Replace float with Decimal

Having float type as a base type for floating point parameters in
ipalib introduces several issues, e.g. problem with representation
or value comparison. Python language provides a Decimal type which
help overcome these issues.

This patch replaces a float type and Float parameter with a
decimal.Decimal type in Decimal parameter. A precision attribute
was added to Decimal parameter that can be used to limit a number
of decimal places in parameter representation. This approach fixes
a problem with API.txt validation where comparison of float values
may fail on different architectures due to float representation error.

In order to safely transfer the parameter value over RPC it is
being converted to string which is then converted back to
decimal.Decimal number on a server side.

https://fedorahosted.org/freeipa/ticket/2260

11 files changed, 160 insertions, 88 deletions

diff --git a/API.txt b/API.txt
index 9048231b..2937c24f 100644
--- a/API.txt
+++ b/API.txt
@@ -654,16 +654,16 @@ option: Str('kx_part_exchanger', attribute=False, cli_name='kx_exchanger', multi
 option: LOCRecord('locrecord', attribute=True, cli_name='loc_rec', csv=True, multivalue=True, option_group=u'LOC Record', required=False)
 option: Int('loc_part_lat_deg', attribute=False, cli_name='loc_lat_deg', maxvalue=90, minvalue=0, multivalue=False, option_group=u'LOC Record', required=False)
 option: Int('loc_part_lat_min', attribute=False, cli_name='loc_lat_min', maxvalue=59, minvalue=0, multivalue=False, option_group=u'LOC Record', required=False)
-option: Float('loc_part_lat_sec', attribute=False, cli_name='loc_lat_sec', maxvalue=59.999, minvalue=0.0, multivalue=False, option_group=u'LOC Record', required=False)
+option: Decimal('loc_part_lat_sec', attribute=False, cli_name='loc_lat_sec', maxvalue=Decimal('59.999'), minvalue=Decimal('0.0'), multivalue=False, option_group=u'LOC Record', precision=3, required=False)
 option: StrEnum('loc_part_lat_dir', attribute=False, cli_name='loc_lat_dir', multivalue=False, option_group=u'LOC Record', required=False, values=(u'N', u'S'))
 option: Int('loc_part_lon_deg', attribute=False, cli_name='loc_lon_deg', maxvalue=180, minvalue=0, multivalue=False, option_group=u'LOC Record', required=False)
 option: Int('loc_part_lon_min', attribute=False, cli_name='loc_lon_min', maxvalue=59, minvalue=0, multivalue=False, option_group=u'LOC Record', required=False)
-option: Float('loc_part_lon_sec', attribute=False, cli_name='loc_lon_sec', maxvalue=59.999, minvalue=0.0, multivalue=False, option_group=u'LOC Record', required=False)
+option: Decimal('loc_part_lon_sec', attribute=False, cli_name='loc_lon_sec', maxvalue=Decimal('59.999'), minvalue=Decimal('0.0'), multivalue=False, option_group=u'LOC Record', precision=3, required=False)
 option: StrEnum('loc_part_lon_dir', attribute=False, cli_name='loc_lon_dir', multivalue=False, option_group=u'LOC Record', required=False, values=(u'E', u'W'))
-option: Float('loc_part_altitude', attribute=False, cli_name='loc_altitude', maxvalue=42849672.95, minvalue=-100000.0, multivalue=False, option_group=u'LOC Record', required=False)
-option: Float('loc_part_size', attribute=False, cli_name='loc_size', maxvalue=90000000.0, minvalue=0.0, multivalue=False, option_group=u'LOC Record', required=False)
-option: Float('loc_part_h_precision', attribute=False, cli_name='loc_h_precision', maxvalue=90000000.0, minvalue=0.0, multivalue=False, option_group=u'LOC Record', required=False)
-option: Float('loc_part_v_precision', attribute=False, cli_name='loc_v_precision', maxvalue=90000000.0, minvalue=0.0, multivalue=False, option_group=u'LOC Record', required=False)
+option: Decimal('loc_part_altitude', attribute=False, cli_name='loc_altitude', maxvalue=Decimal('42849672.95'), minvalue=Decimal('-100000.00'), multivalue=False, option_group=u'LOC Record', precision=2, required=False)
