Fix: Enforce 10MB upload limit for knowledge base with clear error handling (#1755)

* Initial plan

* Set MAX_CONTENT_LENGTH to 10MB and add file size validation

Co-authored-by: RockChinQ <45992437+RockChinQ@users.noreply.github.com>

* Add custom error handler for 413 RequestEntityTooLarge

Co-authored-by: RockChinQ <45992437+RockChinQ@users.noreply.github.com>

* Refactor: Extract MAX_FILE_SIZE constant to avoid duplication

Co-authored-by: RockChinQ <45992437+RockChinQ@users.noreply.github.com>

* Fix file name extraction and add missing file validation

Co-authored-by: RockChinQ <45992437+RockChinQ@users.noreply.github.com>

* Apply file size validation to all upload endpoints consistently

Co-authored-by: RockChinQ <45992437+RockChinQ@users.noreply.github.com>

* Add frontend file size validation for knowledge base and plugin uploads

Co-authored-by: RockChinQ <45992437+RockChinQ@users.noreply.github.com>

* Remove file size validation from plugin uploads, keep only for knowledge base

Co-authored-by: RockChinQ <45992437+RockChinQ@users.noreply.github.com>

* perf: ui

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: RockChinQ <45992437+RockChinQ@users.noreply.github.com>
Co-authored-by: Junyan Qin <rockchinq@gmail.com>

web/src/app/home/knowledge/components/kb-docs/FileUploadZone.tsx

@@ -23,6 +23,13 @@ export default function FileUploadZone({
     async (file: File) => {
       if (isUploading) return;
 
+      // Check file size (10MB limit)
+      const MAX_FILE_SIZE = 10 * 1024 * 1024; // 10MB
+      if (file.size > MAX_FILE_SIZE) {
+        toast.error(t('knowledge.documentsTab.fileSizeExceeded'));
+        return;
+      }
+
       setIsUploading(true);
       const toastId = toast.loading(t('knowledge.documentsTab.uploadingFile'));
 
@@ -46,7 +53,7 @@ export default function FileUploadZone({
         setIsUploading(false);
       }
     },
-    [kbId, isUploading, onUploadSuccess, onUploadError],
+    [kbId, isUploading, onUploadSuccess, onUploadError, t],
   );
 
   const handleDragOver = useCallback((e: React.DragEvent) => {

web/src/i18n/locales/en-US.ts

@@ -503,6 +503,8 @@ const enUS = {
       uploadSuccess: 'File uploaded successfully!',
       uploadError: 'File upload failed, please try again',
       uploadingFile: 'Uploading file...',
+      fileSizeExceeded:
+        'File size exceeds 10MB limit. Please split into smaller files.',
       actions: 'Actions',
       delete: 'Delete File',
       fileDeleteSuccess: 'File deleted successfully',

web/src/i18n/locales/ja-JP.ts

@@ -506,6 +506,8 @@ const jaJP = {
       uploadSuccess: 'ファイルのアップロードに成功しました！',
       uploadError: 'ファイルのアップロードに失敗しました。再度お試しください',
       uploadingFile: 'ファイルをアップロード中...',
+      fileSizeExceeded:
+        'ファイルサイズが10MBの制限を超えています。より小さいファイルに分割してください。',
       actions: 'アクション',
       delete: 'ドキュメントを削除',
       fileDeleteSuccess: 'ドキュメントの削除に成功しました',

web/src/i18n/locales/zh-Hans.ts

@@ -483,6 +483,7 @@ const zhHans = {
       uploadSuccess: '文件上传成功！',
       uploadError: '文件上传失败，请重试',
       uploadingFile: '上传文件中...',
+      fileSizeExceeded: '文件大小超过 10MB 限制，请分割成较小的文件后上传',
       actions: '操作',
       delete: '删除文件',
       fileDeleteSuccess: '文件删除成功',

web/src/i18n/locales/zh-Hant.ts

@@ -480,6 +480,7 @@ const zhHant = {
       uploadSuccess: '文檔上傳成功！',
       uploadError: '文檔上傳失敗，請重試',
       uploadingFile: '上傳文檔中...',
+      fileSizeExceeded: '檔案大小超過 10MB 限制，請分割成較小的檔案後上傳',
       actions: '操作',
       delete: '刪除文檔',
       fileDeleteSuccess: '文檔刪除成功',