Add JSON Marshal/Unmarshal to Proof

parsers/parsers_test.go

@@ -1,10 +1,12 @@
 package parsers
 
 import (
+	"encoding/json"
 	"io/ioutil"
 	"os"
 	"testing"
 
+	"github.com/iden3/go-circom-prover-verifier/types"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -194,5 +196,18 @@ func TestProofSmartContractFormat(t *testing.T) {
 
 	pSC2 := ProofStringToSmartContractFormat(pS)
 	assert.Equal(t, pSC, pSC2)
+}
+
+func TestProofJSON(t *testing.T) {
+	proofJson, err := ioutil.ReadFile("../testdata/circuit1k/proof.json")
+	require.Nil(t, err)
+	proof, err := ParseProof(proofJson)
+	require.Nil(t, err)
 
+	proof1JSON, err := json.Marshal(proof)
+	require.Nil(t, err)
+	var proof1 types.Proof
+	err = json.Unmarshal(proof1JSON, &proof1)
+	require.Nil(t, err)
+	require.Equal(t, *proof, proof1)
 }

types/types.go

@@ -1,6 +1,8 @@
 package types
 
 import (
+	"encoding/hex"
+	"encoding/json"
 	"math/big"
 
 	bn256 "github.com/ethereum/go-ethereum/crypto/bn256/cloudflare"
@@ -16,6 +18,52 @@ type Proof struct {
 	C *bn256.G1
 }
 
+type proofAux struct {
+	A string `json:"pi_a"`
+	B string `json:"pi_b"`
+	C string `json:"pi_c"`
+}
+
+func (p Proof) MarshalJSON() ([]byte, error) {
+	var pa proofAux
+	pa.A = hex.EncodeToString(p.A.Marshal())
+	pa.B = hex.EncodeToString(p.B.Marshal())
+	pa.C = hex.EncodeToString(p.C.Marshal())
+	return json.Marshal(pa)
+}
+
+func (p *Proof) UnmarshalJSON(data []byte) error {
+	var pa proofAux
+	if err := json.Unmarshal(data, &pa); err != nil {
+		return err
+	}
+	aBytes, err := hex.DecodeString(pa.A)
+	if err != nil {
+		return err
+	}
+	p.A = new(bn256.G1)
+	if _, err := p.A.Unmarshal(aBytes); err != nil {
+		return err
+	}
+	bBytes, err := hex.DecodeString(pa.B)
+	if err != nil {
+		return err
+	}
+	p.B = new(bn256.G2)
+	if _, err := p.B.Unmarshal(bBytes); err != nil {
+		return err
+	}
+	cBytes, err := hex.DecodeString(pa.C)
+	if err != nil {
+		return err
+	}
+	p.C = new(bn256.G1)
+	if _, err := p.C.Unmarshal(cBytes); err != nil {
+		return err
+	}
+	return nil
+}
+
 // Pk holds the data structure of the ProvingKey
 type Pk struct {
 	A          []*bn256.G1