Enable contenthash in filename for dynamic assets (#20813)

This should solve the main problem of dynamic assets getting stale after
a version upgrade. Everything not affected will use query-string based
cache busting, which includes files loaded via HTML or worker scripts.

modules/setting/setting.go

@@ -92,6 +92,8 @@ var (
 	// LocalURL is the url for locally running applications to contact Gitea. It always has a '/' suffix
 	// It maps to ini:"LOCAL_ROOT_URL"
 	LocalURL string
+	// AssetVersion holds a opaque value that is used for cache-busting assets
+	AssetVersion string
 
 	// Server settings
 	Protocol                   Scheme
@@ -759,6 +761,7 @@ func loadFromConf(allowEmpty bool, extraConfig string) {
 	}
 
 	AbsoluteAssetURL = MakeAbsoluteAssetURL(AppURL, StaticURLPrefix)
+	AssetVersion = strings.ReplaceAll(AppVer, "+", "~") // make sure the version string is clear (no real escaping is needed)
 
 	manifestBytes := MakeManifestData(AppName, AppURL, AbsoluteAssetURL)
 	ManifestData = `application/json;base64,` + base64.StdEncoding.EncodeToString(manifestBytes)

modules/templates/helper.go

@@ -81,6 +81,9 @@ func NewFuncMap() []template.FuncMap {
 		"AppDomain": func() string {
 			return setting.Domain
 		},
+		"AssetVersion": func() string {
+			return setting.AssetVersion
+		},
 		"DisableGravatar": func() bool {
 			return setting.DisableGravatar
 		},
@@ -150,7 +153,6 @@ func NewFuncMap() []template.FuncMap {
 		"DiffTypeToStr":                  DiffTypeToStr,
 		"DiffLineTypeToStr":              DiffLineTypeToStr,
 		"ShortSha":                       base.ShortSha,
-		"MD5":                            base.EncodeMD5,
 		"ActionContent2Commits":          ActionContent2Commits,
 		"PathEscape":                     url.PathEscape,
 		"PathEscapeSegments":             util.PathEscapeSegments,