✨ Make get and first cache keys match

Previously, the cache key generated for get() and first() were different
because the names of the dictionary key containing the parms to bind
where different ('id' if get, 'param' if first).

This change injects the bound params into the query and then hashes
that.

The purpose for this change, was that previously, it was impossible to
invalidate cache for a get() or get_or_404().

Author: bbelyeu

flask_sqlalchemy_caching/core.py

@@ -44,8 +44,8 @@ def __iter__(self):
         the items in the cache are not the same ones in the current Session.
         """
         if hasattr(self, '_cache'):
-            func = lambda: list(BaseQuery.__iter__(self))
-            return iter(self.get_value(createfunc=func))
+            def create_func(): return list(BaseQuery.__iter__(self))
+            return iter(self.get_value(createfunc=create_func))
         else:
             return BaseQuery.__iter__(self)
 
@@ -98,21 +98,15 @@ def key_from_query(self, qualifier=None):
         Given a Query, create a cache key.
 
         There are many approaches to this; here we use the simplest, which is
-        to create an md5 hash of the text of the SQL statement, combined with
-        stringified versions of all the bound parameters within it.
+        to create an md5 hash of the text of the SQL statement compiled with
+        the bound parameters in it.
 
         There's a bit of a performance hit with compiling out "query.statement"
         here; other approaches include setting up an explicit cache key with a
         particular Query, then combining that with the bound parameter values.
         """
         stmt = self.with_labels().statement
-        compiled = stmt.compile()
-        params = compiled.params
-
-        values = [str(compiled)]
-        for k in sorted(params):
-            values.append(repr(params[k]))
-        key = u" ".join(values)
+        key = str(stmt.compile(compile_kwargs={'literal_binds': True}))
         return md5(key.encode('utf8')).hexdigest()