Added refresh user token flow using httpOnly cookies

api/utils/fetchEbayApplicationToken.js

@@ -0,0 +1,40 @@
+// Need to figoure out expiration and make sure to cycle this appropriately to avoid unnecessary calls
+import fetch from "node-fetch";
+
+const fetchEbayApplicationToken = async () => {
+  const ebayClientId = process.env.EBAY_CLIENT_ID;
+  const ebayClientSecret = process.env.EBAY_CLIENT_SECRET;
+  const credentials = Buffer.from(
+    `${ebayClientId}:${ebayClientSecret}`
+  ).toString("base64");
+
+  try {
+    const response = await fetch(
+      "https://api.ebay.com/identity/v1/oauth2/token",
+      {
+        method: "POST",
+        headers: {
+          "Content-Type": "application/x-www-form-urlencoded",
+          "authorization": `Basic ${credentials}`,
+        },
+        body: "grant_type=client_credentials&scope=https%3A%2F%2Fapi.ebay.com%2Foauth%2Fapi_scope",
+      }
+    );
+
+    if (!response.ok) {
+      const errorBody = await response.text();
+      throw new Error(
+        `Failed to fetch eBay OAuth token: ${response.status} ${response.statusText} - ${errorBody}`
+      );
+    }
+
+    const data = await response.json();
+
+    return data.access_token;
+  } catch (error) {
+    console.error("Error fetching eBay OAuth token:", error);
+    throw error; // Throw the error to be handled by the caller
+  }
+};
+
+export default fetchEbayApplicationToken;