Parametrizing app by its location (host's URL)

Used for authorization re-directs.

Makefile

@@ -1,6 +1,6 @@
 NAME = webshell.exe
 
-SRC  = parser.opa editor.opa webshell.opa login.opa facebook.opa serach.opa dropbox.opa
+SRC  = parser.opa editor.opa webshell.opa login.opa facebook.opa search.opa dropbox.opa config.opa
 SRCS = $(SRC:%=src/%)
 
 all: $(NAME)

src/config.opa

@@ -0,0 +1,37 @@
+// license: AGPL
+// (c) MLstate, 2011, 2012
+// author: Adam Koprowski
+
+database string /host
+
+module Config {
+
+   // TODO: abstract away this pattern
+  server host =
+    _ = CommandLine.filter(
+      { init: void
+      , parsers: [{ CommandLine.default_parser with
+          names: ["--host"],
+          param_doc: "HOST",
+          description: "Sets the address of the application (needed for all redirects)",
+          function on_param(state) {
+            parser host=(.*) ->
+            {
+              /host <- Text.to_string(host)
+              {no_params: state}
+            }
+          }
+        }]
+      , anonymous: []
+      , title: "General options"
+      }
+    )
+    match (?/host) {
+      case {some: host}: host
+      default:
+        Log.error("webshell[config]", "Cannot read host configuration
+Please re-run your application with: --host option")
+        System.exit(1)
+    }
+
+}

src/facebook.opa

@@ -46,7 +46,7 @@ Please re-run your application with: --fb-config option")
   private FBA = FbAuth(config)
   private FBG = FbGraph
 
-  private redirect = "http://webshell.tutorials.opalang.org/connect"
+  private redirect = "http://{Config.host}/connect/facebook"
 
   private function get_fb_name(token) {
     opts = { FBG.Read.default_object with token:token.token }