Merge pull request #8 from Permissionless-Software-Foundation/bot-unstable

Add multi-facilitator support with Dexter integration

.env-example

@@ -34,13 +34,19 @@ export X402_PRICE_USDC=0.1
 # Use 'eip155:84532' for Base Sepolia (testnet)
 export x402_NETWORK=eip155:8453
 
-# Facilitator URL
+# Primary Facilitator
+# Options: 'cdp' (Coinbase) or 'dexter' (Dexter.cash - no API keys required)
+export PRIMARY_FACILITATOR=cdp
+
+# Facilitator URLs
 # For Coinbase CDP (recommended): https://api.cdp.coinbase.com/platform/v2/x402
-# For custom/local facilitator: http://localhost:4022
-export x402_FACILITATOR_URL=https://api.cdp.coinbase.com/platform/v2/x402
+# For Dexter (no API keys):https://x402.dexter.cash
+# URL are not used when PRIMARY_FACILITATOR is set
+# export x402_FACILITATOR_URL=https://api.cdp.coinbase.com/platform/v2/x402
 
 # CDP API Credentials (required when using CDP facilitator)
 # Get these from https://cdp.coinbase.com - API Keys section
+# Not required for Dexter facilitator
 export FACILITATOR_KEY_ID=your_key_id_here
 export FACILITATOR_SECRET_KEY=your_secret_key_here
 

bin/server.js

@@ -18,7 +18,7 @@ import { dirname, join } from 'path'
 import config from '../src/config/index.js'
 import Controllers from '../src/controllers/index.js'
 import wlogger from '../src/adapters/wlogger.js'
-import { buildX402Routes, getX402Settings, getBasicAuthSettings, createAuthHeader } from '../src/config/x402.js'
+import { buildX402Routes, getX402Settings, getBasicAuthSettings, createAuthHeader, getFacilitatorConfig } from '../src/config/x402.js'
 import { basicAuthMiddleware } from '../src/middleware/basic-auth.js'
 import DiscoveryRouter from '../src/controllers/discovery/router.js'
 
@@ -125,14 +125,15 @@ class Server {
       if (x402Settings.enabled && basicAuthSettings.enabled) {
         // X402_ENABLED=true AND USE_BASIC_AUTH=true: Apply x402 conditionally
         const routes = buildX402Routes(this.config.apiPrefix)
-        const facilitatorOptions = x402Settings.facilitatorUrl
-          ? {
-              url: x402Settings.facilitatorUrl,
-              createAuthHeaders: createAuthHeader
-            }
-          : undefined
 
-        wlogger.info(`x402 v2 middleware enabled with basic auth bypass; enforcing ${x402Settings.priceUSDC} USDC per request (unless basic auth provided)`)
+        const primaryFacilitator = x402Settings.primaryFacilitator || 'cdp'
+        const facilitatorConfig = getFacilitatorConfig(primaryFacilitator)
+        const facilitatorOptions = {
+          url: facilitatorConfig.url,
+          createAuthHeaders: facilitatorConfig.requiresAuth ? createAuthHeader : null
+        }
+
+        wlogger.info(`x402 v2 middleware enabled with basic auth bypass; enforcing ${x402Settings.priceUSDC} USDC per request (unless basic auth provided) [facilitator: ${facilitatorConfig.name}]`)
 
         const facilitatorClient = new HTTPFacilitatorClient(facilitatorOptions)
         // x402 v2 exports use lowercase class names (x402ResourceServer).
@@ -141,6 +142,7 @@ class Server {
         registerExactEvmScheme(resourceServer, {})
         const x402Mw = x402PaymentMiddleware(routes, resourceServer)
 
+        // Create conditional x402 middleware that bypasses if basic auth is valid
         const conditionalX402Middleware = (req, res, next) => {
           if (req.locals?.basicAuthValid === true) {
             return next()
@@ -149,16 +151,19 @@ class Server {
         }
 
         app.use(conditionalX402Middleware)
+
+        // Display facilitator running url
+        console.log(`Facilitator running on: ${facilitatorOptions.url}`)
       } else if (x402Settings.enabled && !basicAuthSettings.enabled) {
         const routes = buildX402Routes(this.config.apiPrefix)
-        const facilitatorOptions = x402Settings.facilitatorUrl
-          ? {
-              url: x402Settings.facilitatorUrl,
-              createAuthHeaders: createAuthHeader
-            }
-          : undefined
+        const primaryFacilitator = x402Settings.primaryFacilitator || 'cdp'
+        const facilitatorConfig = getFacilitatorConfig(primaryFacilitator)
+        const facilitatorOptions = {
+          url: facilitatorConfig.url,
+          createAuthHeaders: facilitatorConfig.requiresAuth ? createAuthHeader : null
+        }
 
