Add new simple examples for Sepolia testnet (#89)

* Only execute "eth_callBundle" when in mainnet as the sunset of Goerli.

* Implement new simple example based on "simple.py".

* 1. Change testnet as sepolia; 2. Provide extra builder RPCs compatible with flashbots.

* Update simple_new.py example for multi-network support

- Add support for Sepolia, Holesky, and Mainnet networks
- Introduce NETWORK_CONFIG for network-specific settings
- Update provider and relay URL handling
- Improve comments and documentation
- Enhance error handling and logging

* Replace simple.py with simple_new.py

* Update .gitignore

* Resolve black formatter  issue

---------

Co-authored-by: George Zhang <georgezhangtj97@gmail.com>

Author: jasonthewhale

.gitignore

@@ -4,3 +4,5 @@ __pycache__
 build/
 dist/
 flashbots.egg-info/
+.venv/
+.mise.toml

examples/simple.py

@@ -2,26 +2,57 @@
 Minimal viable example of flashbots usage with dynamic fee transactions.
 Sends a bundle of two transactions which transfer some ETH into a random account.
 
+"eth_sendBundle" is a generic method that can be used to send a bundle to any relay.
+For instance, you can use the following relay URLs:
+    titan: 'https://rpc.titanbuilder.xyz/'
+    beaver: 'https://rpc.beaverbuild.org/'
+    builder69: 'https://builder0x69.io/'
+    rsync: 'https://rsync-builder.xyz/'
+    flashbots: 'https://relay.flashbots.net'
+
+You can simply replace the URL in the flashbot method to use a different relay like:
+    flashbot(w3, signer, YOUR_CHOSEN_RELAY_URL)
+
 Environment Variables:
 - ETH_SENDER_KEY: Private key of account which will send the ETH.
 - ETH_SIGNER_KEY: Private key of account which will sign the bundle. 
     - This account is only used for reputation on flashbots and should be empty.
-- PROVIDER_URL: HTTP JSON-RPC Ethereum provider URL.
+- PROVIDER_URL: (Optional) HTTP JSON-RPC Ethereum provider URL. If not set, Flashbots Protect RPC will be used.
 """
 
 import os
 import secrets
 from uuid import uuid4
+
 from eth_account.account import Account
 from eth_account.signers.local import LocalAccount
-from flashbots import flashbot
-from web3 import Web3, HTTPProvider
+from web3 import HTTPProvider, Web3
 from web3.exceptions import TransactionNotFound
 from web3.types import TxParams
 
-# change this to `False` if you want to use mainnet
-USE_GOERLI = True
-CHAIN_ID = 5 if USE_GOERLI else 1
+from flashbots import flashbot
+
+# Define the network to use
+NETWORK = "holesky"  # Options: "sepolia", "holesky", "mainnet"
+
+# Define chain IDs and Flashbots Protect RPC URLs
+NETWORK_CONFIG = {
+    "sepolia": {
+        "chain_id": 11155111,
+        "provider_url": "https://rpc-sepolia.flashbots.net",
+        "relay_url": "https://relay-sepolia.flashbots.net",
+    },
+    "holesky": {
+        "chain_id": 17000,
+        "provider_url": "https://rpc-holesky.flashbots.net",
+        "relay_url": "https://relay-holesky.flashbots.net",
+    },
+    "mainnet": {
+        "chain_id": 1,
+        "provider_url": "https://rpc.flashbots.net",
+        "relay_url": None,  # Mainnet uses default Flashbots relay
+    },
+}
 
 
 def env(key: str) -> str:
@@ -42,9 +73,20 @@ def main() -> None:
     # NOTE: this account should not store funds
     signer: LocalAccount = Account.from_key(env("ETH_SIGNER_KEY"))
 
-    w3 = Web3(HTTPProvider(env("PROVIDER_URL")))
-    if USE_GOERLI:
-        flashbot(w3, signer, "https://relay-goerli.flashbots.net")
+    # Use user-provided RPC URL if available, otherwise use Flashbots Protect RPC
+    user_provider_url = env("PROVIDER_URL")
+    if user_provider_url:
+        provider_url = user_provider_url
+        print(f"Using user-provided RPC: {provider_url}")
+    else:
+        provider_url = NETWORK_CONFIG[NETWORK]["provider_url"]
+        print(f"Using Flashbots Protect RPC: {provider_url}")
+
+    w3 = Web3(HTTPProvider(provider_url))
+
+    relay_url = NETWORK_CONFIG[NETWORK]["relay_url"]
+    if relay_url:
+        flashbot(w3, signer, relay_url)
     else:
         flashbot(w3, signer)
 
