From 18aab16f815da1a9ffb0d34a0def3d182bfe03f1 Mon Sep 17 00:00:00 2001
From: Rashmi <rashmi.angadi@sap.com>
Date: Sun, 26 May 2024 15:46:44 +0530
Subject: [PATCH] changes

---
 lib/sdm.js        |  4 ++--
 lib/util/index.js | 59 +++++++++++++++++++++++++++++------------------
 2 files changed, 39 insertions(+), 24 deletions(-)

diff --git a/lib/sdm.js b/lib/sdm.js
index 7506212..86dcb6b 100644
--- a/lib/sdm.js
+++ b/lib/sdm.js
@@ -29,7 +29,7 @@ module.exports = class SDMAttachmentsService extends (
 
   async get(attachments, keys) {
     const response = await getURLFromAttachments(keys, attachments);
-    const token = await fetchAccessToken(this.creds);
+    const token = await fetchAccessToken(this.creds,req.user.tokeninfo.getTokenValue());
     try {
       const Key = response?.url;
       const content = await readAttachment(Key, token, this.creds);
@@ -264,4 +264,4 @@ module.exports = class SDMAttachmentsService extends (
     );
     return;
   }
-};
+};
\ No newline at end of file
diff --git a/lib/util/index.js b/lib/util/index.js
index 1048ddd..15dfa26 100644
--- a/lib/util/index.js
+++ b/lib/util/index.js
@@ -3,31 +3,46 @@ const cds = require("@sap/cds");
 const requests = xssec.requests;
 const NodeCache = require("node-cache");
 const cache = new NodeCache();
-
-function fetchAccessToken(credentials) {
-  const access_token = cache.get("SDM_ACCESS_TOKEN"); // to check if token exists
+async function fetchAccessToken(credentials,jwt) {
+  let access_token = cache.get("SDM_ACCESS_TOKEN"); // to check if token exists
   if (access_token === undefined) {
-    return new Promise(function (resolve, reject) {
-      requests.requestClientCredentialsToken(
-        null,
-        credentials.uaa,
-        null,
-        (error, response) => {
-          if (error) {
-            console.error(
-              `Response error while fetching access token ${response.statusCode}`
-            );
-            reject(err);
-          } else {
-            cache.set("SDM_ACCESS_TOKEN", response, 11); //expires after 11 hours
-            resolve(response);
-          }
-        }
-      );
-    });
+    access_token = await generateSDMBearerToken(credentials,jwt);
+    cache.set("SDM_ACCESS_TOKEN", access_token, 11); //expires after 11 hours
   } else {
-    return access_token;
+    if(isTokenExpired(access_token)){
+access_token = generateSDMBearerToken(credentials,jwt);
+cache.set("SDM_ACCESS_TOKEN", access_token, 11); //expires after 11 hours
+    }
+
   }
+  return access_token;
+}
+async function generateSDMBearerToken(credentials,jwt){
+return new Promise(function (resolve, reject) {
+  requests.requestUserToken(
+         jwt,
+         credentials.uaa,
+         null, null, null, null, (error, response)=>{
+       if (error) {
+         console.error(
+           `Response error while fetching access token ${response.statusCode}`
+         );
+         reject(err);
+       } else {
+       console.log("TOKEN EXCHANGE "+response);
+         resolve(response);
+       }
+     }
+   );
+ });
+}
+function isTokenExpired(jwtEncoded){
+  const jwtBase64Encoded = jwtEncoded.split('.')[1]
+  const jwtDecodedAsString = Buffer.from(jwtBase64Encoded, 'base64').toString('ascii')
+  const jwtDecodedJson = JSON.parse(jwtDecodedAsString)
+  var expiry = new Date(jwtDecodedJson.exp * 1000);
+  var now = new Date();
+ return now>expiry;
 }
 
 function getConfigurations() {