Fix comments

CHANGELOG.md

@@ -65,6 +65,7 @@ and tx hash will be returned for specific Tendermint errors:
   * `CodeTxInMempoolCache`
   * `CodeMempoolIsFull`
   * `CodeTxTooLarge`
+* (cli) [\#3872](https://github.com/cosmos/cosmos-sdk/issues/3872) Implement a RESTful endpoint and cli command to decode txs via `POST /txs/decode`
 
 ### Improvements
 

x/auth/client/cli/tx.go

@@ -20,6 +20,7 @@ func GetTxCmd(cdc *codec.Codec) *cobra.Command {
 	txCmd.AddCommand(
 		GetMultiSignCommand(cdc),
 		GetSignCommand(cdc),
+		GetDecodeCommand(cdc),
 	)
 	return txCmd
 }

x/auth/client/cli/tx_decode.go

@@ -0,0 +1,52 @@
+package cli
+
+import (
+	"encoding/base64"
+
+	"github.com/spf13/cobra"
+	"github.com/tendermint/go-amino"
+
+	"github.com/cosmos/cosmos-sdk/client"
+	"github.com/cosmos/cosmos-sdk/client/context"
+	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
+)
+
+// txDecodeRespStr implements a simple Stringer wrapper for a decoded tx.
+type txDecodeRespTx authtypes.StdTx
+
+func (tx txDecodeRespTx) String() string {
+	return tx.String()
+}
+
+// GetDecodeCommand returns the decode command to take Amino-serialized bytes and turn it into
+// a JSONified transaction
+func GetDecodeCommand(codec *amino.Codec) *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "decode [amino-byte-string]",
+		Short: "Decode an amino-encoded transaction string",
+		Args:  cobra.ExactArgs(1),
+		RunE: func(cmd *cobra.Command, args []string) (err error) {
+			cliCtx := context.NewCLIContext().WithCodec(codec)
+
+			txBytesBase64 := args[0]
+
+			txBytes, err := base64.StdEncoding.DecodeString(txBytesBase64)
+			if err != nil {
+				return err
+			}
+
+			var stdTx authtypes.StdTx
+			err = cliCtx.Codec.UnmarshalBinaryLengthPrefixed(txBytes, &stdTx)
+			if err != nil {
+				return err
+			}
+
+			response := txDecodeRespTx(stdTx)
+			_ = cliCtx.PrintOutput(response)
+
+			return nil
+		},
+	}
+
+	return client.PostCommands(cmd)[0]
+}