Use md5 hash

* added a test to check if different arguments returned different cache
hits

* added a test for TypeErrors from Workplane arguments

Author: marcus7070

plugins/cq_cache/cq_cache.py

@@ -9,6 +9,8 @@
 from OCP.BRepTools import BRepTools
 from OCP.BRep import BRep_Builder
 from OCP.TopoDS import TopoDS_Shape
+from itertools import chain
+import hashlib
 
 
 TEMPDIR_PATH = tempfile.gettempdir()
@@ -74,24 +76,19 @@ def build_file_name(fct, *args, **kwargs):
     Returns a file name given the specified function and args.
     If the function and the args are the same this function returns the same filename
     """
-    SPACER = "_"
-    file_name = fct.__name__
-    for arg in args:
-        if isinstance(arg, cq.Workplane):
-            raise TypeError(
-                "Can not cache a function that accepts Workplane objects as argument"
-            )
-        file_name += SPACER + str(hash(arg))
-    for kwarg_value in kwargs.values():
-        if isinstance(kwarg_value, cq.Workplane):
-            raise TypeError(
-                "Can not cache a function that accepts Workplane objects as argument"
-            )
-        file_name += SPACER + str(hash(kwarg_value))
-    file_name = bytes(file_name, "utf-8")
-    return base64.urlsafe_b64encode(file_name).decode(
-        "utf-8"
-    )  # compacts the long string of hash ints into a urlsafe string
+    if cq.Workplane in (type(x) for x in chain(args, kwargs.values())):
+        raise TypeError(
+            "Can not cache a function that accepts Workplane objects as argument"
+        )
+
+    # hash all relevant variables
+    hasher = hashlib.md5()
+    for val in [fct.__name__, args.__repr__(), kwargs.__repr__()]:
+        hasher.update(bytes(val, "utf-8"))
+    # encode the hash as a filesystem safe string
+    filename = base64.urlsafe_b64encode(hasher.digest()).decode("utf-8")
+    # strip the padding
+    return filename.rstrip("=")
 
 
 def clear_cq_cache():

tests/test_cq_cache.py

@@ -3,6 +3,7 @@
 from plugins.cq_cache.cq_cache import cq_cache, clear_cq_cache, get_cache_dir_size
 import tempfile
 import os
+import pytest
 
 TEMPDIR_PATH = tempfile.gettempdir()
 CACHE_DIR_NAME = "cadquery_geom_cache"
@@ -38,8 +39,17 @@ def test_cache_file_creation():
     cube2 = cube(1, 1, 1)
     files = os.listdir(CACHE_DIR_PATH)
     assert len(files) == 2
-    assert "Y3ViZV8xXzFfMQ==.brep" in files
-    assert "Y3ViZV8xXzFfMQ==" in files
+    assert "Fv2MB2hDeoH6xwu4aBh5wA.brep" in files
+    assert "Fv2MB2hDeoH6xwu4aBh5wA" in files
+
+
+def test_cache_unique():
+    clear_cq_cache()
+    for _ in range(2):
+        cube1 = cube(1, 1, 1)
+        cube2 = cube(2, 2, 2)
+    assert cube1.BoundingBox().zlen == pytest.approx(1)
+    assert cube2.BoundingBox().zlen == pytest.approx(2)
 
 
 def test_not_exceeding_size():
@@ -78,3 +88,15 @@ def cube(a, b, c):
     cube4 = cube(1, 1, 1)
     assert isinstance(cube3, cq.Solid)
     assert isinstance(cube4, cq.Solid)
+
+
+def test_workplane_typeerror():
+    @cq_cache(CACHE_SIZE)
+    def wp(a, kwarg=None):
+        return a
+
+    with pytest.raises(TypeError):
+        wp(cq.Workplane())
+
+    with pytest.raises(TypeError):
+        wp(1, kwarg=cq.Workplane())