Enable TRON mainnet gasfree USDT

README.md

@@ -50,15 +50,15 @@ The demo simulates a payment workflow involving three conceptual agents:
 |---------|----------|--------|-----------------|
 | TRON Nile (testnet) | `tron:nile` | USDT, USDD | `exact_permit`, `exact_gasfree` |
 | TRON Shasta (testnet) | `tron:shasta` | USDT | `exact_permit` |
-| TRON Mainnet | `tron:mainnet` | USDT, USDD | `exact_permit` |
+| TRON Mainnet | `tron:mainnet` | USDT, USDD | `exact_permit`, `exact_gasfree` (USDT only) |
 | BSC Testnet (optional) | `eip155:97` | USDT, USDC, DHLU | `exact_permit`, `exact` |
 | BSC Mainnet (optional) | `eip155:56` | USDC, USDT, EPS | `exact_permit`, `exact` |
 
 > BSC support requires `BSC_PRIVATE_KEY` to be configured.
 
 ### GasFree (Gasless Transactions)
 
-GasFree eliminates transaction fees for TRON payments. When enabled, the client can use a custom selection policy (`PreferGasFreeUSDTPolicy`) to automatically prefer gasless transactions.
+GasFree eliminates transaction fees for TRON payments. When enabled, the client can use a custom selection policy (`PreferGasFreeUSDTPolicy`) to automatically prefer gasless transactions. In this demo, GasFree is available on Nile and Mainnet (USDT only) when the corresponding `GASFREE_API_KEY_*` / `GASFREE_API_SECRET_*` values are set.
 
 ---
 
@@ -100,6 +100,8 @@ BSC_PAY_TO_ADDRESS=<server_recipient_evm_address>
 # Optional: GasFree gasless transactions (per-network)
 GASFREE_API_KEY_NILE=<key>
 GASFREE_API_SECRET_NILE=<secret>
+GASFREE_API_KEY_MAINNET=<key>
+GASFREE_API_SECRET_MAINNET=<secret>
 
 # Optional: Facilitator authentication
 FACILITATOR_API_KEY=<your_api_key>

client/python/main.py

@@ -105,7 +105,7 @@ async def main():
     # Balance policy: auto-resolves signers from registered mechanisms
     x402_client.register_policy(SufficientBalancePolicy)
     # Register custom selection policy (AFTER balance check)
-    x402_client.register_policy(PreferGasFreeUSDTPolicy)
+    # x402_client.register_policy(PreferGasFreeUSDTPolicy)
 
     print(f"\nSupported Networks and Tokens:")
     for network_name in ["tron:mainnet", "tron:nile", "tron:shasta", "eip155:97"]:

facilitator/main.py

@@ -84,17 +84,23 @@ class FeeQuoteRequest(BaseModel):
 gasfree_api_secret_nile = os.getenv("GASFREE_API_SECRET_NILE") or os.getenv("GASFREE_API_SECRET")
 gasfree_enabled_nile = bool(gasfree_api_key_nile and gasfree_api_secret_nile)
 
-gasfree_clients = (
-    {
-        "tron:nile": GasFreeAPIClient(
-            NetworkConfig.get_gasfree_api_base_url("tron:nile"),
-            api_key=gasfree_api_key_nile,
-            api_secret=gasfree_api_secret_nile,
-        ),
-    }
-    if gasfree_enabled_nile
-    else {}
-)
+gasfree_api_key_mainnet = os.getenv("GASFREE_API_KEY_MAINNET") or os.getenv("GASFREE_API_KEY")
+gasfree_api_secret_mainnet = os.getenv("GASFREE_API_SECRET_MAINNET") or os.getenv("GASFREE_API_SECRET")
+gasfree_enabled_mainnet = bool(gasfree_api_key_mainnet and gasfree_api_secret_mainnet)
+
+gasfree_clients: dict[str, GasFreeAPIClient] = {}
+if gasfree_enabled_nile:
+    gasfree_clients["tron:nile"] = GasFreeAPIClient(
+        NetworkConfig.get_gasfree_api_base_url("tron:nile"),
+        api_key=gasfree_api_key_nile,
+        api_secret=gasfree_api_secret_nile,
+    )
+if gasfree_enabled_mainnet:
+    gasfree_clients["tron:mainnet"] = GasFreeAPIClient(
+        NetworkConfig.get_gasfree_api_base_url("tron:mainnet"),
+        api_key=gasfree_api_key_mainnet,
+        api_secret=gasfree_api_secret_mainnet,
+    )
 
