Improve filesystem support.

context_fs_go1.16.go

@@ -15,6 +15,11 @@ func (c *context) File(file string) error {
 	return fsFile(c, file, c.echo.Filesystem)
 }
 
+// FileFS serves file from given file system.
+//
+// When dealing with `embed.FS` use `fs := echo.MustSubFS(fs, "rootDirectory") to create sub fs which uses necessary
+// prefix for directory path. This is necessary as `//go:embed assets/images` embeds files with paths
+// including `assets/images` as their prefix.
 func (c *context) FileFS(file string, filesystem fs.FS) error {
 	return fsFile(c, file, filesystem)
 }
@@ -28,7 +33,7 @@ func fsFile(c Context, file string, filesystem fs.FS) error {
 
 	fi, _ := f.Stat()
 	if fi.IsDir() {
-		file = filepath.ToSlash(filepath.Join(file, indexPage))
+		file = filepath.Join(file, indexPage)
 		f, err = filesystem.Open(file)
 		if err != nil {
 			return ErrNotFound

context_fs_go1.16_test.go

@@ -4,7 +4,7 @@
 package echo
 
 import (
-	testify "github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/assert"
 	"io/fs"
 	"net/http"
 	"net/http/httptest"
@@ -62,18 +62,18 @@ func TestContext_File(t *testing.T) {
 
 			err := handler(c)
 
-			testify.Equal(t, tc.expectStatus, rec.Code)
+			assert.Equal(t, tc.expectStatus, rec.Code)
 			if tc.expectError != "" {
-				testify.EqualError(t, err, tc.expectError)
+				assert.EqualError(t, err, tc.expectError)
 			} else {
-				testify.NoError(t, err)
+				assert.NoError(t, err)
 			}
 
 			body := rec.Body.Bytes()
 			if len(body) > len(tc.expectStartsWith) {
 				body = body[:len(tc.expectStartsWith)]
 			}
-			testify.Equal(t, tc.expectStartsWith, body)
+			assert.Equal(t, tc.expectStartsWith, body)
 		})
 	}
 }
@@ -118,18 +118,18 @@ func TestContext_FileFS(t *testing.T) {
 
 			err := handler(c)
 
-			testify.Equal(t, tc.expectStatus, rec.Code)
+			assert.Equal(t, tc.expectStatus, rec.Code)
 			if tc.expectError != "" {
-				testify.EqualError(t, err, tc.expectError)
+				assert.EqualError(t, err, tc.expectError)
 			} else {
-				testify.NoError(t, err)
+				assert.NoError(t, err)
 			}
 
 			body := rec.Body.Bytes()
 			if len(body) > len(tc.expectStartsWith) {
 				body = body[:len(tc.expectStartsWith)]
 			}
-			testify.Equal(t, tc.expectStartsWith, body)
+			assert.Equal(t, tc.expectStartsWith, body)
 		})
 	}
 }

echo_fs_go1.16.go

@@ -16,6 +16,10 @@ import (
 type filesystem struct {
 	// Filesystem is file system used by Static and File handlers to access files.
 	// Defaults to os.DirFS(".")
+	//
+	// When dealing with `embed.FS` use `fs := echo.MustSubFS(fs, "rootDirectory") to create sub fs which uses necessary
+	// prefix for directory path. This is necessary as `//go:embed assets/images` embeds files with paths
+	// including `assets/images` as their prefix.
 	Filesystem fs.FS
 }
 
@@ -26,12 +30,8 @@ func createFilesystem() filesystem {
 }
 
 // Static registers a new route with path prefix to serve static files from the provided root directory.
-func (e *Echo) Static(pathPrefix, root string) *Route {
-	subFs, err := subFS(e.Filesystem, root)
-	if err != nil {
-		// happens when `root` contains invalid path according to `fs.ValidPath` rules and we are unable to create FS
-		panic(fmt.Errorf("invalid root given to echo.Static, err %w", err))
-	}
+func (e *Echo) Static(pathPrefix, fsRoot string) *Route {
+	subFs := MustSubFS(e.Filesystem, fsRoot)
 	return e.Add(
 		http.MethodGet,
 		pathPrefix+"*",
@@ -40,11 +40,15 @@ func (e *Echo) Static(pathPrefix, root string) *Route {
 }
 
 // StaticFS registers a new route with path prefix to serve static files from the provided file system.
-func (e *Echo) StaticFS(pathPrefix string, fileSystem fs.FS) *Route {
+//
+// When dealing with `embed.FS` use `fs := echo.MustSubFS(fs, "rootDirectory") to create sub fs which uses necessary
+// prefix for directory path. This is necessary as `//go:embed assets/images` embeds files with paths
+// including `assets/images` as their prefix.
+func (e *Echo) StaticFS(pathPrefix string, filesystem fs.FS) *Route {
 	return e.Add(
 		http.MethodGet,
 		pathPrefix+"*",
-		StaticDirectoryHandler(fileSystem, false),
+		StaticDirectoryHandler(filesystem, false),
 	)
 }
 
