From 3251ddc7b6dfe48301421bb54ab572699cb90fa3 Mon Sep 17 00:00:00 2001
From: Jean-Paul Calderone <exarkun@twistedmatrix.com>
Date: Wed, 4 Sep 2019 14:59:59 -0400
Subject: [PATCH] a few more comments
---
src/PaymentServer/Redemption.hs | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/src/PaymentServer/Redemption.hs b/src/PaymentServer/Redemption.hs
index 87e3ed0..1d0593c 100644
--- a/src/PaymentServer/Redemption.hs
+++ b/src/PaymentServer/Redemption.hs
@@ -81,9 +81,13 @@ data Result
-- signatures returned to the caller.
type BlindedToken = Text
+-- | A complete redemption attempt which can be presented at the redemption
+-- endpoint.
data Redeem
- = Redeem { redeemVoucher :: Voucher, redeemTokens :: [BlindedToken] }
- deriving (Show, Eq, Generic)
+ = Redeem
+ { redeemVoucher :: Voucher -- ^ The voucher being redeemed.
+ , redeemTokens :: [BlindedToken] -- ^ Tokens to be signed as part of this redemption.
+ } deriving (Show, Eq, Generic)
instance FromJSON Redeem
@@ -120,6 +124,9 @@ jsonErr400 = err400
redemptionServer :: VoucherDatabase d => d -> Server RedemptionAPI
redemptionServer = redeem
+-- | Handler for redemption requests. Use the database to try to redeem the
+-- voucher and return signatures. Return a failure if this is not possible
+-- (eg because the voucher was already redeemed).
redeem :: VoucherDatabase d => d -> Redeem -> Handler Result
redeem database (Redeem voucher tokens) = do
let fingerprint = fingerprintFromTokens tokens
@@ -128,6 +135,8 @@ redeem database (Redeem voucher tokens) = do
Left err -> throwError jsonErr400
Right () -> return $ Succeeded "" [] ""
+-- | Compute a cryptographic hash (fingerprint) of a list of tokens which can
+-- be used as an identifier for this exact sequence of tokens.
fingerprintFromTokens :: [BlindedToken] -> Fingerprint
fingerprintFromTokens =
let
--
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