actor: extend documentation, add example

pkg/rpcclient/actor/actor.go

@@ -1,10 +1,11 @@
 /*
 Package actor provides a way to change chain state via RPC client.
 
-This layer builds on top of the basic RPC client and simplifies creating,
-signing and sending transactions to the network (since that's the only way chain
-state is changed). It's generic enough to be used for any contract that you may
-want to invoke and contract-specific functions can build on top of it.
+This layer builds on top of the basic RPC client and [invoker] package, it
+simplifies creating, signing and sending transactions to the network (since
+that's the only way chain state is changed). It's generic enough to be used for
+any contract that you may want to invoke and contract-specific functions can
+build on top of it.
 */
 package actor
 
@@ -44,6 +45,14 @@ type SignerAccount struct {
 // state-changing actions (via transactions that can also be created without
 // sending them to the network) on behalf of a set of signers. It also provides
 // an Invoker interface to perform test calls with the same set of signers.
+//
+// Actor-specific APIs follow the naming scheme set by Invoker in method
+// suffixes. *Call methods operate with function calls and require a contract
+// hash, a method and parameters if any. *Run methods operate with scripts and
+// require a NeoVM script that will be used directly. Prefixes denote the
+// action to be performed, "Make" prefix is used for methods that create
+// transactions in various ways, while "Send" prefix is used by methods that
+// directly transmit created transactions to the RPC server.
 type Actor struct {
 	invoker.Invoker
 

pkg/rpcclient/actor/doc_test.go

@@ -0,0 +1,122 @@
+package actor_test
+
+import (
+	"context"
+	"encoding/json"
+	"os"
+
+	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
+	"github.com/nspcc-dev/neo-go/pkg/neorpc/result"
+	"github.com/nspcc-dev/neo-go/pkg/rpcclient"
+	"github.com/nspcc-dev/neo-go/pkg/rpcclient/actor"
+	"github.com/nspcc-dev/neo-go/pkg/rpcclient/neo"
+	"github.com/nspcc-dev/neo-go/pkg/rpcclient/policy"
+	sccontext "github.com/nspcc-dev/neo-go/pkg/smartcontract/context"
+	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/vm/vmstate"
+	"github.com/nspcc-dev/neo-go/pkg/wallet"
+)
+
+func ExampleActor() {
+	// No error checking done at all, intentionally.
+	w, _ := wallet.NewWalletFromFile("somewhere")
+	defer w.Close()
+
+	c, _ := rpcclient.New(context.Background(), "url", rpcclient.Options{})
+
+	// Create a simple CalledByEntry-scoped actor (assuming there are accounts
+	// inside the wallet).
+	a, _ := actor.NewSimple(c, w.Accounts[0])
+
+	customContract := util.Uint160{9, 8, 7}
+	// Actor has an Invoker inside, so we can perform test invocations, it will
+	// have a signer with the first wallet account and CalledByEntry scope.
+	res, _ := a.Call(customContract, "method", 1, 2, 3)
+	if res.State != vmstate.Halt.String() {
+		// The call failed.
+	}
+	// All of the side-effects in res can be analyzed.
+
+	// Now we want to send the same invocation in a transaction, but we already
+	// have the script and a proper system fee for it, therefore SendUncheckedRun
+	// can be used.
+	txid, vub, _ := a.SendUncheckedRun(res.Script, res.GasConsumed, nil, nil)
+	_ = txid
+	_ = vub
+	// You need to wait for it to persist and then check the on-chain result of it.
+
+	// Now we want to send some transaction, but give it a priority by increasing
+	// its network fee, this can be done with Tuned APIs.
+	txid, vub, _ = a.SendTunedCall(customContract, "method", nil, func(r *result.Invoke, t *transaction.Transaction) error {
+		// This code is run after the test-invocation done by *Call methods.
+		// Reuse the default function to check for HALT execution state.
+		err := actor.DefaultCheckerModifier(r, t)
+		if err != nil {
+			return err
+		}
+		// Some additional checks can be performed right here, but we only
+		// want to raise the network fee by ~20%.
+		t.NetworkFee += (t.NetworkFee / 5)
+		return nil
+	}, 1, 2, 3)
+	_ = txid
+	_ = vub
+
+	// Actor can be used for higher-level wrappers as well, if we want to interact with
+	// NEO then [neo] package can accept our Actor and allow to easily use NEO methods.
+	neoContract := neo.New(a)
+	balance, _ := neoContract.BalanceOf(a.Sender())
+	_ = balance
+
+	// Now suppose the second wallet account is a committee account. We want to
+	// create and sign transactions for committee, but use the first account as
+	// a sender (because committee account has no GAS). We at the same time want
+	// to make all transactions using this actor high-priority ones, because
+	// committee can use this attribute.
+
+	// Get the default options to have CheckerModifier/Modifier set up correctly.
+	opts := actor.NewDefaultOptions()
+	// And override attributes.
+	opts.Attributes = []transaction.Attribute{{Type: transaction.HighPriority}}
+
+	// Create an Actor.
+	a, _ = actor.NewTuned(c, []actor.SignerAccount{{
+		// Sender, regular account with None scope.
+		Signer: transaction.Signer{
+			Account: w.Accounts[0].ScriptHash(),
+			Scopes:  transaction.None,
+		},
+		Account: w.Accounts[0],
+	}, {
+		// Commmitee.
+		Signer: transaction.Signer{
+			Account: w.Accounts[1].ScriptHash(),
+			Scopes:  transaction.CalledByEntry,
+		},
+		Account: w.Accounts[1],
+	}}, opts)
+
+	// Use policy contract wrapper to simplify things. All changes in the
+	// Policy contract are made by the committee.
+	policyContract := policy.New(a)
+
+	// Create a transaction to set storage price, it'll be high-priority and have two
+	// signers from above. Committee is a multisignature account, so we can't sign/send
+	// it right away, w.Accounts[1] has only one public key. Therefore, we need to
+	// create a partially signed transaction and save it, then collect other signatures
+	// and send.
+	tx, _ := policyContract.SetStoragePriceUnsigned(10)
+
+	net := a.GetNetwork()
+	scCtx := sccontext.NewParameterContext("Neo.Network.P2P.Payloads.Transaction", net, tx)
+	sign := w.Accounts[0].SignHashable(net, tx)
+	_ = scCtx.AddSignature(w.Accounts[0].ScriptHash(), w.Accounts[0].Contract, w.Accounts[0].PublicKey(), sign)
+
+	sign = w.Accounts[1].SignHashable(net, tx)
+	_ = scCtx.AddSignature(w.Accounts[1].ScriptHash(), w.Accounts[1].Contract, w.Accounts[1].PublicKey(), sign)
+
+	data, _ := json.Marshal(scCtx)
+	_ = os.WriteFile("tx.json", data, 0644)
+
+	// Signature collection is out of scope, usually it's manual for cases like this.
+}