包简介

A PHP library for generating Captcha challenges using libgd.

README 文档

README

Description

A PHP library for generating Captcha challenges using libgd.

Captcha examples

Easy expression captcha:
Hard expression captcha:
Easy string captcha:
Hard string captcha (colored):

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?).

// 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.

$_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.

$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.

$base64_image = $captcha->render();
echo sprintf('<img src="data:image/png;base64,%s">', $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('<img src="/%s">', $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(
    '<img src="data:image/png;base64,%s">',
    $another_base64_image
);

Example implementation of the library

<?php

require_once 'vendor/autoload.php';

use Dkh\ExpressionCaptcha;

session_start();

// Verify user's captcha input
if (isset($_POST['captcha']) && isset($_SESSION['captcha'])) {
    $is_matched = $_POST['captcha'] === $_SESSION['captcha'];
} else {
    $is_matched = null;
}
$message = $is_matched !== null ?
    ($is_matched ? 'Captcha matched' : 'Captcha not matched') :
    'Try solving the captcha';

// Create a captcha
$captcha = new ExpressionCaptcha();
// Store captcha's solved value
$_SESSION['captcha'] = $captcha->solve();
// Render the captcha into image
// The return value is a PNG image string encoded with base64
$base64_image = $captcha->render();

echo sprintf(
    '<!DOCTYPE html>' .
    '<html>' .
    '<body>' .
    '<form method="POST">' .
    '<img src="data:image/png;base64,%s"><br>' .
    '<input name="captcha" placeholder="Input captcha">' .
    '<input type="submit" value="Submit"><br>' .
    '</form>' .
    '<div>Message: %s</div>' .
    '</body>' .
    '</html>',
    $base64_image,
    $message
);

dkh/captcha-generator 适用场景与选型建议

dkh/captcha-generator 是一款基于 PHP 开发的 Composer 扩展包，目前已累计 6.73k 次下载、GitHub Stars 达 1，最近一次更新时间为 2018 年 07 月 10 日，在 PHP 生态内属于活跃度较高的组件。

它主要适用于以下技术方向：「generator」「php」「captcha」「dkh」等业务场景。在实际项目中，围绕这些方向常见需要落地的问题包括：接口对接、性能调优、并发安全、与既有框架（Laravel / ThinkPHP / Yii / Webman 等）的兼容适配，以及生产环境的日志埋点与稳定性保障。

我们在过去多个企业项目中使用过 dkh/captcha-generator 或与其功能相近的方案，如果你在选型或落地过程中遇到问题，例如 版本兼容、二次改造、私有化封装、与内部系统对接、生产 BUG 排查，欢迎联系我们协助评估。

围绕 dkh/captcha-generator 我们能提供哪些服务？

定制开发 / 二次开发

基于 dkh/captcha-generator 在你已有业务上做功能扩展、字段裁剪、UI 适配、与内部账号 / 权限 / 日志系统的深度对接。

BUG 修复 & 性能优化

线上偶发问题、内存泄漏、慢查询、并发异常等排查修复；针对高流量场景做缓存、队列、索引层面的调优。

项目外包 & 长期维护

承接完整的项目从需求 → 设计 → 开发 → 上线 → 长期运维；也可按月提供技术保姆服务。

yvsm@zunyunkeji.com QQ：316430983 微信：yvsm316 西安尊云信息科技 · 专注 PHP / Go / 分布式系统研发

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包简介

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