Add lightweight observed request explorer

src/background.js

@@ -81,6 +81,10 @@ async function handleVendorGetMessage(message, sender) {
     return handleListRecentConsentStatesMessage();
   }
 
+  if (message.type === "list_recent_observed_requests") {
+    return handleListRecentObservedRequestsMessage();
+  }
+
   if (message.type === "purge_unlocked_evidence_records") {
     return handlePurgeUnlockedEvidenceRecordsMessage();
   }
@@ -316,6 +320,16 @@ async function handleListRecentConsentStatesMessage() {
   };
 }
 
+async function handleListRecentObservedRequestsMessage() {
+  const db = await openVendorGetDb();
+  const observedRequests = await listRecentObservedRequests(db, 50);
+
+  return {
+    success: true,
+    observedRequests
+  };
+}
+
 function getLatestConsentState(db) {
   return new Promise((resolve, reject) => {
     const tx = db.transaction(["consent_states"], "readonly");
@@ -368,6 +382,38 @@ function listRecentConsentStates(db, limit) {
   });
 }
 
+function listRecentObservedRequests(db, limit) {
+  return new Promise((resolve, reject) => {
+    const observedRequests = [];
+    const tx = db.transaction(
+      [VENDORGET_STORE_NAMES.observedRequests],
+      "readonly"
+    );
+    const requestsStore = tx.objectStore(VENDORGET_STORE_NAMES.observedRequests);
+    const lastSeenAtIndex = requestsStore.index("lastSeenAt");
+    const cursorRequest = lastSeenAtIndex.openCursor(null, "prev");
+
+    cursorRequest.onerror = () => reject(cursorRequest.error);
+    cursorRequest.onsuccess = () => {
+      const cursor = cursorRequest.result;
+
+      if (!cursor || observedRequests.length >= limit) {
+        return;
+      }
+
+      observedRequests.push(cursor.value);
+
+      if (observedRequests.length < limit) {
+        cursor.continue();
+      }
+    };
+
+    tx.onerror = () => reject(tx.error);
+    tx.onabort = () => reject(tx.error);
+    tx.oncomplete = () => resolve(observedRequests);
+  });
+}
+
 function listRecentGvlSnapshots(db, limit) {
   return new Promise((resolve, reject) => {
     const snapshots = [];