Add separate sign and send methods to `contract.AssembledTransact…

…ion` (stellar#992)

* add auto restore functionality for contract client
* extract getAccount to utils
* add changelog entry for auto restore functionality

Co-authored-by: Chad Ostrowski <221614+chadoh@users.noreply.github.com>
Co-authored-by: blaineheffron <baheffron@gmail.com>

CHANGELOG.md

@@ -10,6 +10,7 @@ A breaking change will get clearly marked in this log.
 - `contract.AssembledTransaction` now has:
   - `toXDR` and `fromXDR` methods for serializing the transaction to and from XDR. Additionally, `contract.Client` now has a `txFromXDR`. These methods should be used in place of `AssembledTransaction.toJSON`, `AssembledTransaction.fromJSON`, and `Client.txFromJSON` for multi-auth signing. The JSON methods are now deprecated. **Note you must now call `simulate` on the transaction before the final `signAndSend` call after all required signatures are gathered when using the XDR methods.
   -  a `restoreFootprint` method which accepts the `restorePreamble` returned when a simulation call fails due to some contract state that has expired. When invoking a contract function, one can now set `restore` to `true` in the `MethodOptions`. When enabled, a `restoreFootprint` transaction will be created and await signing when required.
+  - separate `sign` and `send` methods so that you can sign a transaction without sending it. You can continue to use `signAndSend` if you prefer.
 
 ### Deprecated
 - In `contract.AssembledTransaction`, `toJSON` and `fromJSON` should be replaced with `toXDR` and

src/contract/assembled_transaction.ts

@@ -303,6 +303,11 @@ export class AssembledTransaction<T> {
    */
   private server: Server;
 
+  /**
+   * The signed transaction.
+   */
+  public signed?: Tx;
+
   /**
    * A list of the most important errors that various AssembledTransaction
    * methods can throw. Feel free to catch specific errors in your application
@@ -595,13 +600,10 @@ export class AssembledTransaction<T> {
   }
 
   /**
-   * Sign the transaction with the `wallet`, included previously. If you did
-   * not previously include one, you need to include one now that at least
-   * includes the `signTransaction` method. After signing, this method will
-   * send the transaction to the network and return a `SentTransaction` that
-   * keeps track of all the attempts to fetch the transaction.
+   * Sign the transaction with the signTransaction function included previously. 
+   * If you did not previously include one, you need to include one now.
    */
-  signAndSend = async ({
+  sign = async ({
     force = false,
     signTransaction = this.options.signTransaction,
   }: {
@@ -613,7 +615,7 @@ export class AssembledTransaction<T> {
      * You must provide this here if you did not provide one before
      */
     signTransaction?: ClientOptions["signTransaction"];
-  } = {}): Promise<SentTransaction<T>> => {
+  } = {}): Promise<void> => {
     if (!this.built) {
       throw new Error("Transaction has not yet been simulated");
     }
@@ -635,16 +637,68 @@ export class AssembledTransaction<T> {
     if (this.needsNonInvokerSigningBy().length) {
       throw new AssembledTransaction.Errors.NeedsMoreSignatures(
         "Transaction requires more signatures. " +
-        "See `needsNonInvokerSigningBy` for details."
+        "See `needsNonInvokerSigningBy` for details.",
       );
     }
 
-    const typeChecked: AssembledTransaction<T> = this;
-    const sent = await SentTransaction.init(
-      signTransaction,
-      typeChecked,
+    const timeoutInSeconds =
+      this.options.timeoutInSeconds ?? DEFAULT_TIMEOUT;
+    this.built = TransactionBuilder.cloneFrom(this.built!, {
+      fee: this.built!.fee,
+      timebounds: undefined,
+      sorobanData: this.simulationData.transactionData,
+    })
+      .setTimeout(timeoutInSeconds)
+      .build();
+
+    const signature = await signTransaction(
+      this.built.toXDR(),
+      {
+        networkPassphrase: this.options.networkPassphrase,
+      },
     );
+
+    this.signed = TransactionBuilder.fromXDR(
+      signature,
+      this.options.networkPassphrase,
+    ) as Tx;
+  };
+
+  /**
+   * Sends the transaction to the network to return a `SentTransaction` that
+   * keeps track of all the attempts to fetch the transaction.
+   */
+  async send(){
+    if(!this.signed){
+      throw new Error("The transaction has not yet been signed. Run `sign` first, or use `signAndSend` instead.");
+    }
+    const sent = await SentTransaction.init(undefined, this);
     return sent;
+  }
+
+  /**
+   * Sign the transaction with the `signTransaction` function included previously. 
+   * If you did not previously include one, you need to include one now. 
+   * After signing, this method will send the transaction to the network and 
+   * return a `SentTransaction` that keeps track * of all the attempts to fetch the transaction.
+   */
+  signAndSend = async ({
+    force = false,
+    signTransaction = this.options.signTransaction,
+  }: {
+    /**
+     * If `true`, sign and send the transaction even if it is a read call
+     */
+    force?: boolean;
+    /**
+     * You must provide this here if you did not provide one before
+     */
+    signTransaction?: ClientOptions["signTransaction"];
+  } = {}): Promise<SentTransaction<T>> => {
+    if(!this.signed){
+      await this.sign({ force, signTransaction });
+    }
+    return this.send();
   };
 
