ip/resolver: move decoders into sub package

ip/resolver/decoder/jsonip.go

@@ -0,0 +1,20 @@
+package decoder
+
+import (
+	"encoding/json"
+	"io"
+)
+
+func Jsonip(r io.Reader) ([]byte, error) {
+	var v struct {
+		Ip       string `json:"ip"`
+		Location string `json:"geo-ip"`
+		Help     string `json:"API Help"`
+	}
+	var val []byte
+	err := json.NewDecoder(r).Decode(&v)
+	if err == nil {
+		val = []byte(v.Ip)
+	}
+	return val, err
+}