config validation

src/modules/config.coffee

@@ -18,6 +18,19 @@ defaults =
     # Making NSA (err taxpayer) work for it.
     'protocol': 'https'
 
+# Validators of config fields.
+validators =
+    'host': (value) ->
+        _.isString value
+    'protocol': (value) ->
+        _.isString(value) and value.match /^http(s?)$/
+    'token': (value) ->
+        _.isString value
+    'off_days': (value) ->
+        return no unless _.isArray value
+        ( return no for day in value when day not in [ 1..7 ] )
+        yes
+
 # Get (& cache) configuration from the server.
 module.exports = (cb) ->
     # Have config?
@@ -42,6 +55,11 @@ module.exports = (cb) ->
             else
                 config.size_label = regex.size_label
 
+            # Validate it.
+            for field, validator of validators when config[field]
+                unless validator config[field]
+                    return cb "Config field `#{field}` misconfigured"
+
             # Call back for each enqueued.
             _.each queue, (cb) ->
                 cb null, config