Browser storage adapter

Contract

Browser storage is exposed as a small key-value interface for non-secret client preferences and session markers. Tokens and credentials must remain owned by the application security layer.

import "errors"
import gxwasm "github.com/busdk/bus-gx/pkg/gx/wasm"

store := gxwasm.SessionStorage()
if err := store.Set("sidebar", "collapsed"); err != nil {
	if errors.Is(err, gxwasm.ErrUnavailable) {
		reportBrowserUnavailable(err)
		return
	}
	report(err)
	return
}

Storage adapters are optional. Tests can provide in-memory fakes, and server-side rendering must not require browser storage.

The shared interface is:

type Storage interface {
	Get(key string) (value string, ok bool, err error)
	Set(key string, value string) error
	Delete(key string) error
	Clear() error
}

The constructors all return gxwasm.Storage directly:

func MemoryStorage(initial map[string]string) Storage
func LocalStorage() Storage
func SessionStorage() Storage

gxwasm.MemoryStorage(initial) returns an in-memory implementation for tests. gxwasm.LocalStorage() and gxwasm.SessionStorage() return browser-backed adapters when the browser API exists. Host builds and unsupported browsers return storage values whose Get, Set, Delete, and Clear methods return errors matching gxwasm.ErrUnavailable.

Requirements

  • The storage interface supports get, set, delete, and clear operations.
  • SessionStorage and local storage adapters are browser-only bindings.
  • Memory storage is available as a deterministic test seam.
  • Missing browser storage returns errors matching gxwasm.ErrUnavailable.
  • Stored values are strings; structured data encoding belongs to caller code.

Boundary

The storage adapter is not an auth/session policy layer. It must not encourage rendering bearer tokens, raw credentials, CSRF secrets, or other authority values into public browser state.

← File adapter UI framework index

Sources