Merge pull request #414 from Emurgo/add-mint-nft-example

add mint nft example

Author: vsubhuman

doc/getting-started/minting-nfts.md

@@ -0,0 +1,251 @@
+
+# Minting Nfts using yoroi backend and cardano-serialization-lib
+
+This example mints nfts directly to an account on testnet.
+
+code taken from (here)[https://github.com/ozgrakkurt/cardano-mint-nft]
+
+```javascript
+import CardanoWasm from "@emurgo/cardano-serialization-lib-nodejs";
+import axios from "axios";
+import cbor from "cbor";
+
+const mintNft = async (
+  privateKey,
+  policy,
+  assetName,
+  description,
+  imageUrl,
+  mediaType
+) => {
+  const FEE = 300000;
+
+  const publicKey = privateKey.to_public();
+
+  const addr = CardanoWasm.BaseAddress.new(
+    CardanoWasm.NetworkInfo.testnet().network_id(),
+    CardanoWasm.StakeCredential.from_keyhash(publicKey.hash()),
+    CardanoWasm.StakeCredential.from_keyhash(publicKey.hash())
+  ).to_address();
+
+  const policyPubKey = policy.privateKey.to_public();
+
+  const policyAddr = CardanoWasm.BaseAddress.new(
+    CardanoWasm.NetworkInfo.testnet().network_id(),
+    CardanoWasm.StakeCredential.from_keyhash(policyPubKey.hash()),
+    CardanoWasm.StakeCredential.from_keyhash(policyPubKey.hash())
+  ).to_address();
+
+  console.log(`ADDR: ${addr.to_bech32()}`);
+
+  // get utxos for our address and select one that is probably big enough to pay the tx fee
+  const utxoRes = await axios.post(
+    "https://testnet-backend.yoroiwallet.com/api/txs/utxoForAddresses",
+    {
+      addresses: [addr.to_bech32()],
+    }
+  );
+
+  let utxo = null;
+
+  if (utxoRes.data) {
+    for (const utxoEntry of utxoRes.data) {
+      if (utxoEntry.amount > FEE) {
+        utxo = utxoEntry;
+      }
+    }
+  }
+
+  if (utxo === null) {
+    throw new Error("no utxo found with sufficient ADA.");
+  }
+
+  console.log(`UTXO: ${JSON.stringify(utxo, null, 4)}`);
+
+  // get current global slot from yoroi backend
+  const { data: slotData } = await axios.get(
+    "https://testnet-backend.yoroiwallet.com/api/v2/bestblock"
+  );
+
+  const ttl = slotData.globalSlot + 60 * 60 * 2;  // two hours from now
+
+  const txBuilder = CardanoWasm.TransactionBuilder.new(
+    CardanoWasm.TransactionBuilderConfigBuilder.new()
+      .fee_algo(
+        CardanoWasm.LinearFee.new(
+          CardanoWasm.BigNum.from_str("44"),
+          CardanoWasm.BigNum.from_str("155381")
+        )
+      )
+      .coins_per_utxo_word(CardanoWasm.BigNum.from_str("34482"))
+      .pool_deposit(CardanoWasm.BigNum.from_str("500000000"))
+      .key_deposit(CardanoWasm.BigNum.from_str("2000000"))
+      .max_value_size(5000)
+      .max_tx_size(16384)
+      .build()
+  );
+
+  const scripts = CardanoWasm.NativeScripts.new();
+
+  const policyKeyHash = CardanoWasm.BaseAddress.from_address(policyAddr)
+    .payment_cred()
+    .to_keyhash();
+
+  console.log(
+    `POLICY_KEYHASH: ${Buffer.from(policyKeyHash.to_bytes()).toString("hex")}`
+  );
+
+  // add key hash script so only people with policy key can mint assets using this policyId
+  const keyHashScript = CardanoWasm.NativeScript.new_script_pubkey(
+    CardanoWasm.ScriptPubkey.new(policyKeyHash)
+  );
+  scripts.add(keyHashScript);
+
+  const policyTtl = policy.ttl || ttl;
+
+  console.log(`POLICY_TTL: ${policyTtl}`);
+
+  // add timelock so policy is locked after this slot
+  const timelock = CardanoWasm.TimelockExpiry.new(policyTtl);
+  const timelockScript = CardanoWasm.NativeScript.new_timelock_expiry(timelock);
+  scripts.add(timelockScript);
+
+  const mintScript = CardanoWasm.NativeScript.new_script_all(
+    CardanoWasm.ScriptAll.new(scripts)
+  );
+
+  const privKeyHash = CardanoWasm.BaseAddress.from_address(addr)
+    .payment_cred()
+    .to_keyhash();
+  txBuilder.add_key_input(
+    privKeyHash,
+    CardanoWasm.TransactionInput.new(
+      CardanoWasm.TransactionHash.from_bytes(Buffer.from(utxo.tx_hash, "hex")),
