🧹fix: Handle Abort Message Edge Cases (#1462)

* chore: bump langchain to v0.0.213 from v0.0.186

* fix: handle abort edge cases:
- abort message server-side if response experienced error mid-generation
- attempt to recover message if aborting resulted in error
- if abortKey is not provided, use conversationId if it exists
- if headers were already sent, send an Event stream message
- issue warning for possible Google censor/filter

refactor(streamResponse): for `sendError`, allow passing overrides so that error can include partial generation, improve typing for `sendMessage`

* chore(MessageContent): remove eslint warning for unused `i`, rephrase unfinished message text

* fix(useSSE): avoid invoking cancelHandler if the abort response was 404

* chore(TMessage): remove unnecessary, unused legacy message property `submitting`

* chore(TMessage): remove unnecessary legacy message property `cancelled`

* chore(abortMiddleware): remove unused `errorText` property to avoid confusion

api/server/utils/streamResponse.js

@@ -1,5 +1,6 @@
 const crypto = require('crypto');
-const { saveMessage } = require('~/models/Message');
+const { saveMessage, getMessages } = require('~/models/Message');
+const { getConvo } = require('~/models/Conversation');
 
 /**
  * Sends error data in Server Sent Events format and ends the response.
@@ -15,7 +16,7 @@ const handleError = (res, message) => {
  * Sends message data in Server Sent Events format.
  * @param {object} res - - The server response.
  * @param {string} message - The message to be sent.
- * @param {string} event - [Optional] The type of event. Default is 'message'.
+ * @param {'message' | 'error' | 'cancel'} event - [Optional] The type of event. Default is 'message'.
  */
 const sendMessage = (res, message, event = 'message') => {
   if (message.length === 0) {
@@ -32,19 +33,27 @@ const sendMessage = (res, message, event = 'message') => {
  * @param {function} callback - [Optional] The callback function to be executed.
  */
 const sendError = async (res, options, callback) => {
-  const { user, sender, conversationId, messageId, parentMessageId, text, shouldSaveMessage } =
-    options;
+  const {
+    user,
+    sender,
+    conversationId,
+    messageId,
+    parentMessageId,
+    text,
+    shouldSaveMessage,
+    overrideProps = {},
+  } = options;
   const errorMessage = {
     sender,
     messageId: messageId ?? crypto.randomUUID(),
     conversationId,
     parentMessageId,
     unfinished: false,
-    cancelled: false,
     error: true,
     final: true,
     text,
     isCreatedByUser: false,
+    ...overrideProps,
   };
   if (callback && typeof callback === 'function') {
     await callback();
@@ -54,6 +63,17 @@ const sendError = async (res, options, callback) => {
     await saveMessage({ ...errorMessage, user });
   }
 
+  if (!errorMessage.error) {
+    const requestMessage = { messageId: parentMessageId, conversationId };
+    const query = await getMessages(requestMessage);
+    return sendMessage(res, {
+      final: true,
+      requestMessage: query?.[0] ? query[0] : requestMessage,
+      responseMessage: errorMessage,
+      conversation: await getConvo(user, conversationId),
+    });
+  }
+
   handleError(res, errorMessage);
 };