feat(events): process transactional invalidations

lib/events/invalidation.ts

@@ -0,0 +1,83 @@
+export const INVALIDATION_TYPES = [
+  "directory.updated",
+  "page.updated",
+  "data-source.updated",
+  "admin.updated",
+] as const;
+
+export type InvalidationType = (typeof INVALIDATION_TYPES)[number];
+
+export interface InvalidationEvent {
+  type: InvalidationType;
+  id: string;
+  version: number;
+}
+
+export interface OutboxEventLike {
+  aggregateId: string;
+  eventType: string;
+  payload: Record<string, unknown>;
+  topic: string;
+}
+
+function isInvalidationType(value: string): value is InvalidationType {
+  return INVALIDATION_TYPES.some((type) => type === value);
+}
+
+export function expectedTopic(event: InvalidationEvent): string {
+  switch (event.type) {
+    case "directory.updated":
+      return "directory";
+    case "page.updated":
+      return `page:${event.id}`;
+    case "data-source.updated":
+      return `data-source:${event.id}`;
+    case "admin.updated":
+      return "admin";
+  }
+}
+
+export function toInvalidationEvent(
+  record: OutboxEventLike,
+): InvalidationEvent | null {
+  if (!isInvalidationType(record.eventType)) return null;
+  const id = record.payload.id;
+  const version = record.payload.version;
+  if (
+    typeof id !== "string" ||
+    id !== record.aggregateId ||
+    typeof version !== "number" ||
+    !Number.isSafeInteger(version) ||
+    version < 0
+  ) {
+    return null;
+  }
+  const event: InvalidationEvent = {
+    type: record.eventType,
+    id,
+    version,
+  };
+  return expectedTopic(event) === record.topic ? event : null;
+}
+
+export function parseInvalidationEvent(value: string): InvalidationEvent | null {
+  try {
+    const parsed = JSON.parse(value) as Record<string, unknown>;
+    const type = parsed.type;
+    const id = parsed.id;
+    const version = parsed.version;
+    if (
+      typeof type !== "string" ||
+      !isInvalidationType(type) ||
+      typeof id !== "string" ||
+      typeof version !== "number" ||
+      !Number.isSafeInteger(version) ||
+      version < 0
+    ) {
+      return null;
+    }
+    return { type, id, version };
+  } catch {
+    return null;
+  }
+}