feat: file viewer added

webui/backend/app/api/routes_files.py

@@ -2,7 +2,7 @@ from __future__ import annotations
 
 from fastapi import APIRouter, Depends
 
-from backend.app.api.schemas import DeleteRequest, DeleteResponse, MkdirRequest, MkdirResponse, RenameRequest, RenameResponse
+from backend.app.api.schemas import DeleteRequest, DeleteResponse, MkdirRequest, MkdirResponse, RenameRequest, RenameResponse, ViewResponse
 from backend.app.dependencies import get_file_ops_service
 from backend.app.services.file_ops_service import FileOpsService
 
@@ -31,3 +31,11 @@ async def delete(
     service: FileOpsService = Depends(get_file_ops_service),
 ) -> DeleteResponse:
     return service.delete(path=request.path)
+
+
+@router.get("/view", response_model=ViewResponse)
+async def view(
+    path: str,
+    service: FileOpsService = Depends(get_file_ops_service),
+) -> ViewResponse:
+    return service.view(path=path)

webui/backend/app/api/schemas.py

@@ -58,6 +58,16 @@ class DeleteResponse(BaseModel):
     path: str
 
 
+class ViewResponse(BaseModel):
+    path: str
+    name: str
+    content_type: str
+    encoding: str
+    truncated: bool
+    size: int
+    content: str
+
+
 class TaskListItem(BaseModel):
     id: str
     operation: str

webui/backend/app/fs/filesystem_adapter.py

@@ -59,3 +59,17 @@ class FilesystemAdapter:
                 if on_progress:
                     on_progress(out_f.tell())
         shutil.copystat(src, dst, follow_symlinks=False)
+
+    def read_text_preview(self, path: Path, max_bytes: int, encoding: str = "utf-8") -> dict:
+        size = int(path.stat().st_size)
+        limit = max_bytes + 1
+        with path.open("rb") as in_f:
+            raw = in_f.read(limit)
+        truncated = size > max_bytes or len(raw) > max_bytes
+        if truncated:
+            raw = raw[:max_bytes]
+        return {
+            "size": size,
+            "truncated": truncated,
+            "content": raw.decode(encoding, errors="replace"),
+        }

webui/backend/app/services/file_ops_service.py

@@ -3,10 +3,27 @@ from __future__ import annotations
 from pathlib import Path
 
 from backend.app.api.errors import AppError
-from backend.app.api.schemas import DeleteResponse, MkdirResponse, RenameResponse
+from backend.app.api.schemas import DeleteResponse, MkdirResponse, RenameResponse, ViewResponse
 from backend.app.fs.filesystem_adapter import FilesystemAdapter
 from backend.app.security.path_guard import PathGuard
 
+TEXT_PREVIEW_MAX_BYTES = 256 * 1024
+TEXT_CONTENT_TYPES = {
+    ".txt": "text/plain",
+    ".log": "text/plain",
+    ".md": "text/markdown",
+    ".yml": "text/yaml",
+    ".yaml": "text/yaml",
+    ".json": "application/json",
+    ".js": "text/javascript",
+    ".css": "text/css",
+    ".html": "text/html",
+}
+SPECIAL_TEXT_FILENAMES = {
+    "dockerfile": "text/plain",
+    "containerfile": "text/plain",
+}
+
 
 class FileOpsService:
     def __init__(self, path_guard: PathGuard, filesystem: FilesystemAdapter):
@@ -129,6 +146,64 @@ class FileOpsService:
 
         return DeleteResponse(path=resolved_target.relative)
 
+    def view(self, path: str) -> ViewResponse:
+        resolved_target = self._path_guard.resolve_existing_path(path)
+
+        if resolved_target.absolute.is_dir():
+            raise AppError(
+                code="type_conflict",
+                message="Source must be a file",
+                status_code=409,
+                details={"path": resolved_target.relative},
+            )
+        if not resolved_target.absolute.is_file():
+            raise AppError(
+                code="type_conflict",
+                message="Unsupported path type for view",
+                status_code=409,
+                details={"path": resolved_target.relative},
+            )
+
+        content_type = self._content_type_for(resolved_target.absolute)
+        if content_type is None:
+            raise AppError(
+                code="unsupported_type",
+                message="File type is not supported for preview",
+                status_code=409,
+                details={"path": resolved_target.relative},
+            )
+
+        try:
+            preview = self._filesystem.read_text_preview(
+                resolved_target.absolute,
+                max_bytes=TEXT_PREVIEW_MAX_BYTES,
+                encoding="utf-8",
+            )
+        except OSError as exc:
+            raise AppError(
+                code="io_error",
+                message="Filesystem operation failed",
+                status_code=500,
+                details={"reason": str(exc)},
+            )
+
+        return ViewResponse(
+            path=resolved_target.relative,
+            name=resolved_target.absolute.name,
+            content_type=content_type,
+            encoding="utf-8",
+            truncated=preview["truncated"],
+            size=preview["size"],
+            content=preview["content"],
+        )
+
     @staticmethod
     def _join_relative(base: str, name: str) -> str:
         return f"{base}/{name}" if base else name
+
+    @staticmethod
+    def _content_type_for(path: Path) -> str | None:
+        special_name = SPECIAL_TEXT_FILENAMES.get(path.name.lower())
+        if special_name:
+            return special_name
+        return TEXT_CONTENT_TYPES.get(path.suffix.lower())

