308 lines
8.0 KiB
Go
308 lines
8.0 KiB
Go
// proxy/handler.go
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package proxy
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import (
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"compress/gzip"
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"io"
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"log"
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"net/http"
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"strings"
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"time"
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"siteproxy/cache"
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"siteproxy/security"
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)
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type ProxyHandler struct {
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validator *security.RequestValidator
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rateLimiter *security.RateLimiter
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cache *cache.MemoryCache
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userAgent string
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maxResponseSize int64
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}
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func NewHandler(
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validator *security.RequestValidator,
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rateLimiter *security.RateLimiter,
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cache *cache.MemoryCache,
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userAgent string,
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maxResponseSize int64,
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) *ProxyHandler {
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return &ProxyHandler{
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validator: validator,
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rateLimiter: rateLimiter,
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cache: cache,
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userAgent: userAgent,
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maxResponseSize: maxResponseSize,
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}
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}
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func (h *ProxyHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
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// 获取目标 URL
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targetURL := r.URL.Query().Get("url")
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if targetURL == "" {
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http.Error(w, "Missing url parameter", http.StatusBadRequest)
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return
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}
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// 验证 URL
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if err := h.validator.ValidateURL(targetURL); err != nil {
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log.Printf("URL validation failed: %v", err)
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http.Error(w, "Invalid or blocked URL: "+err.Error(), http.StatusForbidden)
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return
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}
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// 速率限制
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clientIP := getClientIP(r)
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if !h.rateLimiter.Allow(clientIP) {
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http.Error(w, "Rate limit exceeded", http.StatusTooManyRequests)
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return
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}
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// 检查缓存
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if entry := h.cache.Get(targetURL); entry != nil {
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log.Printf("Cache HIT: %s", targetURL)
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h.serveCached(w, entry)
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return
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}
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log.Printf("Cache MISS: %s", targetURL)
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// 创建代理请求
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proxyReq, err := http.NewRequest(r.Method, targetURL, r.Body)
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if err != nil {
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http.Error(w, "Failed to create request", http.StatusInternalServerError)
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return
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}
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// 设置请求头
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h.setProxyHeaders(proxyReq, r)
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// 发送请求
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client := &http.Client{
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Timeout: 30 * time.Second,
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CheckRedirect: func(req *http.Request, via []*http.Request) error {
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// 验证重定向 URL
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if err := h.validator.ValidateURL(req.URL.String()); err != nil {
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return err
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}
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return nil
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},
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}
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resp, err := client.Do(proxyReq)
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if err != nil {
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log.Printf("Request failed: %v", err)
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http.Error(w, "Failed to fetch URL", http.StatusBadGateway)
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return
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}
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defer resp.Body.Close()
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// 读取响应体
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body, err := h.readResponseBody(resp)
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if err != nil {
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log.Printf("Failed to read response: %v", err)
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http.Error(w, "Failed to read response", http.StatusInternalServerError)
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return
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}
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// 重写内容
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contentType := resp.Header.Get("Content-Type")
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body = h.rewriteContent(body, targetURL, contentType)
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// 缓存响应 - 转换 http.Header 为 map[string]string
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if h.shouldCache(resp) {
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headers := make(map[string]string)
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for key, values := range resp.Header {
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if len(values) > 0 {
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headers[key] = values[0]
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}
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}
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h.cache.Set(targetURL, body, headers)
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}
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// 发送响应
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h.sendResponse(w, resp, body)
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}
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func (h *ProxyHandler) rewriteContent(body []byte, targetURL, contentType string) []byte {
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rewriter, err := NewContentRewriter(targetURL)
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if err != nil {
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log.Printf("Failed to create rewriter: %v", err)
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return body
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}
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contentType = strings.ToLower(contentType)
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// HTML 内容
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if strings.Contains(contentType, "text/html") {
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rewritten, err := rewriter.RewriteHTML(body)
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if err != nil {
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log.Printf("HTML rewrite failed: %v", err)
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return body
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}
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return rewritten
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}
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// CSS 内容
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if strings.Contains(contentType, "text/css") {
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return rewriter.RewriteCSS(body)
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}
