Read the served hostname from the config file

src/main.cpp

@@ -5,26 +5,42 @@
 #include <iostream>
 #include <memory>
 
+/**
+ * Provide an helpful message to help the user write a minimal working
+ * configuration file.
+ */
+int config_help(const std::string& missing_option)
+{
+  if (!missing_option.empty())
+    std::cerr << "Error: empty value for option " << missing_option << "." << std::endl;
+  std::cerr <<
+    "Please provide a configuration file filled like this:\n\n"
+    "hostname=irc.example.com\npassword=S3CR3T"
+            << std::endl;
+  return 1;
+}
+
 int main(int ac, char** av)
 {
   if (ac > 1)
     Config::filename = av[1];
   Config::file_must_exist = true;
+  std::cerr << "Using configuration file: " << Config::filename << std::endl;
 
   std::string password;
   try { // The file must exist
     password = Config::get("password", "");
   }
   catch (const std::ios::failure& e) {
-    return 1;
+    return config_help("");
   }
+  const std::string hostname = Config::get("hostname", "");
   if (password.empty())
-    {
-      std::cerr << "No password provided." << std::endl;
-      return 1;
-    }
+    return config_help("hostname");
+  if (hostname.empty())
+    return config_help("password");
   std::shared_ptr<XmppComponent> xmpp_component =
-    std::make_shared<XmppComponent>("irc.abricot", password);
+    std::make_shared<XmppComponent>(hostname, password);
 
   Poller p;
   p.add_socket_handler(xmpp_component);