feat(workspace): jsonl text preview and Files tab load stability

flocks/server/routes/workspace.py

@@ -57,6 +57,7 @@
 # Upload size limit read at request time so env-var changes take effect
 # without restarting the process.
 _DEFAULT_MAX_UPLOAD_MB = 100
+_DEFAULT_MAX_READ_BYTES = 2 * 1024 * 1024
 _ALLOWED_UPLOAD_EXTENSIONS = {
     ".txt", ".md", ".json", ".yaml", ".yml", ".xml", ".csv",
     ".pdf", ".doc", ".docx", ".html", ".htm", ".ppt", ".pptx", ".xls", ".xlsx",
@@ -68,6 +69,10 @@ def _max_upload_bytes() -> int:
     return int(os.getenv("FLOCKS_WORKSPACE_MAX_UPLOAD_MB", str(_DEFAULT_MAX_UPLOAD_MB))) * 1024 * 1024
 
 
+def _max_read_bytes() -> int:
+    return int(os.getenv("FLOCKS_WORKSPACE_MAX_READ_BYTES", str(_DEFAULT_MAX_READ_BYTES)))
+
+
 # ─── helpers ────────────────────────────────────────────────────────────────
 
 def _get_manager() -> WorkspaceManager:
@@ -144,6 +149,16 @@ def _dir_stats_sync(root: Path):
     return file_count, dir_count, total_size
 
 
+def _read_text_preview_sync(path: Path, max_bytes: int) -> tuple[str, bool]:
+    """Read at most ``max_bytes`` from a text file for safe preview."""
+    with path.open("rb") as handle:
+        data = handle.read(max_bytes + 1)
+    truncated = len(data) > max_bytes
+    if truncated:
+        data = data[:max_bytes]
+    return data.decode("utf-8", errors="replace"), truncated
+
+
 # ─── directory operations ───────────────────────────────────────────────────
 
 @router.get("/tree", response_model=WorkspaceNode, summary="List directory tree")
@@ -314,11 +329,22 @@ async def read_file(
             status_code=400,
             detail="Binary file — use /download endpoint instead",
         )
+    max_read_bytes = _max_read_bytes()
     try:
-        content = target.read_text(encoding="utf-8", errors="replace")
+        content, truncated = await asyncio.to_thread(
+            _read_text_preview_sync,
+            target,
+            max_read_bytes,
+        )
     except Exception as e:
         raise HTTPException(status_code=500, detail=str(e))
-    return {"path": path, "content": content}
+    return {
+        "path": path,
+        "content": content,
+        "truncated": truncated,
+        "size": target.stat().st_size,
+        "preview_limit_bytes": max_read_bytes,
+    }
 
 
 class FileWriteRequest(BaseModel):
@@ -470,11 +496,22 @@ async def read_memory_file(
         raise HTTPException(status_code=404, detail=f"Memory file not found: {path}")
     if not target.is_file():
         raise HTTPException(status_code=400, detail=f"Not a file: {path}")
+    max_read_bytes = _max_read_bytes()
     try:
-        content = target.read_text(encoding="utf-8", errors="replace")
+        content, truncated = await asyncio.to_thread(
+            _read_text_preview_sync,
+            target,
+            max_read_bytes,
+        )
     except Exception as e:
         raise HTTPException(status_code=500, detail=str(e))
-    return {"path": path, "content": content}
+    return {
+        "path": path,
+        "content": content,
+        "truncated": truncated,
+        "size": target.stat().st_size,
+        "preview_limit_bytes": max_read_bytes,
+    }
 
 
 # ─── stats ──────────────────────────────────────────────────────────────────

flocks/workspace/manager.py

@@ -24,7 +24,7 @@
 # Note: dotfiles like .gitignore have suffix='' in Python, so they are NOT
 # matched here; they will fall through to the binary-file path (download only).
 TEXT_EXTENSIONS = {
-    ".md", ".txt", ".log", ".json", ".yaml", ".yml",
+    ".md", ".txt", ".log", ".json", ".jsonl", ".yaml", ".yml",
     ".toml", ".ini", ".cfg", ".py", ".js", ".ts",
     ".sh", ".bash", ".csv", ".xml", ".html", ".css",
     ".tsx", ".jsx", ".env",

tests/workspace/test_workspace_manager.py

@@ -151,6 +151,7 @@ class TestIsTextFile:
         ("notes.txt", True),
         ("server.log", True),
         ("config.json", True),
+        ("events.jsonl", True),
         ("settings.yaml", True),
         ("settings.yml", True),
         ("pyproject.toml", True),

tests/workspace/test_workspace_routes.py

@@ -344,6 +344,29 @@ def test_read_text_file(self, workspace_client):
         assert data["path"] == "outputs/note.md"
         assert data["content"] == "# Hello\nWorld"
 
