Use standard HTTP library to serve files (#24693)

`http.ServeFile/ServeContent` handles `If-xxx`, `Content-Length`,
`Range` and `Etag` correctly

After this PR, storage files (eg: avatar) could be responded with
correct Content-Length.

2 files changed, 8 insertions, 17 deletions

diff --git a/routers/web/base.go b/routers/web/base.go
index b9b5958389..1f6c4fbfc5 100644
--- a/routers/web/base.go
+++ b/routers/web/base.go
@@ -6,7 +6,6 @@ package web
 import (
 	"errors"
 	"fmt"
-	"io"
 	"net/http"
 	"os"
 	"path"
@@ -76,12 +75,6 @@ func storageHandler(storageSetting setting.Storage, prefix string, objStore stor
 			}
 
 			fi, err := objStore.Stat(rPath)
-			if err == nil && httpcache.HandleTimeCache(req, w, fi) {
-				return
-			}
-
-			// If we have matched and access to release or issue
-			fr, err := objStore.Open(rPath)
 			if err != nil {
 				if os.IsNotExist(err) || errors.Is(err, os.ErrNotExist) {
 					log.Warn("Unable to find %s %s", prefix, rPath)
@@ -92,14 +85,15 @@ func storageHandler(storageSetting setting.Storage, prefix string, objStore stor
 				http.Error(w, fmt.Sprintf("Error whilst opening %s %s", prefix, rPath), http.StatusInternalServerError)
 				return
 			}
-			defer fr.Close()
 
-			_, err = io.Copy(w, fr)
+			fr, err := objStore.Open(rPath)
 			if err != nil {
-				log.Error("Error whilst rendering %s %s. Error: %v", prefix, rPath, err)
-				http.Error(w, fmt.Sprintf("Error whilst rendering %s %s", prefix, rPath), http.StatusInternalServerError)
+				log.Error("Error whilst opening %s %s. Error: %v", prefix, rPath, err)
+				http.Error(w, fmt.Sprintf("Error whilst opening %s %s", prefix, rPath), http.StatusInternalServerError)
 				return
 			}
+			defer fr.Close()
+			httpcache.ServeContentWithCacheControl(w, req, path.Base(rPath), fi.ModTime(), fr)
 		})
 	}
 }
diff --git a/routers/web/misc/misc.go b/routers/web/misc/misc.go
index 582179990a..6ed3b5c3ad 100644
--- a/routers/web/misc/misc.go
+++ b/routers/web/misc/misc.go
@@ -5,13 +5,13 @@ package misc
 
 import (
 	"net/http"
-	"os"
 	"path"
 
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/httpcache"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/util"
 )
 
 func SSHInfo(rw http.ResponseWriter, req *http.Request) {
@@ -34,11 +34,8 @@ func DummyOK(w http.ResponseWriter, req *http.Request) {
 }
 
 func RobotsTxt(w http.ResponseWriter, req *http.Request) {
-	filePath := path.Join(setting.CustomPath, "robots.txt")
-	fi, err := os.Stat(filePath)
-	if err == nil && httpcache.HandleTimeCache(req, w, fi) {
-		return
-	}
+	filePath := util.FilePathJoinAbs(setting.CustomPath, "robots.txt")
+	httpcache.SetCacheControlInHeader(w.Header(), setting.StaticCacheTime)
 	http.ServeFile(w, req, filePath)
 }