Function RegisterAvailable

clientapi/routing/register.go:1011–1060

RegisterAvailable checks if the username is already taken or invalid.

(
	req *http.Request,
	cfg *config.ClientAPI,
	registerAPI userapi.ClientUserAPI,
)

// RegisterAvailable checks if the username is already taken or invalid.
func RegisterAvailable(
	req *http.Request,
	cfg *config.ClientAPI,
	registerAPI userapi.ClientUserAPI,
) util.JSONResponse {
	username := req.URL.Query().Get("username")

	// Squash username to all lowercase letters
	username = strings.ToLower(username)

	if err := validateUsername(username); err != nil {
		return *err
	}

	// Check if this username is reserved by an application service
	userID := userutil.MakeUserID(username, cfg.Matrix.ServerName)
	for _, appservice := range cfg.Derived.ApplicationServices {
		if appservice.OwnsNamespaceCoveringUserId(userID) {
			return util.JSONResponse{
				Code: http.StatusBadRequest,
				JSON: jsonerror.UserInUse("Desired user ID is reserved by an application service."),
			}
		}
	}

	res := &userapi.QueryAccountAvailabilityResponse{}
	err := registerAPI.QueryAccountAvailability(req.Context(), &userapi.QueryAccountAvailabilityRequest{
		Localpart: username,
	}, res)
	if err != nil {
		return util.JSONResponse{
			Code: http.StatusInternalServerError,
			JSON: jsonerror.Unknown("failed to check availability:" + err.Error()),
		}
	}

	if !res.Available {
		return util.JSONResponse{
			Code: http.StatusBadRequest,
			JSON: jsonerror.UserInUse("Desired User ID is already taken."),
		}
	}

	return util.JSONResponse{
		Code: http.StatusOK,
		JSON: availableResponse{
			Available: true,
		},
	}
}

func handleSharedSecretRegistration(userAPI userapi.ClientUserAPI, sr *SharedSecretRegistration, req *http.Request) util.JSONResponse {
	ssrr, err := NewSharedSecretRegistrationRequest(req.Body)