+option: Decimal('loc_part_size', attribute=False, cli_name='loc_size', maxvalue=Decimal('90000000.00'), minvalue=Decimal('0.0'), multivalue=False, option_group=u'LOC Record', precision=2, required=False)
+option: Decimal('loc_part_h_precision', attribute=False, cli_name='loc_h_precision', maxvalue=Decimal('90000000.00'), minvalue=Decimal('0.0'), multivalue=False, option_group=u'LOC Record', precision=2, required=False)
+option: Decimal('loc_part_v_precision', attribute=False, cli_name='loc_v_precision', maxvalue=Decimal('90000000.00'), minvalue=Decimal('0.0'), multivalue=False, option_group=u'LOC Record', precision=2, required=False)
 option: MXRecord('mxrecord', attribute=True, cli_name='mx_rec', csv=True, multivalue=True, option_group=u'MX Record', required=False)
 option: Int('mx_part_preference', attribute=False, cli_name='mx_preference', maxvalue=65535, minvalue=0, multivalue=False, option_group=u'MX Record', required=False)
 option: Str('mx_part_exchanger', attribute=False, cli_name='mx_exchanger', multivalue=False, option_group=u'MX Record', required=False)
@@ -831,16 +831,16 @@ option: Str('kx_part_exchanger', attribute=False, autofill=False, cli_name='kx_e
 option: LOCRecord('locrecord', attribute=True, autofill=False, cli_name='loc_rec', csv=True, multivalue=True, option_group=u'LOC Record', query=True, required=False)
 option: Int('loc_part_lat_deg', attribute=False, autofill=False, cli_name='loc_lat_deg', maxvalue=90, minvalue=0, multivalue=False, option_group=u'LOC Record', query=True, required=False)
 option: Int('loc_part_lat_min', attribute=False, autofill=False, cli_name='loc_lat_min', maxvalue=59, minvalue=0, multivalue=False, option_group=u'LOC Record', query=True, required=False)
-option: Float('loc_part_lat_sec', attribute=False, autofill=False, cli_name='loc_lat_sec', maxvalue=59.999, minvalue=0.0, multivalue=False, option_group=u'LOC Record', query=True, required=False)
+option: Decimal('loc_part_lat_sec', attribute=False, autofill=False, cli_name='loc_lat_sec', maxvalue=Decimal('59.999'), minvalue=Decimal('0.0'), multivalue=False, option_group=u'LOC Record', precision=3, query=True, required=False)
 option: StrEnum('loc_part_lat_dir', attribute=False, autofill=False, cli_name='loc_lat_dir', multivalue=False, option_group=u'LOC Record', query=True, required=False, values=(u'N', u'S'))
 option: Int('loc_part_lon_deg', attribute=False, autofill=False, cli_name='loc_lon_deg', maxvalue=180, minvalue=0, multivalue=False, option_group=u'LOC Record', query=True, required=False)
 option: Int('loc_part_lon_min', attribute=False, autofill=False, cli_name='loc_lon_min', maxvalue=59, minvalue=0, multivalue=False, option_group=u'LOC Record', query=True, required=False)
-option: Float('loc_part_lon_sec', attribute=False, autofill=False, cli_name='loc_lon_sec', maxvalue=59.999, minvalue=0.0, multivalue=False, option_group=u'LOC Record', query=True, required=False)
+option: Decimal('loc_part_lon_sec', attribute=False, autofill=False, cli_name='loc_lon_sec', maxvalue=Decimal('59.999'), minvalue=Decimal('0.0'), multivalue=False, option_group=u'LOC Record', precision=3, query=True, required=False)
 option: StrEnum('loc_part_lon_dir', attribute=False, autofill=False, cli_name='loc_lon_dir', multivalue=False, option_group=u'LOC Record', query=True, required=False, values=(u'E', u'W'))
-option: Float('loc_part_altitude', attribute=False, autofill=False, cli_name='loc_altitude', maxvalue=42849672.95, minvalue=-100000.0, multivalue=False, option_group=u'LOC Record', query=True, required=False)
-option: Float('loc_part_size', attribute=False, autofill=False, cli_name='loc_size', maxvalue=90000000.0, minvalue=0.0, multivalue=False, option_group=u'LOC Record', query=True, required=False)
