b64 encode the BoxRef names in a txn when marshaling to json

Author: jannotti

data/basics/fields_test.go

@@ -172,6 +172,9 @@ func TestBlockFields(t *testing.T) {
 		typePath{}.addField("Payset").addValue().addField("SignedTxnWithAD").addField("ApplyData").addField("EvalDelta").addField("LocalDeltas").addValue().addMapKey(),
 		typePath{}.addField("Payset").addValue().addField("SignedTxnWithAD").addField("ApplyData").addField("EvalDelta").addField("LocalDeltas").addValue().addValue().addField("Bytes"),
 		typePath{}.addField("Payset").addValue().addField("SignedTxnWithAD").addField("ApplyData").addField("EvalDelta").addField("Logs").addValue(),
+
+		// This exception is for a NEW string field.  See transactions/json.go to see how we get b64 output.
+		typePath{}.addField("Payset").addValue().addField("SignedTxnWithAD").addField("SignedTxn").addField("Txn").addField("ApplicationCallTxnFields").addField("Boxes").addValue().addField("Name"),
 	}
 
 	seen := make(map[reflect.Type]bool)

data/transactions/json.go

@@ -0,0 +1,57 @@
+// Copyright (C) 2019-2022 Algorand, Inc.
+// This file is part of go-algorand
+//
+// go-algorand is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// go-algorand is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with go-algorand.  If not, see <https://www.gnu.org/licenses/>.
+
+/*
+   This file contains code to adjust the json serialization of
+   Transaction. Currently the only change from the standard serialization
+   provided by the codec package is to cause BoxRefs to be serialized with b64
+   names, rather than the default for string, which would not properly encode
+   their binary nature in JSON.
+
+   Had we done it from the beginning, it would be reasonable to do the same for
+   some other fields that are declared as string, but can contain arbitrary
+   binary data, such as AssetParams fields like unitname and url. We can't do
+   that now, to preserve the shape of our REST APIs. But perhaps we can do it
+   for a v3 REST API.
+
+*/
+
+package transactions
+
+import "github.com/algorand/go-algorand/protocol"
+
+type boxRefStringly struct {
+	_struct struct{} `codec:",omitempty,omitemptyarray"`
+	Index   uint64   `codec:"i"`
+	Name    []byte   `codec:"n"`
+}
+
+// MarshalJSON makes it so BoxRefs emit b64 encoded names
+func (br BoxRef) MarshalJSON() ([]byte, error) {
+	return protocol.EncodeJSON(boxRefStringly{
+		Index: br.Index,
+		Name:  []byte(br.Name),
+	}), nil
+}
+
+// UnmarshalJSON makes it so BoxRefs read u64 names
+func (br *BoxRef) UnmarshalJSON(data []byte) error {
+	var x boxRefStringly
+	protocol.DecodeJSON(data, &x)
+	br.Index = x.Index
+	br.Name = string(x.Name)
+	return nil
+}

data/transactions/json_test.go

@@ -0,0 +1,91 @@
+// Copyright (C) 2019-2022 Algorand, Inc.
+// This file is part of go-algorand
+//
+// go-algorand is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// go-algorand is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with go-algorand.  If not, see <https://www.gnu.org/licenses/>.
+
+package transactions_test
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/algorand/go-algorand/data/basics"
+	"github.com/algorand/go-algorand/data/transactions"
+	"github.com/algorand/go-algorand/data/txntest"
+	"github.com/algorand/go-algorand/protocol"
+	"github.com/stretchr/testify/require"
+)
+
+func decode(data string, v interface{}) error {
+	err := protocol.DecodeJSON([]byte(data), v)
+	if err != nil {
+		panic(err)
+	}
+	return err
+}
+
+func compact(data []byte) string {
+	return strings.ReplaceAll(strings.ReplaceAll(string(data), " ", ""), "\n", "")
+}
+
+// TestJsonMarshal ensures that BoxRef names are b64 encoded, since they may not be characters.
+func TestJsonMarshal(t *testing.T) {
+	marshal := protocol.EncodeJSON(transactions.BoxRef{Index: 4, Name: "joe"})
+	require.Equal(t, `{"i":4,"n":"am9l"}`, compact(marshal))
+
+	marshal = protocol.EncodeJSON(transactions.BoxRef{Index: 0, Name: "joe"})
+	require.Equal(t, `{"n":"am9l"}`, compact(marshal))
+
+	marshal = protocol.EncodeJSON(transactions.BoxRef{Index: 1, Name: ""})
+	require.Equal(t, `{"i":1}`, compact(marshal))
+
+	marshal = protocol.EncodeJSON(transactions.BoxRef{Index: 0, Name: ""})
+	require.Equal(t, `{}`, compact(marshal))
+}
+
+// TestJsonUnmarshal ensures that BoxRef unmarshaling expects b64 names
+func TestJsonUnmarshal(t *testing.T) {
+	var br transactions.BoxRef
+
+	decode(`{"i":4,"n":"am9l"}`, &br)
+	require.Equal(t, transactions.BoxRef{Index: 4, Name: "joe"}, br)
+
+	decode(`{"n":"am9l"}`, &br)
+	require.Equal(t, transactions.BoxRef{Index: 0, Name: "joe"}, br)
+
+	decode(`{"i":4}`, &br)
+	require.Equal(t, transactions.BoxRef{Index: 4, Name: ""}, br)
+
+	decode(`{}`, &br)
+	require.Equal(t, transactions.BoxRef{Index: 0, Name: ""}, br)
+}
+
+// TestTxnJson tests a few more things about how our Transactions get JSON
+// encoded. These things could change without breaking the protocol, should stay
+// the same for the sake of REST API compatibility.
+func TestTxnJson(t *testing.T) {
+	txn := txntest.Txn{
+		Sender: basics.Address{0x01, 0x02, 0x03},
+	}
+	marshal := protocol.EncodeJSON(txn.Txn())
+	require.Contains(t, compact(marshal), `"snd":"AEBA`)
+
+	txn = txntest.Txn{
+		Boxes: []transactions.BoxRef{{Index: 3, Name: "john"}},
+	}
+	marshal = protocol.EncodeJSON(txn.Txn())
+	require.Contains(t, compact(marshal), `"apbx":[{"i":3,"n":"am9obg=="}]`)
+
+	marshal = protocol.EncodeJSON(txn.Txn())
+}