exit if no website(s) are configured and remove default host

isso/__init__.py

@@ -167,7 +167,9 @@ def make_app(conf=None, threading=True, multiprocessing=False, uwsgi=False):
                 logger.info("connected to %s", host)
                 break
     else:
-        logger.warn("unable to connect to %s", ", ".join(conf.getiter("general", "host")))
+        logger.warn("unable to connect to your website, Isso will probably not "
+                    "work correctly. Please make sure, Isso can reach your "
+                    "website via HTTP(S).")
 
     wrapper = [local_manager.make_middleware]
 
@@ -215,6 +217,10 @@ def main():
         migrate.disqus(db.SQLite3(dbpath, conf), args.dump)
         sys.exit(0)
 
+    if not any(conf.getiter("general", "host")):
+        logger.error("No website(s) configured, Isso won't work.")
+        sys.exit(1)
+
     if conf.get("server", "listen").startswith("http://"):
         host, port, _ = parse.host(conf.get("server", "listen"))
         try:

isso/core.py

@@ -114,7 +114,8 @@ class Config:
         "[general]",
         "name = ",
         "dbpath = /tmp/isso.db",
-        "host = http://localhost:8080/", "max-age = 15m",
+        "host = ",
+        "max-age = 15m",
         "notify = ",
         "[moderation]",
         "enabled = false",

isso/utils/__init__.py

@@ -125,10 +125,18 @@ class JSONResponse(Response):
 
 
 def origin(hosts):
+    """
+    Return a function that returns a valid HTTP Origin or localhost
+    if none found.
+    """
 
     hosts = [x.rstrip("/") for x in hosts]
 
     def func(environ):
+
+        if not hosts:
+            return "http://localhost/"
+
         for host in hosts:
             if environ.get("HTTP_ORIGIN", None) == host:
                 return host