-option: Float('loc_part_h_precision', attribute=False, autofill=False, cli_name='loc_h_precision', maxvalue=90000000.0, minvalue=0.0, multivalue=False, option_group=u'LOC Record', query=True, required=False)
-option: Float('loc_part_v_precision', attribute=False, autofill=False, cli_name='loc_v_precision', maxvalue=90000000.0, minvalue=0.0, multivalue=False, option_group=u'LOC Record', query=True, required=False)
+option: Decimal('loc_part_altitude', attribute=False, autofill=False, cli_name='loc_altitude', maxvalue=Decimal('42849672.95'), minvalue=Decimal('-100000.00'), multivalue=False, option_group=u'LOC Record', precision=2, query=True, required=False)
+option: Decimal('loc_part_size', attribute=False, autofill=False, cli_name='loc_size', maxvalue=Decimal('90000000.00'), minvalue=Decimal('0.0'), multivalue=False, option_group=u'LOC Record', precision=2, query=True, required=False)
+option: Decimal('loc_part_h_precision', attribute=False, autofill=False, cli_name='loc_h_precision', maxvalue=Decimal('90000000.00'), minvalue=Decimal('0.0'), multivalue=False, option_group=u'LOC Record', precision=2, query=True, required=False)
+option: Decimal('loc_part_v_precision', attribute=False, autofill=False, cli_name='loc_v_precision', maxvalue=Decimal('90000000.00'), minvalue=Decimal('0.0'), multivalue=False, option_group=u'LOC Record', precision=2, query=True, required=False)
 option: MXRecord('mxrecord', attribute=True, autofill=False, cli_name='mx_rec', csv=True, multivalue=True, option_group=u'MX Record', query=True, required=False)
 option: Int('mx_part_preference', attribute=False, autofill=False, cli_name='mx_preference', maxvalue=65535, minvalue=0, multivalue=False, option_group=u'MX Record', query=True, required=False)
 option: Str('mx_part_exchanger', attribute=False, autofill=False, cli_name='mx_exchanger', multivalue=False, option_group=u'MX Record', query=True, required=False)
@@ -952,16 +952,16 @@ option: Str('kx_part_exchanger', attribute=False, autofill=False, cli_name='kx_e
 option: LOCRecord('locrecord', attribute=True, autofill=False, cli_name='loc_rec', csv=True, multivalue=True, option_group=u'LOC Record', required=False)
 option: Int('loc_part_lat_deg', attribute=False, autofill=False, cli_name='loc_lat_deg', maxvalue=90, minvalue=0, multivalue=False, option_group=u'LOC Record', required=False)
 option: Int('loc_part_lat_min', attribute=False, autofill=False, cli_name='loc_lat_min', maxvalue=59, minvalue=0, multivalue=False, option_group=u'LOC Record', required=False)
-option: Float('loc_part_lat_sec', attribute=False, autofill=False, cli_name='loc_lat_sec', maxvalue=59.999, minvalue=0.0, multivalue=False, option_group=u'LOC Record', required=False)
+option: Decimal('loc_part_lat_sec', attribute=False, autofill=False, cli_name='loc_lat_sec', maxvalue=Decimal('59.999'), minvalue=Decimal('0.0'), multivalue=False, option_group=u'LOC Record', precision=3, required=False)
 option: StrEnum('loc_part_lat_dir', attribute=False, autofill=False, cli_name='loc_lat_dir', multivalue=False, option_group=u'LOC Record', required=False, values=(u'N', u'S'))
 option: Int('loc_part_lon_deg', attribute=False, autofill=False, cli_name='loc_lon_deg', maxvalue=180, minvalue=0, multivalue=False, option_group=u'LOC Record', required=False)
 option: Int('loc_part_lon_min', attribute=False, autofill=False, cli_name='loc_lon_min', maxvalue=59, minvalue=0, multivalue=False, option_group=u'LOC Record', required=False)
-option: Float('loc_part_lon_sec', attribute=False, autofill=False, cli_name='loc_lon_sec', maxvalue=59.999, minvalue=0.0, multivalue=False, option_group=u'LOC Record', required=False)
+option: Decimal('loc_part_lon_sec', attribute=False, autofill=False, cli_name='loc_lon_sec', maxvalue=Decimal('59.999'), minvalue=Decimal('0.0'), multivalue=False, option_group=u'LOC Record', precision=3, required=False)
