Use (Un)MarshalText instead of (Un)MarshalJSON for encoding.

This is more to the point and will also allow the use of apicid.Hash
as keys is JSON objects.

apicid/apicid.go

@@ -1,8 +1,6 @@
 package apicid
 
 import (
-	"encoding/json"
-
 	cid "github.com/ipfs/go-cid"
 	"github.com/ipfs/go-cidutil/cidenc"
 	mbase "github.com/multiformats/go-multibase"
@@ -12,12 +10,12 @@ import (
 var JSONBase mbase.Encoder = mbase.MustNewEncoder(mbase.Base58BTC)
 
 // apicid.Hash is a type to respesnt a CID in the API which marshals
-// as a hash
+// as a string
 type Hash struct {
-	str string // always in CidJSONBase
+	str string
 }
 
-// FromCid created an APICid from a Cid
+// FromCid creates an APICid from a Cid
 func FromCid(c cid.Cid) Hash {
 	return Hash{c.Encode(JSONBase)}
 }
@@ -42,12 +40,13 @@ func (c Hash) Encode(enc cidenc.Interface) string {
 	return str
 }
 
-func (c *Hash) UnmarshalJSON(b []byte) error {
-	return json.Unmarshal(b, &c.str)
+func (c *Hash) UnmarshalText(b []byte) error {
+	c.str = string(b)
+	return nil
 }
 
-func (c Hash) MarshalJSON() ([]byte, error) {
-	return json.Marshal(c.str)
+func (c Hash) MarshalText() ([]byte, error) {
+	return []byte(c.str), nil
 }
 
 // Cid is type to represent a normal CID in the API which marshals

apicid/apicid_test.go

@@ -0,0 +1,48 @@
+package apicid
+
+import (
+	"encoding/json"
+	"testing"
+
+	cid "github.com/ipfs/go-cid"
+)
+
+func TestJson(t *testing.T) {
+	cid, _ := cid.Decode("zb2rhak9iRgDiik36KQBRr2qiCJHdyBH7YxFmw7FTdM6zo31m")
+	hash := FromCid(cid)
+	data, err := json.Marshal(hash)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if string(data) != `"zb2rhak9iRgDiik36KQBRr2qiCJHdyBH7YxFmw7FTdM6zo31m"` {
+		t.Fatalf("json string incorrect: %s\n", data)
+	}
+	var hash2 Hash
+	err = json.Unmarshal(data, &hash2)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if hash != hash2 {
+		t.Fatal("round trip failed")
+	}
+}
+
+func TestJsonMap(t *testing.T) {
+	cid1, _ := cid.Decode("zb2rhak9iRgDiik36KQBRr2qiCJHdyBH7YxFmw7FTdM6zo31m")
+	cid2, _ := cid.Decode("QmRJggJREPCt7waGQKMXymrXRvrvsSiiPjgFbLK9isuM8K")
+	hash1 := FromCid(cid1)
+	hash2 := FromCid(cid2)
+	m := map[Hash]string{hash1: "a value", hash2: "something else"}
+	data, err := json.Marshal(m)
+	if err != nil {
+		t.Fatal(err)
+	}
+	m2 := map[Hash]string{}
+	err = json.Unmarshal(data, &m2)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(m2) != 2 || m[hash1] != m2[hash1] || m[hash2] != m2[hash2] {
+		t.Fatal("round trip failed")
+	}
+}