   private getStorageExpiration = async () => {

src/contract/sent_transaction.ts

@@ -1,7 +1,6 @@
 /* disable max-classes rule, because extending error shouldn't count! */
 /* eslint max-classes-per-file: 0 */
-import { TransactionBuilder } from "@stellar/stellar-base";
-import type { ClientOptions, MethodOptions, Tx } from "./types";
+import type { MethodOptions } from "./types";
 import { Server } from "../rpc/server"
 import { Api } from "../rpc/api"
 import { DEFAULT_TIMEOUT, withExponentialBackoff } from "./utils";
@@ -24,8 +23,6 @@ import type { AssembledTransaction } from "./assembled_transaction";
 export class SentTransaction<T> {
   public server: Server;
 
-  public signed?: Tx;
-
   /**
    * The result of calling `sendTransaction` to broadcast the transaction to the
    * network.
@@ -53,61 +50,32 @@ export class SentTransaction<T> {
   };
 
   constructor(
-    public signTransaction: ClientOptions["signTransaction"],
+    _: any, // deprecated: used to take sentTransaction, need to wait for major release for breaking change
     public assembled: AssembledTransaction<T>,
   ) {
-    if (!signTransaction) {
-      throw new Error(
-        "You must provide a `signTransaction` function to send a transaction",
-      );
-    }
     this.server = new Server(this.assembled.options.rpcUrl, {
       allowHttp: this.assembled.options.allowHttp ?? false,
     });
   }
 
   /**
-   * Initialize a `SentTransaction` from an existing `AssembledTransaction` and
-   * a `signTransaction` function. This will also send the transaction to the
-   * network.
+   * Initialize a `SentTransaction` from `options` and a `signed` 
+   * AssembledTransaction. This will also send the transaction to the network.
    */
   static init = async <U>(
-    /** More info in {@link MethodOptions} */
-    signTransaction: ClientOptions["signTransaction"],
+    /** @deprecated variable is ignored. Now handled by AssembledTransaction. */
+    _: any, // eslint-disable-line @typescript-eslint/no-unused-vars
     /** {@link AssembledTransaction} from which this SentTransaction was initialized */
     assembled: AssembledTransaction<U>,
   ): Promise<SentTransaction<U>> => {
-    const tx = new SentTransaction(signTransaction, assembled);
+    const tx = new SentTransaction(undefined, assembled);
     const sent = await tx.send();
     return sent;
   };
 
   private send = async (): Promise<this> => {
-    const timeoutInSeconds =
-      this.assembled.options.timeoutInSeconds ?? DEFAULT_TIMEOUT;
-    this.assembled.built = TransactionBuilder.cloneFrom(this.assembled.built!, {
-      fee: this.assembled.built!.fee,
-      timebounds: undefined, // intentionally don't clone timebounds
-      sorobanData: this.assembled.simulationData.transactionData
-    })
-      .setTimeout(timeoutInSeconds)
-      .build();
-
-    const signature = await this.signTransaction!(
-      // `signAndSend` checks for `this.built` before calling `SentTransaction.init`
-      this.assembled.built!.toXDR(),
-      {
-        networkPassphrase: this.assembled.options.networkPassphrase,
-      },
-    );
-
-    this.signed = TransactionBuilder.fromXDR(
-      signature,
-      this.assembled.options.networkPassphrase,
-    ) as Tx;
-
     this.sendTransactionResponse = await this.server.sendTransaction(
-      this.signed,
+      this.assembled.signed!,
     );
 
     if (this.sendTransactionResponse.status !== "PENDING") {
@@ -122,6 +90,8 @@ export class SentTransaction<T> {
 
     const { hash } = this.sendTransactionResponse;
 
+    const timeoutInSeconds =
+      this.assembled.options.timeoutInSeconds ?? DEFAULT_TIMEOUT;
     this.getTransactionResponseAll = await withExponentialBackoff(
       () => this.server.getTransaction(hash),
       (resp) => resp.status === Api.GetTransactionStatus.NOT_FOUND,
@@ -183,7 +153,7 @@ export class SentTransaction<T> {
 
     // 3. finally, if neither of those are present, throw an error
     throw new Error(
-      `Sending transaction failed: ${JSON.stringify(this.assembled)}`,
+      `Sending transaction failed: ${JSON.stringify(this.assembled.signed)}`,
     );
   }
 }