72 lines
2.2 KiB
TypeScript
72 lines
2.2 KiB
TypeScript
import {
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Injectable,
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NestMiddleware,
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BadRequestException,
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} from '@nestjs/common';
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import { Request, Response, NextFunction } from 'express';
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import multer, { Multer } from 'multer';
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import path from 'path';
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import fs from 'fs';
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const ALLOWED_MIME = ['image/jpeg', 'image/png', 'image/webp'];
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const MAX_SIZE = 2 * 1024 * 1024; // 2M
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/**
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* 文件上传中间件（按日期分文件夹）
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* 单图字段名固定：file
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*/
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@Injectable()
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export class UploadMiddleware implements NestMiddleware {
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private readonly upload: Multer;
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constructor() {
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const root = process.env.UPLOAD_ROOT ?? './uploads';
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this.upload = multer({
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storage: multer.diskStorage({
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destination: (_req, _file, cb) => {
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const date = new Date();
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const dir = path.join(
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process.cwd(),
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root.replace(/^\.\/?/, ''),
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`${date.getFullYear()}/${String(date.getMonth() + 1).padStart(2, '0')}`,
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);
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fs.mkdirSync(dir, { recursive: true });
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cb(null, dir);
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},
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filename: (_req, file, cb) => {
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const ext = path.extname(file.originalname).toLowerCase();
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const name = `${Date.now()}_${Math.random().toString(36).slice(2, 8)}${ext}`;
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cb(null, name);
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},
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}),
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fileFilter: (_req, file, cb) => {
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if (ALLOWED_MIME.includes(file.mimetype)) {
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cb(null, true);
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} else {
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// FileFilterCallback 重载：错误时只传 Error，不传 acceptFile
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cb(new Error('仅支持 jpg/png/jpeg/webp 格式图片'));
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}
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},
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limits: { fileSize: MAX_SIZE },
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});
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}
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use(req: Request, _res: Response, next: NextFunction): void {
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// @types/express 与 @types/multer 内嵌的 @types/express-serve-static-core 版本不一致，
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// 运行时完全等价，用 unknown 中转两次绕过编译期差异
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const single = this.upload.single('file') as unknown as (
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req: Request,
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res: Response,
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cb: (err: unknown) => void,
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) => void;
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single(req, _res, (err) => {
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if (err) {
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const msg = err instanceof Error ? err.message : '文件上传失败';
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next(new BadRequestException(msg));
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return;
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}
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next();
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});
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}
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}
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