middleware: add method override

middleware/method_override.go

@@ -0,0 +1,39 @@
+package middleware
+
+import (
+	"github.com/labstack/echo"
+)
+
+const (
+	HttpMethodOverrideHeader = "X-HTTP-Method-Override"
+)
+
+func OverrideMethod() echo.MiddlewareFunc {
+	return Override()
+}
+
+// Override checks for the X-HTTP-Method-Override header
+// or the body for parameter, `_method`
+// and uses the http method instead of Request.Method.
+// It isn't secure to override e.g a GET to a POST,
+// so only Request.Method which are POSTs are considered.
+func Override() echo.MiddlewareFunc {
+	return func(next echo.HandlerFunc) echo.HandlerFunc {
+		return func(c echo.Context) error {
+			originalMethod := c.Request().Method()
+
+			if originalMethod == "POST" {
+				m := c.FormValue("_method")
+				if m != "" {
+					c.Request().SetMethod(m)
+				}
+				m = c.Request().Header().Get(HttpMethodOverrideHeader)
+				if m != "" {
+					c.Request().SetMethod(m)
+				}
+			}
+
+			return next(c)
+		}
+	}
+}

middleware/method_override_test.go

@@ -0,0 +1,43 @@
+package middleware
+
+import (
+	"bytes"
+	"net/http"
+	"testing"
+
+	"github.com/labstack/echo"
+	"github.com/labstack/echo/test"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestOverrideMtrhod(t *testing.T) {
+	e := echo.New()
+	methodOverride := OverrideMethod()
+	h := methodOverride(func(c echo.Context) error {
+		return c.String(http.StatusOK, c.Request().Method())
+	})
+
+	// Override with http header
+	rq := test.NewRequest(echo.POST, "/", nil)
+	rq.Header().Set(HttpMethodOverrideHeader, "DELETE")
+	rc := test.NewResponseRecorder()
+	c := e.NewContext(rq, rc)
+	h(c)
+	assert.Equal(t, "DELETE", rc.Body.String())
+
+	// Override with body parameter
+	rq = test.NewRequest(echo.POST, "/", bytes.NewReader([]byte("_method=DELETE")))
+	rq.Header().Set(echo.HeaderContentType, echo.MIMEApplicationForm)
+	rc = test.NewResponseRecorder()
+	c = e.NewContext(rq, rc)
+	h(c)
+	assert.Equal(t, "DELETE", rc.Body.String())
+
+	// Ignore GET
+	rq = test.NewRequest(echo.GET, "/", nil)
+	rq.Header().Set(HttpMethodOverrideHeader, "DELETE")
+	rc = test.NewResponseRecorder()
+	c = e.NewContext(rq, rc)
+	h(c)
+	assert.Equal(t, "GET", rc.Body.String())
+}