make cache reusable

Author: ysmood

utils.go

@@ -209,21 +209,21 @@ func (ut Utils) ToJSONString(obj interface{}) string {
 // If obj is not []byte, string, or io.Reader, it will be encoded as JSON.
 func (ut Utils) Write(obj interface{}) (writer func(io.Writer)) {
 	lock := sync.Mutex{}
-	var cache io.ReadWriter
+	var cache []byte
 	return func(w io.Writer) {
 		lock.Lock()
 		defer lock.Unlock()
 
 		ut.Helper()
 
 		if cache != nil {
-			_, err := io.Copy(w, cache)
+			_, err := w.Write(cache)
 			ut.err(err)
 			return
 		}
 
-		cache = bytes.NewBuffer(nil)
-		w = io.MultiWriter(cache, w)
+		buf := bytes.NewBuffer(nil)
+		w = io.MultiWriter(buf, w)
 
 		var err error
 		switch v := obj.(type) {
@@ -237,6 +237,7 @@ func (ut Utils) Write(obj interface{}) (writer func(io.Writer)) {
 			err = json.NewEncoder(w).Encode(v)
 		}
 		ut.err(err)
+		cache = buf.Bytes()
 	}
 }
 

utils_test.go

@@ -2,8 +2,10 @@ package got_test
 
 import (
 	"bytes"
+	"io"
 	"net/http"
 	"os"
+	"sync"
 	"testing"
 
 	"github.com/ysmood/got"
@@ -116,3 +118,34 @@ func TestHelper(t *testing.T) {
 	mut.Skipf("test skip")
 	ut.Eq(m.msg, "test skip")
 }
+
+func TestServe(t *testing.T) {
+	ut := got.New(t)
+
+	key := ut.Srand(8)
+	s := ut.Serve().Route("/", "", key)
+	count := 30
+
+	wg := sync.WaitGroup{}
+	wg.Add(count)
+
+	request := func() {
+		req, err := http.NewRequest(http.MethodGet, s.URL(), nil)
+		ut.E(err)
+
+		res, err := http.DefaultClient.Do(req)
+		ut.E(err)
+
+		b, err := io.ReadAll(res.Body)
+		ut.E(err)
+
+		ut.Eq(string(b), key)
+		wg.Done()
+	}
+
+	for i := 0; i < count; i++ {
+		go request()
+	}
+
+	wg.Wait()
+}