Cleanup of some old code

Remove the StaticCacheDuration unused package-level variable from context/context.go and /core/router/api_builder.go it should be removed a year ago, now all the cache funcs and middlewares accept their own options |  Remove duplicated header keys that are used on both context/context.go and core/router/fs.go by exporting context's one.


Former-commit-id: 2a5c840d26b32144d2b5b3173a1e4bb4324cecba

core/router/api_builder.go

@@ -549,23 +549,6 @@ func (api *APIBuilder) Any(relativePath string, handlers ...context.Handler) (ro
 	return
 }
 
-// StaticCacheDuration expiration duration for INACTIVE file handlers, it's the only one global configuration
-// which can be changed.
-var StaticCacheDuration = 20 * time.Second
-
-const (
-	lastModifiedHeaderKey       = "Last-Modified"
-	ifModifiedSinceHeaderKey    = "If-Modified-Since"
-	contentDispositionHeaderKey = "Content-Disposition"
-	cacheControlHeaderKey       = "Cache-Control"
-	contentEncodingHeaderKey    = "Content-Encoding"
-	acceptEncodingHeaderKey     = "Accept-Encoding"
-	// contentLengthHeaderKey represents the header["Content-Length"]
-	contentLengthHeaderKey = "Content-Length"
-	contentTypeHeaderKey   = "Content-Type"
-	varyHeaderKey          = "Vary"
-)
-
 func (api *APIBuilder) registerResourceRoute(reqPath string, h context.Handler) *Route {
 	api.Head(reqPath, h)
 	return api.Get(reqPath, h)

core/router/fs.go

@@ -517,8 +517,8 @@ func serveContent(ctx context.Context, name string, modtime time.Time, sizeFunc
 			}()
 		}
 		ctx.Header("Accept-Ranges", "bytes")
-		if ctx.ResponseWriter().Header().Get(contentEncodingHeaderKey) == "" {
-			ctx.Header(contentLengthHeaderKey, strconv.FormatInt(sendSize, 10))
+		if ctx.ResponseWriter().Header().Get(context.ContentEncodingHeaderKey) == "" {
+			ctx.Header(context.ContentLengthHeaderKey, strconv.FormatInt(sendSize, 10))
 		}
 	}