add cache-policy

cmd/proxy/main.go

@@ -10,6 +10,7 @@ import (
 	"os"
 	"path/filepath"
 	"regexp"
+	"slices"
 	"strings"
 	"sync"
 	"time"
@@ -60,8 +61,14 @@ type Storage struct {
 	Accel Accel         `yaml:"accel"`
 }
 
+type CachePolicyOnPath struct {
+	Match        string `yaml:"match"`
+	RefreshAfter string `yaml:"refresh-after"`
+}
+
 type Cache struct {
-	Timeout time.Duration `yaml:"timeout"`
+	RefreshAfter time.Duration       `yaml:"refresh-after"`
+	Policies     []CachePolicyOnPath `yaml:"policies"`
 }
 
 type MiscConfig struct {
@@ -162,7 +169,7 @@ func configFromFile(path string) (*Config, error) {
 			ChunkBytes:      1024 * 1024,
 		},
 		Cache: Cache{
-			Timeout: time.Hour,
+			RefreshAfter: time.Hour,
 		},
 	}
 
@@ -249,7 +256,26 @@ const (
 
 func (server *Server) checkLocal(w http.ResponseWriter, _ *http.Request, key string) (exists localStatus, mtime time.Time, err error) {
 	if stat, err := os.Stat(key); err == nil {
-		if mtime := stat.ModTime(); mtime.Add(server.Cache.Timeout).Before(time.Now()) {
+		refreshAfter := server.Cache.RefreshAfter
+		refresh := ""
+
+		for _, policy := range server.Cache.Policies {
+			if match, err := regexp.MatchString(policy.Match, key); err != nil {
+				return 0, zeroTime, err
+			} else if match {
+				if dur, err := time.ParseDuration(policy.RefreshAfter); err != nil {
+					if slices.Contains([]string{"always", "never"}, policy.RefreshAfter) {
+						refresh = policy.RefreshAfter
+					} else {
+						return 0, zeroTime, err
+					}
+				} else {
+					refreshAfter = dur
+				}
+				break
+			}
+		}
+		if mtime := stat.ModTime(); mtime.Add(refreshAfter).Before(time.Now()) || refresh == "always" && refresh != "never" {
 			return localExistsButNeedHead, mtime.In(time.UTC), nil
 		}
 		return localExists, mtime.In(time.UTC), nil

config.yaml

@@ -40,6 +40,12 @@ misc:
   first-chunk-bytes: 31457280 # 1024*1024*30, all upstreams with 200 response will wait for the first chunks to select a upstream by bandwidth, instead of by latency. defaults to 50M
   # chunk-bytes: 1048576 # 1024*1024
 
+cache:
+  timeout: 1h
+  policies:
+  - match: '.*\.(rpm|deb)$'
+    fresh-after: never
+
 storage:
   type: local # ignored
   local: