refactor: move logStdout/corsPolicy to Middleware

* remove configQuiet from Config

configQuiet was not an end user setting.
The logging setup is now an internal parameter.

* move proxy uri validation to Private dir

src/PostgREST/Private/ProxyUri.hs

@@ -0,0 +1,72 @@
+
+{-|
+Module      : PostgREST.Private.ProxyUri
+Description : Proxy Uri validator
+-}
+module PostgREST.Private.ProxyUri (
+  isMalformedProxyUri
+, toURI
+) where
+
+import Data.Maybe  (fromJust)
+import Data.Text   (pack, toLower)
+import Network.URI (URI (..), URIAuth (..), isAbsoluteURI, parseURI)
+
+import Protolude      hiding (Proxy, dropWhile, get, intercalate,
+                       toLower, toS, (&))
+import Protolude.Conv (toS)
+
+{-|
+  Test whether a proxy uri is malformed or not.
+  A valid proxy uri should be an absolute uri without query and user info,
+  only http(s) schemes are valid, port number range is 1-65535.
+
+  For example
+  http://postgrest.com/openapi.json
+  https://postgrest.com:8080/openapi.json
+-}
+isMalformedProxyUri :: Maybe Text -> Bool
+isMalformedProxyUri Nothing =  False
+isMalformedProxyUri (Just uri)
+  | isAbsoluteURI (toS uri) = not $ isUriValid $ toURI uri
+  | otherwise = True
+
+toURI :: Text -> URI
+toURI uri = fromJust $ parseURI (toS uri)
+
+isUriValid:: URI -> Bool
+isUriValid = fAnd [isSchemeValid, isQueryValid, isAuthorityValid]
+
+fAnd :: [a -> Bool] -> a -> Bool
+fAnd fs x = all ($ x) fs
+
+isSchemeValid :: URI -> Bool
+isSchemeValid URI {uriScheme = s}
+  | toLower (pack s) == "https:" = True
+  | toLower (pack s) == "http:" = True
+  | otherwise = False
+
+isQueryValid :: URI -> Bool
+isQueryValid URI {uriQuery = ""} = True
+isQueryValid _                   = False
+
+isAuthorityValid :: URI -> Bool
+isAuthorityValid URI {uriAuthority = a}
+  | isJust a = fAnd [isUserInfoValid, isHostValid, isPortValid] $ fromJust a
+  | otherwise = False
+
+isUserInfoValid :: URIAuth -> Bool
+isUserInfoValid URIAuth {uriUserInfo = ""} = True
+isUserInfoValid _                          = False
+
+isHostValid :: URIAuth -> Bool
+isHostValid URIAuth {uriRegName = ""} = False
+isHostValid _                         = True
+
+isPortValid :: URIAuth -> Bool
+isPortValid URIAuth {uriPort = ""} = True
+isPortValid URIAuth {uriPort = (':':p)} =
+  case readMaybe p of
+    Just i  -> i > (0 :: Integer) && i < 65536
+    Nothing -> False
+isPortValid _ = False