 option: StrEnum('loc_part_lon_dir', attribute=False, autofill=False, cli_name='loc_lon_dir', multivalue=False, option_group=u'LOC Record', required=False, values=(u'E', u'W'))
-option: Float('loc_part_altitude', attribute=False, autofill=False, cli_name='loc_altitude', maxvalue=42849672.95, minvalue=-100000.0, multivalue=False, option_group=u'LOC Record', required=False)
-option: Float('loc_part_size', attribute=False, autofill=False, cli_name='loc_size', maxvalue=90000000.0, minvalue=0.0, multivalue=False, option_group=u'LOC Record', required=False)
-option: Float('loc_part_h_precision', attribute=False, autofill=False, cli_name='loc_h_precision', maxvalue=90000000.0, minvalue=0.0, multivalue=False, option_group=u'LOC Record', required=False)
-option: Float('loc_part_v_precision', attribute=False, autofill=False, cli_name='loc_v_precision', maxvalue=90000000.0, minvalue=0.0, multivalue=False, option_group=u'LOC Record', required=False)
+option: Decimal('loc_part_altitude', attribute=False, autofill=False, cli_name='loc_altitude', maxvalue=Decimal('42849672.95'), minvalue=Decimal('-100000.00'), multivalue=False, option_group=u'LOC Record', precision=2, required=False)
+option: Decimal('loc_part_size', attribute=False, autofill=False, cli_name='loc_size', maxvalue=Decimal('90000000.00'), minvalue=Decimal('0.0'), multivalue=False, option_group=u'LOC Record', precision=2, required=False)
+option: Decimal('loc_part_h_precision', attribute=False, autofill=False, cli_name='loc_h_precision', maxvalue=Decimal('90000000.00'), minvalue=Decimal('0.0'), multivalue=False, option_group=u'LOC Record', precision=2, required=False)
+option: Decimal('loc_part_v_precision', attribute=False, autofill=False, cli_name='loc_v_precision', maxvalue=Decimal('90000000.00'), minvalue=Decimal('0.0'), multivalue=False, option_group=u'LOC Record', precision=2, required=False)
 option: MXRecord('mxrecord', attribute=True, autofill=False, cli_name='mx_rec', csv=True, multivalue=True, option_group=u'MX Record', required=False)
 option: Int('mx_part_preference', attribute=False, autofill=False, cli_name='mx_preference', maxvalue=65535, minvalue=0, multivalue=False, option_group=u'MX Record', required=False)
 option: Str('mx_part_exchanger', attribute=False, autofill=False, cli_name='mx_exchanger', multivalue=False, option_group=u'MX Record', required=False)
diff --git a/doc/guide/guide.org b/doc/guide/guide.org
index 68858166..bca7b34f 100644
--- a/doc/guide/guide.org
+++ b/doc/guide/guide.org
@@ -227,7 +227,7 @@ verbose = Flag('verbose', default=True)
            specified when constructing =Int= parameter:
            - /minvalue/ :: minimal value that this parameter accepts, defaults to =MININT=
            - /maxvalue/ :: maximum value this parameter can accept, defaults to =MAXINT=
-- /Float/ :: floating point parameters that are stored in Python's float type. =Float= has
+- /Decimal/ :: floating point parameters that are stored in Python's Decimal type. =Decimal= has
              the same two additional properties as =Int=. Unlike =Int=, there are no
              default values for the minimal and maximum boundaries.
 - /Bytes/ :: a parameter to represent binary data.
@@ -294,9 +294,9 @@ class tank(Object):
     takes_params = (
         StrEnum('species*', label=u'Species', doc=u'Fish species',
                  values=(u'Angelfish', u'Betta', u'Cichlid', u'Firemouth')),
-        Float('height', label=u'Height', doc=u'height in mm', default=400.0),
-        Float('width', label=u'Width', doc=u'width in mm', default=400.0),
-        Float('depth', label=u'Depth', doc=u'Depth in mm', default=300.0)
+        Decimal('height', label=u'Height', doc=u'height in mm', default='400.0'),
+        Decimal('width', label=u'Width', doc=u'width in mm', default='400.0'),
+        Decimal('depth', label=u'Depth', doc=u'Depth in mm', default='300.0')
     )
 
