diff --git a/wsme/utils.py b/wsme/utils.py
new file mode 100644
index 0000000..b2290e3
--- /dev/null
+++ b/wsme/utils.py
@@ -0,0 +1,75 @@
+import re
+import datetime
+
+date_re = r'(?P<year>-?\d{4,})-(?P<month>\d{2})-(?P<day>\d{2})'
+time_re = r'(?P<hour>\d{2}):(?P<min>\d{2}):(?P<sec>\d{2})' + \
+          r'(\.(?P<sec_frac>\d+))?'
+tz_re = r'((?P<tz_sign>[+-])(?P<tz_hour>\d{2}):(?P<tz_min>\d{2}))' + \
+        r'|(?P<tz_z>Z)'
+
+datetime_re = re.compile(
+    '%sT%s(%s)?' % (date_re, time_re, tz_re))
+date_re = re.compile(date_re)
+time_re = re.compile(time_re)
+
+
+def parse_isodate(value):
+    m = date_re.match(value)
+    if m is None:
+        raise validators.Invalid("%s is not a legal date value" % (value),
+                                 value, None)
+    try:
+        return datetime.date(
+            int(m.group('year')),
+            int(m.group('month')),
+            int(m.group('day')))
+    except ValueError, e:
+        raise validators.Invalid("%s is a out-of-range date" % (value),
+                                 value, None)
+
+
+def parse_isotime(value):
+    m = time_re.match(value)
+    if m is None:
+        raise validators.Invalid("%s is not a legal time value" % (value),
+                                 value, None)
+    try:
+        ms = 0
+        if m.group('sec_frac') is not None:
+            f = decimal.Decimal('0.' + m.group('sec_frac'))
+            f = str(f.quantize(decimal.Decimal('0.000001')))
+            ms = int(f[2:])
+        return datetime.time(
+            int(m.group('hour')),
+            int(m.group('min')),
+            int(m.group('sec')),
+            ms)
+    except ValueError, e:
+        raise validators.Invalid("%s is a out-of-range time" % (value),
+                                 value, None)
+
+
+# TODO handle timezone
+def parse_isodatetime(value):
+    m = datetime_re.match(value)
+    if m is None:
+        raise validators.Invalid("%s is not a legal datetime value" % (value),
+                                 value, None)
+    try:
+        ms = 0
+        if m.group('sec_frac') is not None:
+            f = decimal.Decimal('0.' + m.group('sec_frac'))
+            f = f.quantize(decimal.Decimal('0.000001'))
+            ms = int(str(f)[2:])
+        return datetime.datetime(
+            int(m.group('year')),
+            int(m.group('month')),
+            int(m.group('day')),
+            int(m.group('hour')),
+            int(m.group('min')),
+            int(m.group('sec')),
+            ms)
+    except ValueError, e:
+        raise validators.Invalid("%s is a out-of-range datetime" % (value),
+                                 value, None)
+