-        wlogger.info(`x402 v2 middleware enabled (basic auth disabled); enforcing ${x402Settings.priceUSDC} USDC per request`)
+        wlogger.info(`x402 v2 middleware enabled (basic auth disabled); enforcing ${x402Settings.priceUSDC} USDC per request [facilitator: ${facilitatorConfig.name}]`)
 
         const facilitatorClient = new HTTPFacilitatorClient(facilitatorOptions)
         // eslint-disable-next-line new-cap

src/config/env/common.js

@@ -57,6 +57,7 @@ const x402Defaults = {
   serverAddress: (process.env.SERVER_BASE_ADDRESS || '').trim(),
   facilitatorKeyId: process.env.FACILITATOR_KEY_ID || '',
   facilitatorSecretKey: process.env.FACILITATOR_SECRET_KEY || '',
+  primaryFacilitator: process.env.PRIMARY_FACILITATOR || 'cdp',
   network: x402Network,
   priceUSDC,
   // Optional: USDC token contract (0x…). If unset, Base / Base Sepolia use built-in USDC addresses.

src/config/x402.js

@@ -5,9 +5,23 @@ const DEFAULT_DESCRIPTION = 'Access to protected psf-bch-api resources'
 const DEFAULT_TIMEOUT_SECONDS = 120
 
 /**
- * Resolve USDC contract + EIP-712 domain hints for the configured network.
- * @param {string} network CAIP-2
+ * Facilitator configurations
+ * Supports multiple facilitators for redundancy and market coverage
  */
+const FACILITATORS = {
+  cdp: {
+    name: 'Coinbase CDP',
+    url: 'https://api.cdp.coinbase.com/platform/v2/x402',
+    requiresAuth: true,
+    authType: 'jwt'
+  },
+  dexter: {
+    name: 'Dexter',
+    url: 'https://x402.dexter.cash',
+    requiresAuth: false,
+    authType: 'none'
+  }
+}
 
 /** x402 `exact` on EVM expects a checksummable 0x address for `payTo`. */
 function assertEvmPayTo (payTo) {
@@ -22,6 +36,7 @@ function assertEvmPayTo (payTo) {
  * Builds x402 v2 RoutesConfig for @x402/express (CAIP-2 network + accepts[]).
  * Payment asset is explicitly USDC (ERC-20) via AssetAmount, not generic "money".
  * @see https://docs.x402.org/guides/migration-v1-to-v2
+ * @param {string} apiPrefix Express API prefix (e.g., "/v6")
  */
 export function buildX402Routes (apiPrefix = '/v6') {
   const normalizedPrefix = apiPrefix.endsWith('/')
@@ -65,7 +80,9 @@ export function getX402Settings () {
     serverAddress: config.x402?.serverAddress,
     priceUSDC: config.x402?.priceUSDC,
     usdcAssetAddress: config.x402?.usdcAssetAddress,
-    network: config.x402?.network
+    network: config.x402?.network,
+    facilitators: FACILITATORS,
+    primaryFacilitator: config.x402?.primaryFacilitator || 'cdp'
   }
 }
 
@@ -194,3 +211,22 @@ export async function createAuthHeader () {
     }
   }
 }
+
+/**
+ * Get facilitator configuration by name
+ * @param {string} name - Facilitator name ('cdp' or 'dexter')
+ * @returns {Object} Facilitator config
+ */
+export function getFacilitatorConfig (name = 'cdp') {
+  return FACILITATORS[name] || FACILITATORS.cdp
+}
+
+/**
+ * Check if facilitator requires authentication
+ * @param {string} name - Facilitator name
+ * @returns {boolean}
+ */
+export function facilitatorRequiresAuth (name = 'cdp') {
+  const cfg = FACILITATORS[name]
+  return cfg ? cfg.requiresAuth : false
+}