clef: bidirectional communication with UI (#19018)

* clef: initial implementation of bidirectional RPC communication for the UI

* signer: fix tests to pass + formatting

* clef: fix unused import + formatting

* signer: gosimple nitpicks

cmd/clef/extapi_changelog.md

@@ -1,5 +1,10 @@
 ### Changelog for external API
 
+### 6.0.0
+
+* `New` was changed to deliver only an address, not the full `Account` data
+* `Export` was moved from External API to the UI Server API
+
 #### 5.0.0
 
 * The external `account_EcRecover`-method was reimplemented.

cmd/clef/intapi_changelog.md

@@ -1,5 +1,29 @@
 ### Changelog for internal API (ui-api)
 
+### 4.0.0
+
+* Bidirectional communication implemented, so the UI can query `clef` via the stdin/stdout RPC channel. Methods implemented are:
+  - `clef_listWallets` 
+  - `clef_listAccounts`
+  - `clef_listWallets`
+  - `clef_deriveAccount`
+  - `clef_importRawKey`
+  - `clef_openWallet`
+  - `clef_chainId`
+  - `clef_setChainId`
+  - `clef_export`
+  - `clef_import`
+ 
+* The type `Account` was modified (the json-field `type` was removed), to consist of 
+
+```golang
+type Account struct {
+	Address common.Address `json:"address"` // Ethereum account address derived from the key
+	URL     URL            `json:"url"`     // Optional resource locator within a backend
+}
+```
+
+
 ### 3.2.0
 
 * Make `ShowError`, `OnApprovedTx`, `OnSignerStartup` be json-rpc [notifications](https://www.jsonrpc.org/specification#notification):

cmd/clef/main.go

@@ -344,7 +344,7 @@ func signer(c *cli.Context) error {
 		return err
 	}
 	var (
-		ui core.SignerUI
+		ui core.UIClientAPI
 	)
 	if c.GlobalBool(stdiouiFlag.Name) {
 		log.Info("Using stdin/stdout as UI-channel")
@@ -408,18 +408,21 @@ func signer(c *cli.Context) error {
 			}
 		}
 	}
-	log.Info("Starting signer", "chainid", c.GlobalInt64(chainIdFlag.Name),
-		"keystore", c.GlobalString(keystoreFlag.Name),
-		"light-kdf", c.GlobalBool(utils.LightKDFFlag.Name),
-		"advanced", c.GlobalBool(advancedMode.Name))
+	var (
+		chainId  = c.GlobalInt64(chainIdFlag.Name)
+		ksLoc    = c.GlobalString(keystoreFlag.Name)
+		lightKdf = c.GlobalBool(utils.LightKDFFlag.Name)
+		advanced = c.GlobalBool(advancedMode.Name)
+		nousb    = c.GlobalBool(utils.NoUSBFlag.Name)
+	)
+	log.Info("Starting signer", "chainid", chainId, "keystore", ksLoc,
+		"light-kdf", lightKdf, "advanced", advanced)
+	am := core.StartClefAccountManager(ksLoc, nousb, lightKdf)
+	apiImpl := core.NewSignerAPI(am, chainId, nousb, ui, db, advanced)
 
-	apiImpl := core.NewSignerAPI(
-		c.GlobalInt64(chainIdFlag.Name),
-		c.GlobalString(keystoreFlag.Name),
-		c.GlobalBool(utils.NoUSBFlag.Name),
-		ui, db,
-		c.GlobalBool(utils.LightKDFFlag.Name),
-		c.GlobalBool(advancedMode.Name))
+	// Establish the bidirectional communication, by creating a new UI backend and registering
+	// it with the UI.
+	ui.RegisterUIServer(core.NewUIServerAPI(apiImpl))
 	api = apiImpl
 	// Audit logging
 	if logfile := c.GlobalString(auditLogFlag.Name); logfile != "" {
@@ -539,7 +542,7 @@ func homeDir() string {
 	}
 	return ""
 }
-func readMasterKey(ctx *cli.Context, ui core.SignerUI) ([]byte, error) {
+func readMasterKey(ctx *cli.Context, ui core.UIClientAPI) ([]byte, error) {
 	var (
 		file      string
 		configDir = ctx.GlobalString(configdirFlag.Name)
@@ -674,10 +677,6 @@ func testExternalUI(api *core.SignerAPI) {
 	checkErr("List", err)
 	_, err = api.New(ctx)
 	checkErr("New", err)
-	_, err = api.Export(ctx, common.Address{})
-	checkErr("Export", err)
-	_, err = api.Import(ctx, json.RawMessage{})
-	checkErr("Import", err)
 
 	api.UI.ShowInfo("Tests completed")