add test case

fix lint

context.go

@@ -21,6 +21,7 @@ import (
 	"time"
 
 	"github.com/gin-contrib/sse"
+
 	"github.com/gin-gonic/gin/binding"
 	"github.com/gin-gonic/gin/render"
 )
@@ -983,6 +984,8 @@ func (c *Context) Status(code int) {
 // It writes a header in the response.
 // If value == "", this method removes the header `c.Writer.Header().Del(key)`
 func (c *Context) Header(key, value string) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
 	if value == "" {
 		c.Writer.Header().Del(key)
 		return
@@ -992,6 +995,8 @@ func (c *Context) Header(key, value string) {
 
 // GetHeader returns value from request headers.
 func (c *Context) GetHeader(key string) string {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
 	return c.requestHeader(key)
 }
 

context_test.go

@@ -27,11 +27,12 @@ import (
 	"time"
 
 	"github.com/gin-contrib/sse"
-	"github.com/gin-gonic/gin/binding"
-	testdata "github.com/gin-gonic/gin/testdata/protoexample"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"google.golang.org/protobuf/proto"
+
+	"github.com/gin-gonic/gin/binding"
+	testdata "github.com/gin-gonic/gin/testdata/protoexample"
 )
 
 var _ context.Context = (*Context)(nil)
@@ -166,7 +167,7 @@ func TestSaveUploadedFileWithPermission(t *testing.T) {
 	require.NoError(t, err)
 	mw.Close()
 	c, _ := CreateTestContext(httptest.NewRecorder())
-	c.Request, _ = http.NewRequest("POST", "/", buf)
+	c.Request, _ = http.NewRequest(http.MethodPost, "/", buf)
 	c.Request.Header.Set("Content-Type", mw.FormDataContentType())
 	f, err := c.FormFile("file")
 	require.NoError(t, err)
@@ -187,7 +188,7 @@ func TestSaveUploadedFileWithPermissionFailed(t *testing.T) {
 	require.NoError(t, err)
 	mw.Close()
 	c, _ := CreateTestContext(httptest.NewRecorder())
-	c.Request, _ = http.NewRequest("POST", "/", buf)
+	c.Request, _ = http.NewRequest(http.MethodPost, "/", buf)
 	c.Request.Header.Set("Content-Type", mw.FormDataContentType())
 	f, err := c.FormFile("file")
 	require.NoError(t, err)
@@ -3123,3 +3124,23 @@ func TestContextNext(t *testing.T) {
 	assert.True(t, exists)
 	assert.Equal(t, "value3", value)
 }
+
+func TestParallelHeaderWrite(t *testing.T) {
+	c, _ := CreateTestContext(httptest.NewRecorder())
+	wg := sync.WaitGroup{}
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		for i := 0; i < 1000; i++ {
+			c.Header("key", "value")
+		}
+	}()
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		for i := 0; i < 1000; i++ {
+			c.Header("key", "value")
+		}
+	}()
+	wg.Wait()
+}