Fix #1787: Add support for optional filesystem to the static middlewa…

…re (#1797)

* Add optional filesystem to static middleware.

middleware/static.go

@@ -42,6 +42,10 @@ type (
  // the filesystem path is not doubled
  // Optional. Default value false.
  IgnoreBase bool `yaml:"ignoreBase"`
+
+ // Filesystem provides access to the static content.
+ // Optional. Defaults to http.Dir(config.Root)
+ Filesystem http.FileSystem `yaml:"-"`
  }
 )
 
@@ -146,6 +150,10 @@ func StaticWithConfig(config StaticConfig) echo.MiddlewareFunc {
  if config.Index == "" {
  config.Index = DefaultStaticConfig.Index
  }
+ if config.Filesystem == nil {
+ config.Filesystem = http.Dir(config.Root)
+ config.Root = "."
+ }
 
  // Index template
  t, err := template.New("index").Parse(html)
@@ -178,49 +186,73 @@ func StaticWithConfig(config StaticConfig) echo.MiddlewareFunc {
  }
  }
 
- fi, err := os.Stat(name)
+ file, err := openFile(config.Filesystem, name)
  if err != nil {
- if os.IsNotExist(err) {
- if err = next(c); err != nil {
- if he, ok := err.(*echo.HTTPError); ok {
- if config.HTML5 && he.Code == http.StatusNotFound {
- return c.File(filepath.Join(config.Root, config.Index))
- }
- }
- return
- }
+ if !os.IsNotExist(err) {
+ return err
+ }
+
+ if err = next(c); err == nil {
+ return err
+ }
+
+ he, ok := err.(*echo.HTTPError)
+ if !(ok && config.HTML5 && he.Code == http.StatusNotFound) {
+ return err
+ }
+
+ file, err = openFile(config.Filesystem, filepath.Join(config.Root, config.Index))
+ if err != nil {
+ return err
  }
- return
  }
 
- if fi.IsDir() {
- index := filepath.Join(name, config.Index)
- fi, err = os.Stat(index)
+ defer file.Close()
+
+ info, err := file.Stat()
+ if err != nil {
+ return err
+ }
 
+ if info.IsDir() {
+ index, err := openFile(config.Filesystem, filepath.Join(name, config.Index))
  if err != nil {
  if config.Browse {
- return listDir(t, name, c.Response())
+ return listDir(t, name, file, c.Response())
  }
+
  if os.IsNotExist(err) {
  return next(c)
  }
- return
  }
 
- return c.File(index)
+ defer index.Close()
+
+ info, err = index.Stat()
+ if err != nil {
+ return err
+ }
+
+ return serveFile(c, index, info)
  }
 
- return c.File(name)
+ return serveFile(c, file, info)
  }
  }
 }
 
-func listDir(t *template.Template, name string, res *echo.Response) (err error) {
- file, err := os.Open(name)
- if err != nil {
- return
- }
- files, err := file.Readdir(-1)
+func openFile(fs http.FileSystem, name string) (http.File, error) {
+ pathWithSlashes := filepath.ToSlash(name)
+ return fs.Open(pathWithSlashes)
+}
+
+func serveFile(c echo.Context, file http.File, info os.FileInfo) error {
+ http.ServeContent(c.Response(), c.Request(), info.Name(), info.ModTime(), file)
+ return nil
+}
+
+func listDir(t *template.Template, name string, dir http.File, res *echo.Response) (err error) {
+ files, err := dir.Readdir(-1)
  if err != nil {
  return
  }

