soroban-rpc: Implement getNetwork method (#366)

* Add friendbotURL and networkPassphrase getNetwork method

* Get the current protocol version directly from core

This sucks. It would be good to cache it when we see new ledgers?

* Add a test for getNetwork

* Remove coreclient failing test. we can't really integration test that easily

* Set expected/actual correctly

* Fix test

* Update description

* privatize test constants where possible

Author: Paul Bellamy

Diff for: cmd/soroban-rpc/internal/config/config.go

@@ -14,6 +14,7 @@ type LocalConfig struct {
 	CaptiveCoreStoragePath    string
 	CaptiveCoreHTTPPort       uint16
 	CaptiveCoreUseDB          bool
+	FriendbotURL              string
 	NetworkPassphrase         string
 	HistoryArchiveURLs        []string
 	LogLevel                  logrus.Level

Diff for: cmd/soroban-rpc/internal/daemon/daemon.go

@@ -125,12 +125,14 @@ func MustNew(cfg config.LocalConfig) *Daemon {
 	)
 
 	handler, err := internal.NewJSONRPCHandler(internal.HandlerParams{
-		AccountStore:     methods.AccountStore{Client: hc},
-		EventStore:       methods.EventStore{Client: hc},
-		Logger:           logger,
-		TransactionProxy: transactionProxy,
-		CoreClient:       &stellarcore.Client{URL: cfg.StellarCoreURL},
-		DB:               db,
+		AccountStore:      methods.AccountStore{Client: hc},
+		EventStore:        methods.EventStore{Client: hc},
+		FriendbotURL:      cfg.FriendbotURL,
+		NetworkPassphrase: cfg.NetworkPassphrase,
+		Logger:            logger,
+		TransactionProxy:  transactionProxy,
+		CoreClient:        &stellarcore.Client{URL: cfg.StellarCoreURL},
+		DB:                db,
 	})
 	if err != nil {
 		logger.Fatalf("could not create handler: %v", err)

Diff for: cmd/soroban-rpc/internal/jsonrpc.go

@@ -40,6 +40,7 @@ func (h Handler) Close() {
 type HandlerParams struct {
 	AccountStore      methods.AccountStore
 	EventStore        methods.EventStore
+	FriendbotURL      string
 	TransactionProxy  *methods.TransactionProxy
 	CoreClient        *stellarcore.Client
 	DB                db.DB
@@ -54,6 +55,7 @@ func NewJSONRPCHandler(params HandlerParams) (Handler, error) {
 		"getAccount":           methods.NewAccountHandler(params.AccountStore),
 		"getEvents":            methods.NewGetEventsHandler(params.EventStore),
 		"getLedgerEntry":       methods.NewGetLedgerEntryHandler(params.Logger, params.DB),
+		"getNetwork":           methods.NewGetNetworkHandler(params.NetworkPassphrase, params.FriendbotURL, params.CoreClient),
 		"getTransactionStatus": methods.NewGetTransactionStatusHandler(params.TransactionProxy),
 		"sendTransaction":      methods.NewSendTransactionHandler(params.TransactionProxy),
 		"simulateTransaction":  methods.NewSimulateTransactionHandler(params.Logger, params.NetworkPassphrase, params.DB),

Diff for: cmd/soroban-rpc/internal/methods/get_network.go

@@ -0,0 +1,37 @@
+package methods
+
+import (
+	"context"
+
+	"github.com/creachadair/jrpc2"
+	"github.com/creachadair/jrpc2/code"
+	"github.com/creachadair/jrpc2/handler"
+
+	"github.com/stellar/go/clients/stellarcore"
+)
+
+type GetNetworkRequest struct{}
+
+type GetNetworkResponse struct {
+	FriendbotURL    string `json:"friendbotUrl,omitempty"`
+	Passphrase      string `json:"passphrase"`
+	ProtocolVersion int    `json:"protocolVersion,string"`
+}
+
+// NewGetNetworkHandler returns a json rpc handler to for the getNetwork method
+func NewGetNetworkHandler(networkPassphrase, friendbotURL string, coreClient *stellarcore.Client) jrpc2.Handler {
+	return handler.New(func(ctx context.Context, request GetNetworkRequest) (GetNetworkResponse, error) {
+		info, err := coreClient.Info(ctx)
+		if err != nil {
+			return GetNetworkResponse{}, (&jrpc2.Error{
+				Code:    code.InternalError,
+				Message: err.Error(),
+			})
+		}
+		return GetNetworkResponse{
+			FriendbotURL:    friendbotURL,
+			Passphrase:      networkPassphrase,
+			ProtocolVersion: info.Info.ProtocolVersion,
+		}, nil
+	})
+}