webui/backend/tests/golden/test_api_view_golden.py

@@ -0,0 +1,107 @@
+from __future__ import annotations
+
+import asyncio
+import sys
+import tempfile
+import unittest
+from pathlib import Path
+
+import httpx
+
+sys.path.insert(0, str(Path(__file__).resolve().parents[3]))
+
+from backend.app.dependencies import get_file_ops_service
+from backend.app.fs.filesystem_adapter import FilesystemAdapter
+from backend.app.main import app
+from backend.app.security.path_guard import PathGuard
+from backend.app.services.file_ops_service import FileOpsService
+
+
+class ViewApiGoldenTest(unittest.TestCase):
+    def setUp(self) -> None:
+        self.temp_dir = tempfile.TemporaryDirectory()
+        self.root = Path(self.temp_dir.name) / "root"
+        self.root.mkdir(parents=True, exist_ok=True)
+        path_guard = PathGuard({"storage1": str(self.root)})
+        service = FileOpsService(path_guard=path_guard, filesystem=FilesystemAdapter())
+
+        async def _override_file_ops_service() -> FileOpsService:
+            return service
+
+        app.dependency_overrides[get_file_ops_service] = _override_file_ops_service
+
+    def tearDown(self) -> None:
+        app.dependency_overrides.clear()
+        self.temp_dir.cleanup()
+
+    def _request(self, path: str) -> httpx.Response:
+        async def _run() -> httpx.Response:
+            transport = httpx.ASGITransport(app=app)
+            async with httpx.AsyncClient(transport=transport, base_url="http://testserver") as client:
+                return await client.get("/api/files/view", params={"path": path})
+
+        return asyncio.run(_run())
+
+    def test_view_supported_text_success(self) -> None:
+        file_path = self.root / "notes.md"
+        file_path.write_text("# title\nhello\n", encoding="utf-8")
+
+        response = self._request("storage1/notes.md")
+
+        self.assertEqual(response.status_code, 200)
+        self.assertEqual(
+            response.json(),
+            {
+                "path": "storage1/notes.md",
+                "name": "notes.md",
+                "content_type": "text/markdown",
+                "encoding": "utf-8",
+                "truncated": False,
+                "size": len("# title\nhello\n".encode("utf-8")),
+                "content": "# title\nhello\n",
+            },
+        )
+
+    def test_view_unsupported_type(self) -> None:
+        (self.root / "report.pdf").write_bytes(b"%PDF-1.4")
+
+        response = self._request("storage1/report.pdf")
+
+        self.assertEqual(response.status_code, 409)
+        self.assertEqual(response.json()["error"]["code"], "unsupported_type")
+
+    def test_view_directory_type_conflict(self) -> None:
+        (self.root / "docs").mkdir()
+
+        response = self._request("storage1/docs")
+
+        self.assertEqual(response.status_code, 409)
+        self.assertEqual(response.json()["error"]["code"], "type_conflict")
+
+    def test_view_path_not_found(self) -> None:
+        response = self._request("storage1/missing.txt")
+
+        self.assertEqual(response.status_code, 404)
+        self.assertEqual(response.json()["error"]["code"], "path_not_found")
+
+    def test_view_traversal_attempt(self) -> None:
+        response = self._request("storage1/../etc/passwd")
+
+        self.assertEqual(response.status_code, 403)
+        self.assertEqual(response.json()["error"]["code"], "path_traversal_detected")
+
+    def test_view_truncated_response_for_large_file(self) -> None:
+        content = "x" * (300 * 1024)
+        (self.root / "big.log").write_text(content, encoding="utf-8")
+
+        response = self._request("storage1/big.log")
+
+        self.assertEqual(response.status_code, 200)
+        body = response.json()
+        self.assertTrue(body["truncated"])
+        self.assertEqual(body["size"], len(content.encode("utf-8")))
+        self.assertEqual(len(body["content"]), 256 * 1024)
+
+
+if __name__ == "__main__":
+    unittest.main()

webui/backend/tests/golden/test_ui_smoke_golden.py

@@ -35,6 +35,8 @@ class UiSmokeGoldenTest(unittest.TestCase):
         self.assertIn('id="function-bar"', body)
         self.assertIn('id="view-btn"', body)
         self.assertIn('id="edit-btn"', body)
+        self.assertIn('id="viewer-modal"', body)
+        self.assertIn('id="viewer-content"', body)
         self.assertIn('id="mkdir-btn"', body)
         self.assertIn('id="copy-btn"', body)
         self.assertIn('id="move-btn"', body)