api: Allow reseting of request body

api/request.go

@@ -14,6 +14,7 @@ type Request struct {
 	Method   string
 	URL      *url.URL
 	Params   url.Values
+	Obj      interface{}
 	Body     io.Reader
 	BodySize int64
 }
@@ -26,11 +27,20 @@ func (r *Request) SetJSONBody(val interface{}) error {
 		return err
 	}
 
+	r.Obj = val
 	r.Body = buf
 	r.BodySize = int64(buf.Len())
 	return nil
 }
 
+// ResetJSONBody is used to reset the body for a redirect
+func (r *Request) ResetJSONBody() error {
+	if r.Body == nil {
+		return nil
+	}
+	return r.SetJSONBody(r.Obj)
+}
+
 // ToHTTP turns this request into a valid *http.Request for use with the
 // net/http package.
 func (r *Request) ToHTTP() (*http.Request, error) {

api/request_test.go

@@ -29,3 +29,35 @@ func TestRequestSetJSONBody(t *testing.T) {
 		t.Fatalf("bad: %d", len(actual))
 	}
 }
+
+func TestRequestResetJSONBody(t *testing.T) {
+	var r Request
+	raw := map[string]interface{}{"foo": "bar"}
+	if err := r.SetJSONBody(raw); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	var buf bytes.Buffer
+	if _, err := io.Copy(&buf, r.Body); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	if err := r.ResetJSONBody(); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	var buf2 bytes.Buffer
+	if _, err := io.Copy(&buf2, r.Body); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	expected := `{"foo":"bar"}`
+	actual := strings.TrimSpace(buf2.String())
+	if actual != expected {
+		t.Fatalf("bad: %s", actual)
+	}
+
+	if int64(len(buf2.String())) != r.BodySize {
+		t.Fatalf("bad: %d", len(actual))
+	}
+}