https://github.com/dangkyokhoang/php-captcha-generator

PHP Captcha Generator using libgd
https://github.com/dangkyokhoang/php-captcha-generator

captcha captcha-generator captcha-image captcha-service expression-captcha php php-captcha-generator php7

Last synced: 9 months ago
JSON representation

PHP Captcha Generator using libgd

• Host: GitHub
• URL: https://github.com/dangkyokhoang/php-captcha-generator
• Owner: dangkyokhoang
• License: mit
• Created: 2018-07-08T06:59:03.000Z (over 7 years ago)
• Default Branch: master
• Last Pushed: 2018-07-11T20:09:19.000Z (over 7 years ago)
• Last Synced: 2024-11-18T19:52:32.659Z (about 1 year ago)
• Topics: captcha, captcha-generator, captcha-image, captcha-service, expression-captcha, php, php-captcha-generator, php7
• Language: PHP
• Homepage: https://packagist.org/packages/dkh/captcha-generator
• Size: 25.4 KB
• Stars: 2
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

README

          
# PHP Captcha Generator

### Description

A PHP library for generating Captcha challenges using libgd.  

### Captcha examples

- Easy expression captcha:  

  ![PHP Captcha Generator - Expression - Easy](https://image.ibb.co/bSWhE8/index.png)  

- Hard expression captcha:  

  ![PHP Captcha Generator - Expression - Hard](https://preview.ibb.co/cejpu8/index.png)  

- Easy string captcha:  

  ![PHP Catpcha Generator - String - Easy](https://image.ibb.co/mqXFj8/index.png)  

- Hard string captcha (colored):  

  ![PHP Captcha Generator - String - Hard](https://image.ibb.co/eTV1P8/index.png)

### Repositories

- GitHub: https://github.com/dangkyokhoang/PHP-Captcha-Generator.

- Packagist: https://packagist.org/packages/dkh/captcha-generator.

### Required dependencies

- GD Graphics Library (ext-gd).

# User Guide

## Installation

You can easily get the library installed on your project by running this command.

  ```

  composer require dkh/captcha-generator

  ```

## Implementation

### Captcha types

- `ExpressionCaptcha` expression captcha requires users to do basic arithmetic operations (addition, subtraction, multiplication and division) to solve.

- `StringCaptcha` string captcha only requires users to recognize the characters in the string.

### Create a captcha

To create a captcha, use `new *Captcha($size?, $level?)`.

  ```php

  // Default size: 3 and default difficulty level: 1

  $expression_captcha = new ExpressionCaptcha();

  $string_captcha = new StringCaptcha();

  

  // Specific size and difficulty level

  $size = 10;

  $level = 2;

  $another_expression_captcha = new ExpressionCaptcha($size, $level);

  ```

### Get captcha's solved value

To get captcha's solved value, call `$captcha->solve()` or `*Captcha::solveString($string)`.  

Store the solved value somewhere, e.g in a session variable, to later verify user's captcha input.

  ```php

  $_SESSION['captcha'] = $captcha->solve();

  

  // Or in a way that is infrequent,

  // use static method *Captcha::solveString()

  $my_expression = '1+6:3-2*4';

  $_SESSION['my_captcha'] = ExpressionCaptcha::solveString($my_expression);

  ```

### Verify user's captcha input

To verify user's captcha input, compare it with the captcha's previously solved value stored somewhere.

  ```php

  $user_captcha_input = $_POST['captcha'] ?? '';

  $is_matched = $_SESSION['captcha'] === $user_captcha_input;

  ```

### Display the captcha image

To render captcha into image, call `$captcha->render($options?)`, `Captcha::renderString($string, $options?)`. Return value is a PNG image data string encoded with base64.  

To dislay the captcha image, use data URL `data:image/png;base64`, or save the rendered image somewhere and return the image's path.

  ```php

  $base64_image = $captcha->render();

  echo sprintf('', $base64_image);

  

  // Or in a way like this:

  $my_string = 'any will do?';

  $image_path = 'captcha.png';

  $base64_image_to_be_saved = Captcha::renderString($my_string);

  file_put_contents(

      $image_path,

      base64_decode($base64_image_to_be_saved)

  );

  echo sprintf('', $image_path);

  

  // Image rendered with some options

  $another_base64_image = $captcha->render([

      'height' => 50,

      'fill' => [0, 0, 0, 30],

      // The alpha channel is optional

      'color' => [255, 255, 255]

  ]);

  echo sprintf(

      '',

      $another_base64_image

  );

  ```

### Example implementation of the library

  ```php

  solve();

  // Render the captcha into image

  // The return value is a PNG image string encoded with base64

  $base64_image = $captcha->render();

  echo sprintf(

      '' .

      '' .

      '' .

      '' .

      '
' .

      '' .

      '
' .

      '' .

      '
Message: %s
' .

      '' .

      '',

      $base64_image,

      $message

  );

  ```