Modifies options so that the use of code is strongly encouraged.

scat.cabal

@@ -10,7 +10,7 @@ name:                scat
 -- PVP summary:      +-+------- breaking API changes
 --                   | | +----- non-breaking API additions
 --                   | | | +--- code changes with no API change
-version:             0.2.1.0
+version:             1.0.0.0
 
 -- A short (one-line) description of the package.
 synopsis:            Generates unique passwords for various websites from a single password.
@@ -63,5 +63,5 @@ executable scat
   other-modules:       Scat.Builder, Scat.Schemas, Scat.Options, Scat.Utils.Permutation, Paths_scat
   
   -- Other library packages from which modules are imported.
-  build-depends:       base ==4.5.*, scrypt ==0.3.*, bytestring ==0.9.*, optparse-applicative ==0.5.*, mtl ==2.1.*, vector ==0.10.*
+  build-depends:       base ==4.5.*, scrypt ==0.3.*, bytestring ==0.9.*, optparse-applicative ==0.5.*, mtl ==2.1.*, vector ==0.10.*, ansi-terminal ==0.6.*
   

src/Scat.hs

@@ -9,6 +9,7 @@ import Data.ByteString (unpack)
 import qualified Data.ByteString.Char8 as C
 import System.IO
 import System.Exit
+import System.Console.ANSI
 import Control.Exception
 import Control.Monad.Reader
 import Crypto.Scrypt
@@ -17,19 +18,34 @@ import Scat.Schemas
 import Scat.Builder
 import Scat.Options
 
--- | Generates the seed integer given a key and a password.
+-- | Generates the seed integer given a service, a password and a code.
 scatter :: ByteString -> ByteString -> ByteString -> Integer
 scatter k pw c = foldr (\ n s -> fromIntegral n + 256 * s) 0 $
-        unpack $ unHash $ scrypt params (Salt k) (Pass $ pw <> c)
-    where
-        Just params = scryptParams 14 8 50
+    unpack $ unHash $ scrypt params (Salt k) (Pass $ pw <> c)
+  where
+    Just params = scryptParams 14 8 50
 
 -- | Main type of the program.
 type Scat a = ReaderT Options IO a
 
+-- | Input visibility.
+data Visibility = Shown | Hidden | Erased
+
+-- | Should the input be echoed?
+shouldShow :: Visibility -> Bool
+shouldShow Shown  = True
+shouldShow Hidden = False
+shouldShow Erased = True
+
+-- | Should the input be erased afterwards?
+shouldErase :: Visibility -> Bool
+shouldErase Shown  = False
+shouldErase Hidden = False
+shouldErase Erased = True 
+
 {- | Generates a password, given a input password,
-     a key (category, website, etc.),
-     and a password `Schema`.
+     a service name (category, website, etc.),
+     a code, and a password `Schema`.
 
      The parameters are specified as command line arguments.
      The password can be read from @stdin@ if not already provided. -}
@@ -39,7 +55,7 @@ main = getOptions >>= runReaderT scat
 -- | Main program.
 scat :: Scat ()
 scat = do
-    k  <- getKey
+    k  <- getService
     s  <- getSchema
     pw <- getPassword
     c  <- getCode
@@ -69,32 +85,41 @@ getPassword = do
         -- Retrieve the password from the arguments.
         Just st -> return $ C.pack st
   where
-    getPass = askPassword False "Password: "
+    getPass = prompt Hidden "Password: "
 
     getPassConfirm = do
-        a <- askPassword False "Password: "
-        b <- askPassword False "Confirm: "
+        a <- prompt Hidden "Password: "
+        b <- prompt Hidden "Confirm: "
         if a == b
             then return a
             else do
                 printVerbose "Passwords do not match, please retry.\n"
                 getPassConfirm
 
--- | Ask a password on the command line, with the specified prompt.
-askPassword :: Bool -> String -> Scat ByteString
-askPassword echo str = do
+-- | Ask a for input on the command line, with the specified prompt.
+prompt :: Visibility -> String -> Scat ByteString
+prompt vis str = do
     printVerbose str
     old <- liftIO $ hGetEcho stdin
     pw <- liftIO $ bracket_
-        (hSetEcho stdin echo)
+        (hSetEcho stdin $ shouldShow vis)
         (hSetEcho stdin old)
         C.getLine
-    unless echo $ printVerbose "\n"
+    when (shouldErase vis) $ liftIO $ do
+        cursorUpLine 1
+        cursorForward $ length str
+        clearFromCursorToScreenEnd
+        cursorDownLine 1
+    unless (shouldShow vis) $ printVerbose "\n"
     return pw
 