middleware/static_1_16_test.go

@@ -0,0 +1,106 @@
+// +build go1.16
+
+package middleware
+
+import (
+ "io/fs"
+ "net/http"
+ "net/http/httptest"
+ "os"
+ "testing"
+ "testing/fstest"
+
+ "github.com/labstack/echo/v4"
+ "github.com/stretchr/testify/assert"
+)
+
+func TestStatic_CustomFS(t *testing.T) {
+ var testCases = []struct {
+ name string
+ filesystem fs.FS
+ root string
+ whenURL string
+ expectContains string
+ expectCode int
+ }{
+ {
+ name: "ok, serve index with Echo message",
+ whenURL: "/",
+ filesystem: os.DirFS("../_fixture"),
+ expectCode: http.StatusOK,
+ expectContains: "<title>Echo</title>",
+ },
+
+ {
+ name: "ok, serve index with Echo message",
+ whenURL: "/_fixture/",
+ filesystem: os.DirFS(".."),
+ expectCode: http.StatusOK,
+ expectContains: "<title>Echo</title>",
+ },
+ {
+ name: "ok, serve file from map fs",
+ whenURL: "/file.txt",
+ filesystem: fstest.MapFS{
+ "file.txt": &fstest.MapFile{Data: []byte("file.txt is ok")},
+ },
+ expectCode: http.StatusOK,
+ expectContains: "file.txt is ok",
+ },
+ {
+ name: "nok, missing file in map fs",
+ whenURL: "/file.txt",
+ expectCode: http.StatusNotFound,
+ filesystem: fstest.MapFS{
+ "file2.txt": &fstest.MapFile{Data: []byte("file2.txt is ok")},
+ },
+ },
+ {
+ name: "nok, file is not a subpath of root",
+ whenURL: `/../../secret.txt`,
+ root: "/nested/folder",
+ filesystem: fstest.MapFS{
+ "secret.txt": &fstest.MapFile{Data: []byte("this is a secret")},
+ },
+ expectCode: http.StatusNotFound,
+ },
+ {
+ name: "nok, backslash is forbidden",
+ whenURL: `/..\..\secret.txt`,
+ expectCode: http.StatusNotFound,
+ root: "/nested/folder",
+ filesystem: fstest.MapFS{
+ "secret.txt": &fstest.MapFile{Data: []byte("this is a secret")},
+ },
+ },
+ }
+
+ for _, tc := range testCases {
+ t.Run(tc.name, func(t *testing.T) {
+ e := echo.New()
+
+ config := StaticConfig{
+ Root: ".",
+ Filesystem: http.FS(tc.filesystem),
+ }
+
+ if tc.root != "" {
+ config.Root = tc.root
+ }
+
+ middlewareFunc := StaticWithConfig(config)
+ e.Use(middlewareFunc)
+
+ req := httptest.NewRequest(http.MethodGet, tc.whenURL, nil)
+ rec := httptest.NewRecorder()
+
+ e.ServeHTTP(rec, req)
+
+ assert.Equal(t, tc.expectCode, rec.Code)
+ if tc.expectContains != "" {
+ responseBody := rec.Body.String()
+ assert.Contains(t, responseBody, tc.expectContains)
+ }
+ })
+ }
+}

middleware/static_test.go

@@ -94,6 +94,32 @@ func TestStatic(t *testing.T) {
  expectCode: http.StatusNotFound,
  expectContains: "{\"message\":\"Not Found\"}\n",
  },
+ {
+ name: "ok, do not serve file, when a handler took care of the request",
+ whenURL: "/regular-handler",
+ expectCode: http.StatusOK,
+ expectContains: "ok",
+ },
+ {
+ name: "nok, when html5 fail if the index file does not exist",
+ givenConfig: &StaticConfig{
+ Root: "../_fixture",
+ HTML5: true,
+ Index: "missing.html",
+ },
+ whenURL: "/random",
+ expectCode: http.StatusInternalServerError,
+ },
+ {
+ name: "ok, serve from http.FileSystem",
+ givenConfig: &StaticConfig{
+ Root: "_fixture",
+ Filesystem: http.Dir(".."),
+ },
+ whenURL: "/",
+ expectCode: http.StatusOK,
+ expectContains: "<title>Echo</title>",
+ },
  }
 
  for _, tc := range testCases {
@@ -115,6 +141,9 @@ func TestStatic(t *testing.T) {
  } else {
  // middleware is on root level
  e.Use(middlewareFunc)
+ e.GET("/regular-handler", func(c echo.Context) error {
+ return c.String(http.StatusOK, "ok")
+ })
  }
 
  req := httptest.NewRequest(http.MethodGet, tc.whenURL, nil)