completed using libraries

challenge.py

@@ -1,9 +1,12 @@
-""" Mini-Challenge """
+""" Mini-Challenge"""
 
+from os.path import join
+from xml.etree import ElementTree as ET
 from twisted.internet import defer
 
-class Adapter():
-    """ Adapter class
+
+class Adapter:
+    """Adapter class
 
     Aufgabe: Asynchron XML-Daten lesen, konvertieren und zurückliefern.
     """
@@ -11,14 +14,30 @@ class Adapter():
     def __init__(self, path):
         self.path = path
 
+    def _read(self, name):
+        with open(join(self.path, name + ".xml")) as f:
+            return f.read()
+
+    def _parse(self, xml_data):
+        root = ET.fromstring(xml_data)
+        token = root.find("{*}Token").text
+        return token
+
+    def _convert(self, token):
+        return '{"token": %s}' % token
+
     def retrieve_token(self, name):
         """
         Retrieve the content from file name.xml in adapters path directory
         in a synchronous way, extract the DataReceived/Token and return it
         as a JSON-Object (stringified) '{"token": value}'.
         """
-        # return '{"token": 42}' - don't do this, just a test
-        raise NotImplementedError
+        try:
+            xml_data = self._read(name)
+            token = self._parse(xml_data)
+            return self._convert(token)
+        except Exception as e:
+            raise ValueError("Could not retrieve token: %s" % e)
 
     def retrieve_token_async(self, name):
         """
@@ -31,5 +50,20 @@ class Adapter():
         Hint: The simple way is to use defer.succeed(), bonus points for doing
               it with a callback chain read->parse->convert.
         """
-        #return defer.succeed('{"token": 42}') - don't do this, just a test
-        raise NotImplementedError
+        d = defer.Deferred()
+
+        def on_success(xml_data):
+            try:
+                token = self._parse(xml_data)
+                converted = self._convert(token)
+                d.callback(converted)
+            except Exception as e:
+                d.errback(e)
+
+        def on_error(error):
+            d.errback(error)
+
+        deferred = defer.maybeDeferred(self._read, name)
+        deferred.addCallbacks(on_success, on_error)
+
+        return d