Make sure event body is a string (#393)

* Add form to string conversion in eventFromRequest

* Reformat logic

* Change a func name

* Update the switch case logic

* Remove the function

* Add comment to explain the process

* Update comment

* Add Provider mock

* Add encoding test

* Add missing break

* Fix the test

* Remove breaks

* Rename a test func

* Add multiple scenarios in the test

* Change a key name

* Add test case for multipart/form-data

router/event.go

@@ -21,6 +21,8 @@ type HTTPResponse struct {
 
 const (
 	mimeJSON = "application/json"
+	mimeFormMultipart = "multipart/form-data"
+	mimeFormURLEncoded = "application/x-www-form-urlencoded"
 )
 
 func isHTTPEvent(r *http.Request) bool {
@@ -63,10 +65,18 @@ func (router *Router) eventFromRequest(r *http.Request) (*eventpkg.Event, string
 	}
 
 	event := eventpkg.New(eventType, mime, body)
-	if mime == mimeJSON && len(body) > 0 {
-		err = json.Unmarshal(body, &event.Data)
-		if err != nil {
-			return nil, "", errors.New("malformed JSON body")
+
+	// Because event.Data is []bytes here, it will be base64 encoded by default when being sent to remote function,
+	// which is why we change the event.Data type to "string" for forms, so that, it is left intact.
+	if len(body) > 0 {
+		switch {
+		case mime == mimeJSON:
+			err := json.Unmarshal(body, &event.Data)
+			if err != nil {
+				return nil, "", errors.New("malformed JSON body")
+			}
+		case strings.HasPrefix(mime, mimeFormMultipart), mime == mimeFormURLEncoded:
+			event.Data = string(body)
 		}
 	}
 

router/mock/mock.go

@@ -1,3 +1,4 @@
 //go:generate mockgen -package mock -destination ./targetcache.go github.com/serverless/event-gateway/router Targeter
+//go:generate mockgen -package mock -destination ./provider.go github.com/serverless/event-gateway/function Provider
 
 package mock

router/router_test.go

@@ -1,6 +1,7 @@
 package router_test
 
 import (
+	"encoding/json"
 	"net/http"
 	"net/http/httptest"
 	"strings"
@@ -13,6 +14,7 @@ import (
 	"github.com/serverless/event-gateway/function"
 	"github.com/serverless/event-gateway/internal/pathtree"
 	"github.com/serverless/event-gateway/plugin"
+	httpprovider "github.com/serverless/event-gateway/providers/http"
 	"github.com/serverless/event-gateway/router"
 	"github.com/serverless/event-gateway/router/mock"
 	"github.com/serverless/event-gateway/subscription"
@@ -101,6 +103,58 @@ func TestRouterServeHTTP_ErrorMalformedCustomEventJSONRequest(t *testing.T) {
 	assert.Equal(t, `{"errors":[{"message":"malformed JSON body"}]}`+"\n", recorder.Body.String())
 }
 
+func TestRouterServeHTTP_Encoding(t *testing.T) {
+	ctrl := gomock.NewController(t)
+	defer ctrl.Finish()
+	tests := []map[string]string{
+		{
+			"body": "some=thing",
+			"expected": "c29tZT10aGluZw==",
+			"content-type": "",
+		},
+		{
+			"body": "some=thing",
+			"expected": "some=thing",
+			"content-type": "application/x-www-form-urlencoded",
+		},
+		{
+			"body": "--X-INSOMNIA-BOUNDARY\r\nContent-Disposition: form-data; name=\"some\"\r\n\r\nthing\r\n--X-INSOMNIA-BOUNDARY--\r\n",
+			"expected": "--X-INSOMNIA-BOUNDARY\r\nContent-Disposition: form-data; name=\"some\"\r\n\r\nthing\r\n--X-INSOMNIA-BOUNDARY--\r\n",
+			"content-type": "multipart/form-data; boundary=X-INSOMNIA-BOUNDARY",
+		},
+	}
+	for _, test := range tests {
+		testListServer := httptest.NewServer(http.HandlerFunc(
+			func(w http.ResponseWriter, r *http.Request) {
+				testevent := event.Event{
+					Data: event.HTTPEvent{},
+				}
+				json.NewDecoder(r.Body).Decode(&testevent)
+
+				assert.Equal(t, test["expected"], testevent.Data.(map[string]interface{})["body"])
+			}))
+		defer testListServer.Close()
+		target := mock.NewMockTargeter(ctrl)
+		someFunc := function.Function{
+			Space:        "",
+			ID:           "somefunc",
+			ProviderType: httpprovider.Type,
+			Provider: httpprovider.HTTP{
+				URL: testListServer.URL,
+			},
+		}
+		target.EXPECT().HTTPBackingFunction(http.MethodPost, "/").Return("", &someFunc.ID, pathtree.Params{}, nil)
+		target.EXPECT().Function("", someFunc.ID).Return(&someFunc)
+		target.EXPECT().SubscribersOfEvent(gomock.Any(), gomock.Any()).Return([]router.FunctionInfo{}).MaxTimes(3)
+		router := testrouter(target)
+
+		req, _ := http.NewRequest(http.MethodPost, "/", strings.NewReader(test["body"]))
+		req.Header.Set("content-type", test["content-type"])
+		recorder := httptest.NewRecorder()
+		router.ServeHTTP(recorder, req)
+	}
+}
+
 func TestRouterServeHTTP_ErrorOnCustomEventEmittedWithNonPostMethod(t *testing.T) {
 	ctrl := gomock.NewController(t)
 	defer ctrl.Finish()