+    def test_read_jsonl_file(self, workspace_client):
+        ws = _ws(workspace_client)
+        (ws / "outputs" / "events.jsonl").write_text('{"id": 1}\n{"id": 2}\n')
+        r = _client(workspace_client).get("/api/workspace/file?path=outputs/events.jsonl")
+        assert r.status_code == 200
+        data = r.json()
+        assert data["path"] == "outputs/events.jsonl"
+        assert data["content"] == '{"id": 1}\n{"id": 2}\n'
+        assert data["truncated"] is False
+
+    def test_read_large_text_file_returns_truncated_preview(self, workspace_client, monkeypatch):
+        monkeypatch.setenv("FLOCKS_WORKSPACE_MAX_READ_BYTES", "10")
+        ws = _ws(workspace_client)
+        (ws / "outputs" / "large.jsonl").write_text("0123456789ABCDEF", encoding="utf-8")
+        r = _client(workspace_client).get("/api/workspace/file?path=outputs/large.jsonl")
+        assert r.status_code == 200
+        data = r.json()
+        assert data["path"] == "outputs/large.jsonl"
+        assert data["content"] == "0123456789"
+        assert data["truncated"] is True
+        assert data["size"] == 16
+        assert data["preview_limit_bytes"] == 10
+
     def test_read_nonexistent_returns_404(self, workspace_client):
         r = _client(workspace_client).get("/api/workspace/file?path=ghost.txt")
         assert r.status_code == 404
@@ -545,6 +568,19 @@ def test_read_memory_file(self, workspace_client):
         data = r.json()
         assert data["path"] == "MEMORY.md"
         assert "Key facts" in data["content"]
+        assert data["truncated"] is False
+
+    def test_read_large_memory_file_returns_truncated_preview(self, workspace_client, monkeypatch):
+        monkeypatch.setenv("FLOCKS_WORKSPACE_MAX_READ_BYTES", "8")
+        mem = _mem(workspace_client)
+        (mem / "large.md").write_text("abcdefghijk", encoding="utf-8")
+        r = _client(workspace_client).get("/api/workspace/memory/file?path=large.md")
+        assert r.status_code == 200
+        data = r.json()
+        assert data["content"] == "abcdefgh"
+        assert data["truncated"] is True
+        assert data["size"] == 11
+        assert data["preview_limit_bytes"] == 8
 
     def test_read_memory_nonexistent_returns_404(self, workspace_client):
         r = _client(workspace_client).get("/api/workspace/memory/file?path=ghost.md")

webui/src/api/workspace.ts

@@ -30,6 +30,14 @@ export interface UploadResult {
   error?: string;
 }
 
+export interface WorkspaceFileContentResponse {
+  path: string;
+  content: string;
+  truncated?: boolean;
+  size?: number;
+  preview_limit_bytes?: number;
+}
+
 export type UploadPurpose = 'chat';
 
 // ─── API ───────────────────────────────────────────────────────────────────
@@ -66,7 +74,7 @@ export const workspaceAPI = {
   },
 
   readFile: (path: string) =>
-    client.get<{ path: string; content: string }>('/api/workspace/file', { params: { path } }),
+    client.get<WorkspaceFileContentResponse>('/api/workspace/file', { params: { path } }),
 
   writeFile: (path: string, content: string) =>
     client.put<{ path: string; written: boolean }>('/api/workspace/file', { path, content }),
@@ -92,7 +100,7 @@ export const workspaceAPI = {
     client.get<WorkspaceNode[]>('/api/workspace/memory/list'),
 
   readMemoryFile: (path: string) =>
-    client.get<{ path: string; content: string }>('/api/workspace/memory/file', { params: { path } }),
+    client.get<WorkspaceFileContentResponse>('/api/workspace/memory/file', { params: { path } }),
 
   // Stats
   stats: () =>
@@ -118,7 +126,7 @@ export function fileIcon(node: WorkspaceNode): string {
   if (node.type === 'directory') return '📁';
   const ext = node.name.split('.').pop()?.toLowerCase() ?? '';
   const map: Record<string, string> = {
-    md: '📝', txt: '📄', log: '📋', json: '🔧', yaml: '🔧', yml: '🔧',
+    md: '📝', txt: '📄', log: '📋', json: '🔧', jsonl: '🔧', yaml: '🔧', yml: '🔧',
     py: '🐍', js: '🟨', ts: '🔷', tsx: '🔷', jsx: '🟨',
     sh: '⚙️', bash: '⚙️', csv: '📊', pdf: '📕', png: '🖼️',
     jpg: '🖼️', jpeg: '🖼️', gif: '🖼️', zip: '🗜️', tar: '🗜️', gz: '🗜️',

webui/src/locales/en-US/workspace.json

@@ -26,6 +26,7 @@
     "close": "Close",
     "uploading": "Uploading...",
     "binaryPreview": "Binary files cannot be previewed",
+    "truncatedPreview": "This file is large, so only the first {{limit}} is previewed. Inline editing is disabled to avoid saving truncated content; download the file for the full contents.",
     "downloadFile": "Download File",
     "toast": {
       "loadDirFailed": "Failed to load directory",

webui/src/locales/zh-CN/workspace.json

@@ -26,6 +26,7 @@
     "close": "关闭",
     "uploading": "上传中...",
     "binaryPreview": "二进制文件无法预览",
+    "truncatedPreview": "文件较大，当前仅预览前 {{limit}} 内容。为避免误保存截断内容，已禁用在线编辑；如需完整内容请下载文件。",
     "downloadFile": "下载文件",
     "toast": {
       "loadDirFailed": "加载目录失败",