Improve exception handling5.2.0

6 files changed, 73 insertions, 26 deletions

diff --git a/cfetch/__init__.py b/cfetch/__init__.py
index 281555a..ad01e57 100644
--- a/cfetch/__init__.py
+++ b/cfetch/__init__.py
@@ -23,6 +23,12 @@ from requests import get
 
 __version__ = '5.2.0'
 
+class NoSuchPairException(Exception):
+    pass
+
+class NoSuchKindException(Exception):
+    pass
+
 ## A cryptocurrency exchange rate ticker.
 class Ticker():
     ## Constructor for this class.
@@ -47,9 +53,25 @@ class Ticker():
         else:
             raise TypeError('pair cannot be {}'.format(type(pair)))
 
-    def _get_single_rate(self, a, b, amt, power, kind):
+    ## Gets the exchange rate between two currencies raised to a power.
+    #  @param a The first currency.
+    #  @param b The second currency.
+    #  @param amt The number quantity of 'a' currency.
+    #  @param power The power to which the calculation will be raised.
+    #  @param kind The type of rate to calculate.
+    #  @return The exchange rate between 'a' and 'b' currencies raised to
+    # 'power'.
+    def get_rate_pow(self, a, b, amt, power, kind):
         r = get(self.path + self.get_pair(a, b))
-        res = self.get_pair_data(r, (a, b))
+
+        try:
+            res = self.get_pair_data(r, (a, b))
+        except KeyError as e:
+            raise NoSuchPairException(str(e))
+
+        if kind not in res:
+            raise NoSuchKindException(kind)
+
         return (float(res[kind]) ** power) * amt
 
     ## Calculates the exchange rate between two currencies.
@@ -60,12 +82,9 @@ class Ticker():
     #  @return The exchange rate between 'a' and 'b' currencies.
     def get_rate(self, a, b, amt=1, kind='avg'):
         try:
-            return self._get_single_rate(a, b, amt, 1, kind)
-        except (KeyError, TypeError):
-            try:
-                return self._get_single_rate(b, a, amt, -1, kind)
-            except (KeyError, TypeError) as e:
-                raise ValueError(str(e)) # currency pair not found
+            return self.get_rate_pow(a, b, amt, 1, kind)
+        except NoSuchPairException:
+            return self.get_rate_pow(b, a, amt, -1, kind)
 
 _INDEX = {
     'description': 0,
diff --git a/cfetch/plugins/bitcoinaverage.py b/cfetch/plugins/bitcoinaverage.py
index df1cebd..2e045af 100644
--- a/cfetch/plugins/bitcoinaverage.py
+++ b/cfetch/plugins/bitcoinaverage.py
@@ -15,7 +15,8 @@
 ##  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ##
 
-from cfetch import register_ticker, Ticker
+from cfetch import register_ticker, NoSuchKindException, NoSuchPairException
+from cfetch import Ticker
 from requests import get
 
 class BitcoinAverageTicker(Ticker):
@@ -28,7 +29,7 @@ class BitcoinAverageTicker(Ticker):
     def get_rate(self, a, b, amt=1, kind='24h_avg'):
         a = a.upper()
         b = b.upper()
-        if 'BTC' not in (a, b):
+        if 'BTC' not in (a, b) or 'USD' not in (a, b):
             self._fail(a, b)
 
         r = get(self.path)
@@ -47,11 +48,11 @@ class BitcoinAverageTicker(Ticker):
 
             res = res[a]
             return (float(res[kind]) ** -1) * amt
-        except (KeyError, TypeError) as e:
-            raise ValueError(str(e))
+        except KeyError as e:
+            raise NoSuchKindException(str(e))
 
     def _fail(self, a, b):
-        raise ValueError('{}/{}'.format(a, b))
+        raise NoSuchPairException('{}/{}'.format(a, b))
 
 register_ticker('ba', 'The BitcoinAverage ticker (built-in)',
                 BitcoinAverageTicker('https://api.bitcoinaverage.com/ticker/all'))
diff --git a/cfetch/plugins/bitstamp.py b/cfetch/plugins/bitstamp.py
index 7af3883..c808995 100644
--- a/cfetch/plugins/bitstamp.py
+++ b/cfetch/plugins/bitstamp.py
@@ -15,7 +15,8 @@
 ##  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ##
 
