feat(router): add merchantId authentication for Payments v2 (#8239)

Co-authored-by: Aishwariyaa Anand <aishwariyaa.anand@Aishwariyaa-Anand-C3PGW02T6Y.local>

crates/router/src/configs/secrets_transformers.rs

@@ -540,6 +540,7 @@ pub(crate) async fn fetch_raw_secrets(
         revenue_recovery: conf.revenue_recovery,
         debit_routing_config: conf.debit_routing_config,
         clone_connector_allowlist: conf.clone_connector_allowlist,
+        merchant_id_auth: conf.merchant_id_auth,
         infra_values: conf.infra_values,
     }
 }

crates/router/src/configs/settings.rs

@@ -158,6 +158,7 @@ pub struct Settings<S: SecretState> {
     #[cfg(feature = "v2")]
     pub revenue_recovery: revenue_recovery::RevenueRecoverySettings,
     pub clone_connector_allowlist: Option<CloneConnectorAllowlistConfig>,
+    pub merchant_id_auth: MerchantIdAuthSettings,
     #[serde(default)]
     pub infra_values: Option<HashMap<String, String>>,
 }
@@ -817,6 +818,12 @@ pub struct DrainerSettings {
     pub loop_interval: u32,     // in milliseconds
 }
 
+#[derive(Debug, Clone, Default, Deserialize)]
+#[serde(default)]
+pub struct MerchantIdAuthSettings {
+    pub merchant_id_auth_enabled: bool,
+}
+
 #[derive(Debug, Clone, Default, Deserialize)]
 #[serde(default)]
 pub struct WebhooksSettings {

crates/router/src/routes/payments.rs

@@ -262,6 +262,27 @@ pub async fn payments_create_and_confirm_intent(
         }
     };
 
+    let auth_type = if state.conf.merchant_id_auth.merchant_id_auth_enabled {
+        &auth::MerchantIdAuth
+    } else {
+        match env::which() {
+            env::Env::Production => &auth::V2ApiKeyAuth {
+                is_connected_allowed: false,
+                is_platform_allowed: false,
+            },
+            _ => auth::auth_type(
+                &auth::V2ApiKeyAuth {
+                    is_connected_allowed: false,
+                    is_platform_allowed: false,
+                },
+                &auth::JWTAuth {
+                    permission: Permission::ProfilePaymentWrite,
+                },
+                req.headers(),
+            ),
+        }
+    };
+
     Box::pin(api::server_wrap(
         flow,
         state,
@@ -280,22 +301,7 @@ pub async fn payments_create_and_confirm_intent(
                 header_payload.clone(),
             )
         },
-        match env::which() {
-            env::Env::Production => &auth::V2ApiKeyAuth {
-                is_connected_allowed: false,
-                is_platform_allowed: false,
-            },
-            _ => auth::auth_type(
-                &auth::V2ApiKeyAuth {
-                    is_connected_allowed: false,
-                    is_platform_allowed: false,
-                },
-                &auth::JWTAuth {
-                    permission: Permission::ProfilePaymentWrite,
-                },
-                req.headers(),
-            ),
-        },
+        auth_type,
         api_locking::LockAction::NotApplicable,
     ))
     .await

crates/router/src/services/authentication.rs

@@ -2184,6 +2184,7 @@ where
 }
 
 #[derive(Debug)]
+#[cfg(feature = "v1")]
 pub struct MerchantIdAuth(pub id_type::MerchantId);
 
 #[cfg(feature = "v1")]
@@ -2233,6 +2234,10 @@ where
     }
 }
 
+#[derive(Debug)]
+#[cfg(feature = "v2")]
+pub struct MerchantIdAuth;
+
 #[cfg(feature = "v2")]
 #[async_trait]
 impl<A> AuthenticateAndFetch<AuthenticationData, A> for MerchantIdAuth
@@ -2249,6 +2254,8 @@ where
         }
 
         let key_manager_state = &(&state.session_state()).into();
+        let merchant_id = HeaderMapStruct::new(request_headers)
+            .get_id_type_from_header::<id_type::MerchantId>(headers::X_MERCHANT_ID)?;
         let profile_id =
             get_id_type_by_key_from_headers(headers::X_PROFILE_ID.to_string(), request_headers)?
                 .get_required_value(headers::X_PROFILE_ID)?;
@@ -2256,7 +2263,7 @@ where
             .store()
             .get_merchant_key_store_by_merchant_id(
                 key_manager_state,
-                &self.0,
+                &merchant_id,
                 &state.store().get_master_key().to_vec().into(),
             )
             .await
@@ -2267,14 +2274,14 @@ where
             .find_business_profile_by_merchant_id_profile_id(
                 key_manager_state,
                 &key_store,
-                &self.0,
+                &merchant_id,
                 &profile_id,
             )
             .await
             .to_not_found_response(errors::ApiErrorResponse::Unauthorized)?;
         let merchant = state
             .store()
-            .find_merchant_account_by_merchant_id(key_manager_state, &self.0, &key_store)
+            .find_merchant_account_by_merchant_id(key_manager_state, &merchant_id, &key_store)
             .await
             .to_not_found_response(errors::ApiErrorResponse::Unauthorized)?;