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return body
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}
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func (h *ProxyHandler) readResponseBody(resp *http.Response) ([]byte, error) {
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var reader io.Reader = resp.Body
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// 处理 gzip 压缩
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if resp.Header.Get("Content-Encoding") == "gzip" {
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gzReader, err := gzip.NewReader(resp.Body)
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if err != nil {
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return nil, err
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}
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defer gzReader.Close()
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reader = gzReader
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}
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// 限制读取大小
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limitReader := io.LimitReader(reader, h.maxResponseSize)
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return io.ReadAll(limitReader)
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}
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func (h *ProxyHandler) setProxyHeaders(proxyReq, originalReq *http.Request) {
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// 复制必要的请求头
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headersToForward := []string{
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"Accept",
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"Accept-Language",
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"Accept-Encoding",
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"Cache-Control",
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"Referer",
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}
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for _, header := range headersToForward {
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if value := originalReq.Header.Get(header); value != "" {
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proxyReq.Header.Set(header, value)
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}
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}
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// 设置自定义 User-Agent
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proxyReq.Header.Set("User-Agent", h.userAgent)
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// 移除可能暴露代理的头
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proxyReq.Header.Del("X-Forwarded-For")
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proxyReq.Header.Del("X-Real-IP")
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proxyReq.Header.Del("Via")
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}
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func (h *ProxyHandler) shouldCache(resp *http.Response) bool {
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// 只缓存成功的 GET 请求
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if resp.Request.Method != "GET" {
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return false
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}
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if resp.StatusCode != http.StatusOK {
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return false
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}
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// 检查 Cache-Control
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cacheControl := resp.Header.Get("Cache-Control")
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if strings.Contains(cacheControl, "no-store") ||
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strings.Contains(cacheControl, "no-cache") ||
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strings.Contains(cacheControl, "private") {
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return false
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}
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// 检查内容类型
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contentType := resp.Header.Get("Content-Type")
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cacheableTypes := []string{
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"text/html",
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"text/css",
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"application/javascript",
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"image/",
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"font/",
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}
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for _, ct := range cacheableTypes {
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if strings.Contains(contentType, ct) {
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return true
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}
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}
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return false
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}
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func (h *ProxyHandler) sendResponse(w http.ResponseWriter, resp *http.Response, body []byte) {
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// 复制响应头
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headersToForward := []string{
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"Content-Type",
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"Content-Language",
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"Last-Modified",
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"ETag",
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"Expires",
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}
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for _, header := range headersToForward {
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if value := resp.Header.Get(header); value != "" {
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w.Header().Set(header, value)
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}
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}
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// 添加自定义头
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w.Header().Set("X-Proxied-By", "SiteProxy")
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w.Header().Set("X-Cache-Status", "MISS")
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// 安全头
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w.Header().Set("X-Content-Type-Options", "nosniff")
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w.Header().Set("X-Frame-Options", "SAMEORIGIN")
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w.Header().Set("Referrer-Policy", "no-referrer")
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// 不设置 Content-Encoding 和 Content-Length，让 Go 自动处理
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w.WriteHeader(resp.StatusCode)
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w.Write(body)
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}
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func (h *ProxyHandler) serveCached(w http.ResponseWriter, entry *cache.CacheEntry) {
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for key, value := range entry.Headers {
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// 跳过这些头，让 Go 自动处理
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if key == "Content-Encoding" || key == "Content-Length" {
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continue
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}
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w.Header().Set(key, value)
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}
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w.Header().Set("X-Cache-Status", "HIT")
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w.Header().Set("X-Proxied-By", "SiteProxy")
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w.Header().Set("Age", entry.Age())
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w.WriteHeader(http.StatusOK)
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w.Write(entry.Data)
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}
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func getClientIP(r *http.Request) string {
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// 尝试从各种头中获取真实 IP
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if ip := r.Header.Get("X-Real-IP"); ip != "" {
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return ip
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}
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if ip := r.Header.Get("X-Forwarded-For"); ip != "" {
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// X-Forwarded-For 可能包含多个 IP
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ips := strings.Split(ip, ",")
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if len(ips) > 0 {
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return strings.TrimSpace(ips[0])
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}
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}
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// 使用远程地址
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ip := r.RemoteAddr
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if idx := strings.LastIndex(ip, ":"); idx != -1 {
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ip = ip[:idx]
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}
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return ip
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}
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