeallocate($image, $backColor);
if ($this->transparent) {
imagecolortransparent($image, $backColor);
}
$foreColor = imagecolorallocate(
$image,
(int) ($this->foreColor % 0x1000000 / 0x10000),
(int) ($this->foreColor % 0x10000 / 0x100),
$this->foreColor % 0x100
);
$length = strlen($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) (random_int(26, 32) * $scale * 0.8);
$angle = random_int(-10, 10);
$letter = $code[$i];
$box = imagettftext($image, $fontSize, $angle, $x, $y, $foreColor, $this->fontFile, $letter);
$x = $box[2] + $this->offset;
}
imagecolordeallocate($image, $foreColor);
ob_start();
imagepng($image);
imagedestroy($image);
return ob_get_clean();
}
/**
* Renders the CAPTCHA image based on the code using ImageMagick library.
* @param string $code the verification code
* @return string image contents in PNG format.
*/
protected function renderImageByImagick($code)
{
$backColor = $this->transparent ? new \ImagickPixel('transparent') : new \ImagickPixel('#' . str_pad(dechex($this->backColor), 6, 0, STR_PAD_LEFT));
$foreColor = new \ImagickPixel('#' . str_pad(dechex($this->foreColor), 6, 0, STR_PAD_LEFT));
$image = new \Imagick();
$image->newImage($this->width, $this->height, $backColor);
$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) (random_int(26, 32) * $scale * 0.8));
$draw->setFillColor($foreColor);
$image->annotateImage($draw, $x, $y, random_int(-10, 10), $code[$i]);
$fontMetrics = $image->queryFontMetrics($draw, $code[$i]);
$x += (int) $fontMetrics['textWidth'] + $this->offset;
}
$image->setImageFormat('png');
return $image->getImageBlob();
}
/**
* Sets the HTTP headers needed by image response.
*/
protected function setHttpHeaders()
{
Yii::$app->getResponse()->getHeaders()
->set('Pragma', 'public')
->set('Expires', '0')
->set('Cache-Control', 'must-revalidate, post-check=0, pre-check=0')
->set('Content-Transfer-Encoding', 'binary')
->set('Content-type', 'image/png');
}
}