 api.register(tank) (ref:register)
diff --git a/ipalib/__init__.py b/ipalib/__init__.py
index 29ba0bb9..1efeeab4 100644
--- a/ipalib/__init__.py
+++ b/ipalib/__init__.py
@@ -878,7 +878,7 @@ from backend import Backend
 from frontend import Command, LocalOrRemote, Updater
 from frontend import Object, Method, Property
 from crud import Create, Retrieve, Update, Delete, Search
-from parameters import DefaultFrom, Bool, Flag, Int, Float, Bytes, Str, IA5Str, Password
+from parameters import DefaultFrom, Bool, Flag, Int, Decimal, Bytes, Str, IA5Str, Password
 from parameters import BytesEnum, StrEnum, AccessTime, File
 from errors import SkipPluginModule
 from text import _, ngettext, GettextFactory, NGettextFactory
diff --git a/ipalib/encoder.py b/ipalib/encoder.py
index f23e5659..8d59bd31 100644
--- a/ipalib/encoder.py
+++ b/ipalib/encoder.py
@@ -20,6 +20,8 @@
 Encoding capabilities.
 """
 
+from decimal import Decimal
+
 class EncoderSettings(object):
     """
     Container for encoder settings.
@@ -77,7 +79,7 @@ class Encoder(object):
             return self.encoder_settings.encode_postprocessor(
                 var.encode(self.encoder_settings.encode_to)
             )
-        elif isinstance(var, (bool, float, int, long)):
+        elif isinstance(var, (bool, float, Decimal, int, long)):
             return self.encoder_settings.encode_postprocessor(
                 str(var).encode(self.encoder_settings.encode_to)
             )
@@ -131,7 +133,7 @@ class Encoder(object):
             return self.encoder_settings.decode_postprocessor(
                 var.decode(self.encoder_settings.decode_from)
             )
-        elif isinstance(var, (bool, float, int, long)):
+        elif isinstance(var, (bool, float, Decimal, int, long)):
             return var
         elif isinstance(var, list):
             return [self.decode(m) for m in var]
diff --git a/ipalib/parameters.py b/ipalib/parameters.py
index be210864..d918a573 100644
--- a/ipalib/parameters.py
+++ b/ipalib/parameters.py
@@ -100,6 +100,7 @@ a more detailed description for clarity.
 """
 
 import re
+import decimal
 from types import NoneType
 from util import make_repr
 from text import _ as ugettext
@@ -723,8 +724,6 @@ class Param(ReadOnly):
                     else:
                         newval += (v,)
                 value = newval
-        if self.normalizer is None:
-            return value
         if self.multivalue:
             return tuple(
                 self._normalize_scalar(v) for v in value
@@ -740,6 +739,8 @@ class Param(ReadOnly):
         """
         if type(value) is not unicode:
             return value
+        if self.normalizer is None:
+            return value
         try:
             return self.normalizer(value)
         except StandardError:
@@ -1100,7 +1101,7 @@ class Flag(Bool):
 
 class Number(Param):
     """
-    Base class for the `Int` and `Float` parameters.
+    Base class for the `Int` and `Decimal` parameters.
     """
 
     def _convert_scalar(self, value, index=None):
@@ -1225,36 +1226,59 @@ class Int(Number):
                 )
 
 
-class Float(Number):
+class Decimal(Number):
     """
-    A parameter for floating-point values (stored in the ``float`` type).
+    A parameter for floating-point values (stored in the ``Decimal`` type).
+
+    Python Decimal type helps overcome problems tied to plain "float" type,
+    e.g. problem with representation or value comparison. In order to safely
+    transfer the value over RPC libraries, it is being converted to string
+    which is then converted back to Decimal number.
     """
 
-    type = float
+    type = decimal.Decimal
     type_error = _('must be a decimal number')
 
     kwargs = Param.kwargs + (
-        ('minvalue', float, None),
-        ('maxvalue', float, None),
+        ('minvalue', decimal.Decimal, None),
+        ('maxvalue', decimal.Decimal, None),
+        ('precision', int, None),
     )
 
     def __init__(self, name, *rules, **kw):
-        #pylint: disable=E1003
-        super(Number, self).__init__(name, *rules, **kw)
-
-        if (self.minvalue > self.maxvalue) and (self.minvalue is not None and self.maxvalue is not None):
+        for kwparam in ('minvalue', 'maxvalue', 'default'):
+            value = kw.get(kwparam)
+            if value is None:
+                continue
+            if isinstance(value, (basestring, float)):
+                try:
+                    value = decimal.Decimal(value)
+                except Exception, e:
+                    raise ValueError(
+                       '%s: cannot parse kwarg %s: %s' % (
+                        name, kwparam, str(e)))
+                kw[kwparam] = value
+
+        super(Decimal, self).__init__(name, *rules, **kw)
+
+        if (self.minvalue > self.maxvalue) \
+            and (self.minvalue is not None and \
+                 self.maxvalue is not None):
             raise ValueError(
-                '%s: minvalue > maxvalue (minvalue=%r, maxvalue=%r)' % (
+                '%s: minvalue > maxvalue (minvalue=%s, maxvalue=%s)' % (
                     self.nice, self.minvalue, self.maxvalue)
             )
 
