Add handling for empty content type in request header

bind.go

@@ -90,6 +90,8 @@ func (b *DefaultBinder) BindBody(c Context, i interface{}) (err error) {
 		if err = b.bindData(i, params, "form"); err != nil {
 			return NewHTTPError(http.StatusBadRequest, err.Error()).SetInternal(err)
 		}
+	case ctype == "":
+		return ErrEmptyContentType
 	default:
 		return ErrUnsupportedMediaType
 	}
@@ -114,7 +116,7 @@ func (b *DefaultBinder) Bind(i interface{}, c Context) (err error) {
 	// Only bind query parameters for GET/DELETE/HEAD to avoid unexpected behavior with destination struct binding from body.
 	// For example a request URL `&id=1&lang=en` with body `{"id":100,"lang":"de"}` would lead to precedence issues.
 	// The HTTP method check restores pre-v4.1.11 behavior to avoid these problems (see issue #1670)
-  method := c.Request().Method
+	method := c.Request().Method
 	if method == http.MethodGet || method == http.MethodDelete || method == http.MethodHead {
 		if err = b.BindQueryParams(c, i); err != nil {
 			return err

bind_test.go

@@ -429,6 +429,10 @@ func TestBindUnsupportedMediaType(t *testing.T) {
 	testBindError(t, strings.NewReader(invalidContent), MIMEApplicationJSON, &json.SyntaxError{})
 }
 
+func TestBindErrEmptyContentType(t *testing.T) {
+	testBindError(t, strings.NewReader(invalidContent), "", errors.New("missing content type header"))
+}
+
 func TestBindbindData(t *testing.T) {
 	ts := new(bindTestStruct)
 	b := new(DefaultBinder)
@@ -674,6 +678,11 @@ func testBindError(t *testing.T, r io.Reader, ctype string, expectedInternal err
 			assert.Equal(t, http.StatusBadRequest, err.(*HTTPError).Code)
 			assert.IsType(t, expectedInternal, err.(*HTTPError).Internal)
 		}
+	case ctype == "": // no content type
+		if assert.IsType(t, new(HTTPError), err) {
+			assert.Equal(t, ErrEmptyContentType, err)
+			assert.IsType(t, expectedInternal, err.(*HTTPError).Internal)
+		}
 	default:
 		if assert.IsType(t, new(HTTPError), err) {
 			assert.Equal(t, ErrUnsupportedMediaType, err)

binder_test.go

@@ -4,7 +4,6 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"github.com/stretchr/testify/assert"
 	"io"
 	"math/big"
 	"net/http"
@@ -13,6 +12,8 @@ import (
 	"strings"
 	"testing"
 	"time"
+
+	"github.com/stretchr/testify/assert"
 )
 
 func createTestContext(URL string, body io.Reader, pathParams map[string]string) Context {

echo.go

@@ -338,6 +338,7 @@ var (
 	ErrCookieNotFound         = errors.New("cookie not found")
 	ErrInvalidCertOrKeyType   = errors.New("invalid cert or key type, must be string or []byte")
 	ErrInvalidListenerNetwork = errors.New("invalid listener network")
+	ErrEmptyContentType       = ErrUnsupportedMediaType.WithInternal(errors.New("missing content type header"))
 )
 
 // Error handlers