From c9ff6a10d34e30e2f631de14683bbd9fbd2d05ea Mon Sep 17 00:00:00 2001
From: Kevin Wan <wanjunfeng@gmail.com>
Date: Sun, 13 Jul 2025 00:00:52 +0800
Subject: [PATCH] feat: support serverless in rest (#5001)

Signed-off-by: kevin <wanjunfeng@gmail.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
---
 rest/server.go          | 10 ++++++
 rest/server_test.go     |  4 +--
 rest/serverless.go      | 27 +++++++++++++++++
 rest/serverless_test.go | 67 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 106 insertions(+), 2 deletions(-)
 create mode 100644 rest/serverless.go
 create mode 100644 rest/serverless_test.go

diff --git a/rest/server.go b/rest/server.go
index df025ebfc..6cb7914b7 100644
--- a/rest/server.go
+++ b/rest/server.go
@@ -119,6 +119,16 @@ func (s *Server) Use(middleware Middleware) {
 	s.ngin.use(middleware)
 }
 
+// build builds the Server and binds the routes to the router.
+func (s *Server) build() error {
+	return s.ngin.bindRoutes(s.router)
+}
+
+// serve serves the HTTP requests using the Server's router.
+func (s *Server) serve(w http.ResponseWriter, r *http.Request) {
+	s.router.ServeHTTP(w, r)
+}
+
 // ToMiddleware converts the given handler to a Middleware.
 func ToMiddleware(handler func(next http.Handler) http.Handler) Middleware {
 	return func(handle http.HandlerFunc) http.HandlerFunc {
diff --git a/rest/server_test.go b/rest/server_test.go
index 9676b3f87..a0b0fbe1f 100644
--- a/rest/server_test.go
+++ b/rest/server_test.go
@@ -819,6 +819,6 @@ func TestServerEmbedFileSystem(t *testing.T) {
 //	serve(server, w, r)
 //	// verify the response
 func serve(s *Server, w http.ResponseWriter, r *http.Request) {
-	s.ngin.bindRoutes(s.router)
-	s.router.ServeHTTP(w, r)
+	_ = s.build()
+	s.serve(w, r)
 }
diff --git a/rest/serverless.go b/rest/serverless.go
new file mode 100644
index 000000000..84c25c949
--- /dev/null
+++ b/rest/serverless.go
@@ -0,0 +1,27 @@
+package rest
+
+import "net/http"
+
+// Serverless is a wrapper around Server that allows it to be used in serverless environments.
+type Serverless struct {
+	server *Server
+}
+
+// NewServerless creates a new Serverless instance from the provided Server.
+func NewServerless(server *Server) (*Serverless, error) {
+	// Ensure the server is built before using it in a serverless context.
+	// Why not call server.build() when serving requests,
+	// is because we need to ensure fail fast behavior.
+	if err := server.build(); err != nil {
+		return nil, err
+	}
+
+	return &Serverless{
+		server: server,
+	}, nil
+}
+
+// Serve handles HTTP requests by delegating them to the underlying Server instance.
+func (s *Serverless) Serve(w http.ResponseWriter, r *http.Request) {
+	s.server.serve(w, r)
+}
diff --git a/rest/serverless_test.go b/rest/serverless_test.go
new file mode 100644
index 000000000..c7e5a6904
--- /dev/null
+++ b/rest/serverless_test.go
@@ -0,0 +1,67 @@
+package rest
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/zeromicro/go-zero/core/conf"
+	"github.com/zeromicro/go-zero/core/logx/logtest"
+)
+
+func TestNewServerless(t *testing.T) {
+	logtest.Discard(t)
+
+	const configYaml = `
+Name: foo
+Host: localhost
+Port: 0
+`
+	var cnf RestConf
+	assert.Nil(t, conf.LoadFromYamlBytes([]byte(configYaml), &cnf))
+
+	svr, err := NewServer(cnf)
+	assert.NoError(t, err)
+
+	svr.AddRoute(Route{
+		Method: http.MethodGet,
+		Path:   "/",
+		Handler: func(w http.ResponseWriter, r *http.Request) {
+			w.Write([]byte("Hello World"))
+		},
+	})
+
+	serverless, err := NewServerless(svr)
+	assert.NoError(t, err)
+
+	w := httptest.NewRecorder()
+	r := httptest.NewRequest(http.MethodGet, "/", nil)
+	serverless.Serve(w, r)
+	assert.Equal(t, http.StatusOK, w.Code)
+	assert.Equal(t, "Hello World", w.Body.String())
+}
+
+func TestNewServerlessWithError(t *testing.T) {
+	logtest.Discard(t)
+
+	const configYaml = `
+Name: foo
+Host: localhost
+Port: 0
+`
+	var cnf RestConf
+	assert.Nil(t, conf.LoadFromYamlBytes([]byte(configYaml), &cnf))
+
+	svr, err := NewServer(cnf)
+	assert.NoError(t, err)
+
+	svr.AddRoute(Route{
+		Method:  http.MethodGet,
+		Path:    "notstartwith/",
+		Handler: nil,
+	})
+
+	_, err = NewServerless(svr)
+	assert.Error(t, err)
+}