feat: support file server in rest (#4244)

rest/internal/fileserver/filehandler.go

@@ -0,0 +1,39 @@
+package fileserver
+
+import (
+	"net/http"
+	"strings"
+)
+
+func Middleware(path, dir string) func(http.HandlerFunc) http.HandlerFunc {
+	fileServer := http.FileServer(http.Dir(dir))
+	pathWithTrailSlash := ensureTrailingSlash(path)
+	pathWithoutTrailSlash := ensureNoTrailingSlash(path)
+
+	return func(next http.HandlerFunc) http.HandlerFunc {
+		return func(w http.ResponseWriter, r *http.Request) {
+			if r.Method == http.MethodGet && strings.HasPrefix(r.URL.Path, pathWithTrailSlash) {
+				r.URL.Path = strings.TrimPrefix(r.URL.Path, pathWithoutTrailSlash)
+				fileServer.ServeHTTP(w, r)
+			} else {
+				next(w, r)
+			}
+		}
+	}
+}
+
+func ensureTrailingSlash(path string) string {
+	if strings.HasSuffix(path, "/") {
+		return path
+	}
+
+	return path + "/"
+}
+
+func ensureNoTrailingSlash(path string) string {
+	if strings.HasSuffix(path, "/") {
+		return path[:len(path)-1]
+	}
+
+	return path
+}

rest/internal/fileserver/filehandler_test.go

@@ -0,0 +1,99 @@
+package fileserver
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMiddleware(t *testing.T) {
+	tests := []struct {
+		name            string
+		path            string
+		dir             string
+		requestPath     string
+		expectedStatus  int
+		expectedContent string
+	}{
+		{
+			name:            "Serve static file",
+			path:            "/static/",
+			dir:             "./testdata",
+			requestPath:     "/static/example.txt",
+			expectedStatus:  http.StatusOK,
+			expectedContent: "1",
+		},
+		{
+			name:           "Pass through non-matching path",
+			path:           "/static/",
+			dir:            "./testdata",
+			requestPath:    "/other/path",
+			expectedStatus: http.StatusNotFound,
+		},
+		{
+			name:            "Directory with trailing slash",
+			path:            "/assets",
+			dir:             "testdata",
+			requestPath:     "/assets/sample.txt",
+			expectedStatus:  http.StatusOK,
+			expectedContent: "2",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			middleware := Middleware(tt.path, tt.dir)
+			nextHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				w.WriteHeader(http.StatusNotFound)
+			})
+
+			handlerToTest := middleware(nextHandler)
+
+			req := httptest.NewRequest("GET", tt.requestPath, nil)
+			rr := httptest.NewRecorder()
+
+			handlerToTest.ServeHTTP(rr, req)
+
+			assert.Equal(t, tt.expectedStatus, rr.Code)
+			if len(tt.expectedContent) > 0 {
+				assert.Equal(t, tt.expectedContent, rr.Body.String())
+			}
+		})
+	}
+}
+
+func TestEnsureTrailingSlash(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected string
+	}{
+		{"path", "path/"},
+		{"path/", "path/"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.input, func(t *testing.T) {
+			result := ensureTrailingSlash(tt.input)
+			assert.Equal(t, tt.expected, result)
+		})
+	}
+}
+
+func TestEnsureNoTrailingSlash(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected string
+	}{
+		{"path", "path"},
+		{"path/", "path"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.input, func(t *testing.T) {
+			result := ensureNoTrailingSlash(tt.input)
+			assert.Equal(t, tt.expected, result)
+		})
+	}
+}

rest/internal/fileserver/testdata/example.txt

@@ -0,0 +1 @@
+1

rest/internal/fileserver/testdata/sample.txt

@@ -0,0 +1 @@
+2

rest/server.go

@@ -13,6 +13,7 @@ import (
 	"github.com/zeromicro/go-zero/rest/httpx"
 	"github.com/zeromicro/go-zero/rest/internal"
 	"github.com/zeromicro/go-zero/rest/internal/cors"
+	"github.com/zeromicro/go-zero/rest/internal/fileserver"
 	"github.com/zeromicro/go-zero/rest/router"
 )
 
@@ -170,6 +171,13 @@ func WithCustomCors(middlewareFn func(header http.Header), notAllowedFn func(htt
 	}
 }
 
+// WithFileServer returns a RunOption to serve files from given dir with given path.
+func WithFileServer(path, dir string) RunOption {
+	return func(server *Server) {
+		server.router = newFileServingRouter(server.router, path, dir)
+	}
+}
+
 // WithJwt returns a func to enable jwt authentication in given route.
 func WithJwt(secret string) RouteOption {
 	return func(r *featuredRoutes) {
@@ -337,3 +345,19 @@ func newCorsRouter(router httpx.Router, headerFn func(http.Header), origins ...s
 func (c *corsRouter) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	c.middleware(c.Router.ServeHTTP)(w, r)
 }
+
+type fileServingRouter struct {
+	httpx.Router
+	middleware Middleware
+}
+
+func newFileServingRouter(router httpx.Router, path, dir string) httpx.Router {
+	return &fileServingRouter{
+		Router:     router,
+		middleware: fileserver.Middleware(path, dir),
+	}
+}
+
+func (f *fileServingRouter) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	f.middleware(f.Router.ServeHTTP)(w, r)
+}

rest/server_test.go

@@ -184,6 +184,56 @@ func TestWithMiddleware(t *testing.T) {
 	}, m)
 }
 
+func TestWithFileServerMiddleware(t *testing.T) {
+	tests := []struct {
+		name            string
+		path            string
+		dir             string
+		requestPath     string
+		expectedStatus  int
+		expectedContent string
+	}{
+		{
+			name:            "Serve static file",
+			path:            "/assets/",
+			dir:             "./testdata",
+			requestPath:     "/assets/example.txt",
+			expectedStatus:  http.StatusOK,
+			expectedContent: "example content",
+		},
+		{
+			name:           "Pass through non-matching path",
+			path:           "/static/",
+			dir:            "./testdata",
+			requestPath:    "/other/path",
+			expectedStatus: http.StatusNotFound,
+		},
+		{
+			name:            "Directory with trailing slash",
+			path:            "/static",
+			dir:             "testdata",
+			requestPath:     "/static/sample.txt",
+			expectedStatus:  http.StatusOK,
+			expectedContent: "sample content",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			server := MustNewServer(RestConf{}, WithFileServer(tt.path, tt.dir))
+			req := httptest.NewRequest(http.MethodGet, tt.requestPath, nil)
+			rr := httptest.NewRecorder()
+
+			server.ServeHTTP(rr, req)
+
+			assert.Equal(t, tt.expectedStatus, rr.Code)
+			if len(tt.expectedContent) > 0 {
+				assert.Equal(t, tt.expectedContent, rr.Body.String())
+			}
+		})
+	}
+}
+
 func TestMultiMiddlewares(t *testing.T) {
 	m := make(map[string]string)
 	rt := router.NewRouter()

rest/testdata/example.txt

@@ -0,0 +1 @@
+example content

rest/testdata/sample.txt

@@ -0,0 +1 @@
+sample content