🐛 fix(cache/manager.py): change CACHE variable to _cache to follow naming conventions

✨ feat(cache/utils.py): add support for clearing old cache files and memoization of dictionary functions
The CACHE variable in CacheManager class has been renamed to _cache to follow naming conventions. The utils.py module now supports clearing old cache files and memoization of dictionary functions. The clear_old_cache_files function removes old cache files if the number of cache files exceeds the max_cache_size. The memoize_dict decorator memoizes dictionary functions and clears the cache when the clear_cache method is called.

src/backend/langflow/cache/manager.py

@@ -54,7 +54,7 @@ class CacheManager(Subject):
 
     def __init__(self):
         super().__init__()
-        self.CACHE = {}
+        self._cache = {}
         self.current_client_id = None
         self.current_cache = {}
 
@@ -68,12 +68,12 @@ class CacheManager(Subject):
         """
         previous_client_id = self.current_client_id
         self.current_client_id = client_id
-        self.current_cache = self.CACHE.setdefault(client_id, {})
+        self.current_cache = self._cache.setdefault(client_id, {})
         try:
             yield
         finally:
             self.current_client_id = previous_client_id
-            self.current_cache = self.CACHE.get(self.current_client_id, {})
+            self.current_cache = self._cache.get(self.current_client_id, {})
 
     def add(self, name: str, obj: Any, obj_type: str, extension: Optional[str] = None):
         """

src/backend/langflow/cache/utils.py

@@ -0,0 +1,154 @@
+import base64
+import contextlib
+import functools
+import hashlib
+import json
+import os
+import tempfile
+from collections import OrderedDict
+from pathlib import Path
+from typing import Any, Dict
+
+import dill  # type: ignore
+
+CACHE: Dict[str, Any] = {}
+
+
+def create_cache_folder(func):
+    def wrapper(*args, **kwargs):
+        # Get the destination folder
+        cache_path = Path(tempfile.gettempdir()) / PREFIX
+
+        # Create the destination folder if it doesn't exist
+        os.makedirs(cache_path, exist_ok=True)
+
+        return func(*args, **kwargs)
+
+    return wrapper
+
+
+def memoize_dict(maxsize=128):
+    cache = OrderedDict()
+
+    def decorator(func):
+        @functools.wraps(func)
+        def wrapper(*args, **kwargs):
+            hashed = compute_dict_hash(args[0])
+            key = (func.__name__, hashed, frozenset(kwargs.items()))
+            if key not in cache:
+                result = func(*args, **kwargs)
+                cache[key] = result
+                if len(cache) > maxsize:
+                    cache.popitem(last=False)
+            else:
+                result = cache[key]
+            return result
+
+        def clear_cache():
+            cache.clear()
+
+        wrapper.clear_cache = clear_cache  # type: ignore
+        wrapper.cache = cache  # type: ignore
+        return wrapper
+
+    return decorator
+
+
+PREFIX = "langflow_cache"
+
+
+@create_cache_folder
+def clear_old_cache_files(max_cache_size: int = 3):
+    cache_dir = Path(tempfile.gettempdir()) / PREFIX
+    cache_files = list(cache_dir.glob("*.dill"))
+
+    if len(cache_files) > max_cache_size:
+        cache_files_sorted_by_mtime = sorted(
+            cache_files, key=lambda x: x.stat().st_mtime, reverse=True
+        )
+
+        for cache_file in cache_files_sorted_by_mtime[max_cache_size:]:
+            with contextlib.suppress(OSError):
+                os.remove(cache_file)
+
+
+def compute_dict_hash(graph_data):
+    graph_data = filter_json(graph_data)
+
+    cleaned_graph_json = json.dumps(graph_data, sort_keys=True)
+    return hashlib.sha256(cleaned_graph_json.encode("utf-8")).hexdigest()
+
+
+def filter_json(json_data):
+    filtered_data = json_data.copy()
+
+    # Remove 'viewport' and 'chatHistory' keys
+    if "viewport" in filtered_data:
+        del filtered_data["viewport"]
+    if "chatHistory" in filtered_data:
+        del filtered_data["chatHistory"]
+
+    # Filter nodes
+    if "nodes" in filtered_data:
+        for node in filtered_data["nodes"]:
+            if "position" in node:
+                del node["position"]
+            if "positionAbsolute" in node:
+                del node["positionAbsolute"]
+            if "selected" in node:
+                del node["selected"]
+            if "dragging" in node:
+                del node["dragging"]
+
+    return filtered_data
+
+
+@create_cache_folder
+def save_binary_file(content: str, file_name: str, accepted_types: list[str]) -> str:
+    """
+    Save a binary file to the specified folder.
+
+    Args:
+        content: The content of the file as a bytes object.
+        file_name: The name of the file, including its extension.
+
+    Returns:
+        The path to the saved file.
+    """
+    if not any(file_name.endswith(suffix) for suffix in accepted_types):
+        raise ValueError(f"File {file_name} is not accepted")
+
+    # Get the destination folder
+    cache_path = Path(tempfile.gettempdir()) / PREFIX
+    if not content:
+        raise ValueError("Please, reload the file in the loader.")
+    data = content.split(",")[1]
+    decoded_bytes = base64.b64decode(data)
+
+    # Create the full file path
+    file_path = os.path.join(cache_path, file_name)
+
+    # Save the binary content to the file
+    with open(file_path, "wb") as file:
+        file.write(decoded_bytes)
+
+    return file_path
+
+
+@create_cache_folder
+def save_cache(hash_val: str, chat_data, clean_old_cache_files: bool):
+    cache_path = Path(tempfile.gettempdir()) / PREFIX / f"{hash_val}.dill"
+    with cache_path.open("wb") as cache_file:
+        dill.dump(chat_data, cache_file)
+
+    if clean_old_cache_files:
+        clear_old_cache_files()
+
+
+@create_cache_folder
+def load_cache(hash_val):
+    cache_path = Path(tempfile.gettempdir()) / PREFIX / f"{hash_val}.dill"
+    if cache_path.exists():
+        with cache_path.open("rb") as cache_file:
+            return dill.load(cache_file)
+    return None