78 lines
2.6 KiB
PHP
78 lines
2.6 KiB
PHP
<?php
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namespace App\Http\Controllers\Auth;
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use App\Http\Controllers\Controller;
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use Illuminate\Http\Request;
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use Illuminate\Support\Facades\Session;
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/**
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* 图形验证码（轻量、零依赖，基于 GD 绘制）。
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* - GET /captcha 生成一张 4 位字符的图片，并把答案写入 session('captcha')。
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* - 登录接口校验用户输入与 session 中的值（大小写不敏感），校验后清空，防止复用。
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* - 仅用于「人/机」区分，配合登录限流构成基础安全管控。
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*/
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class CaptchaController extends Controller
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{
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public function show(Request $request)
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{
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$code = $this->generateCode(4);
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Session::put('captcha', $code);
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$width = 120;
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$height = 44;
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$img = imagecreatetruecolor($width, $height);
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// 背景
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$bg = imagecolorallocate($img, 244, 247, 250);
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imagefilledrectangle($img, 0, 0, $width, $height, $bg);
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// 干扰线
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for ($i = 0; $i < 6; $i++) {
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$c = imagecolorallocate($img, rand(160, 210), rand(160, 210), rand(160, 210));
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imageline($img, rand(0, $width), rand(0, $height), rand(0, $width), rand(0, $height), $c);
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}
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// 字符（随机色 + 轻微纵向抖动）
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$palette = [[74, 138, 244], [110, 140, 176], [43, 182, 164], [123, 126, 240], [200, 120, 60]];
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$len = strlen($code);
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$step = (int) ($width / ($len + 1));
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for ($i = 0; $i < $len; $i++) {
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$col = $palette[array_rand($palette)];
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$c = imagecolorallocate($img, $col[0], $col[1], $col[2]);
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$x = $step * ($i + 1) - 10 + rand(-3, 3);
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$y = rand(8, 18);
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imagestring($img, 5, $x, $y, $code[$i], $c);
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}
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// 噪点
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for ($i = 0; $i < 50; $i++) {
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$c = imagecolorallocate($img, rand(180, 225), rand(180, 225), rand(180, 225));
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imagesetpixel($img, rand(0, $width), rand(0, $height), $c);
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}
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ob_start();
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imagepng($img);
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$data = ob_get_clean();
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imagedestroy($img);
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return response($data, 200)
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->header('Content-Type', 'image/png')
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->header('Cache-Control', 'no-store, no-cache, must-revalidate, private')
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->header('Pragma', 'no-cache');
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}
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/**
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* 生成验证码字符（去除易混淆的 0/O/1/I/L）。
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*/
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protected function generateCode(int $len): string
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{
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$pool = 'ABCDEFGHJKLMNPQRSTUVWXYZ23456789';
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$out = '';
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for ($i = 0; $i < $len; $i++) {
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$out .= $pool[random_int(0, strlen($pool) - 1)];
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}
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return $out;
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}
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}
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