@@ -69,7 +111,7 @@ def main() -> None:
         "maxFeePerGas": Web3.toWei(200, "gwei"),
         "maxPriorityFeePerGas": Web3.toWei(50, "gwei"),
         "nonce": nonce,
-        "chainId": CHAIN_ID,
+        "chainId": NETWORK_CONFIG[NETWORK]["chain_id"],
         "type": 2,
     }
     tx1_signed = sender.sign_transaction(tx1)
@@ -81,7 +123,7 @@ def main() -> None:
         "maxFeePerGas": Web3.toWei(200, "gwei"),
         "maxPriorityFeePerGas": Web3.toWei(50, "gwei"),
         "nonce": nonce + 1,
-        "chainId": CHAIN_ID,
+        "chainId": NETWORK_CONFIG[NETWORK]["chain_id"],
         "type": 2,
     }
 
@@ -93,14 +135,19 @@ def main() -> None:
     # keep trying to send bundle until it gets mined
     while True:
         block = w3.eth.block_number
-        print(f"Simulating on block {block}")
-        # simulate bundle on current block
-        try:
-            w3.flashbots.simulate(bundle, block)
-            print("Simulation successful.")
-        except Exception as e:
-            print("Simulation error", e)
-            return
+
+        # Simulation is only supported on mainnet
+        if NETWORK == "mainnet":
+            print(f"Simulating on block {block}")
+            # Simulate bundle on current block.
+            # If your RPC provider is not fast enough, you may get "block extrapolation negative"
+            # error message triggered by "extrapolate_timestamp" function in "flashbots.py".
+            try:
+                w3.flashbots.simulate(bundle, block)
+                print("Simulation successful.")
+            except Exception as e:
+                print("Simulation error", e)
+                return
 
         # send bundle targeting next block
         print(f"Sending bundle targeting block {block+1}")

flashbots/flashbots.py

@@ -101,7 +101,8 @@ def __init__(self, w3: Web3, signed_tx: HexBytes, max_block_number: int):
     def wait(self) -> bool:
         """Waits up to max block number, returns `True` if/when tx has been mined.
 
-        If tx has not been mined by the time the current block > max_block_number, returns `False`."""
+        If tx has not been mined by the time the current block > max_block_number, returns `False`.
+        """
         while True:
             try:
                 self.w3.eth.get_transaction(self.tx["hash"])
@@ -220,12 +221,12 @@ def send_raw_bundle_munger(
                 "blockNumber": hex(target_block_number),
                 "minTimestamp": opts["minTimestamp"] if "minTimestamp" in opts else 0,
                 "maxTimestamp": opts["maxTimestamp"] if "maxTimestamp" in opts else 0,
-                "revertingTxHashes": opts["revertingTxHashes"]
-                if "revertingTxHashes" in opts
-                else [],
-                "replacementUuid": opts["replacementUuid"]
-                if "replacementUuid" in opts
-                else None,
+                "revertingTxHashes": (
+                    opts["revertingTxHashes"] if "revertingTxHashes" in opts else []
+                ),
+                "replacementUuid": (
+                    opts["replacementUuid"] if "replacementUuid" in opts else None
+                ),
             }
         ]
 
@@ -400,7 +401,8 @@ def send_private_transaction_munger(
     ) -> Any:
         """Sends a single transaction to Flashbots.
 
-        If `max_block_number` is set, Flashbots will try to submit the transaction in every block <= that block (max 25 blocks from present)."""
+        If `max_block_number` is set, Flashbots will try to submit the transaction in every block <= that block (max 25 blocks from present).
+        """
         signed_transaction: str
         if "signed_transaction" in transaction:
             signed_transaction = transaction["signed_transaction"]
@@ -438,7 +440,8 @@ def cancel_private_transaction_munger(
     ) -> bool:
         """Stops a private transaction from being sent to miners by Flashbots.
 
-        Note: if a transaction has already been received by a miner, it may still be mined. This simply stops further submissions."""
+        Note: if a transaction has already been received by a miner, it may still be mined. This simply stops further submissions.
+        """
         params = {
             "txHash": tx_hash,
         }