refactor(connector): [Paypal] Add support for both BodyKey and Signat…

…ureKey (#2633)

Co-authored-by: Mani Chandra Dulam <mani.dchandra@juspay.in>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Mani Chandra <84711804+ThisIsMani@users.noreply.github.com>

crates/router/src/connector/paypal.rs

@@ -5,10 +5,10 @@ use base64::Engine;
 use common_utils::ext_traits::ByteSliceExt;
 use diesel_models::enums;
 use error_stack::{IntoReport, ResultExt};
-use masking::PeekInterface;
+use masking::{ExposeInterface, PeekInterface, Secret};
 use transformers as paypal;
 
-use self::transformers::{PaypalAuthResponse, PaypalMeta, PaypalWebhookEventType};
+use self::transformers::{auth_headers, PaypalAuthResponse, PaypalMeta, PaypalWebhookEventType};
 use super::utils::PaymentsCompleteAuthorizeRequestData;
 use crate::{
     configs::settings,
@@ -31,7 +31,7 @@ use crate::{
         self,
         api::{self, CompleteAuthorize, ConnectorCommon, ConnectorCommonExt, VerifyWebhookSource},
         transformers::ForeignFrom,
-        ErrorResponse, Response,
+        ConnectorAuthType, ErrorResponse, Response,
     },
     utils::{self, BytesExt},
 };
@@ -110,8 +110,8 @@ where
             .clone()
             .ok_or(errors::ConnectorError::FailedToObtainAuthType)?;
         let key = &req.attempt_id;
-
-        Ok(vec![
+        let auth = paypal::PaypalAuthType::try_from(&req.connector_auth_type)?;
+        let mut headers = vec![
             (
                 headers::CONTENT_TYPE.to_string(),
                 self.get_content_type().to_string().into(),
@@ -121,17 +121,57 @@ where
                 format!("Bearer {}", access_token.token.peek()).into_masked(),
             ),
             (
-                "Prefer".to_string(),
+                auth_headers::PREFER.to_string(),
                 "return=representation".to_string().into(),
             ),
             (
-                "PayPal-Request-Id".to_string(),
+                auth_headers::PAYPAL_REQUEST_ID.to_string(),
                 key.to_string().into_masked(),
             ),
-        ])
+        ];
+        if let Ok(paypal::PaypalConnectorCredentials::PartnerIntegration(credentials)) =
+            auth.get_credentials()
+        {
+            let auth_assertion_header =
+                construct_auth_assertion_header(&credentials.payer_id, &credentials.client_id);
+            headers.extend(vec![
+                (
+                    auth_headers::PAYPAL_AUTH_ASSERTION.to_string(),
+                    auth_assertion_header.to_string().into_masked(),
+                ),
+                (
+                    auth_headers::PAYPAL_PARTNER_ATTRIBUTION_ID.to_string(),
+                    "HyperSwitchPPCP_SP".to_string().into(),
+                ),
+            ])
+        } else {
+            headers.extend(vec![(
+                auth_headers::PAYPAL_PARTNER_ATTRIBUTION_ID.to_string(),
+                "HyperSwitchlegacy_Ecom".to_string().into(),
+            )])
+        }
+        Ok(headers)
     }
 }
 
+fn construct_auth_assertion_header(
+    payer_id: &Secret<String>,
+    client_id: &Secret<String>,
+) -> String {
+    let algorithm = consts::BASE64_ENGINE
+        .encode("{\"alg\":\"none\"}")
+        .to_string();
+    let merchant_credentials = format!(
+        "{{\"iss\":\"{}\",\"payer_id\":\"{}\"}}",
+        client_id.clone().expose(),
+        payer_id.clone().expose()
+    );
+    let encoded_credentials = consts::BASE64_ENGINE
+        .encode(merchant_credentials)
+        .to_string();
+    format!("{algorithm}.{encoded_credentials}.")
+}
+
 impl ConnectorCommon for Paypal {
     fn id(&self) -> &'static str {
         "paypal"
@@ -151,14 +191,14 @@ impl ConnectorCommon for Paypal {
 
     fn get_auth_header(
         &self,
-        auth_type: &types::ConnectorAuthType,
+        auth_type: &ConnectorAuthType,
     ) -> CustomResult<Vec<(String, request::Maskable<String>)>, errors::ConnectorError> {
-        let auth: paypal::PaypalAuthType = auth_type
-            .try_into()
-            .change_context(errors::ConnectorError::FailedToObtainAuthType)?;
+        let auth = paypal::PaypalAuthType::try_from(auth_type)?;
+        let credentials = auth.get_credentials()?;
+
         Ok(vec![(
             headers::AUTHORIZATION.to_string(),
-            auth.api_key.into_masked(),
+            credentials.get_client_secret().into_masked(),
         )])
     }
 
@@ -260,15 +300,9 @@ impl ConnectorIntegration<api::AccessTokenAuth, types::AccessTokenRequestData, t
         req: &types::RefreshTokenRouterData,
         _connectors: &settings::Connectors,
     ) -> CustomResult<Vec<(String, request::Maskable<String>)>, errors::ConnectorError> {
-        let auth: paypal::PaypalAuthType = (&req.connector_auth_type)
-            .try_into()
-            .change_context(errors::ConnectorError::FailedToObtainAuthType)?;
-
-        let auth_id = auth
-            .key1
-            .zip(auth.api_key)
-            .map(|(key1, api_key)| format!("{}:{}", key1, api_key));
-        let auth_val = format!("Basic {}", consts::BASE64_ENGINE.encode(auth_id.peek()));
+        let auth = paypal::PaypalAuthType::try_from(&req.connector_auth_type)?;
+        let credentials = auth.get_credentials()?;
+        let auth_val = credentials.generate_authorization_value();
 
         Ok(vec![
             (
@@ -998,15 +1032,9 @@ impl
         >,
         _connectors: &settings::Connectors,
     ) -> CustomResult<Vec<(String, request::Maskable<String>)>, errors::ConnectorError> {
-        let auth: paypal::PaypalAuthType = (&req.connector_auth_type)
-            .try_into()
-            .change_context(errors::ConnectorError::FailedToObtainAuthType)?;
-
-        let auth_id = auth
-            .key1
-            .zip(auth.api_key)
-            .map(|(key1, api_key)| format!("{}:{}", key1, api_key));
-        let auth_val = format!("Basic {}", consts::BASE64_ENGINE.encode(auth_id.peek()));
+        let auth = paypal::PaypalAuthType::try_from(&req.connector_auth_type)?;
+        let credentials = auth.get_credentials()?;
+        let auth_val = credentials.generate_authorization_value();
 
         Ok(vec![
             (