1 files changed, 88 insertions, 0 deletions
diff --git a/boto/dynamodb/types.py b/boto/dynamodb/types.py
new file mode 100644
index 00000000..723d33d8
--- /dev/null
+++ b/boto/dynamodb/types.py
@@ -0,0 +1,88 @@
+# Copyright (c) 2011 Mitch Garnaat http://garnaat.org/
+# Copyright (c) 2011 Amazon.com, Inc. or its affiliates.  All Rights Reserved
+#
+# Permission is hereby granted, free of charge, to any person obtaining a
+# copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish, dis-
+# tribute, sublicense, and/or sell copies of the Software, and to permit
+# persons to whom the Software is furnished to do so, subject to the fol-
+# lowing conditions:
+#
+# The above copyright notice and this permission notice shall be included
+# in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABIL-
+# ITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+# SHALL THE AUTHOR BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, 
+# WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+# IN THE SOFTWARE.
+#
+"""
+Some utility functions to deal with mapping Amazon DynamoDB types to
+Python types and vice-versa.
+"""
+
+def is_num(n):
+    return isinstance(n, (int, long, float, bool))
+
+def is_str(n):
+    return isinstance(n, basestring)
+
+def convert_num(s):
+    if '.' in s:
+        n = float(s)
+    else:
+        n = int(s)
+    return n
+
+def get_dynamodb_type(val):
+    """
+    Take a scalar Python value and return a string representing
+    the corresponding Amazon DynamoDB type.  If the value passed in is
+    not a supported type, raise a TypeError.
+    """
+    dynamodb_type = None
+    if is_num(val):
+        dynamodb_type = 'N'
+    elif is_str(val):
+        dynamodb_type = 'S'
+    elif isinstance(val, (set, frozenset)):
+        if False not in map(is_num, val):
+            dynamodb_type = 'NS'
+        elif False not in map(is_str, val):
+            dynamodb_type = 'SS'
+    if dynamodb_type is None:
+        raise TypeError('Unsupported type "%s" for value "%s"' % (type(val), val))
+    return dynamodb_type
+
+def dynamize_value(val):
+    """
+    Take a scalar Python value and return a dict consisting
+    of the Amazon DynamoDB type specification and the value that
+    needs to be sent to Amazon DynamoDB.  If the type of the value
+    is not supported, raise a TypeError
+    """
+    def _str(val):
+        """
+        DynamoDB stores booleans as numbers. True is 1, False is 0.
+        This function converts Python booleans into DynamoDB friendly
+        representation.
+        """
+        if isinstance(val, bool):
+            return str(int(val))
+        return str(val)
+
+    dynamodb_type = get_dynamodb_type(val)
+    if dynamodb_type == 'N':
+        val = {dynamodb_type : _str(val)}
+    elif dynamodb_type == 'S':
+        val = {dynamodb_type : val}
+    elif dynamodb_type == 'NS':
+        val = {dynamodb_type : [ str(n) for n in val]}
+    elif dynamodb_type == 'SS':
+        val = {dynamodb_type : [ n for n in val]}
+    return val
+