+        if self.precision is not None and self.precision < 0:
+            raise ValueError('%s: precision must be at least 0' % self.nice)
+
     def _rule_minvalue(self, _, value):
         """
         Check min constraint.
         """
-        assert type(value) is float
+        assert type(value) is decimal.Decimal
         if value < self.minvalue:
-            return _('must be at least %(minvalue)f') % dict(
+            return _('must be at least %(minvalue)s') % dict(
                 minvalue=self.minvalue,
             )
 
@@ -1262,12 +1286,39 @@ class Float(Number):
         """
         Check max constraint.
         """
-        assert type(value) is float
+        assert type(value) is decimal.Decimal
         if value > self.maxvalue:
-            return _('can be at most %(maxvalue)f') % dict(
+            return _('can be at most %(maxvalue)s') % dict(
                 maxvalue=self.maxvalue,
             )
 
+    def _enforce_precision(self, value):
+        assert type(value) is decimal.Decimal
+        if self.precision is not None:
+            quantize_exp = decimal.Decimal(10) ** -self.precision
+            return value.quantize(quantize_exp)
+
+        return value
+
+    def _convert_scalar(self, value, index=None):
+        if isinstance(value, (basestring, float)):
+            try:
+                value = decimal.Decimal(value)
+            except Exception, e:
+                raise ConversionError(name=self.name, index=index,
+                                      error=unicode(e))
+
+        if isinstance(value, decimal.Decimal):
+            x = self._enforce_precision(value)
+            return x
+
+        return super(Decimal, self)._convert_scalar(value, index)
+
+    def _normalize_scalar(self, value):
+        if isinstance(value, decimal.Decimal):
+            value = self._enforce_precision(value)
+
+        return super(Decimal, self)._normalize_scalar(value)
 
 class Data(Param):
     """
@@ -1423,7 +1474,7 @@ class Str(Data):
         """
         if type(value) is self.type:
             return value
-        if type(value) in (int, float):
+        if type(value) in (int, float, decimal.Decimal):
             return self.type(value)
         if type(value) in (tuple, list):
             raise ConversionError(name=self.name, index=index,
diff --git a/ipalib/plugins/dns.py b/ipalib/plugins/dns.py
index 8042c3a1..abb2e90b 100644
--- a/ipalib/plugins/dns.py
+++ b/ipalib/plugins/dns.py
@@ -25,7 +25,7 @@ import re
 from ipalib.request import context
 from ipalib import api, errors, output
 from ipalib import Command
-from ipalib.parameters import Flag, Bool, Int, Float, Str, StrEnum, Any
+from ipalib.parameters import Flag, Bool, Int, Decimal, Str, StrEnum, Any
 from ipalib.plugins.baseldap import *
 from ipalib import _, ngettext
 from ipalib.util import validate_zonemgr, normalize_zonemgr, validate_hostname
@@ -345,7 +345,12 @@ class DNSRecord(Str):
             if not values:
                 return value
 
-            new_values = [ part.normalize(values[part_id]) \
+            converted_values = [ part._convert_scalar(values[part_id]) \
+                                 if values[part_id] is not None else None
+                                 for part_id, part in enumerate(self.parts)
+                               ]
+
+            new_values = [ part.normalize(converted_values[part_id]) \
                             for part_id, part in enumerate(self.parts) ]
 
