Implement !convert command

clients/discord.py

@@ -65,6 +65,8 @@ class DiscordClient(discord.Client):
             (re.compile(r'^!cheese\s+(?P<q>")?(?P<query>.+)(?(q)")$'), self._do_cheese),
             (re.compile(r'^!roll(\s+(?P<q>")?(?P<formula>.+)(?(q)"))?$'), self._do_roll),
             (re.compile(r'^!nextstream$'), self._do_nextstream),
+            (re.compile(r'^!conv(ert)?\s+(?P<q1>")?(?P<expression>.+?)(?(q1)")'
+                        r'(\s+(?P<q2>")?(?P<unit>[^\s]+)(?(q2)"))?$'), self._do_convert),
         ]
         super(DiscordClient, self).__init__()
 
@@ -287,3 +289,12 @@ class DiscordClient(discord.Client):
             embed.add_field(name=format_delta(time - datetime.datetime.utcnow()),
                 value=time.strftime('%Y-%m-%d %I:%M %p GMT'), inline=False)
             await message.channel.send(embed=embed)
+
+    async def _do_convert(self, server, user, message, expression, unit, **kwargs):
+        try:
+            result = self.commands.convert(expression, unit)
+        except CommandError as e:
+            await message.channel.send('Sorry {0}, {1}'.format(message.author.mention, e))
+        else:
+            embed = discord.Embed(description='**{0}**'.format(result), color=0x39ad0f)
+            await message.channel.send(embed=embed)

clients/twitch.py

@@ -105,6 +105,8 @@ class TwitchClient(irc.bot.SingleServerIRCBot):
             (re.compile(r'^!(find)?clip\s+(?P<q>")?(?P<filter>.+)(?(q)")$'), self._do_clip),
             (re.compile(r'^!roll(\s+(?P<q>")?(?P<formula>.+)(?(q)"))?$'), self._do_roll),
             (re.compile(r'^!giveaway$'), self._do_giveaway),
+            (re.compile(r'^!conv(ert)?\s+(?P<q1>")?(?P<expression>.+?)(?(q1)")'
+                        r'(\s+(?P<q2>")?(?P<unit>[^\s]+)(?(q2)"))?$'), self._do_convert),
             (re.compile(r'^!command\s+set\s+(?P<q1>")?(?P<cmd>.+?)(?(q1)")\s+'
                         r'(?P<q2>")?(?P<resp>.+)(?(q2)")$'), self._do_command_set),
             (re.compile(r'^!command\s+unset\s+(?P<q>")?(?P<cmd>.+)(?(q)")$'), self._do_command_unset),
@@ -342,6 +344,14 @@ class TwitchClient(irc.bot.SingleServerIRCBot):
         if self.giveaway['command']:
             send_response('Type {0} to join!'.format(self.giveaway['command']))
 
+    def _do_convert(self, tags, send_response, expression, unit, **kwargs):
+        try:
+            result = self.commands.convert(expression, unit)
+        except CommandError as e:
+            send_response('Sorry @{0}, {1}'.format(tags['display-name'], e))
+        else:
+            send_response(result)
+
     def _do_command_set(self, tags, send_response, cmd, resp, **kwargs):
         if not self._is_mod(tags):
             send_response('Sorry @{0}, you are not allowed to do this'.format(tags['display-name']))

commands.py

@@ -4,9 +4,10 @@ import unicodedata
 import dateutil.parser
 import requests
 
-from services.youtube import Youtube, YoutubeError
 from services.cheesecom import CheeseCom, CheeseComError
+from services.converter import Converter, ConverterError
 from services.roll20 import Roll20, Roll20Error
+from services.youtube import Youtube, YoutubeError
 
 
 INSTAGRAM_BASE_URL = 'https://www.instagram.com'
@@ -210,6 +211,13 @@ class Commands(object):
             self.last_roll_formula = formula
             return result
 
+    def convert(self, expression, unit=None):
+        c = Converter()
+        try:
+            return c.convert(expression, unit)
+        except ConverterError as e:
+            raise CommandError(str(e))
+
     def _get_instagram_media(self, params):
         api_url = self.config['Instagram'].get('api_url')
         r = requests.get('{0}/media'.format(api_url), params=params)

requirements.txt

@@ -3,6 +3,7 @@ fuzzywuzzy[speedup]
 google-api-python-client
 irc
 parsy
+pint
 pyquery
 python-dateutil
 python-twitter

services/converter.py

@@ -0,0 +1,65 @@
+import pint
+
+
+class ConverterError(Exception):
+    pass
+
+
+class Converter(object):
+    def __init__(self):
+        self.ureg = pint.UnitRegistry(autoconvert_offset_to_baseunit=True)
+        self.ureg.define('degreeC = kelvin; offset: 273.15 = °C = C')
+        self.ureg.define('degreeF = 5 / 9 * kelvin; offset: 255.372222 = °F = F')
+        self.default_units = {
+            self.ureg.degC: self.ureg.degreeF,
+            self.ureg.degreeC: self.ureg.degreeF,
+            self.ureg.degF: self.ureg.degreeC,
+            self.ureg.degreeF: self.ureg.degreeC,
+            self.ureg.kilometer: self.ureg.mile,
+            self.ureg.meter: self.ureg.foot,
+            self.ureg.centimeter: self.ureg.inch,
+            self.ureg.millimeter: self.ureg.inch,
+            self.ureg.mile: self.ureg.kilometer,
+            self.ureg.foot: self.ureg.meter,
+            self.ureg.inch: self.ureg.millimeter,
+            self.ureg.kilogram: self.ureg.pound,
+            self.ureg.pound: self.ureg.kilogram,
+            self.ureg.ounce: self.ureg.kilogram,
+            self.ureg.liter: self.ureg.gallon,
+            self.ureg.milliliter: self.ureg.floz,
+            self.ureg.gallon: self.ureg.liter,
+            self.ureg.floz: self.ureg.milliliter,
+        }
+
+    def convert(self, expression, unit=None):
+        try:
+            q = self.ureg.parse_expression(expression)
+        except pint.errors.UndefinedUnitError:
+            raise ConverterError('unknown units')
+        try:
+            q.units
+        except AttributeError:
+            if unit is not None:
+                q = self.ureg.parse_expression(expression + unit)
+                unit = None
+            else:
+                raise ConverterError('unknown units')
+        try:
+            q.units
+        except AttributeError:
+            raise ConverterError('unknown units')
+        if unit is not None:
+            try:
+                u = self.ureg.parse_units(unit)
+            except pint.errors.UndefinedUnitError:
+                raise ConverterError('unknown units')
+        else:
+            try:
+                u = self.default_units[q.units]
+            except KeyError:
+                raise ConverterError('no target units specified')
+        try:
+            result = q.to(u)
+        except pint.errors.DimensionalityError:
+            raise ConverterError('invalid conversion')
+        return '{:0.5g~P}'.format(result)