Create gallery_history.py

gallery_history.py

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+"""
+How to use:
+1. Create a Space with a Persistent Storage attached. Filesystem will be available under `/data`.
+2. Add `hf_oauth: true` to the Space metadata (README.md). Make sure to have Gradio>=3.41.0 configured.
+3. Add `HISTORY_FOLDER` as a Space variable (example. `"/data/history"`).
+4. Add `filelock` as dependency in `requirements.txt`.
+5. Add history gallery to your Gradio app:
+    a. Add imports: `from gallery_history import fetch_gallery_history, show_gallery_history`
+    a. Add `history = show_gallery_history()` within `gr.Blocks` context.
+    b. Add `.then(fn=fetch_gallery_history, inputs=[prompt, result], outputs=history)` on the generate event.
+"""
+import json
+import os
+import numpy as np
+import shutil
+from pathlib import Path
+from PIL import Image
+from typing import Dict, List, Optional, Tuple
+from uuid import uuid4
+
+import gradio as gr
+from filelock import FileLock
+
+_folder = os.environ.get("HISTORY_FOLDER")
+if _folder is None:
+    print(
+        "'HISTORY_FOLDER' environment variable not set. User history will be saved "
+        "locally and will be lost when the Space instance is restarted."
+    )
+    _folder = Path(__file__).parent / "history"
+HISTORY_FOLDER_PATH = Path(_folder)
+
+IMAGES_FOLDER_PATH = HISTORY_FOLDER_PATH / "images"
+IMAGES_FOLDER_PATH.mkdir(parents=True, exist_ok=True)
+
+
+def show_gallery_history():
+    gr.Markdown(
+        "## Your past generations\n\n(Log in to keep a gallery of your previous generations."
+        " Your history will be saved and available on your next visit.)"
+    )
+    with gr.Column():
+        with gr.Row():
+            gr.LoginButton(min_width=250)
+            gr.LogoutButton(min_width=250)
+        gallery = gr.Gallery(
+            label="Past images",
+            show_label=True,
+            elem_id="gallery",
+            object_fit="contain",
+            columns=3,
+            height=300,
+            preview=False,
+            show_share_button=False,
+            show_download_button=False,
+        )
+        gr.Markdown(
+            "Make sure to save your images from time to time, this gallery may be deleted in the future."
+        )
+        gallery.attach_load_event(fetch_gallery_history, every=None)
+        return gallery
+
+
+def fetch_gallery_history(
+    prompt: Optional[str] = None,
+    result: Optional[np.ndarray] = None,
+    user: Optional[gr.OAuthProfile] = None,
+):
+    if user is None:
+        return []
+    try:
+        if prompt is not None and result is not None:  # None values means no new images
+            new_image = Image.fromarray(result, 'RGB')
+            return _update_user_history(user["preferred_username"], new_image, prompt)
+        else:
+            return _read_user_history(user["preferred_username"])
+    except Exception as e:
+        raise gr.Error(f"Error while fetching history: {e}") from e
+
+
+####################
+# Internal helpers #
+####################
+
+
+def _read_user_history(username: str) -> List[Tuple[str, str]]:
+    """Return saved history for that user."""
+    with _user_lock(username):
+        path = _user_history_path(username)
+        if path.exists():
+            return json.loads(path.read_text())
+        return []  # No history yet
+
+
+def _update_user_history(
+    username: str, new_image: Image.Image, prompt: str
+) -> List[Tuple[str, str]]:
+    """Update history for that user and return it."""
+    with _user_lock(username):
+        # Read existing
+        path = _user_history_path(username)
+        if path.exists():
+            images = json.loads(path.read_text())
+        else:
+            images = []  # No history yet
+
+        # Copy image to persistent folder
+        images = [(_copy_image(new_image), prompt)] + images
+
+        # Save and return
+        path.write_text(json.dumps(images))
+        return images
+
+
+def _user_history_path(username: str) -> Path:
+    return HISTORY_FOLDER_PATH / f"{username}.json"
+
+
+def _user_lock(username: str) -> FileLock:
+    """Ensure history is not corrupted if concurrent calls."""
+    return FileLock(f"{_user_history_path(username)}.lock")
+
+
+def _copy_image(new_image: Image.Image) -> str:
+    """Copy image to the persistent storage."""
+    dst = str(IMAGES_FOLDER_PATH / f"{uuid4().hex}.png")
+    new_image.save(dst)
+    return dst