config: use from_json to read ogserver config

This patch introduces the usage of Flask.Config class so the config can
be read at startup (__init__) only once. Config keys must be uppercase
so that from_json method does take it into account.

 dormousehole.readthedocs.io/en/stable/api.html#flask.Config.from_json

Prior to this patch each request required opening and closing the
ogserver.json file via load_config in views.py.

In the future the decorated load_config function inside views.py
may be removed to avoid creating multiple instances of the OGServer
class.

ogcp/__init__.py

@@ -5,10 +5,12 @@ from flask import Flask
 from os import urandom
 
 app = Flask(__name__)
+app.config.from_json('cfg/ogserver.json')
+app.secret_key = urandom(16)
+
 babel = Babel(app)
 csrf = CSRFProtect(app)
 bootstrap = Bootstrap(app)
 
-app.secret_key = urandom(16)
 
 import ogcp.views

ogcp/cfg/ogserver.json

@@ -1,5 +1,5 @@
 {
-	"ip": "127.0.0.1",
-	"port": 8888,
-	"api_token": "c3fe7bb0395747ec42a25df027585871"
+	"IP": "127.0.0.1",
+	"PORT": 8888,
+	"API_TOKEN": "c3fe7bb0395747ec42a25df027585871"
 }

ogcp/og_server.py

@@ -1,22 +1,17 @@
+from ogcp import app
+
 import requests
 import json
 
 class OGServer:
-    def __init__(self, ip='127.0.0.1', port=8888, api_token=""):
+    def __init__(self, ip=app.config['IP'],
+                 port=app.config['PORT'],
+                 api_token=app.config['API_TOKEN']):
         self.ip = ip
         self.port = port
         self.api_token = api_token
         self._prepare_requests()
 
-    def load_config(self, path):
-        with open(path, 'r') as f:
-            cfg = json.load(f)
-
-        self.ip = cfg['ip']
-        self.port = cfg['port']
-        self.api_token = cfg['api_token']
-        self._prepare_requests()
-
     def _prepare_requests(self):
         self.URL = f'http://{self.ip}:{self.port}'
         self.HEADERS = {'Authorization' : self.api_token}

ogcp/views.py

@@ -52,7 +52,6 @@ def parse_scopes_from_tree(tree, scope_type):
 @app.before_request
 def load_config():
     g.server = OGServer()
-    g.server.load_config('ogcp/cfg/ogserver.json')
 
 @app.errorhandler(404)
 def page_not_found(error):