diff --git a/cmd/dendritejs/main.go b/cmd/dendritejs/main.go index 6339bfbc..618ebbc6 100644 --- a/cmd/dendritejs/main.go +++ b/cmd/dendritejs/main.go @@ -20,6 +20,7 @@ import ( "crypto/ed25519" "fmt" "net/http" + "syscall/js" "github.com/matrix-org/dendrite/appservice" "github.com/matrix-org/dendrite/clientapi" @@ -49,11 +50,89 @@ func init() { fmt.Println("dendrite.js starting...") } +const keyNameEd25519 = "_go_ed25519_key" + +func readKeyFromLocalStorage() (key ed25519.PrivateKey, err error) { + localforage := js.Global().Get("localforage") + if !localforage.Truthy() { + err = fmt.Errorf("readKeyFromLocalStorage: no localforage") + return + } + // https://localforage.github.io/localForage/ + item, ok := await(localforage.Call("getItem", keyNameEd25519)) + if !ok || !item.Truthy() { + err = fmt.Errorf("readKeyFromLocalStorage: no key in localforage") + return + } + fmt.Println("Found key in localforage") + // extract []byte and make an ed25519 key + seed := make([]byte, 32, 32) + js.CopyBytesToGo(seed, item) + + return ed25519.NewKeyFromSeed(seed), nil +} + +func writeKeyToLocalStorage(key ed25519.PrivateKey) error { + localforage := js.Global().Get("localforage") + if !localforage.Truthy() { + return fmt.Errorf("writeKeyToLocalStorage: no localforage") + } + + // make a Uint8Array from the key's seed + seed := key.Seed() + jsSeed := js.Global().Get("Uint8Array").New(len(seed)) + js.CopyBytesToJS(jsSeed, seed) + // write it + localforage.Call("setItem", keyNameEd25519, jsSeed) + return nil +} + +// taken from https://go-review.googlesource.com/c/go/+/150917 + +// await waits until the promise v has been resolved or rejected and returns the promise's result value. +// The boolean value ok is true if the promise has been resolved, false if it has been rejected. +// If v is not a promise, v itself is returned as the value and ok is true. +func await(v js.Value) (result js.Value, ok bool) { + if v.Type() != js.TypeObject || v.Get("then").Type() != js.TypeFunction { + return v, true + } + done := make(chan struct{}) + onResolve := js.FuncOf(func(this js.Value, args []js.Value) interface{} { + result = args[0] + ok = true + close(done) + return nil + }) + defer onResolve.Release() + onReject := js.FuncOf(func(this js.Value, args []js.Value) interface{} { + result = args[0] + ok = false + close(done) + return nil + }) + defer onReject.Release() + v.Call("then", onResolve, onReject) + <-done + return +} + func generateKey() ed25519.PrivateKey { - _, priv, err := ed25519.GenerateKey(nil) + // attempt to look for a seed in JS-land and if it exists use it. + priv, err := readKeyFromLocalStorage() + if err == nil { + fmt.Println("Read key from localStorage") + return priv + } + // generate a new key + fmt.Println(err, " : Generating new ed25519 key") + _, priv, err = ed25519.GenerateKey(nil) if err != nil { logrus.Fatalf("Failed to generate ed25519 key: %s", err) } + if err := writeKeyToLocalStorage(priv); err != nil { + fmt.Println("failed to write key to localStorage: ", err) + // non-fatal, we'll just have amnesia for a while + } return priv }