Validate url_pattern format in control API append operation

Closes: #38

Co-authored-by: César Gallego Rodríguez <cesar.gallego.next@bbva.com>

internal/server/control/control.go

@@ -70,6 +70,10 @@ func listRoutes(res http.ResponseWriter, req *http.Request) {
 var funcAdd func(model.Route) model.Route = user.Routes.Append
 var idGenerator = uuid.NewUUID
 
+var pathValidator func(string) error = func(path string) error {
+	return mux.NewRouter().NewRoute().BuildOnly().Path(path).GetError()
+}
+
 func addRoute(res http.ResponseWriter, req *http.Request) {
 	var route model.Route
 
@@ -88,6 +92,12 @@ func addRoute(res http.ResponseWriter, req *http.Request) {
 		return
 	}
 
+	err = pathValidator(route.Pattern)
+	if err != nil {
+		res.WriteHeader(http.StatusUnprocessableEntity)
+		return
+	}
+
 	id, err := idGenerator()
 	if err != nil {
 		res.WriteHeader(http.StatusInternalServerError)

internal/server/control/control_test.go

@@ -72,6 +72,22 @@ func TestConfigRouterHasRoutesWellConfigured(t *testing.T) {
 	}
 }
 
+func TestPathValidatorNoErrorWhenCorrectPath(t *testing.T) {
+	err := pathValidator("/routes/{routeID}")
+
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+func TestPathValidatorErrorWhenInvalidPath(t *testing.T) {
+	err := pathValidator("/routes/{routeID{")
+
+	if err == nil {
+		t.FailNow()
+	}
+}
+
 func TestAddRouteReturnsBadRequestWhenMalformedJSONBody(t *testing.T) {
 	reqPayload := `{
     method": "GET",
@@ -181,6 +197,9 @@ func TestAddRouteGeneratesRouteID(t *testing.T) {
 		input.Index = 0
 		return input
 	}
+	origPathValidator := pathValidator
+	defer func() { pathValidator = origPathValidator }()
+	pathValidator = func(path string) error { return nil }
 
 	handler.ServeHTTP(resp, req)
 
@@ -200,6 +219,10 @@ func TestAddRoute500sWhenIDGeneratorFails(t *testing.T) {
 	resp := httptest.NewRecorder()
 	handler := http.HandlerFunc(addRoute)
 
+	origPathValidator := pathValidator
+	defer func() { pathValidator = origPathValidator }()
+	pathValidator = func(path string) error { return nil }
+
 	idGenOrig := idGenerator
 	defer func() { idGenerator = idGenOrig }()
 	idGenerator = func() (uuid.UUID, error) {
@@ -237,6 +260,9 @@ func TestAddRouteReturnsCreated(t *testing.T) {
 
 		return model.Route{}
 	}
+	origPathValidator := pathValidator
+	defer func() { pathValidator = origPathValidator }()
+	pathValidator = func(path string) error { return nil }
 
 	handler.ServeHTTP(resp, req)
 
@@ -259,6 +285,27 @@ func TestAddRouteReturnsCreated(t *testing.T) {
 	}
 }
 
+func TestAddRoute422sWhenInvalidRoute(t *testing.T) {
+	reqPayload := `{
+	"method": "GET",
+	"url_pattern": "/he{{o",
+	"entrypoint": "/bin/sh -c",
+	"command": "echo Hello World | kapow set /response/body"
+}`
+	req := httptest.NewRequest(http.MethodPost, "/routes", strings.NewReader(reqPayload))
+	resp := httptest.NewRecorder()
+	handler := http.HandlerFunc(addRoute)
+	origPathValidator := pathValidator
+	defer func() { pathValidator = origPathValidator }()
+	pathValidator = func(path string) error { return errors.New("Invalid route") }
+
+	handler.ServeHTTP(resp, req)
+
+	if resp.Code != http.StatusUnprocessableEntity {
+		t.Error("Invalid route registered")
+	}
+}
+
 func TestRemoveRouteReturnsNotFound(t *testing.T) {
 	req := httptest.NewRequest(http.MethodDelete, "/routes/ROUTE_XXXXXXXXXXXXXXXXXX", nil)
 	resp := httptest.NewRecorder()