added cache only access server

pkg/srv/cache.go

@@ -0,0 +1,102 @@
+// Copyright (C) 2022 Marius Schellenberger
+
+package srv
+
+import (
+	"io"
+	"net/http"
+	"path"
+	"strings"
+
+	"cachefs/pkg/fs"
+
+	"github.com/go-logr/logr"
+)
+
+type CacheFS struct {
+	fs *fs.FS
+}
+
+func (cfs *CacheFS) Open(name string) (http.File, error) {
+	return cfs.fs.OpenDst(name)
+}
+
+type CacheServer struct {
+	log logr.Logger
+	fs  *fs.FS
+	h   http.Handler
+}
+
+func NewCacheServer(fs *fs.FS, log logr.Logger) http.Handler {
+	return &CacheServer{log, fs, http.FileServer(&CacheFS{fs})}
+}
+
+func (cs *CacheServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	s := &statusInterceptor{w: w}
+	w = s
+	if !skipLog(r.RequestURI) {
+		defer func() {
+			if s.Status() == http.StatusPartialContent {
+				return
+			}
+			cs.log.Info("access",
+				"client", r.RemoteAddr,
+				"method", r.Method,
+				"status", s.Status(),
+				"uri", r.RequestURI,
+			)
+		}()
+	}
+	upath := r.URL.Path
+	if !strings.HasPrefix(upath, "/") {
+		upath = "/" + upath
+		r.URL.Path = upath
+	}
+	p := path.Clean(upath)
+	option := r.FormValue("o")
+	d, err := cs.fs.StatDst(p)
+	if err != nil {
+		msg, code := toHTTPError(err)
+		http.Error(w, msg, code)
+		return
+	}
+	h := w.Header()
+	if option == "v" {
+		h.Set(csp, videoCSP)
+		err = video.Execute(w, r.URL.Path)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+		}
+		return
+	}
+
+	if !d.IsDir() {
+		cs.h.ServeHTTP(w, r)
+		return
+	}
+
+	i := &responseInterceptor{w: w}
+	r.Header.Del("If-Modified-Since")
+	r.Header.Del("Cache-Control")
+	cs.h.ServeHTTP(i, r)
+
+	h.Del("Last-Modified")
+
+	paths, err := i.GetPaths(p, cs.fs, true)
+	if err == io.EOF {
+		w.WriteHeader(i.Status())
+		return
+	}
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	h.Set(csp, indexCSP)
+
+	w.WriteHeader(i.Status())
+	err = cache.Execute(w, paths)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+}