optional simulate & wallet, editable TransactionBuilder

- Can now pass an `account` OR `wallet` when constructing the
  ContractClient, or none! If you pass none, you can still make view
  calls, since they don't need a signer. You will need to pass a
  `wallet` when calling things that need it, like `signAndSend`.

- You can now pass `simulate: false` when first creating your
  transaction to skip simulation. You can then modify the transaction
  using the TransactionBuilder at `tx.raw` before manually calling
  `simulate`. Example:

      const tx = await myContract.myMethod(
        { args: 'for', my: 'method', ... },
        { simulate: false }
      );
      tx.raw.addMemo(Memo.text('Nice memo, friend!'))
      await tx.simulate();

- Error types are now collected under `AssembledTransaction.Errors` and
  `SentTransaction.Errors`.

src/contract_spec.ts

@@ -719,7 +719,7 @@ export class ContractSpec {
         args: Record<string, any>,
         options: MethodOptions
       ) => {
-        return await AssembledTransaction.fromSimulation({
+        return await AssembledTransaction.build({
           method: name,
           args: spec.funcArgsToScVals(name, args),
           ...options,

src/soroban/contract_client.ts

@@ -1,5 +1,5 @@
 import { AssembledTransaction } from '.'
-import { ContractSpec, xdr } from '..'
+import { Account, ContractSpec, SorobanRpc, xdr } from '..'
 
 export type XDR_BASE64 = string;
 
@@ -23,12 +23,7 @@ export interface Wallet {
   ) => Promise<XDR_BASE64>;
 }
 
-
-export type ContractClientOptions = {
-  contractId: string;
-  networkPassphrase: string;
-  rpcUrl: string;
-  errorTypes?: Record<number, { message: string }>;
+export interface AcceptsWalletOrAccount {
   /**
    * A Wallet interface, such as Freighter, that has the methods `isConnected`, `isAllowed`, `getUserInfo`, and `signTransaction`. If not provided, will attempt to import and use Freighter. Example:
    *
@@ -42,14 +37,61 @@ export type ContractClientOptions = {
    * })
    * ```
    */
-  wallet: Wallet;
+  wallet?: Wallet;
+
+  /**
+   * You can pass in `wallet` OR `account`, but not both. If you only pass
+   * `wallet`, `account` will be derived from it. If you can bypass this
+   * behavior by passing in your own account object.
+   */
+  account?: Account | Promise<Account>;
+};
+
+async function getPublicKey(wallet?: Wallet): Promise<string | undefined> {
+  if (!wallet) return undefined;
+  if (!(await wallet.isConnected()) || !(await wallet.isAllowed())) {
+    return undefined;
+  }
+  return (await wallet.getUserInfo()).publicKey;
+};
+
+export const NULL_ACCOUNT =
+  "GAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAWHF";
+
+/**
+ * Get account details from the Soroban network for the publicKey currently
+ * selected in user's wallet. If user is not connected to their wallet, {@link
+ * getPublicKey} returns undefined, and this will return {@link NULL_ACCOUNT}.
+ * This works for simulations, which is all that's needed for most view calls.
+ * If you want the transaction to be included in the ledger, you will need to
+ * provide a connected wallet.
+ */
+export async function getAccount(server: SorobanRpc.Server, wallet?: Wallet): Promise<Account> {
+  const publicKey = await getPublicKey(wallet);
+  return publicKey
+    ? await server.getAccount(publicKey)
+    : new Account(NULL_ACCOUNT, "0");
+};
+
+export type ContractClientOptions = AcceptsWalletOrAccount & {
+  contractId: string;
+  networkPassphrase: string;
+  rpcUrl: string;
+  errorTypes?: Record<number, { message: string }>;
 };
 
 export class ContractClient {
+  private server: SorobanRpc.Server;
+
   constructor(
     public readonly spec: ContractSpec,
     public readonly options: ContractClientOptions,
-  ) {}
+  ) {
+    this.server = new SorobanRpc.Server(this.options.rpcUrl, {
+      allowHttp: this.options.rpcUrl.startsWith("http://"),
+    });
+    options.account = options.account ?? getAccount(this.server, options.wallet);
+  }
 
   txFromJSON = <T>(json: string): AssembledTransaction<T> => {
     const { method, ...tx } = JSON.parse(json)

src/soroban/utils.ts

@@ -6,3 +6,5 @@ export function hasOwnProperty<X extends {}, Y extends PropertyKey>(
 ): obj is X & Record<Y, unknown> {
   return obj.hasOwnProperty(prop);
 }
+
+export type PartiallyRequired<T, K extends keyof T> = Omit<T, K> & Required<Pick<T, K>>;

test/e2e/initialize.sh

@@ -40,11 +40,8 @@ exe() { echo"${@/eval/}" ; "$@" ; }
 
 function fund_all() {
   exe eval "$soroban keys generate root"
-  exe eval "$soroban keys fund root"
   exe eval "$soroban keys generate alice"
-  exe eval "$soroban keys fund alice"
   exe eval "$soroban keys generate bob"
-  exe eval "$soroban keys fund bob"
 }
 function upload() {
   exe eval "($soroban contract $1 --source root --wasm $dirname/$2 --ignore-checks) > $dirname/$3"

test/e2e/src/test-hello-world.js

@@ -1,6 +1,6 @@
 const test = require('ava')
 const fs = require('node:fs')
-const { ContractSpec } = require('../../..')
+const { ContractSpec, SorobanRpc } = require('../../..')
 const { root, wallet, rpcUrl, networkPassphrase } = require('./util')
 const xdr = require('../wasms/specs/test_hello_world.json')
 

test/e2e/src/test-swap.js

@@ -52,7 +52,7 @@ test('calling `signAndSend()` too soon throws descriptive error', async t => {
     min_b_for_a: amountBToSwap,
   })
   const error = await t.throwsAsync(tx.signAndSend())
-  t.true(error instanceof SorobanRpc.AssembledTransaction.NeedsMoreSignaturesError, `error is not of type 'NeedsMoreSignaturesError'; instead it is of type '${error?.constructor.name}'`)
+  t.true(error instanceof SorobanRpc.AssembledTransaction.Errors.NeedsMoreSignatures, `error is not of type 'NeedsMoreSignaturesError'; instead it is of type '${error?.constructor.name}'`)
   if (error) t.regex(error.message, /needsNonInvokerSigningBy/)
 })
 

test/e2e/src/util.js

@@ -36,6 +36,7 @@ module.exports.rpcUrl = rpcUrl
 const networkPassphrase = process.env.SOROBAN_NETWORK_PASSPHRASE ?? "Standalone Network ; February 2017";
 module.exports.networkPassphrase = networkPassphrase
 
+// TODO: export Wallet class from soroban-sdk
 class Wallet {
   constructor(publicKey) {
     this.publicKey = publicKey