--- | Gets the key.
-getKey :: Scat ByteString
-getKey = fmap (C.pack . key) ask
+-- | Gets the service.
+getService :: Scat ByteString
+getService = do
+    mk <- fmap service ask
+    case mk of
+        Just k -> return $ C.pack k
+        Nothing -> prompt Shown "Service: "
 
 -- | Gets the code.
 getCode :: Scat ByteString
@@ -105,7 +130,7 @@ getCode = do
             mc <- fmap code ask
             case mc of
                 Just st -> return $ C.pack st
-                Nothing -> askPassword True "Code: "
+                Nothing -> prompt Erased "Code: "
         else return ""
 
 -- | Gets the schema to generate the new password.

src/Scat/Options.hs

@@ -7,7 +7,7 @@ module Scat.Options
 
     -- * Accessors
     , password
-    , key
+    , service
     , useCode
     , code
     , schema
@@ -19,43 +19,33 @@ module Scat.Options
     ) where
 
 import Data.Monoid
-import Data.Maybe (isJust)
 import Options.Applicative
 
 -- | All program options.
 data Options = Options
     { password :: Maybe String
     -- ^ Password, optionally provided.
-    , key      :: String
-    -- ^ Key or category for the password.
-    , useCode_ :: Bool
+    , service  :: Maybe String
+    -- ^ Service for which to generate the password.
+    , useCode  :: Bool
     -- ^ Indicates if extra code should be used.
     , code     :: Maybe String
-    -- ^ Extra code. Activates code usage.
+    -- ^ Extra code.
     , schema   :: String
     -- ^ Name of the schema to use.
-    , verbose_ :: Bool
+    , verbose  :: Bool
     -- ^ Verbosity. If false, do not print anything but the generated password.
     , confirm  :: Bool
-    -- ^ Indicates if the password must be confirmed. Activates verbosity.
+    -- ^ Indicates if the password must be confirmed.
     }
 
--- | Indicates if extra code should be used.
-useCode :: Options -> Bool
-useCode opts = useCode_ opts || isJust (code opts)
-
-{- | Verbosity. If false, do not print anything but the generated password.
-     True when @--verbose@ or @--confirmation@ are specified. -}
-verbose :: Options -> Bool
-verbose opts = verbose_ opts || confirm opts
-
 -- | Parses the arguments from the command line.
 getOptions :: IO Options
 getOptions = execParser opts
   where
     opts = info (helper <*> options)
         (fullDesc
-        <> progDesc "Safely generate passwords derived from a unique password."
+        <> progDesc "Safely generate passwords derived from a unique password and code."
         <> header "scat - a password scatterer")
 
 -- | Option parser.
@@ -66,18 +56,18 @@ options = Options
         <> long "password"
         <> help "The password"
         <> metavar "PASSWORD"))
-    <*> strOption
-          (short 'k'
-        <> long "key"
-        <> help "Key associated (website, email address, ...) (mandatory)"
-        <> metavar "KEY")
-    <*> switch
-          (short 'x'
-        <> long "extra"
-        <> help "Indicates extra code should be used.")
+    <*> optional (strOption
+          (short 'S'
+        <> long "service"
+        <> help "Service associated (website, email address, ...)"
+        <> metavar "SERVICE"))
+    <*> flag True False
+          (long "nocode"
+        <> help "Indicates that extra code should be not be used")
     <*> optional
-          (strOption (long "code"
-        <> help "Extra code."
+          (strOption (short 'x'
+        <> long "code"
+        <> help "The extra code to use"
         <> metavar "CODE"))
     <*> strOption
           (short 's'
@@ -86,10 +76,9 @@ options = Options
         <> metavar "SCHEMA"
         <> value "safe"
         <> showDefault)
-    <*> switch
-          (short 'v'
-        <> long "verbose"
-        <> help "Prints instructions and information")
+    <*> flag True False
+          (long "silent"
+        <> help "Do not print anything but the generated password")
     <*> switch
           (short 'c'
         <> long "confirmation"