Support setting an fb:app_id in settings.yml

config/settings.yml

@@ -36,3 +36,4 @@ app-name: lebd
 username: dani
 repository: https://gitlab.com/00dani/lebd
 #analytics: UA-YOURCODE
+fb-app-id: "_env:FB_APP_ID:142105433189339"

src/Settings.hs

@@ -62,6 +62,9 @@ data AppSettings = AppSettings
     -- Example app-specific configuration values.
     , appAnalytics              :: Maybe Text
     -- ^ Google Analytics code
+    , appFacebookId          :: Maybe Int
+    -- ^ Facebook app ID, also used for analytics.
+
     , siteTitle                 :: Text
     -- ^ Site-wide title.
     , siteUsername              :: Text
@@ -96,6 +99,7 @@ instance FromJSON AppSettings where
         appSkipCombining          <- o .:? "skip-combining"   .!= defaultDev
 
         appAnalytics              <- o .:? "analytics"
+        appFacebookId             <- o .:? "fb-app-id"
         siteTitle                 <- o .: "title"
         siteUsername              <- o .: "username"
 

templates/default-layout-wrapper.hamlet

@@ -9,6 +9,8 @@ $doctype 5
     $maybe route <- mcurrentRoute
       <link rel="canonical" href=@{route}>
       <meta property="og:url" content=@{route}>
+    $maybe fb <- appFacebookId $ appSettings master
+      <meta property="fb:app_id" content=#{fb}>
     <link rel="sitemap" href=@{SitemapR}>
 
     <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/css/bootstrap.min.css" integrity="sha384-/Y6pD6FV/Vv2HJnA6t+vslU6fwYXjCFtcEpHbNJ0lyAFsXTsjBbfaDjzALeQsN6M" crossorigin="anonymous">