实现缓存策略的部分功能

internal/nodes/http_request_cache.go

@@ -0,0 +1,153 @@
+package nodes
+
+import (
+	"bytes"
+	"github.com/TeaOSLab/EdgeNode/internal/caches"
+	"github.com/iwind/TeaGo/logs"
+	"github.com/iwind/TeaGo/types"
+	"net/http"
+	"strconv"
+)
+
+// 读取缓存
+func (this *HTTPRequest) doCacheRead() (shouldStop bool) {
+	if this.web.Cache == nil || !this.web.Cache.IsOn || len(this.web.Cache.CacheRefs) == 0 {
+		return
+	}
+
+	// 检查条件
+	for _, cacheRef := range this.web.Cache.CacheRefs {
+		if !cacheRef.IsOn ||
+			cacheRef.CachePolicyId == 0 ||
+			cacheRef.CachePolicy == nil ||
+			!cacheRef.CachePolicy.IsOn ||
+			cacheRef.Conds == nil ||
+			!cacheRef.Conds.HasRequestConds() {
+			continue
+		}
+		if cacheRef.Conds.MatchRequest(this.Format) {
+			this.cacheRef = cacheRef
+			break
+		}
+	}
+	if this.cacheRef == nil {
+		return
+	}
+
+	// 相关变量
+	this.varMapping["cache.policy.name"] = this.cacheRef.CachePolicy.Name
+	this.varMapping["cache.policy.id"] = strconv.FormatInt(this.cacheRef.CachePolicy.Id, 10)
+	this.varMapping["cache.policy.type"] = this.cacheRef.CachePolicy.Type
+
+	// Cache-Pragma
+	if this.cacheRef.EnableRequestCachePragma {
+		if this.RawReq.Header.Get("Cache-Control") == "no-cache" || this.RawReq.Header.Get("Pragma") == "no-cache" {
+			this.cacheRef = nil
+			return
+		}
+	}
+
+	// TODO 支持Vary Header
+
+	// 检查是否有缓存
+	key := this.Format(this.cacheRef.Key)
+	if len(key) == 0 {
+		this.cacheRef = nil
+		return
+	}
+	this.cacheKey = key
+
+	// 读取缓存
+	storage := caches.SharedManager.FindStorageWithPolicy(this.cacheRef.CachePolicyId)
+	if storage == nil {
+		this.cacheRef = nil
+		return
+	}
+
+	buf := bytePool32k.Get()
+	defer func() {
+		bytePool32k.Put(buf)
+	}()
+
+	isBroken := false
+	headerBuf := []byte{}
+	statusCode := http.StatusOK
+	statusFound := false
+	headerFound := false
+
+	err := storage.Read(key, buf, func(data []byte, valueSize int64, expiredAt int64, isEOF bool) {
+		if isBroken {
+			return
+		}
+
+		// 如果Header已发送完毕
+		if headerFound {
+			_, _ = this.writer.Write(data)
+			return
+		}
+
+		headerBuf = append(headerBuf, data...)
+
+		if !statusFound {
+			lineIndex := bytes.IndexByte(headerBuf, '\n')
+			if lineIndex < 0 {
+				return
+			}
+
+			pieces := bytes.Split(headerBuf[:lineIndex], []byte{' '})
+			if len(pieces) < 2 {
+				isBroken = true
+				return
+			}
+			statusCode = types.Int(string(pieces[1]))
+			statusFound = true
+			headerBuf = headerBuf[lineIndex+1:]
+
+			// cache相关变量
+			this.varMapping["cache.status"] = "HIT"
+		}
+
+		for {
+			lineIndex := bytes.IndexByte(headerBuf, '\n')
+			if lineIndex < 0 {
+				break
+			}
+			if lineIndex == 0 || lineIndex == 1 {
+				headerFound = true
+
+				this.processResponseHeaders(statusCode)
+				this.writer.WriteHeader(statusCode)
+
+				_, _ = this.writer.Write(headerBuf[lineIndex+1:])
+				headerBuf = nil
+				break
+			}
+
+			// 分解Header
+			line := headerBuf[:lineIndex]
+			colonIndex := bytes.IndexByte(line, ':')
+			if colonIndex <= 0 {
+				continue
+			}
+			this.writer.Header().Set(string(line[:colonIndex]), string(bytes.TrimSpace(line[colonIndex+1:])))
+			headerBuf = headerBuf[lineIndex+1:]
+		}
+	})
+
+	if err != nil {
+		if err == caches.ErrNotFound {
+			// cache相关变量
+			this.varMapping["cache.status"] = "MISS"
+			return
+		}
+
+		logs.Println("read from cache failed: " + err.Error())
+		return
+	}
+
+	if isBroken {
+		return
+	}
+
+	return true
+}