+      utxo.tx_index
+    ),
+    CardanoWasm.Value.new(CardanoWasm.BigNum.from_str(utxo.amount))
+  );
+
+  txBuilder.add_mint_asset_and_output_min_required_coin(
+    mintScript,
+    CardanoWasm.AssetName.new(Buffer.from(assetName)),
+    CardanoWasm.Int.new_i32(1),
+    CardanoWasm.TransactionOutputBuilder.new().with_address(addr).next()
+  );
+
+  const policyId = Buffer.from(mintScript.hash().to_bytes()).toString("hex");
+
+  console.log(`POLICY_ID: ${policyId}`);
+
+  const metadata = {
+    [policyId]: {
+      [assetName]: {
+        name: assetName,
+        description,
+        image: imageUrl,
+        mediaType,
+      },
+    },
+  };
+
+  console.log(`METADATA: ${JSON.stringify(metadata, null, 4)}`);
+
+  // transaction ttl can't be later than policy ttl
+  const txTtl = ttl > policyTtl ? policyTtl : ttl;
+
+  console.log(`TX_TTL: ${txTtl}`);
+
+  txBuilder.set_ttl(txTtl);
+  txBuilder.add_json_metadatum(
+    CardanoWasm.BigNum.from_str("721"),
+    JSON.stringify(metadata)
+  );
+
+  txBuilder.add_change_if_needed(addr);
+
+  const txBody = txBuilder.build();
+  const txHash = CardanoWasm.hash_transaction(txBody);
+
+  console.log(`TX_HASH: ${Buffer.from(txHash.to_bytes()).toString("hex")}`);
+
+  // sign the tx using the policy key and main key
+  const witnesses = CardanoWasm.TransactionWitnessSet.new();
+  const vkeyWitnesses = CardanoWasm.Vkeywitnesses.new();
+  vkeyWitnesses.add(CardanoWasm.make_vkey_witness(txHash, policy.privateKey));
+  vkeyWitnesses.add(CardanoWasm.make_vkey_witness(txHash, privateKey));
+  witnesses.set_vkeys(vkeyWitnesses);
+  witnesses.set_native_scripts;
+  const witnessScripts = CardanoWasm.NativeScripts.new();
+  witnessScripts.add(mintScript);
+  witnesses.set_native_scripts(witnessScripts);
+
+  const unsignedTx = txBuilder.build_tx();
+
+  // create signed transaction
+  const tx = CardanoWasm.Transaction.new(
+    unsignedTx.body(),
+    witnesses,
+    unsignedTx.auxiliary_data()
+  );
+
+  const signedTx = Buffer.from(tx.to_bytes()).toString("base64");
+
+  // submit the transaction using yoroi backend
+  try {
+    const { data } = await axios.post(
+      "https://testnet-backend.yoroiwallet.com/api/txs/signed",
+      {
+        signedTx,
+      }
+    );
+
+    console.log(`SUBMIT_RESULT: ${JSON.stringify(data, null, 4)}`);
+  } catch (error) {
+    console.error(
+      `failed to submit tx via yoroi backend: ${error.toString()}. error details: ${JSON.stringify(
+        error.response?.data
+      )}`
+    );
+  }
+};
+
+try {
+  const privateKey = CardanoWasm.PrivateKey.from_bech32(
+    //"ed25519_sk1fde2u8u2qme8uau5ac3w6c082gvtnmxt6uke2w8e07xwzewxee3q3n0f8e"
+    "ed25519_sk18j0a6704zyerm6dsj6p2fp8juw5m43rfgk0y84jnm7w5khs4dpqquewh43"
+  );
+
+  console.log(`PRIVATE KEY: ${privateKey.to_bech32()}`);
+
+  /*
+  const policyPrivateKey = CardanoWasm.PrivateKey.from_bech32(
+    "ed25519_sk1q96x2g66j5g7u5wydl7kcagk0h8upxznt3gj48h6njqthkyr7faqxmnnte"
+  );
+  */
+
+  // import policy key from a .skey file
+  const policyPrivateKey = CardanoWasm.PrivateKey.from_normal_bytes(
+    cbor.decodeFirstSync(
+      "582009ca7f508dd5a5f9823d367e98170f25606799f49ae7363a47a11d7d3502c91f"
+    )
+  );
+
+  console.log(`POLICY_PRIV_KEY: ${policyPrivateKey.to_bech32()}`);
+
+  await mintNft(
+    privateKey, // main key
+    {
+      privateKey: policyPrivateKey, // policy key
+      // pass null here to get automatic ttl for policy
+      // and paste the POLICY_TTL output you get in console to here to mint with same policy
+      ttl: null, // policy ttl
+    },
+    "asdNFT5", // assetName
+    "some descr this is a new nft with same policy", // description
+    "ipfs://QmNhmDPJMgdsFRM9HyiQEJqrKkpsWFshqES8mPaiFRq9Zk", // image url
+    "image/jpeg" // mediaType
+  );
+} catch (err) {
+  console.error(`failed to mint nft: ${err.toString()}`);
+}
+```