 all_networks = [f"tron:{n}" for n in TRON_NETWORKS] + [NetworkConfig.BSC_MAINNET, NetworkConfig.BSC_TESTNET]
 
@@ -112,14 +118,21 @@ async def lifespan(app: FastAPI):
         )
         facilitator.register([f"tron:{network}"], mechanism)
 
-        # Add GasFree support for nile
+        # Add GasFree support for Nile and Mainnet (USDT only; enforced by server pricing)
         if network == "nile" and gasfree_enabled_nile:
             gasfree_mechanism = ExactGasFreeFacilitatorMechanism(
                 tron_signer,
                 clients=gasfree_clients,
                 base_fee=TRON_BASE_FEE,
             )
             facilitator.register([f"tron:{network}"], gasfree_mechanism)
+        if network == "mainnet" and gasfree_enabled_mainnet:
+            gasfree_mechanism = ExactGasFreeFacilitatorMechanism(
+                tron_signer,
+                clients=gasfree_clients,
+                base_fee=TRON_BASE_FEE,
+            )
+            facilitator.register([f"tron:{network}"], gasfree_mechanism)
 
     bsc_signer = await EvmFacilitatorSigner.create()
     bsc_facilitator_address = bsc_signer.get_address()
@@ -152,6 +165,7 @@ async def lifespan(app: FastAPI):
     print("=" * 80)
     print(f"TRON Base Fee: {TRON_BASE_FEE}")
     print(f"GasFree Nile Enabled: {gasfree_enabled_nile}")
+    print(f"GasFree Mainnet Enabled: {gasfree_enabled_mainnet}")
     print(f"Supported Networks: {', '.join(all_networks)}")
 
     print(f"\nNetwork Details:")

requirements.txt

@@ -2,7 +2,7 @@
 # Install with: pip install -r requirements.txt
 
 # Core bankofai-x402 SDK with TRON and FastAPI support (GitHub tag)
-bankofai-x402[tron,fastapi]==0.5.0
+bankofai-x402[tron,fastapi]==0.5.1
 
 # Web framework
 fastapi>=0.104.0

server/main.py

@@ -55,6 +55,15 @@
 if not PAY_TO_ADDRESS:
     raise ValueError("PAY_TO_ADDRESS environment variable is required")
 
