add idempotent example

Author: SwenSchaeferjohann

package-lock.json

@@ -21,6 +21,7 @@
     "airdrop": "ts-node src/scripts/airdrop/airdrop.ts",
     "transfer": "ts-node src/scripts/transfer.ts",
     "compress": "ts-node src/scripts/compress.ts",
+    
     "test": "npm run lamports && npm run token && npm run connection && npm run batch-compress && npm run mint-spl && npm run mint-spl-22 && npm run mint-spl-22-manual"
   },
   "repository": {

package.json

@@ -65,7 +65,7 @@ const recipients = [
   );
   console.log(`ATA: ${ata.address.toBase58()}`);
 
-  //   /// Mint SPL tokens to the sender
+  /// Mint SPL tokens to the sender
   const mintToTxId = await mintTo(
     connection,
     PAYER,

src/scripts/airdrop/airdrop.ts

@@ -11,14 +11,14 @@ import {
   calculateComputeUnitPrice,
   createRpc,
   dedupeSigner,
-  pickRandomTreeAndQueue,
   Rpc,
   selectStateTreeInfo,
   sendAndConfirmTx,
 } from "@lightprotocol/stateless.js";
 import * as splToken from "@solana/spl-token";
 import dotenv from "dotenv";
 import bs58 from "bs58";
+import { createIdempotentAirdropInstruction } from "./idempotent";
 dotenv.config();
 
 const RPC_ENDPOINT = process.env.RPC_ENDPOINT;
@@ -34,9 +34,10 @@ const PAYER_KEYPAIR = Keypair.fromSecretKey(
     const payer = PAYER_KEYPAIR;
 
     const amount = bn(333); // each recipient will receive 111 tokens
-    const recipients = ["GMPWaPPrCeZPse5kwSR3WUrqYAPrVZBSVwymqh7auNW7"].map(
-      (address) => new PublicKey(address)
-    );
+    const recipients = [
+      "GMPWaPPrCeZPse5kwSR3WUrqYAPrVZBSVwymqh7auNW7",
+      "GMPWaPPrCeZPse5kwSR3WUrqYAPrVZBSVwymqh7auNW7",
+    ].map((address) => new PublicKey(address));
     const activeStateTrees = await connection.getStateTreeInfos();
 
     /// Pick a new tree for each transaction!
@@ -54,21 +55,20 @@ const PAYER_KEYPAIR = Keypair.fromSecretKey(
     // Airdrop to example recipients addresses
     // 1 recipient = 120_000 CU
     // 5 recipients = 170_000 CU
-
+    // with idempotent cPDA = +250_000 CU
     const instructions: web3.TransactionInstruction[] = [];
-
     instructions.push(
-      web3.ComputeBudgetProgram.setComputeUnitLimit({ units: 120_000 }),
+      web3.ComputeBudgetProgram.setComputeUnitLimit({ units: 370_000 }),
       web3.ComputeBudgetProgram.setComputeUnitPrice({
-        // ideally replace this with a dynamic priority_fee based on network conditions.
-        microLamports: calculateComputeUnitPrice(20_000, 120_000),
+        // Replace this with a dynamic priority_fee to land during high network load.
+        microLamports: calculateComputeUnitPrice(20_000, 370_000),
       })
     );
 
     const compressInstruction = await CompressedTokenProgram.compress({
       payer: payer.publicKey,
       owner: payer.publicKey,
-      source: sourceTokenAccount.address, // here, the owner of this account is also the payer.
+      source: sourceTokenAccount.address,
       toAddress: recipients,
       amount: recipients.map(() => amount),
       mint: mintAddress,
@@ -79,13 +79,23 @@ const PAYER_KEYPAIR = Keypair.fromSecretKey(
     });
     instructions.push(compressInstruction);
 
+    // Creates a cPDA for a given set of recipients. This lets you retry txns without handling spends client-side.
+    // The whole txn will fail if the same set of seeds (with the same order) is used a second time.
+    instructions.push(
+      await createIdempotentAirdropInstruction(
+        connection,
+        payer.publicKey,
+        mintAddress,
+        recipients,
+        treeInfo
+      )
+    );
+
     // Use zk-compression LUT for your network
     // https://www.zkcompression.com/developers/protocol-addresses-and-urls#lookup-tables
     const lookupTableAddress = new web3.PublicKey(
       "9NYFyEqPkyXUhkerbGHXUXkvb4qpzeEdHuGpgbgpH1NJ" // mainnet
-      // "qAJZMgnQJ8G6vA3WRcjD9Jan1wtKkaCFWLWskxJrR5V" // devnet
     );
-
     // Get the lookup table account state
     const lookupTableAccount = (
       await connection.getAddressLookupTable(lookupTableAddress)
@@ -105,7 +115,6 @@ const PAYER_KEYPAIR = Keypair.fromSecretKey(
       [lookupTableAccount]
     );
 
-    // Uncomment to send the transaction.
     const txId = await sendAndConfirmTx(connection, tx);
     console.log(`txId: ${txId}`);
   } catch (e) {

src/scripts/compress.ts

@@ -0,0 +1,59 @@
+import { PublicKey, TransactionInstruction } from "@solana/web3.js";
+import {
+  bn,
+  Rpc,
+  LightSystemProgram,
+  getDefaultAddressTreeInfo,
+  deriveAddressSeed,
+  deriveAddress,
+  TreeInfo,
+  NewAddressParams,
+} from "@lightprotocol/stateless.js";
+
+// This is a helper function to create a cPDA for a given set of recipients.
+// This lets you retry txns without handling spends client-side.
+// The whole txn will fail if the same set of seeds (with the same order) is used a second time.
+// Change the seeds to fit your use case.
+export async function createIdempotentAirdropInstruction(
+  rpc: Rpc,
+  payer: PublicKey,
+  mint: PublicKey,
+  recipients: PublicKey[],
+  outputStateTreeInfo: TreeInfo
+): Promise<TransactionInstruction> {
+  const { tree, queue } = getDefaultAddressTreeInfo();
+
+  const seeds = recipients
+    .map((recipient) => recipient.toBytes())
+    .concat(mint.toBytes())
+    .concat([new Uint8Array([1])]); // you can pick a discriminator so as to avoid collision in between different drops.
+
+  const seed = deriveAddressSeed(seeds, LightSystemProgram.programId);
+  const address = deriveAddress(seed, tree);
+
+  const proof = await rpc.getValidityProofV0(undefined, [
+    {
+      address: bn(address.toBytes()),
+      tree,
+      queue,
+    },
+  ]);
+
+  const params: NewAddressParams = {
+    seed: seed,
+    addressMerkleTreeRootIndex: proof.rootIndices[0],
+    addressMerkleTreePubkey: proof.treeInfos[0].tree,
+    addressQueuePubkey: proof.treeInfos[0].queue,
+  };
+
+  const ix = await LightSystemProgram.createAccount({
+    payer,
+    newAddressParams: params,
+    newAddress: Array.from(address.toBytes()),
+    recentValidityProof: proof.compressedProof,
+    programId: LightSystemProgram.programId,
+    outputStateTreeInfo,
+  });
+
+  return ix;
+}