Implement multi db backend support;

main.py

@@ -1,5 +1,6 @@
 import json
 import dateutil
+import configparser
 from datetime import datetime, timezone
 
 from flask import Flask, request, abort
@@ -8,10 +9,15 @@ from feedgen.feed import FeedGenerator
 from pony import orm
 from pony.orm import Required, Optional, Set
 
+config = configparser.ConfigParser()
+config.read('settings.ini')
+
+site_url = config['general']['site_url']
+if site_url[:-1] != '/':
+    site_url += '/'
+site_url += 'feeds/'
+
 app = Flask(__name__)
-
-SITE_URL = 'http://localhost:5000/feeds/'
-
 db = orm.Database()
 
 class Feed(db.Entity):
@@ -31,7 +37,21 @@ class Item(db.Entity):
     content = Required(str)
     date = Required(datetime)
 
-db.bind(provider='sqlite', filename='db.sqlite', create_db=True)
+db_config = config['db']
+db_adapter = db_config['adapter']
+
+if db_adapter == 'sqlite':
+    filename = db_config['filename']
+    db.bind(provider='sqlite', filename=filename, create_db=True)
+elif db_adapter == 'postgres':
+    user = db_config['user']
+    password = db_config['password']
+    host = db_config['host']
+    database = db_config['database']
+    db.bind(provider='postgres', user=user, password=password, host=host, database=database)
+else:
+    raise Exception('unhandled db adapter: {}'.format(db_adapter))
+
 db.generate_mapping(create_tables=True)
 orm.set_sql_debug(True)
 
@@ -54,7 +74,7 @@ def add_feed():
     if 'title' not in data or 'description' not in data or 'admin_token' not in data:
         abort(400, "missing title or description or admin_token")
 
-    url = SITE_URL + slug
+    url = site_url + slug
 
     with orm.db_session:
         feed = Feed(slug=slug,

requirements.txt

@@ -1,3 +1,4 @@
 Flask
 feedgen
 pony
+psycopg2cffi

settings.ini

@@ -0,0 +1,9 @@
+[general]
+site_url=http://localhost:5000
+
+[db]
+adapter=postgres
+host=localhost
+user=postgres
+password=mysecretpassword
+database=postgres