From d723c76b7a22730ec37e17cf776afe3972bc44da Mon Sep 17 00:00:00 2001
From: ItalyPaleAle <43508+ItalyPaleAle@users.noreply.github.com>
Date: Fri, 28 Aug 2020 18:20:30 -0700
Subject: [PATCH] Allow bind with a map[string]string

---
 binding/binding_test.go | 66 +++++++++++++++++++++++++++++++++++++++++
 binding/form_mapping.go | 38 ++++++++++++++++++++++++
 binding/json_test.go    |  9 ++++++
 3 files changed, 113 insertions(+)

diff --git a/binding/binding_test.go b/binding/binding_test.go
index 4424bab9cd..351c65c620 100644
--- a/binding/binding_test.go
+++ b/binding/binding_test.go
@@ -200,6 +200,12 @@ func TestBindingJSONDisallowUnknownFields(t *testing.T) {
 		`{"foo": "bar"}`, `{"foo": "bar", "what": "this"}`)
 }
 
+func TestBindingJSONStringMap(t *testing.T) {
+	testBodyBindingStringMap(t, JSON,
+		"/", "/",
+		`{"foo": "bar", "hello": "world"}`, `{"num": 2}`)
+}
+
 func TestBindingForm(t *testing.T) {
 	testFormBinding(t, "POST",
 		"/", "/",
@@ -336,6 +342,16 @@ func TestBindingFormForType(t *testing.T) {
 		"", "", "StructPointer")
 }
 
+func TestBindingFormStringMap(t *testing.T) {
+	testBodyBindingStringMap(t, Form,
+		"/", "",
+		`foo=bar&hello=world`, "")
+	// Should pick the last value
+	testBodyBindingStringMap(t, Form,
+		"/", "",
+		`foo=something&foo=bar&hello=world`, "")
+}
+
 func TestBindingQuery(t *testing.T) {
 	testQueryBinding(t, "POST",
 		"/?foo=bar&bar=foo", "/",
@@ -366,6 +382,28 @@ func TestBindingQueryBoolFail(t *testing.T) {
 		"bool_foo=unused", "")
 }
 
+func TestBindingQueryStringMap(t *testing.T) {
+	b := Query
+
+	obj := make(map[string]string)
+	req := requestWithBody("GET", "/?foo=bar&hello=world", "")
+	err := b.Bind(req, &obj)
+	assert.NoError(t, err)
+	assert.NotNil(t, obj)
+	assert.Len(t, obj, 2)
+	assert.Equal(t, "bar", obj["foo"])
+	assert.Equal(t, "world", obj["hello"])
+
+	obj = make(map[string]string)
+	req = requestWithBody("GET", "/?foo=bar&foo=2&hello=world", "") // should pick last
+	err = b.Bind(req, &obj)
+	assert.NoError(t, err)
+	assert.NotNil(t, obj)
+	assert.Len(t, obj, 2)
+	assert.Equal(t, "2", obj["foo"])
+	assert.Equal(t, "world", obj["hello"])
+}
+
 func TestBindingXML(t *testing.T) {
 	testBodyBinding(t,
 		XML, "xml",
@@ -387,6 +425,13 @@ func TestBindingYAML(t *testing.T) {
 		`foo: bar`, `bar: foo`)
 }
 
+func TestBindingYAMLStringMap(t *testing.T) {
+	// YAML is a superset of JSON, so the test below is JSON (to avoid newlines)
+	testBodyBindingStringMap(t, YAML,
+		"/", "/",
+		`{"foo": "bar", "hello": "world"}`, `{"nested": {"foo": "bar"}}`)
+}
+
 func TestBindingYAMLFail(t *testing.T) {
 	testBodyBindingFail(t,
 		YAML, "yaml",
@@ -1114,6 +1159,27 @@ func testBodyBinding(t *testing.T, b Binding, name, path, badPath, body, badBody
 	assert.Error(t, err)
 }
 
+func testBodyBindingStringMap(t *testing.T, b Binding, path, badPath, body, badBody string) {
+	obj := make(map[string]string)
+	req := requestWithBody("POST", path, body)
+	if b.Name() == "form" {
+		req.Header.Add("Content-Type", MIMEPOSTForm)
+	}
+	err := b.Bind(req, &obj)
+	assert.NoError(t, err)
+	assert.NotNil(t, obj)
+	assert.Len(t, obj, 2)
+	assert.Equal(t, "bar", obj["foo"])
+	assert.Equal(t, "world", obj["hello"])
+
+	if badPath != "" && badBody != "" {
+		obj = make(map[string]string)
+		req = requestWithBody("POST", badPath, badBody)
+		err = b.Bind(req, &obj)
+		assert.Error(t, err)
+	}
+}
+
 func testBodyBindingUseNumber(t *testing.T, b Binding, name, path, badPath, body, badBody string) {
 	assert.Equal(t, name, b.Name())
 
diff --git a/binding/form_mapping.go b/binding/form_mapping.go
index f0913ea5e4..609eec4477 100644
--- a/binding/form_mapping.go
+++ b/binding/form_mapping.go
@@ -29,6 +29,21 @@ func mapForm(ptr interface{}, form map[string][]string) error {
 var emptyField = reflect.StructField{}
 
 func mapFormByTag(ptr interface{}, form map[string][]string, tag string) error {
+	// Check if ptr is a map
+	ptrVal := reflect.ValueOf(ptr)
+	var pointed interface{}
+	if ptrVal.Kind() == reflect.Ptr {
+		ptrVal = ptrVal.Elem()
+		pointed = ptrVal.Interface()
+	}
+	if ptrVal.Kind() == reflect.Map &&
+		ptrVal.Type().Key().Kind() == reflect.String {
+		if pointed != nil {
+			ptr = pointed
+		}
+		return setFormMap(ptr, form)
+	}
+
 	return mappingByPtr(ptr, formSource(form), tag)
 }
 
@@ -349,3 +364,26 @@ func head(str, sep string) (head string, tail string) {
 	}
 	return str[:idx], str[idx+len(sep):]
 }
+
+func setFormMap(ptr interface{}, form map[string][]string) error {
+	el := reflect.TypeOf(ptr).Elem()
+	ptrSlice := (el.Kind() == reflect.Slice)
+	if ptrSlice {
+		fmt.Println(el, el.Elem())
+	}
+	for k, v := range form {
+		if ptrSlice {
+			ptr.(map[string][]string)[k] = v
+			if false {
+				return errors.New("cannot assign string slice value to map")
+			}
+		} else {
+			// Pick last
+			ptr.(map[string]string)[k] = v[len(v)-1]
+			if false {
+				return errors.New("cannot assign string value to map")
+			}
+		}
+	}
+	return nil
+}
diff --git a/binding/json_test.go b/binding/json_test.go
index cae4ccccdd..fbd5c52743 100644
--- a/binding/json_test.go
+++ b/binding/json_test.go
@@ -19,3 +19,12 @@ func TestJSONBindingBindBody(t *testing.T) {
 	require.NoError(t, err)
 	assert.Equal(t, "FOO", s.Foo)
 }
+
+func TestJSONBindingBindBodyMap(t *testing.T) {
+	s := make(map[string]string)
+	err := jsonBinding{}.BindBody([]byte(`{"foo": "FOO","hello":"world"}`), &s)
+	require.NoError(t, err)
+	assert.Len(t, s, 2)
+	assert.Equal(t, "FOO", s["foo"])
+	assert.Equal(t, "world", s["hello"])
+}