Use a more robust check for isUrl validator (#1880)

* Use a more robust check for isUrl

* URL must start with http:// or https://

IHP/ValidationSupport/ValidateField.hs

@@ -18,6 +18,7 @@ import IHP.ModelSupport
 import IHP.HaskellSupport
 import Text.Regex.TDFA
 import Data.List ((!!))
+import Network.URI (parseURI, uriScheme)
 
 -- | A function taking some value and returning a 'ValidatorResult'
 --
@@ -411,10 +412,15 @@ isColor = validateAny [isRgbHexColor, isRgbaHexColor, isRgbColor, isRgbaColor]
 -- Success
 --
 -- >>> isUrl "digitallyinduced.com"
--- Failure "is not a valid url. It needs to start with http:// or https://"
+-- Failure "URL must start with http:// or https://"
 isUrl :: Text -> ValidatorResult
-isUrl text | "http://" `isPrefixOf` text || "https://" `isPrefixOf` text = Success
-isUrl text = Failure "is not a valid url. It needs to start with http:// or https://"
+isUrl url =
+    case parseURI (unpack url) of
+        Just uri ->
+            if uriScheme uri `elem` ["http:", "https:"]
+                then Success
+                else Failure "URL must start with http:// or https://"
+        Nothing  -> Failure "Invalid URL"
 {-# INLINABLE isUrl #-}