78 lines
2.4 KiB
JavaScript
78 lines
2.4 KiB
JavaScript
const path = require('path');
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const sharp = require('sharp');
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// 压缩配置
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const compressOptions = {
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quality: 0.7,
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maxHeight: 800,
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maxWidth: 600
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};
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/**
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* 安全检查：防止路径遍历攻击（如 ../../etc/passwd）
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* @param {string} targetPath 目标文件路径
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* @param {string} baseDir 基础目录
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* @returns {boolean} 是否合法
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*/
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function isSafePath(targetPath, baseDir) {
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const resolvedTarget = path.resolve(targetPath).toLowerCase();
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const resolvedBase = path.resolve(baseDir).toLowerCase();
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return resolvedTarget.startsWith(resolvedBase);
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}
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/**
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* 发送响应
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* @param {ServerResponse} res 响应对象
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* @param {number} statusCode 状态码
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* @param {string} message 信息
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*/
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function sendResponse(res, statusCode, message) {
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res.writeHead(statusCode, { 'Content-Type': 'text/plain; charset=utf-8' });
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res.end(message);
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}
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/**
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* 处理图片压缩和调整大小
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* @param {string} imagePath 图片路径
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* @param {Object} query 查询参数
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* @returns {Promise<Buffer>} 处理后的图片Buffer
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*/
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async function processImage(imagePath, query) {
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let sharpInstance = sharp(imagePath).rotate();
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// 处理宽高参数
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let targetWidth = parseInt(query.w) || parseInt(query.width);
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let targetHeight = parseInt(query.h) || parseInt(query.height);
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// 如果没有指定宽高，使用配置的默认最大宽高
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if (!targetWidth && !targetHeight) {
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targetWidth = compressOptions.maxWidth;
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targetHeight = compressOptions.maxHeight;
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}
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// 如果指定了宽高，进行调整大小处理
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if (targetWidth || targetHeight) {
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const resizeOptions = {
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width: targetWidth,
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height: targetHeight,
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fit: sharp.fit.inside, // 保持宽高比，图片会完整显示在指定区域内
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withoutEnlargement: true // 不放大比原始尺寸小的图片
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};
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sharpInstance = sharpInstance.resize(resizeOptions);
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}
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// 处理质量参数（优先使用查询参数，否则使用配置的默认值）
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const quality = query.q ? Math.max(1, Math.min(100, parseInt(query.q))) :
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Math.round(compressOptions.quality * 100);
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const finalQuality = Math.max(1, Math.min(100, quality));
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// 转换为JPEG格式并压缩
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return sharpInstance.jpeg({quality: finalQuality, mozjpeg: true}).toBuffer();
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}
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module.exports = {
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isSafePath,
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sendResponse,
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processImage
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}
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