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//! Tower service layer for payment middleware
use super::payment::PaymentMiddleware;
use tower::ServiceBuilder;
use tower_http::trace::TraceLayer;
/// Create a service builder with x402 payment middleware
pub fn create_payment_service(
middleware: PaymentMiddleware,
) -> impl tower::Layer<tower::ServiceBuilder<tower::layer::util::Identity>> + Clone {
ServiceBuilder::new()
.layer(TraceLayer::new_for_http())
.layer(tower::layer::util::Stack::new(
tower::layer::util::Identity::new(),
PaymentServiceLayer::new(middleware),
))
}
/// Tower service layer for x402 payment middleware
#[derive(Clone)]
pub struct PaymentServiceLayer {
middleware: PaymentMiddleware,
}
impl PaymentServiceLayer {
pub fn new(middleware: PaymentMiddleware) -> Self {
Self { middleware }
}
}
impl<S> tower::Layer<S> for PaymentServiceLayer {
type Service = PaymentService<S>;
fn layer(&self, inner: S) -> Self::Service {
PaymentService {
inner,
middleware: self.middleware.clone(),
}
}
}
/// Tower service for x402 payment middleware
#[derive(Clone)]
pub struct PaymentService<S> {
inner: S,
middleware: PaymentMiddleware,
}
impl<S, ReqBody, ResBody> tower::Service<http::Request<ReqBody>> for PaymentService<S>
where
S: tower::Service<
http::Request<ReqBody>,
Response = http::Response<ResBody>,
Error = Box<dyn std::error::Error + Send + Sync>,
> + Send
+ 'static,
S::Future: Send + 'static,
ReqBody: Send + 'static,
ResBody: Send + 'static,
{
type Response = S::Response;
type Error = S::Error;
type Future = std::pin::Pin<
Box<
dyn std::future::Future<Output = std::result::Result<Self::Response, Self::Error>>
+ Send,
>,
>;
fn poll_ready(
&mut self,
cx: &mut std::task::Context<'_>,
) -> std::task::Poll<std::result::Result<(), Self::Error>> {
self.inner.poll_ready(cx)
}
fn call(&mut self, req: http::Request<ReqBody>) -> Self::Future {
let middleware = self.middleware.clone();
// Extract payment header before moving the request
let payment_header = req
.headers()
.get("X-PAYMENT")
.and_then(|h| h.to_str().ok())
.map(|s| s.to_string());
let uri_path = req.uri().path().to_string();
let future = self.inner.call(req);
Box::pin(async move {
match payment_header {
Some(payment_b64) => {
// Parse payment payload
match crate::types::PaymentPayload::from_base64(&payment_b64) {
Ok(payment_payload) => {
// Create payment requirements
let requirements =
match middleware.config.create_payment_requirements(&uri_path) {
Ok(req) => req,
Err(e) => {
// Return 500 error if we can't create requirements
return Err(
Box::new(e) as Box<dyn std::error::Error + Send + Sync>
);
}
};
// Verify payment
match middleware
.verify_with_requirements(&payment_payload, &requirements)
.await
{
Ok(true) => {
// Payment is valid, proceed with request
let response = future.await?;
// Settle payment after successful response
if let Ok(settlement) = middleware
.settle_with_requirements(&payment_payload, &requirements)
.await
{
// Note: In a real implementation, we would need to modify the response
// to add the X-PAYMENT-RESPONSE header, but this requires
// more complex response handling in Tower
let _ = settlement; // Acknowledge settlement
}
Ok(response)
}
Ok(false) => {
// Payment verification failed
Err(Box::new(crate::X402Error::payment_verification_failed(
"Payment verification failed",
))
as Box<dyn std::error::Error + Send + Sync>)
}
Err(e) => {
// Error during verification
Err(Box::new(e) as Box<dyn std::error::Error + Send + Sync>)
}
}
}
Err(e) => {
// Invalid payment payload
Err(Box::new(e) as Box<dyn std::error::Error + Send + Sync>)
}
}
}
None => {
// No payment header provided
Err(Box::new(crate::X402Error::payment_verification_failed(
"X-PAYMENT header is required",
))
as Box<dyn std::error::Error + Send + Sync>)
}
}
})
}
}