             value = self._convert_scalar(new_values)
@@ -626,10 +631,11 @@ class LOCRecord(DNSRecord):
             minvalue=0,
             maxvalue=59,
         ),
-        Float('lat_sec?',
+        Decimal('lat_sec?',
             label=_('Seconds Latitude'),
-            minvalue=0.0,
-            maxvalue=59.999,
+            minvalue='0.0',
+            maxvalue='59.999',
+            precision=3,
         ),
         StrEnum('lat_dir',
             label=_('Direction Latitude'),
@@ -645,34 +651,39 @@ class LOCRecord(DNSRecord):
             minvalue=0,
             maxvalue=59,
         ),
-        Float('lon_sec?',
+        Decimal('lon_sec?',
             label=_('Seconds Longtitude'),
-            minvalue=0.0,
-            maxvalue=59.999,
+            minvalue='0.0',
+            maxvalue='59.999',
+            precision=3,
         ),
         StrEnum('lon_dir',
             label=_('Direction Longtitude'),
             values=(u'E', u'W',),
         ),
-        Float('altitude',
+        Decimal('altitude',
             label=_('Altitude'),
-            minvalue=-100000.00,
-            maxvalue=42849672.95,
+            minvalue='-100000.00',
+            maxvalue='42849672.95',
+            precision=2,
         ),
-        Float('size?',
+        Decimal('size?',
             label=_('Size'),
-            minvalue=0.0,
-            maxvalue=90000000.00,
+            minvalue='0.0',
+            maxvalue='90000000.00',
+            precision=2,
         ),
-        Float('h_precision?',
+        Decimal('h_precision?',
             label=_('Horizontal Precision'),
-            minvalue=0.0,
-            maxvalue=90000000.00,
+            minvalue='0.0',
+            maxvalue='90000000.00',
+            precision=2,
         ),
-        Float('v_precision?',
+        Decimal('v_precision?',
             label=_('Vertical Precision'),
-            minvalue=0.0,
-            maxvalue=90000000.00,
+            minvalue='0.0',
+            maxvalue='90000000.00',
+            precision=2,
         ),
     )
 
diff --git a/ipalib/rpc.py b/ipalib/rpc.py
index 8ec3a2f2..5a59ae65 100644
--- a/ipalib/rpc.py
+++ b/ipalib/rpc.py
@@ -31,6 +31,7 @@ Also see the `ipaserver.rpcserver` module.
 """
 
 from types import NoneType
+from decimal import Decimal
 import threading
 import sys
 import os
@@ -86,6 +87,9 @@ def xml_wrap(value):
         )
     if type(value) is str:
         return Binary(value)
+    if type(value) is Decimal:
+        # transfer Decimal as a string
+        return unicode(value)
     assert type(value) in (unicode, int, float, bool, NoneType)
     return value
 
diff --git a/ipaserver/rpcserver.py b/ipaserver/rpcserver.py
index 26850db5..955c11b7 100644
--- a/ipaserver/rpcserver.py
+++ b/ipaserver/rpcserver.py
@@ -37,6 +37,7 @@ from ipapython.version import VERSION
 import base64
 import os
 import string
+from decimal import Decimal
 _not_found_template = """<html>
 <head>
 <title>404 Not Found</title>
@@ -385,6 +386,8 @@ def json_encode_binary(val):
         return new_list
     elif isinstance(val, str):
         return {'__base64__' : base64.b64encode(val)}
+    elif isinstance(val, Decimal):
+        return {'__base64__' : base64.b64encode(str(val))}
     else:
         return val
 
diff --git a/make-lint b/make-lint
index ef241497..5826c322 100755
--- a/make-lint
+++ b/make-lint
@@ -61,7 +61,7 @@ class IPATypeChecker(TypeChecker):
             'sortorder', 'csv', 'csv_separator', 'csv_skipspace'],
         'ipalib.parameters.Bool': ['truths', 'falsehoods'],
         'ipalib.parameters.Int': ['minvalue', 'maxvalue'],
-        'ipalib.parameters.Float': ['minvalue', 'maxvalue'],
+        'ipalib.parameters.Decimal': ['minvalue', 'maxvalue', 'precision'],
         'ipalib.parameters.Data': ['minlength', 'maxlength', 'length',
             'pattern', 'pattern_errmsg'],
         'ipalib.parameters.Enum': ['values'],
diff --git a/tests/test_ipalib/test_parameters.py b/tests/test_ipalib/test_parameters.py
index 5cb7abf2..ad8d8404 100644
--- a/tests/test_ipalib/test_parameters.py
+++ b/tests/test_ipalib/test_parameters.py
@@ -25,6 +25,7 @@ Test the `ipalib.parameters` module.
 import re
 import sys
 from types import NoneType
+from decimal import Decimal
 from inspect import isclass
 from tests.util import raises, ClassChecker, read_only
 from tests.util import dummy_ugettext, assert_equal
@@ -1300,77 +1301,77 @@ class test_Int(ClassChecker):
         assert o._convert_scalar(u'0x10')  == 16
         assert o._convert_scalar(u'020')   == 16
 
