[modules/currency] Enable base and symbol configuration

The "base" currency can now be configured using the parameter "source",
and the "symbols" to be resolved can be configured using the parameter
"destination", which is a comma-separated list.

see #169

bumblebee/modules/currency.py

@@ -8,6 +8,10 @@ Requires the following python packages:
 
 Parameters:
     * currency.interval: Interval in minutes between updates, default is 1.
+    * currency.source: Source currency (defaults to "GBP")
+    * currency.destination: Comma-separated list of destination currencies (defaults to "USD,EUR")
+
+Note: source and destination names right now must correspond to the names used by the API of http://fixer.io
 """
 
 import bumblebee.input
@@ -21,40 +25,40 @@ try:
 except ImportError:
     pass
 
+SYMBOL = {
+    "GBP": u"£", "EUR": u"€", "USD": u"$"
+}
+
 class Module(bumblebee.engine.Module):
     def __init__(self, engine, config):
         super(Module, self).__init__(engine, config,
             bumblebee.output.Widget(full_text=self.price)
         )
-        self._price = "-"
-        self._interval = int(self.parameter("interval", "1"))
+        self._data = {}
+        self._interval = int(self.parameter("interval", 1))
+        self._base = self.parameter("source", "GBP")
+        self._symbols = self.parameter("destination", "USD,EUR")
         self._nextcheck = 0
-        self._valid = False
 
     def price(self, widget):
-        if not self._valid:
-            return u"?"
-        return self._price
+        if self._data == {}:
+            return "?"
+
+        rates = []
+        for sym in self._data["rates"]:
+            rates.append(u"{}{}".format(self._data["rates"][sym], SYMBOL[sym] if sym in SYMBOL else sym))
+
+        return u"{}: {}".format(SYMBOL[self._base] if self._base in SYMBOL else self._base, u"/".join(rates))
 
     def update(self, widgets):
         timestamp = int(time.time())
         if self._nextcheck < int(time.time()):
-            try:
+            self._data = {}
             self._nextcheck = int(time.time()) + self._interval*60
-                price_url = "http://api.fixer.io/latest?symbols=USD,EUR&base=GBP" 
+            url = "http://api.fixer.io/latest?symbols={}&base={}".format(self._symbols, self._base)
             try:
-                    price_json = json.loads( requests.get(price_url).text )
-                    gbpeur = str(price_json['rates']['EUR'])
-                    gbpusd = str(price_json['rates']['USD'])
-                except ValueError:
-                    gbpeur = "-"
-                    gbpusd = "-"
-
-                self._price = u"£/€ " + gbpeur + u" | £/$ " + gbpusd
-                self._valid = True
-            except RequestException:
-                self._price = u"£/€ - | £/$ -"
-                self._valid = True
+                self._data = json.loads(requests.get(url).text)
+            except Exception:
+                pass
 
 # vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4
-