Use symlinks for demo workspace files on Linux

On Linux, create symlinks instead of copying files when setting up
demo workspaces. This improves efficiency by saving disk space and
reducing setup time. Directory structure is still created normally
to allow users to add files without affecting the original demo data.

Author: claude

src/common/common.py

@@ -116,10 +116,34 @@ def find_demo_workspace_path(demo_name: str) -> Path | None:
     return None
 
 
+def _symlink_tree(source: Path, target: Path) -> None:
+    """
+    Recursively create directory structure and symlink files from source to target.
+
+    Creates real directories but symlinks individual files, allowing users to
+    add new files to workspace directories without affecting the original.
+
+    Args:
+        source: Source directory path.
+        target: Target directory path.
+    """
+    target.mkdir(parents=True, exist_ok=True)
+    for item in source.iterdir():
+        target_item = target / item.name
+        if item.is_dir():
+            _symlink_tree(item, target_item)
+        else:
+            # Create symlink to the source file
+            target_item.symlink_to(item.resolve())
+
+
 def copy_demo_workspace(demo_name: str, target_path: Path) -> bool:
     """
     Copy a demo workspace to the target path.
 
+    On Linux, creates symlinks to demo files instead of copying them.
+    On other platforms, copies files normally.
+
     Searches all configured source directories for the demo (first match wins).
 
     Args:
@@ -137,7 +161,12 @@ def copy_demo_workspace(demo_name: str, target_path: Path) -> bool:
     try:
         if target_path.exists():
             shutil.rmtree(target_path)
-        shutil.copytree(demo_path, target_path)
+
+        # Use symlinks on Linux for efficiency
+        if OS_PLATFORM == "linux":
+            _symlink_tree(demo_path, target_path)
+        else:
+            shutil.copytree(demo_path, target_path)
         return True
     except Exception:
         return False
@@ -567,15 +596,24 @@ def change_workspace():
                         if st.button("Load Demo Data"):
                             demo_path = find_demo_workspace_path(selected_demo)
                             if demo_path:
-                                # Copy demo files to current workspace
+                                # Link or copy demo files to current workspace
                                 for item in demo_path.iterdir():
                                     target = st.session_state.workspace / item.name
                                     if item.is_dir():
                                         if target.exists():
                                             shutil.rmtree(target)
-                                        shutil.copytree(item, target)
+                                        # Use symlinks on Linux for efficiency
+                                        if OS_PLATFORM == "linux":
+                                            _symlink_tree(item, target)
+                                        else:
+                                            shutil.copytree(item, target)
                                     else:
-                                        shutil.copy2(item, target)
+                                        if target.exists():
+                                            target.unlink()
+                                        if OS_PLATFORM == "linux":
+                                            target.symlink_to(item.resolve())
+                                        else:
+                                            shutil.copy2(item, target)
                                 st.success(f"Demo data '{selected_demo}' loaded!")
                                 time.sleep(1)
                                 st.rerun()

src/fileupload.py

@@ -3,7 +3,7 @@
 
 import streamlit as st
 
-from src.common.common import reset_directory
+from src.common.common import reset_directory, OS_PLATFORM
 
 
 @st.cache_data
@@ -73,16 +73,24 @@ def load_example_mzML_files() -> None:
     """
     Copies example mzML files to the mzML directory.
 
+    On Linux, creates symlinks to example files instead of copying them.
+
     Args:
         None
 
     Returns:
         None
     """
     mzML_dir = Path(st.session_state.workspace, "mzML-files")
-    # Copy files from example-data/mzML to workspace mzML directory, add to selected files
+    # Copy or symlink files from example-data/mzML to workspace mzML directory
     for f in Path("example-data", "mzML").glob("*.mzML"):
-        shutil.copy(f, mzML_dir)
+        target = mzML_dir / f.name
+        if OS_PLATFORM == "linux":
+            if target.exists():
+                target.unlink()
+            target.symlink_to(f.resolve())
+        else:
+            shutil.copy(f, mzML_dir)
     st.success("Example mzML files loaded!")