Add data-interface-module

* Outsource reading from URL
* Outsource loading from json-data

hc_data.py

+# -*- coding: utf-8 -*-
+
+import os
+import json
+from urllib import request
+
+import hc_head
+
+
+class Data(object):
+    """Class representing a data-interface for hack_count."""
+
+    def __init__(self, var=request.urlopen("http://hack-hro.de/api/users")):
+        """Initialize values and create necessary dirs."""
+
+        #### fetch usercount
+        # fetch data from server
+        self.var = var
+
+        # create data-objects by decoding the json
+        self.json_string = self.var.read()
+        self.json_dict = json.loads(self.json_string.decode('ascii'))
+        self.device_count = self.json_dict['deviceCount']
+        self.users = self.json_dict['users']
+
+        # create picture folder, if not existant
+        if not os.path.exists(hc_head.CACHE_PICTURE_FOLDER):
+            os.makedirs(hc_head.CACHE_PICTURE_FOLDER)
+
+        # fetch avatar picture, if not existant
+        if not os.path.isfile(hc_head.DEFAULT_CACHE_PICTURE):
+            request.urlretrieve("http://hack-hro.de/avatar/default.png",
+                                       hc_head.DEFAULT_CACHE_PICTURE)
+
+    def update(self,
+               var=request.urlopen("http://hack-hro.de/api/users")):
+        """Update values, if required."""
+
+        # replace var, if not already matching
+        if var != self.var:
+            self.var = var
+
+            # create data-objects by decoding the json
+            self.json_string = self.var.read()
+            self.json_dict = json.loads(self.json_string.decode('ascii'))
+            self.device_count = self.json_dict['deviceCount']
+            self.users = self.json_dict['users']
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