Correct fee estimation.

decred/examples/drain_xpriv.py

@@ -7,7 +7,7 @@
 import os
 from urllib.parse import urlunsplit
 
-from base58 import b58decode, b58encode
+from base58 import b58decode
 from decred import DecredError
 from decred.crypto import crypto
 from decred.crypto.secp256k1.curve import curve as Curve
@@ -29,9 +29,11 @@ def cfg(isTestnet):
     cfgPath = os.path.join(dcrdCfgDir, "dcrd.conf")
     if not os.path.isfile(cfgPath):
         return None
-    cfg = helpers.readINI(cfgPath, ["rpcuser", "rpcpass", "rpccert"])
+    cfg = helpers.readINI(cfgPath, ["rpcuser", "rpcpass", "rpccert", "addrindex"])
     assert "rpcuser" in cfg
     assert "rpcpass" in cfg
+    if "addrindex" not in cfg or not cfg["addrindex"]:
+        raise DecredError("addrindex must be enabled")
     if "rpccert" not in cfg:
         cfg["rpccert"] = os.path.join(dcrdCfgDir, "rpc.cert")
     if "rpclisten" not in cfg:
@@ -114,12 +116,12 @@ def getUTXOs(node, key, net):
     idx, txGap = 0, 0
     utxos = []
     while txGap < GAP_LIMIT:
-        addr = ""
         try:
             addr = addrlib.deriveChildAddress(key, idx, net)
         except Exception:
             # Very small chance of a bad address.
-            pass
+            idx += 1
+            continue
         try:
             res = node.searchRawTransactions(addr, verbose=True)
             for rawTx in res:
@@ -176,11 +178,19 @@ def signUTXOs(node, utxos, sendToAddr, totalValue, net):
         expiry=0,
         cachedHash=None,
     )
-    fee = txscript.calcMinRequiredTxRelayFee(FEE_RATE, newTx.serializeSize())
+
+    size = txscript.estimateSerializeSize(
+        [txscript.RedeemP2PKHSigScriptSize for _ in inputs], [output], 0
+    )
+    fee = txscript.calcMinRequiredTxRelayFee(FEE_RATE, size)
+
     if fee > totalValue:
         raise DecredError("Not enough funds to cover the transaction fee.")
 
-    newTx.txOut[0].value = totalValue - int(fee)
+    output.value = totalValue - int(fee)
+
+    if txscript.isDustOutput(output, FEE_RATE):
+        raise DecredError("Transaction is considered dust. Not sending.")
 
     for idx, utxo in enumerate(utxos):
         signatureScript, _, _, _ = txscript.sign(
@@ -201,22 +211,24 @@ def main():
     net = None
     isTestnet = False
     tString = ""
-    netStr = input("Is this mainnet or testnet?\n")
-    if netStr in ["testnet", "test", "t"]:
+    netStr = input("Is this mainnet or testnet? (m/t)\n")
+    if netStr in ("testnet", "test", "t"):
         net = nets.testnet
         isTestnet = True
         tString = "t"
-    elif netStr in ["mainnet", "main", "m"]:
+    elif netStr in ("mainnet", "main", "m"):
         net = nets.mainnet
     else:
         raise DecredError("Unknown network entered.")
 
     xprivStr = input("Enter xpriv: ")
     xpriv = decodeExtendedKey(net, xprivStr)
     # Double check that we can reproduce the xpriv.
-    if b58encode(xpriv.serialize().b).decode() != xprivStr:
+    if xpriv.string() != xprivStr:
         raise DecredError("unknown xpriv parsing error")
 
+    # Printing a newline.
+    print()
     internal = xpriv.child(INTERNAL)
     external = xpriv.child(EXTERNAL)
 
@@ -237,17 +249,33 @@ def main():
 
     print(f"Found {len(utxos)} outputs totalling {totalValue} {tString}dcr.\n")
 
-    sendToAddrStr = input("Input address to send funds: ")
-    # Will throw if bad addr.
-    sendToAddr = addrlib.decodeAddress(sendToAddrStr, net)
+    while True:
+        sendToAddrStr = input("Input address to send funds: ")
+        print()
+        try:
+            # Will throw if bad addr.
+            sendToAddr = addrlib.decodeAddress(sendToAddrStr, net)
+            break
+        except Exception as e:
+            print(e)
+            tryAgain = input("\nBad address. Try again? (y/n)\n")
+            if tryAgain not in ("y", "yes"):
+                print("Aborted")
+                return
+
     signedTx = signUTXOs(node, utxos, sendToAddr, int(totalValue * 1e8), net)
 
+    # Double check output script address.
+    _, gotAddrs, _ = txscript.extractPkScriptAddrs(0, signedTx.txOut[0].pkScript, net)
+    if gotAddrs[0].address() != sendToAddrStr:
+        raise DecredError("unknown output address parsing error")
+
     print(f"Got the raw hex: {signedTx.serialize().hex()}")
     print(f"{repr(signedTx)}\n")
-    doIt = input(f"Really send funds to {sendToAddrStr}?\n")
+    doIt = input(f"Really send funds to {sendToAddrStr}? (y/n)\n")
     if doIt in ("yes", "y"):
         txid = node.sendRawTransaction(signedTx)
-        print(f"Sent transaction: {reversed(txid).hex()}")
+        print(f"\nSent transaction: {reversed(txid).hex()}")
     else:
         print("Aborted.")