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Running on Zero
| """Frame export (last-frame extraction from a generated video). | |
| `export_last_frame` is bound to the "Export Last Frame" button in the UI. | |
| It validates that the input path lies inside the managed task temp root or the | |
| legacy `/tmp/h3-outputs` directory, then runs ffmpeg to extract the final frame. | |
| This is the only place that exposes the disk to client-supplied paths; the | |
| path validation is intentionally strict. | |
| """ | |
| from __future__ import annotations | |
| import os | |
| import subprocess | |
| import tempfile | |
| import uuid | |
| import gradio as gr | |
| from task import _TASK_TEMP_ROOT | |
| def export_last_frame(video_path): | |
| """Extract the last frame from a generated video and return it as an image file. | |
| Path is validated to lie under the managed task/temp root; arbitrary client paths are rejected. | |
| Destination is unique per call. | |
| """ | |
| if not video_path: | |
| raise gr.Error("No video to extract from.") | |
| # Resolve and constrain to managed roots (task temp or legacy h3-outputs). | |
| try: | |
| resolved = os.path.realpath(video_path) | |
| except OSError: | |
| raise gr.Error("Invalid video path.") | |
| # Only managed task/output roots — never the bare system tempdir (symlink surface). | |
| allowed_roots = [ | |
| os.path.realpath(_TASK_TEMP_ROOT), | |
| os.path.realpath(os.path.join(tempfile.gettempdir(), "h3-outputs")), | |
| ] | |
| if not any(resolved == root or resolved.startswith(root + os.sep) for root in allowed_roots): | |
| raise gr.Error("Video path is outside the managed output area.") | |
| # Unique destination under the same parent or task intermediates. | |
| parent = os.path.dirname(resolved) | |
| out = os.path.join(parent, f"lastframe-{uuid.uuid4().hex[:12]}.png") | |
| result = subprocess.run( | |
| ["ffmpeg", "-sseof", "-0.1", "-i", resolved, "-frames:v", "1", "-y", out], | |
| capture_output=True, text=True, | |
| ) | |
| if result.returncode != 0: | |
| raise gr.Error(f"ffmpeg failed: {result.stderr[-300:]}") | |
| return out | |