Remove OPTION method on "/register/available",

Add CheckAccountAvailability method

Signed-off-by: MTRNord <mtrnord1@gmail.com>

src/github.com/matrix-org/dendrite/clientapi/auth/storage/accounts/storage.go

@@ -314,3 +314,13 @@ func (d *Database) GetThreePIDsForLocalpart(
 ) (threepids []authtypes.ThreePID, err error) {
 	return d.threepids.selectThreePIDsForLocalpart(ctx, localpart)
 }
+
+// CheckAccountAvailability checks if the username/localpart is already present in the database.
+// If the DB returns sql.ErrNoRows the Localpart isn't taken.
+func (d *Database) CheckAccountAvailability(ctx context.Context, localpart string) (bool, error) {
+	_, err := d.accounts.selectAccountByLocalpart(ctx, localpart)
+	if err == sql.ErrNoRows {
+		return true, nil
+	}
+	return false, err
+}

src/github.com/matrix-org/dendrite/clientapi/readers/register.go

@@ -50,7 +50,14 @@ func RegisterAvailable(
 		return *resErr
 	}
 
-	if _, resErr := accountDB.GetProfileByLocalpart(req.Context(), username); resErr == nil {
+	availability, availabilityErr := accountDB.CheckAccountAvailability(req.Context(), username)
+	if availabilityErr != nil {
+		return util.JSONResponse{
+			Code: 500,
+			JSON: jsonerror.Unknown("failed to check availability: " + availabilityErr.Error()),
+		}
+	}
+	if !availability {
 		return util.JSONResponse{
 			Code: 400,
 			JSON: jsonerror.InvalidUsername("A different user ID has already been registered for this session"),

src/github.com/matrix-org/dendrite/clientapi/routing/routing.go

@@ -133,7 +133,7 @@ func Setup(
 
 	r0mux.Handle("/register/available", common.MakeExternalAPI("registerAvailable", func(req *http.Request) util.JSONResponse {
 		return readers.RegisterAvailable(req, accountDB)
-	})).Methods("GET", "OPTIONS")
+	})).Methods("GET")
 
 	r0mux.Handle("/directory/room/{roomAlias}",
 		common.MakeAuthAPI("directory_room", deviceDB, func(req *http.Request, device *authtypes.Device) util.JSONResponse {