better module for BytesXX

src/api.ml

@@ -62,6 +62,34 @@ module B32 = struct
       ~decode:B32.decode Caqti_type.string
 end
 
+module Bytes32 = struct
+  include Signatures.Bytes32
+
+  let jsont =
+    let decode s = Result.bind (B32.decode s) of_octets in
+    let encode b = to_octets b |> B32.encode in
+    Jsont.of_of_string ~kind:"Bytes32" decode ~enc:encode
+
+  let caqti =
+    Caqti_type.custom
+      ~encode:(fun v -> Ok (to_octets v))
+      ~decode:of_octets Caqti_type.octets
+end
+
+module Bytes64 = struct
+  include Signatures.Bytes64
+
+  let jsont =
+    let decode s = Result.bind (B32.decode s) of_octets in
+    let encode b = to_octets b |> B32.encode in
+    Jsont.of_of_string ~kind:"Bytes64" decode ~enc:encode
+
+  let caqti =
+    Caqti_type.custom
+      ~encode:(fun v -> Ok (to_octets v))
+      ~decode:of_octets Caqti_type.octets
+end
+
 (* TODO error response
    - use GANA error codes
      https://git.gnunet.org/gana.git/tree/gnu-taler-error-codes/registry.rec *)
@@ -676,7 +704,7 @@ module DrainProfitsMessage = struct
     map ~kind:"DrainProfitsMessage" make
     |> mem "debit_account_section" Jsont.string ~enc:debit_account_section
     |> mem "credit_payto_uri" Jsont.string ~enc:credit_payto_uri
-    |> mem "wtid" B32.jsont ~enc:wtid
+    |> mem "wtid" Bytes32.jsont ~enc:wtid
     |> mem "master_sig" MasterDrainProfit.jsont ~enc:master_sig
     |> mem "date" Timestamp.jsont ~enc:date
     |> mem "amount" Amount.jsont ~enc:amount