Function addX402AxiosInterceptor

src/services/x402/paymentFetch.ts:111–156

(instance: AxiosInstance)

 * @param instance - The axios instance to add the interceptor to
 */
export function addX402AxiosInterceptor(instance: AxiosInstance): void {
  instance.interceptors.response.use(
    // Success handler — pass through non-402 responses
    (response) => response,
    // Error handler — intercept 402 responses
    async (error) => {
      if (
        !error.response ||
        error.response.status !== 402 ||
        !isX402Enabled()
      ) {
        throw error
      }

      const response: AxiosResponse = error.response

      const paymentRequiredHeader =
        response.headers[X402_HEADERS.PAYMENT_REQUIRED]
      if (!paymentRequiredHeader) {
        throw error
      }

      logForDebugging('[x402] Axios interceptor: handling 402 Payment Required')

      const result = handlePaymentRequired(
        paymentRequiredHeader,
        getX402SessionSpentUSD(),
      )

      if (!result) {
        throw error
      }

      // Retry the original request with the payment header
      const retryConfig = {
        ...error.config,
        headers: {
          ...error.config.headers,
          [X402_HEADERS.PAYMENT]: result.paymentHeader,
        },
      }

      return instance.request(retryConfig)
    },
  )
}