-from cfetch import register_ticker, Ticker
+from cfetch import register_ticker, NoSuchKindException, NoSuchPairException
+from cfetch import Ticker
 from requests import get
 
 class BitstampTicker(Ticker):
@@ -29,14 +30,14 @@ class BitstampTicker(Ticker):
         r = get(self.path)
         res = self.get_pair_data(r)
         if kind not in res:
-            raise ValueError('Kind {} not available'.format(kind))
+            raise NoSuchKindException('Kind {} not available'.format(kind))
 
         if a == 'btc' and b == 'usd':
             return float(res[kind]) * amt
         elif a == 'usd' and b == 'btc':
             return (float(res[kind]) ** -1) * amt
         else:
-            raise ValueError('{}/{}'.format(a, b))
+            raise NoSuchPairException('{}/{}'.format(a, b))
 
 register_ticker('bs', 'The Bitstamp ticker (built-in)',
                 BitstampTicker('https://www.bitstamp.net/api/ticker/'))
diff --git a/cfetch/plugins/bter.py b/cfetch/plugins/bter.py
index e18c9f1..2346591 100644
--- a/cfetch/plugins/bter.py
+++ b/cfetch/plugins/bter.py
@@ -1,6 +1,6 @@
 ##
 ##  coinfetch-api-bter - BTer API plugin for coinfetch
-##  Copyright (C) 2015 Delwink, LLC
+##  Copyright (C) 2015-2016 Delwink, LLC
 ##
 ##  This program is free software: you can redistribute it and/or modify
 ##  it under the terms of the GNU Affero General Public License as published by
@@ -15,11 +15,25 @@
 ##  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ##
 
-from cfetch import register_ticker, Ticker
+from cfetch import register_ticker, NoSuchKindException, NoSuchPairException
+from cfetch import Ticker
+from requests import get
 
 class BterTicker(Ticker):
     def get_pair_data(self, response, pair=None):
         return response.json()
 
+    def get_rate_pow(self, a, b, amt, power, kind):
+        r = get(self.path + self.get_pair(a, b))
+        res = self.get_pair_data(r)
+
+        if kind not in res:
+            if res['result'] == 'false':
+                raise NoSuchPairException('{}/{}'.format(a, b))
+
+            raise NoSuchKindException(kind)
+
+        return (float(res[kind]) ** power) * amt
+
 register_ticker('bter', 'The BTer ticker (built-in)',
                 BterTicker('http://data.bter.com/api/1/ticker/'))
diff --git a/cfetch/plugins/ccc.py b/cfetch/plugins/ccc.py
index 07bdb99..3104c46 100644
--- a/cfetch/plugins/ccc.py
+++ b/cfetch/plugins/ccc.py
@@ -15,7 +15,8 @@
 ##  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ##
 
-from cfetch import register_ticker, Ticker
+from cfetch import register_ticker, NoSuchKindException, NoSuchPairException
+from cfetch import Ticker
 
 class CccTicker(Ticker):
     def __init__(self, path):
@@ -24,6 +25,18 @@ class CccTicker(Ticker):
     def get_pair_data(self, response, pair=None):
         return response.json()
 
+    def get_rate_pow(self, a, b, amt, power, kind):
+        r = get(self.path + self.get_pair(a, b))
+        res = self.get_pair_data(r, (a, b))
+
+        if kind not in res:
+            raise NoSuchKindException(kind)
+
+        if res[kind] is None:
+            raise NoSuchPairException('{}/{}'.format(a, b))
+
+        return (float(res[kind]) ** power) * amt
+
     def get_rate(self, a, b, amt=1, kind='price'):
         return super().get_rate(a, b, amt, kind)
 
diff --git a/coinfetch b/coinfetch
index 6618ed6..8edd10b 100755
--- a/coinfetch
+++ b/coinfetch
@@ -19,7 +19,8 @@
 from argparse import Action, ArgumentParser
 from configparser import ConfigParser
 from cfetch import __version__, get_ticker, get_registered_tickers
-from cfetch import load_default_plugins
+from cfetch import load_default_plugins, NoSuchKindException
+from cfetch import NoSuchPairException
 from os.path import expanduser, join, exists
 from os import makedirs
 
@@ -105,12 +106,10 @@ try:
 
     rate = ticker.get_rate(*rate_args)
     print(format(rate, '.8f'))
-except ValueError:
-    if args.kind:
-        print('The', args.kind, 'rate is not available with the', args.api,
-              'API.')
-        exit(10)
-
+except NoSuchKindException:
+    print('The', args.kind, 'rate is not available with the', args.api, 'API.')
+    exit(10)
+except NoSuchPairException:
     pair = '/'.join([args.src, args.dest])
     print('The pair', pair, 'was not found using the', args.api, 'API.')
     exit(11)