108 lines
3.3 KiB
JavaScript
108 lines
3.3 KiB
JavaScript
function getMaxAge (interceptOpt) {
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// 秒
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if (interceptOpt.cacheSeconds > 0 || interceptOpt.cacheMaxAge > 0 || interceptOpt.cache > 0) {
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return interceptOpt.cacheSeconds || interceptOpt.cacheMaxAge || interceptOpt.cache
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}
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// 分钟
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if (interceptOpt.cacheMinutes > 0) {
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return interceptOpt.cacheMinutes * 60 // 60：1分钟
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}
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// 小时
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if (interceptOpt.cacheHours > 0) {
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return interceptOpt.cacheHours * 3600 // 60 * 60 一小时
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}
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// 天
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if (interceptOpt.cacheDays > 0) {
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return interceptOpt.cacheDays * 86400 // 60 * 60 * 24 一天
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}
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// 星期
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if (interceptOpt.cacheWeeks > 0) {
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return interceptOpt.cacheWeeks * 604800 // 60 * 60 * 24 * 7 一周
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}
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// 月
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if (interceptOpt.cacheMonths > 0) {
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return interceptOpt.cacheMonths * 2592000 // 60 * 60 * 24 * 30 一个月
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}
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// 年
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if (interceptOpt.cacheYears > 0) {
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return interceptOpt.cacheYears * 31536000 // 60 * 60 * 24 * 365 一年
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}
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return null
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}
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// 获取 lastModifiedTime 的方法
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function getLastModifiedTimeFromIfModifiedSince (rOptions, log) {
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// 获取 If-Modified-Since 和 If-None-Match 用于判断是否命中缓存
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const lastModified = rOptions.headers['if-modified-since']
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if (lastModified == null || lastModified.length === 0) {
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return null // 没有lastModified，返回null
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}
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try {
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// 尝试解析 lastModified，并获取time
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return new Date(lastModified).getTime()
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} catch (e) {
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// 为数字时，直接返回
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if (/\\d+/.test(lastModified)) {
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return lastModified - 0
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}
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log.warn(`cache intercept: 解析 if-modified-since 失败: '${lastModified}', error:`, e)
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}
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return null
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}
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module.exports = {
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name: 'cacheRequest',
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priority: 104,
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requestIntercept (context, interceptOpt, req, res, ssl, next) {
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const { rOptions, log } = context
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if (rOptions.method !== 'GET') {
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return // 非GET请求，不拦截
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}
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// 获取 Cache-Control 用于判断是否禁用缓存
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const cacheControl = rOptions.headers['cache-control']
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if (cacheControl && (cacheControl.includes('no-cache') || cacheControl.includes('no-store'))) {
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return // 当前请求指定要禁用缓存，跳过当前拦截器
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}
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// 获取 Pragma 用于判断是否禁用缓存
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const pragma = rOptions.headers.pragma
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if (pragma && (pragma.includes('no-cache') || pragma.includes('no-store'))) {
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return // 当前请求指定要禁用缓存，跳过当前拦截器
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}
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// 最近编辑时间
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const lastModifiedTime = getLastModifiedTimeFromIfModifiedSince(rOptions, log)
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if (lastModifiedTime == null) {
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return // 没有 lastModified，不拦截
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}
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// 获取maxAge配置
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const maxAge = getMaxAge(interceptOpt)
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// 判断缓存是否已过期
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const passTime = Date.now() - lastModifiedTime
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if (passTime > maxAge * 1000) {
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return // 缓存已过期，不拦截
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}
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// 缓存未过期，直接拦截请求并响应304
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res.writeHead(304, {
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'DS-Interceptor': `cache: ${maxAge}`,
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})
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res.end()
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const url = `${rOptions.method} ➜ ${rOptions.protocol}//${rOptions.hostname}:${rOptions.port}${req.url}`
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log.info('cache intercept:', url)
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return true
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},
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is (interceptOpt) {
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const maxAge = getMaxAge(interceptOpt)
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return maxAge != null && maxAge > 0
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},
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getMaxAge,
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}
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