Create chatSessionSerializer.js

server/chatSessionSerializer.js

@@ -0,0 +1,139 @@
+const ROOT_JSON_KEY = '__historyRootJson';
+const VERSION_META_FIELDS = ['toolCalls', 'responseEdits', 'responseSegments', 'error'];
+
+function validateAndRepairTree(rootMessage) {
+  const repair = (msg) => {
+    if (!msg) return;
+    if (msg.content === undefined || msg.content === null) {
+      msg.content = '';
+    }
+    if (msg.versions && Array.isArray(msg.versions)) {
+      for (const version of msg.versions) {
+        if (version.content === undefined || version.content === null) {
+          version.content = '';
+        }
+        if (version.tail && Array.isArray(version.tail)) {
+          for (const tailMsg of version.tail) {
+            repair(tailMsg);
+          }
+        }
+      }
+    }
+  };
+  repair(rootMessage);
+  return rootMessage;
+}
+
+function cloneAndRepairTree(rootMessage) {
+  return validateAndRepairTree(JSON.parse(JSON.stringify(rootMessage)));
+}
+
+function getActiveVersion(message) {
+  if (!message) return null;
+  const versions = Array.isArray(message.versions) ? message.versions : [];
+  if (!versions.length) {
+    message.versions = [{ content: message.content ?? '', tail: [], timestamp: Date.now() }];
+    message.currentVersionIdx = 0;
+    return message.versions[0];
+  }
+  const currentVersionIdx = Number.isInteger(message.currentVersionIdx)
+    ? Math.max(0, Math.min(message.currentVersionIdx, versions.length - 1))
+    : 0;
+  message.currentVersionIdx = currentVersionIdx;
+  if (!Array.isArray(message.versions[currentVersionIdx].tail)) {
+    message.versions[currentVersionIdx].tail = [];
+  }
+  if (message.versions[currentVersionIdx].content === undefined || message.versions[currentVersionIdx].content === null) {
+    message.versions[currentVersionIdx].content = message.content ?? '';
+  }
+  return message.versions[currentVersionIdx];
+}
+
+function cloneVersionMetaValue(value) {
+  if (value === undefined) return undefined;
+  return JSON.parse(JSON.stringify(value));
+}
+
+function syncMessageFromActiveVersion(message) {
+  if (!message) return message;
+  const currentVersion = getActiveVersion(message);
+  if (!currentVersion) return message;
+  message.content = currentVersion.content ?? message.content ?? '';
+  VERSION_META_FIELDS.forEach((key) => {
+    if (key in currentVersion) {
+      message[key] = cloneVersionMetaValue(currentVersion[key]);
+    } else {
+      delete message[key];
+    }
+  });
+  return message;
+}
+
+function cloneJson(value) {
+  return JSON.parse(JSON.stringify(value));
+}
+
+export function extractFlatHistory(rootMessage) {
+  if (!rootMessage) return [];
+
+  const toFlatEntry = (message) => {
+    const cloned = cloneJson(message);
+    if (cloned.content === undefined || cloned.content === null) {
+      cloned.content = '';
+    }
+    syncMessageFromActiveVersion(cloned);
+    if (Array.isArray(cloned.versions)) {
+      cloned.versions = cloned.versions.map((version) => ({
+        ...version,
+        tail: [],
+      }));
+    }
+    return cloned;
+  };
+
+  const history = [toFlatEntry(rootMessage)];
+  const currentVerIdx = rootMessage.currentVersionIdx ?? 0;
+
+  if (!Array.isArray(rootMessage.versions) || currentVerIdx >= rootMessage.versions.length) {
+    return history;
+  }
+
+  const currentTail = rootMessage.versions[currentVerIdx]?.tail;
+  if (currentTail && Array.isArray(currentTail)) {
+    const walkTail = (tail) => {
+      for (let i = 0; i < tail.length; i++) {
+        const msg = tail[i];
+        if (msg?.content === undefined || msg?.content === null) {
+          msg.content = '';
+        }
+        syncMessageFromActiveVersion(msg);
+        history.push(toFlatEntry(msg));
+        const ver = msg.versions?.[msg.currentVersionIdx ?? 0];
+        if (ver?.tail && Array.isArray(ver.tail)) {
+          walkTail(ver.tail);
+        }
+        if (msg.role === 'user' && Array.isArray(msg.versions) && msg.versions.length > 1) {
+          break;
+        }
+      }
+    };
+    walkTail(currentTail);
+  }
+
+  return history;
+}
+
+export function serializeSessionForClient(session) {
+  const rootMessage = Array.isArray(session?.history) && session.history[0]
+    ? cloneAndRepairTree(session.history[0])
+    : null;
+  return {
+    id: session?.id,
+    name: session?.name,
+    created: session?.created,
+    history: rootMessage ? extractFlatHistory(rootMessage) : [],
+    model: session?.model || null,
+    updatedAt: session?.updatedAt || null,
+    [ROOT_JSON_KEY]: rootMessage ? JSON.stringify(rootMessage) : null,
+  };
+}