+# GasFree flags (kept in sync with facilitator envs)
+gasfree_api_key_nile = os.getenv("GASFREE_API_KEY_NILE") or os.getenv("GASFREE_API_KEY")
+gasfree_api_secret_nile = os.getenv("GASFREE_API_SECRET_NILE") or os.getenv("GASFREE_API_SECRET")
+gasfree_enabled_nile = bool(gasfree_api_key_nile and gasfree_api_secret_nile)
+
+gasfree_api_key_mainnet = os.getenv("GASFREE_API_KEY_MAINNET") or os.getenv("GASFREE_API_KEY")
+gasfree_api_secret_mainnet = os.getenv("GASFREE_API_SECRET_MAINNET") or os.getenv("GASFREE_API_SECRET")
+gasfree_enabled_mainnet = bool(gasfree_api_key_mainnet and gasfree_api_secret_mainnet)
+
 # Network selection - Change this to use different networks
 # Options: NetworkConfig.TRON_MAINNET, NetworkConfig.TRON_NILE,
 # NetworkConfig.TRON_SHASTA
@@ -75,7 +84,10 @@
 # Initialize server (TRON mechanisms auto-registered by default)
 server = X402Server()
 # Register TRON GasFree mechanism
-server.register(NetworkConfig.TRON_NILE, ExactGasFreeServerMechanism())
+if gasfree_enabled_nile:
+    server.register(NetworkConfig.TRON_NILE, ExactGasFreeServerMechanism())
+if gasfree_enabled_mainnet:
+    server.register(NetworkConfig.TRON_MAINNET, ExactGasFreeServerMechanism())
 # Register BSC mechanisms (optional - requires BSC_PAY_TO_ADDRESS)
 if BSC_PAY_TO_ADDRESS:
     server.register(NetworkConfig.BSC_TESTNET, ExactPermitEvmServerMechanism())
@@ -97,6 +109,8 @@
 print(f"Pay To Address: {PAY_TO_ADDRESS}")
 print(f"Facilitator URL: {FACILITATOR_URL}")
 print(f"Facilitator API Key: {'*configured*' if FACILITATOR_API_KEY else '(not set)'}")
+print(f"GasFree Nile Enabled: {gasfree_enabled_nile}")
+print(f"GasFree Mainnet Enabled: {gasfree_enabled_mainnet}")
 permit_address = NetworkConfig.get_payment_permit_address(CURRENT_NETWORK)
 print(f"PaymentPermit Contract: {permit_address}")
 
@@ -167,11 +181,17 @@ async def root():
     }
 
 
+NILE_PRICES = ["0.0001 USDT", "0.0001 USDD"]
+NILE_SCHEMES = ["exact_permit", "exact_permit"]
+if gasfree_enabled_nile:
+    NILE_PRICES.append("0.0001 USDT")
+    NILE_SCHEMES.append("exact_gasfree")
+
 @app.get("/protected-nile")
 @x402_protected(
     server=server,
-    prices=["0.0001 USDT", "0.0001 USDD", "0.0001 USDT", "0.0001 USDD"],
-    schemes=["exact_permit", "exact_permit", "exact_gasfree", "exact_gasfree"],
+    prices=NILE_PRICES,
+    schemes=NILE_SCHEMES,
     network=CURRENT_NETWORK,
     pay_to=PAY_TO_ADDRESS,
 )
@@ -215,11 +235,18 @@ async def protected_shasta_endpoint(request: Request):
     return StreamingResponse(buf, media_type="image/png")
 
 
+MAINNET_PRICES = ["0.0001 USDT", "0.0001 USDD"]
+MAINNET_SCHEMES = ["exact_permit", "exact_permit"]
+if gasfree_enabled_mainnet:
+    MAINNET_PRICES.append("0.0001 USDT")
+    MAINNET_SCHEMES.append("exact_gasfree")
+
+
 @app.get("/protected-mainnet")
 @x402_protected(
     server=server,
-    prices=["0.0001 USDT", "0.0001 USDD"],
-    schemes=["exact_permit", "exact_permit"],
+    prices=MAINNET_PRICES,
+    schemes=MAINNET_SCHEMES,
     network=NetworkConfig.TRON_MAINNET,
     pay_to=PAY_TO_ADDRESS,
 )
@@ -299,7 +326,7 @@ async def protected_bsc_testnet_endpoint(request: Request):
     print("Endpoints:")
     print("  /protected-nile         - Payment (0.0001 USDT) [Nile testnet]")
     print("  /protected-shasta       - Payment (0.0001 USDT) [Shasta testnet]")
-    print("  /protected-mainnet      - Payment (0.0001 USDT/USDD) [Mainnet]")
+    print("  /protected-mainnet      - Payment (0.0001 USDT/USDD) [Mainnet, GasFree USDT if enabled]")
     print("  /protected-bsc-mainnet  - Payment (0.0001 USDC/USDT/EPS) [BSC Mainnet]")
     print("  /protected-bsc-testnet  - Payment (0.0001 USDT/USDC/DHLU) [BSC Testnet]")
     print("=" * 80 + "\n")