backport: tx format server (#59)

cmd/fetchcli/main.go

@@ -115,6 +115,7 @@ func txCmd(cdc *amino.Codec) *cobra.Command {
 		authcmd.GetBroadcastCommand(cdc),
 		authcmd.GetEncodeCommand(cdc),
 		authcmd.GetDecodeCommand(cdc),
+		txFmtCmd(cdc),
 		// TODO: I think it is safe to remove
 		// authcmd.GetDecodeTxCmd(cdc),
 		flags.LineBreak,

cmd/fetchcli/txfmt.go

@@ -0,0 +1,136 @@
+package main
+
+import (
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"github.com/cosmos/cosmos-sdk/codec"
+	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+	"io"
+	"io/ioutil"
+	"net/http"
+)
+
+const (
+	flagPort = "port"
+)
+
+type EncodeResponse struct {
+	EncodedTx string `json:"encoded_tx"`
+}
+
+type EncodeErrResponse struct {
+	Msg   string `json:"msg"`
+	Error string `json:"error"`
+}
+
+func readStdTx(cdc *codec.Codec, stream io.Reader) (stdTx authtypes.StdTx, err error) {
+	var bytes []byte
+	bytes, err = ioutil.ReadAll(stream)
+
+	if err != nil {
+		return
+	}
+
+	if err = cdc.UnmarshalJSON(bytes, &stdTx); err != nil {
+		return
+	}
+
+	return
+}
+
+func encodeJsonResponse(w http.ResponseWriter, resp interface{}, statusCode int) {
+	encodedResp, err := json.Marshal(resp)
+	if err != nil {
+		return
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	if statusCode != http.StatusOK {
+		w.WriteHeader(statusCode)
+	}
+	w.Write(encodedResp)
+}
+
+func handleEncode(cdc *codec.Codec, w http.ResponseWriter, req *http.Request) {
+	if req.Method != "POST" {
+		resp := EncodeErrResponse{
+			Msg:   "POST only endpoint",
+			Error: "",
+		}
+		encodeJsonResponse(w, resp, http.StatusMethodNotAllowed)
+	}
+
+	// read the transaction as posted into the http response
+	stdTx, err := readStdTx(cdc, req.Body)
+	if err != nil {
+		resp := EncodeErrResponse{
+			Msg:   "Unable to parse input transaction format",
+			Error: err.Error(),
+		}
+		encodeJsonResponse(w, resp, http.StatusBadRequest)
+		return
+	}
+
+	// re-encode it via the Amino wire protocol
+	txBytes, err := cdc.MarshalBinaryLengthPrefixed(stdTx)
+	if err != nil {
+		resp := EncodeErrResponse{
+			Msg:   "Unable to generate encoded transaction",
+			Error: err.Error(),
+		}
+		encodeJsonResponse(w, resp, http.StatusInternalServerError)
+		return
+	}
+
+	// base64 encode the encoded tx bytes (so that they can be passed directly to the tendermint protocol
+	resp := EncodeResponse{
+		EncodedTx: base64.StdEncoding.EncodeToString(txBytes),
+	}
+	encodeJsonResponse(w, resp, http.StatusOK)
+}
+
+func handleDecode(cdc *codec.Codec, w http.ResponseWriter, req *http.Request) {
+	resp := EncodeErrResponse{
+		Msg:   "Not implemented",
+		Error: "",
+	}
+	encodeJsonResponse(w, resp, http.StatusNotImplemented)
+
+}
+
+func runTxFmtServer(cdc *codec.Codec) {
+	bindPort := viper.GetInt(flagPort)
+	bindAddr := fmt.Sprintf(":%d", bindPort)
+
+	fmt.Printf("Listening on %s\n", bindAddr)
+
+	http.HandleFunc("/encode", func(w http.ResponseWriter, req *http.Request) {
+		handleEncode(cdc, w, req)
+	})
+	http.HandleFunc("/decode", func(w http.ResponseWriter, req *http.Request) {
+		handleDecode(cdc, w, req)
+	})
+	http.ListenAndServe(bindAddr, nil)
+}
+
+func txFmtCmd(cdc *codec.Codec) *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "fmtd",
+		Short: "Run the tx format server",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			runTxFmtServer(cdc)
+			return nil
+		},
+		Args: cobra.NoArgs,
+	}
+
+	cmd.Flags().Int(
+		flagPort, 8090,
+		"The port the server should run on",
+	)
+
+	return cmd
+}