Clean up seed input/output code

client/commands/seeds/export.go

@@ -1,15 +1,11 @@
 package seeds
 
 import (
-	"encoding/json"
-	"os"
-
 	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
 
 	"github.com/cosmos/cosmos-sdk/client/commands"
-	"github.com/tendermint/light-client/certifiers"
 )
 
 var exportCmd = &cobra.Command{
@@ -44,17 +40,5 @@ func exportSeed(cmd *cobra.Command, args []string) error {
 	}
 
 	// now get the output file and write it
-	return writeSeed(seed, path)
-}
-
-// TODO use certifiers function
-func writeSeed(seed certifiers.Seed, path string) (err error) {
-	f, err := os.Create(path)
-	if err != nil {
-		return errors.WithStack(err)
-	}
-	defer f.Close()
-	stream := json.NewEncoder(f)
-	err = stream.Encode(seed)
-	return errors.WithStack(err)
+	return seed.WriteJSON(path)
 }

client/commands/seeds/import.go

@@ -42,7 +42,7 @@ func importSeed(cmd *cobra.Command, args []string) error {
 
 	// parse the input file
 	path := args[0]
-	seed, err := certifiers.LoadSeed(path)
+	seed, err := certifiers.LoadSeedJSON(path)
 	if err != nil {
 		return err
 	}

client/commands/seeds/show.go

@@ -47,7 +47,7 @@ func loadSeed(p certifiers.Provider, h int, hash, file string) (seed certifiers.
 			seed, err = p.GetByHash(vhash)
 		}
 	} else if file != "" {
-		seed, err = certifiers.LoadSeed(file)
+		seed, err = certifiers.LoadSeedJSON(file)
 	} else {
 		// default is latest seed
 		seed, err = certifiers.LatestSeed(p)