Merge pull request #124 from input-output-hk/jonathanknowles/encode-l…

…imits-just-once

Encode the minimum and maximum passphrase lengths just once.

src/Cardano/Wallet/Api/Types.hs

@@ -42,6 +42,10 @@ module Cardano.Wallet.Api.Types
     , AddressPoolGap
     , Passphrase(..)
 
+    -- * Limits
+    , passphraseMinLength
+    , passphraseMaxLength
+
     -- * Polymorphic Types
     , ApiT (..)
     , ApiMnemonicT (..)
@@ -176,13 +180,21 @@ instance ToJSON  WalletPostData where
 
 instance FromJSON (ApiT (Passphrase "encryption")) where
     parseJSON = parseJSON >=> \case
-        t | T.length t < 10 ->
-            fail "passphrase is too short: expected at least 10 chars"
-        t | T.length t > 255 ->
-            fail "passphrase is too long: expect at most 255 chars"
+        t | T.length t < passphraseMinLength ->
+            fail $ "passphrase is too short: expected at least "
+                <> show passphraseMinLength <> " chars"
+        t | T.length t > passphraseMaxLength ->
+            fail $ "passphrase is too long: expected at most "
+                <> show passphraseMaxLength <> " chars"
         t ->
             return $ ApiT $ Passphrase $ BA.convert $ T.encodeUtf8 t
 
+passphraseMinLength :: Int
+passphraseMinLength = 10
+
+passphraseMaxLength :: Int
+passphraseMaxLength = 255
+
 instance ToJSON (ApiT (Passphrase "encryption")) where
     toJSON (ApiT (Passphrase bytes)) = toJSON $ T.decodeUtf8 $ BA.convert bytes
 

test/unit/Cardano/Wallet/Api/TypesSpec.hs

@@ -32,6 +32,8 @@ import Cardano.Wallet.Api.Types
     , WalletPassphraseInfo (..)
     , WalletPostData (..)
     , WalletState (..)
+    , passphraseMaxLength
+    , passphraseMinLength
     )
 import Cardano.Wallet.Primitive.Mnemonic
     ( CheckSumBits
@@ -229,12 +231,16 @@ instance Arbitrary WalletName where
 
 instance Arbitrary (Passphrase "encryption") where
     arbitrary = do
-        n <- choose (10, 255)
+        n <- choose (passphraseMinLength, passphraseMaxLength)
         bytes <- T.encodeUtf8 . T.pack <$> replicateM n arbitraryPrintableChar
         return $ Passphrase $ BA.convert bytes
     shrink (Passphrase bytes)
-        | BA.length bytes <= 10 = []
-        | otherwise = [Passphrase $ BA.convert $ B8.take 10 $ BA.convert bytes]
+        | BA.length bytes <= passphraseMinLength = []
+        | otherwise =
+            [ Passphrase
+            $ BA.convert
+            $ B8.take passphraseMinLength
+            $ BA.convert bytes ]
 
 instance Arbitrary WalletPassphraseInfo where
     arbitrary = genericArbitrary