Need to bind localhost explicitly for gunicorn

Without an explicit bind it seems to only bind to the 127.0.0.1 IP. To
support using CLI options with gunicorn the application cannot also
parse the options. Instead only use optparse when running stand-alone.

Author: Zegnat

README.md

@@ -29,7 +29,7 @@ Next, start the server. You can do this in either debugging mode (where `debug=T
 
 ```
 python3 app.py --debug (debug mode)
-gunicorn app:app (production mode)
+gunicorn --bind localhost:8080 app:app (production mode)
 ```
 
 You can view your running local application at this URL:

app.py

@@ -1,24 +1,11 @@
 import json
 import traceback
 from collections import OrderedDict
-from optparse import OptionParser
 
 import mf2py
 import mf2util
 from flask import Flask, jsonify, make_response, render_template, request
 
-parser = OptionParser()
-
-parser.add_option(
-    "-d",
-    "--debug",
-    action="store_true",
-    default=False,
-    help="Run application in debug mode",
-)
-
-(options, args) = parser.parse_args()
-
 app = Flask(__name__)
 
 mf2py.Parser.user_agent = "python.microformats.io (mf2py/" + mf2py.__version__ + ") Mozilla/5.0 Chrome/29.0.1547.57 Safari/537.36"
@@ -68,6 +55,18 @@ def fetch_mf2(url):
         traceback.print_exc()
         return jsonify(error="%s: %s" % (type(e).__name__, e)), 400
 
+if __name__ == "__main__":
+    from optparse import OptionParser
+
+    parser = OptionParser()
+    parser.add_option(
+        "-d",
+        "--debug",
+        action="store_true",
+        default=False,
+        help="Run application in debug mode",
+    )
+    (options, args) = parser.parse_args()
 
-if options.debug:
-    app.run(debug=True, port=8080)
+    if options.debug:
+        app.run(debug=True, port=8080)