Diff for: cmd/soroban-rpc/internal/test/get_network_test.go

@@ -0,0 +1,28 @@
+package test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/creachadair/jrpc2"
+	"github.com/creachadair/jrpc2/jhttp"
+	"github.com/stretchr/testify/assert"
+
+	"github.com/stellar/soroban-tools/cmd/soroban-rpc/internal/methods"
+)
+
+func TestGetNetworkSucceeds(t *testing.T) {
+	test := NewTest(t)
+
+	ch := jhttp.NewChannel(test.server.URL, nil)
+	client := jrpc2.NewClient(ch, nil)
+
+	request := methods.GetNetworkRequest{}
+
+	var result methods.GetNetworkResponse
+	err := client.CallResult(context.Background(), "getNetwork", request, &result)
+	assert.NoError(t, err)
+	assert.Equal(t, friendbotURL, result.FriendbotURL)
+	assert.Equal(t, StandaloneNetworkPassphrase, result.Passphrase)
+	assert.Equal(t, stellarCoreProtocolVersion, result.ProtocolVersion)
+}

Diff for: cmd/soroban-rpc/internal/test/integration.go

@@ -39,6 +39,7 @@ const (
 	stellarCorePort             = 11626
 	goModFile                   = "go.mod"
 	goMonorepoGithubPath        = "github.com/stellar/go"
+	friendbotURL                = "http://localhost:8000/friendbot"
 )
 
 type Test struct {
@@ -103,6 +104,7 @@ func (i *Test) launchDaemon() {
 		CaptiveCoreConfigPath:     path.Join(i.composePath, "captive-core-integration-tests.cfg"),
 		CaptiveCoreHTTPPort:       0,
 		CaptiveCoreStoragePath:    i.t.TempDir(),
+		FriendbotURL:              friendbotURL,
 		NetworkPassphrase:         StandaloneNetworkPassphrase,
 		HistoryArchiveURLs:        []string{"http://localhost:1570"},
 		LogLevel:                  logrus.DebugLevel,

Diff for: cmd/soroban-rpc/main.go

@@ -20,7 +20,7 @@ import (
 )
 
 func main() {
-	var endpoint, horizonURL, stellarCoreURL, binaryPath, configPath, networkPassphrase, dbPath, captivecoreStoragePath string
+	var endpoint, horizonURL, stellarCoreURL, binaryPath, configPath, friendbotURL, networkPassphrase, dbPath, captivecoreStoragePath string
 	var captiveCoreHTTPPort, ledgerEntryStorageTimeoutMinutes uint
 	var checkpointFrequency uint32
 	var useDB bool
@@ -134,6 +134,13 @@ func main() {
 			},
 			Usage: "comma-separated list of stellar history archives to connect with",
 		},
+		{
+			Name:      "friendbot-url",
+			Usage:     "The friendbot URL to be returned by getNetwork endpoint",
+			OptType:   types.String,
+			ConfigKey: &friendbotURL,
+			Required:  false,
+		},
 		{
 			Name:        "network-passphrase",
 			Usage:       "Network passphrase of the Stellar network transactions should be signed for",
@@ -201,6 +208,7 @@ func main() {
 				CaptiveCoreUseDB:          useDB,
 				CaptiveCoreHTTPPort:       uint16(captiveCoreHTTPPort),
 				CaptiveCoreStoragePath:    captivecoreStoragePath,
+				FriendbotURL:              friendbotURL,
 				NetworkPassphrase:         networkPassphrase,
 				HistoryArchiveURLs:        historyArchiveURLs,
 				LogLevel:                  logLevel,