-class test_Float(ClassChecker):
+class test_Decimal(ClassChecker):
     """
-    Test the `ipalib.parameters.Float` class.
+    Test the `ipalib.parameters.Decimal` class.
     """
-    _cls = parameters.Float
+    _cls = parameters.Decimal
 
     def test_init(self):
         """
-        Test the `ipalib.parameters.Float.__init__` method.
+        Test the `ipalib.parameters.Decimal.__init__` method.
         """
         # Test with no kwargs:
         o = self.cls('my_number')
-        assert o.type is float
-        assert isinstance(o, parameters.Float)
+        assert o.type is Decimal
+        assert isinstance(o, parameters.Decimal)
         assert o.minvalue is None
         assert o.maxvalue is None
 
         # Test when min > max:
-        e = raises(ValueError, self.cls, 'my_number', minvalue=22.5, maxvalue=15.1)
+        e = raises(ValueError, self.cls, 'my_number', minvalue=Decimal('22.5'), maxvalue=Decimal('15.1'))
         assert str(e) == \
-            "Float('my_number'): minvalue > maxvalue (minvalue=22.5, maxvalue=15.1)"
+            "Decimal('my_number'): minvalue > maxvalue (minvalue=22.5, maxvalue=15.1)"
 
     def test_rule_minvalue(self):
         """
-        Test the `ipalib.parameters.Float._rule_minvalue` method.
+        Test the `ipalib.parameters.Decimal._rule_minvalue` method.
         """
-        o = self.cls('my_number', minvalue=3.1)
-        assert o.minvalue == 3.1
+        o = self.cls('my_number', minvalue='3.1')
+        assert o.minvalue == Decimal('3.1')
         rule = o._rule_minvalue
-        translation = u'minvalue=%(minvalue)r'
+        translation = u'minvalue=%(minvalue)s'
         dummy = dummy_ugettext(translation)
         assert dummy.translation is translation
 
         # Test with passing values:
-        for value in (3.2, 99.0):
+        for value in (Decimal('3.2'), Decimal('99.0')):
             assert rule(dummy, value) is None
             assert dummy.called() is False
 
         # Test with failing values:
-        for value in (-1.2, 0.0, 3.0):
+        for value in (Decimal('-1.2'), Decimal('0.0'), Decimal('3.0')):
             assert_equal(
                 rule(dummy, value),
-                translation % dict(minvalue=3.1)
+                translation % dict(minvalue=Decimal('3.1'))
             )
-            assert dummy.message == 'must be at least %(minvalue)f'
+            assert dummy.message == 'must be at least %(minvalue)s'
             assert dummy.called() is True
             dummy.reset()
 
     def test_rule_maxvalue(self):
         """
-        Test the `ipalib.parameters.Float._rule_maxvalue` method.
+        Test the `ipalib.parameters.Decimal._rule_maxvalue` method.
         """
-        o = self.cls('my_number', maxvalue=4.7)
-        assert o.maxvalue == 4.7
+        o = self.cls('my_number', maxvalue='4.7')
+        assert o.maxvalue == Decimal('4.7')
         rule = o._rule_maxvalue
         translation = u'maxvalue=%(maxvalue)r'
         dummy = dummy_ugettext(translation)
         assert dummy.translation is translation
 
         # Test with passing values:
-        for value in (-1.0, 0.1, 4.2):
+        for value in (Decimal('-1.0'), Decimal('0.1'), Decimal('4.2')):
             assert rule(dummy, value) is None
             assert dummy.called() is False
 
         # Test with failing values:
-        for value in (5.3, 99.9):
+        for value in (Decimal('5.3'), Decimal('99.9')):
             assert_equal(
                 rule(dummy, value),
-                translation % dict(maxvalue=4.7)
+                translation % dict(maxvalue=Decimal('4.7'))
             )
-            assert dummy.message == 'can be at most %(maxvalue)f'
+            assert dummy.message == 'can be at most %(maxvalue)s'
             assert dummy.called() is True
             dummy.reset()
 
diff --git a/tests/test_xmlrpc/test_dns_plugin.py b/tests/test_xmlrpc/test_dns_plugin.py
index 00d4f9b7..bded2ad4 100644
--- a/tests/test_xmlrpc/test_dns_plugin.py
+++ b/tests/test_xmlrpc/test_dns_plugin.py
@@ -598,7 +598,7 @@ class test_dns(Declarative):
                     'idnsname': [dnszone1],
                     'mxrecord': [u"0 %s" % dnszone1_mname],
                     'nsrecord': [dnszone1_mname],
-                    'locrecord': [u"49 11 42.4 N 16 36 29.6 E 227.64"],
+                    'locrecord': [u"49 11 42.400 N 16 36 29.600 E 227.64"],
                 },
             },
         ),