138 lines
3.6 KiB
PHP
138 lines
3.6 KiB
PHP
<?php
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namespace App\Services;
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use Illuminate\Support\Facades\Cache;
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use Illuminate\Support\Str;
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/**
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* 后台登录图形验证码：SVG 产出 + Cache 短时保存答案摘要（单行文本，便于前台用 img[src=data:...] 展示）。
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*/
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class AdminCaptchaService
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{
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private const PREFIX = 'admin_captcha:';
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private const TTL_SECONDS = 120;
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/** 剔除易混淆字符 */
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private const CHARSET = '23456789abcdefghjkmpqrstuvwxyz';
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/**
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* @return array{captcha_key: string, image_svg: string, image_base64: string}
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*/
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public function create(): array
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{
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$code = $this->randomCode();
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$key = (string) Str::uuid();
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Cache::put(
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self::PREFIX.$key,
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$this->digest($code),
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now()->addSeconds(self::TTL_SECONDS),
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);
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$svg = $this->renderSvg($code);
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return [
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'captcha_key' => $key,
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'image_svg' => $svg,
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'image_base64' => base64_encode($svg),
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];
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}
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public function verify(?string $captchaKey, ?string $captchaInput): bool
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{
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if ($captchaKey === null || $captchaKey === ''
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|| $captchaInput === null || trim($captchaInput) === '') {
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return false;
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}
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$digest = Cache::pull(self::PREFIX.$captchaKey);
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if ($digest === null) {
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return false;
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}
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$guess = strtolower(trim($captchaInput));
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return hash_equals($digest, $this->digest($guess));
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}
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private function digest(string $normalizedCode): string
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{
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return hash_hmac(
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'sha256',
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$normalizedCode,
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(string) config('app.key'),
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);
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}
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private function randomCode(int $length = 4): string
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{
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$out = '';
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$max = strlen(self::CHARSET) - 1;
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for ($i = 0; $i < $length; $i++) {
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$out .= self::CHARSET[random_int(0, $max)];
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}
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return $out;
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}
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private function renderSvg(string $code): string
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{
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$w = 160;
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$h = 48;
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$bg = '#fafafa';
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$escape = static fn (string $c): string => htmlspecialchars($c, ENT_XML1 | ENT_QUOTES);
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$lines = '';
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for ($i = 0; $i < 4; $i++) {
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$x1 = random_int(0, $w);
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$y1 = random_int(0, $h);
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$x2 = random_int(0, $w);
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$y2 = random_int(0, $h);
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$stroke = sprintf('#%06x', random_int(0x9_00_000, 0xBF_BF_BF));
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$lines .= sprintf(
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'<line x1="%d" y1="%d" x2="%d" y2="%d" stroke="%s" stroke-width="1" opacity="0.35"/>',
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$x1,
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$y1,
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$x2,
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$y2,
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$stroke,
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);
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}
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$chars = str_split($code);
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$texts = '';
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$x = 18;
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foreach ($chars as $ch) {
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$rot = random_int(-20, 20);
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$dy = random_int(-3, 3);
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$y = 32 + $dy;
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$fill = sprintf('#%06x', random_int(0x20_20_20, 0x3F_3F_3F));
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$texts .= sprintf(
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'<text x="%d" y="%d" font-family="ui-monospace,monospace" font-size="24" font-weight="600" fill="%s" transform="rotate(%d %d %d)">%s</text>',
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$x,
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$y,
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$fill,
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$rot,
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$x,
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$y,
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$escape($ch),
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);
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$x += 34;
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}
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return sprintf(
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'<svg xmlns="http://www.w3.org/2000/svg" width="%d" height="%d" viewBox="0 0 %d %d"><rect width="100%%" height="100%%" fill="%s"/>%s%s</svg>',
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$w,
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$h,
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$w,
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$h,
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$bg,
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$lines,
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$texts,
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);
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}
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}
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