@@ -125,3 +129,17 @@ func subFS(currentFs fs.FS, root string) (fs.FS, error) {
 	}
 	return fs.Sub(currentFs, root)
 }
+
+// MustSubFS creates sub FS from current filesystem or panic on failure.
+// Panic happens when `fsRoot` contains invalid path according to `fs.ValidPath` rules.
+//
+// MustSubFS is helpful when dealing with `embed.FS` because for example `//go:embed assets/images` embeds files with
+// paths including `assets/images` as their prefix. In that case use `fs := echo.MustSubFS(fs, "rootDirectory") to
+// create sub fs which uses necessary prefix for directory path.
+func MustSubFS(currentFs fs.FS, fsRoot string) fs.FS {
+	subFs, err := subFS(currentFs, fsRoot)
+	if err != nil {
+		panic(fmt.Errorf("can not create sub FS, invalid root given, err: %w", err))
+	}
+	return subFs
+}

echo_fs_go1.16_test.go

@@ -18,6 +18,7 @@ func TestEcho_StaticFS(t *testing.T) {
 		name                 string
 		givenPrefix          string
 		givenFs              fs.FS
+		givenFsRoot          string
 		whenURL              string
 		expectStatus         int
 		expectHeaderLocation string
@@ -31,6 +32,14 @@ func TestEcho_StaticFS(t *testing.T) {
 			expectStatus:         http.StatusOK,
 			expectBodyStartsWith: string([]byte{0x89, 0x50, 0x4e, 0x47}),
 		},
+		{
+			name:                 "ok, from sub fs",
+			givenPrefix:          "/images",
+			givenFs:              MustSubFS(os.DirFS("./_fixture/"), "images"),
+			whenURL:              "/images/walle.png",
+			expectStatus:         http.StatusOK,
+			expectBodyStartsWith: string([]byte{0x89, 0x50, 0x4e, 0x47}),
+		},
 		{
 			name:                 "No file",
 			givenPrefix:          "/images",
@@ -135,7 +144,12 @@ func TestEcho_StaticFS(t *testing.T) {
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
 			e := New()
-			e.StaticFS(tc.givenPrefix, tc.givenFs)
+
+			tmpFs := tc.givenFs
+			if tc.givenFsRoot != "" {
+				tmpFs = MustSubFS(tmpFs, tc.givenFsRoot)
+			}
+			e.StaticFS(tc.givenPrefix, tmpFs)
 
 			req := httptest.NewRequest(http.MethodGet, tc.whenURL, nil)
 			rec := httptest.NewRecorder()
@@ -229,12 +243,12 @@ func TestEcho_StaticPanic(t *testing.T) {
 		{
 			name:        "panics for ../",
 			givenRoot:   "../assets",
-			expectError: "invalid root given to echo.Static, err sub ../assets: invalid name",
+			expectError: "can not create sub FS, invalid root given, err: sub ../assets: invalid name",
 		},
 		{
 			name:        "panics for /",
 			givenRoot:   "/assets",
-			expectError: "invalid root given to echo.Static, err sub /assets: invalid name",
+			expectError: "can not create sub FS, invalid root given, err: sub /assets: invalid name",
 		},
 	}
 

group_fs_go1.16.go

@@ -4,27 +4,26 @@
 package echo
 
 import (
-	"fmt"
 	"io/fs"
 	"net/http"
 )
 
 // Static implements `Echo#Static()` for sub-routes within the Group.
-func (g *Group) Static(pathPrefix, root string) {
-	subFs, err := subFS(g.echo.Filesystem, root)
-	if err != nil {
-		// happens when `root` contains invalid path according to `fs.ValidPath` rules and we are unable to create FS
-		panic(fmt.Errorf("invalid root given to group.Static, err %w", err))
-	}
+func (g *Group) Static(pathPrefix, fsRoot string) {
+	subFs := MustSubFS(g.echo.Filesystem, fsRoot)
 	g.StaticFS(pathPrefix, subFs)
 }
 
 // StaticFS implements `Echo#StaticFS()` for sub-routes within the Group.
-func (g *Group) StaticFS(pathPrefix string, fileSystem fs.FS) {
+//
+// When dealing with `embed.FS` use `fs := echo.MustSubFS(fs, "rootDirectory") to create sub fs which uses necessary
+// prefix for directory path. This is necessary as `//go:embed assets/images` embeds files with paths
+// including `assets/images` as their prefix.
+func (g *Group) StaticFS(pathPrefix string, filesystem fs.FS) {
 	g.Add(
 		http.MethodGet,
 		pathPrefix+"*",
-		StaticDirectoryHandler(fileSystem, false),
+		StaticDirectoryHandler(filesystem, false),
 	)
 }
 

group_fs_go1.16_test.go

@@ -82,12 +82,12 @@ func TestGroup_StaticPanic(t *testing.T) {
 		{
 			name:        "panics for ../",
 			givenRoot:   "../images",
-			expectError: "invalid root given to group.Static, err sub ../images: invalid name",
+			expectError: "can not create sub FS, invalid root given, err: sub ../images: invalid name",
 		},
 		{
 			name:        "panics for /",
 			givenRoot:   "/images",
-			expectError: "invalid root given to group.Static, err sub /images: invalid name",
+			expectError: "can not create sub FS, invalid root given, err: sub /images: invalid name",
 		},
 	}