Started implementing nonce REST query handler

cmd/baseserver/main.go

@@ -13,6 +13,7 @@ import (
 	"github.com/tendermint/basecoin/client/commands"
 	rest "github.com/tendermint/basecoin/client/rest"
 	coinrest "github.com/tendermint/basecoin/modules/coin/rest"
+	noncerest "github.com/tendermint/basecoin/modules/nonce/rest"
 	rolerest "github.com/tendermint/basecoin/modules/roles/rest"
 	"github.com/tendermint/tmlibs/cli"
 )
@@ -58,6 +59,9 @@ func serve(cmd *cobra.Command, args []string) error {
 		rest.RegisterSignTx,
 		// Basecoin post transaction handler
 		rest.RegisterPostTx,
+
+		// Nonce query handler
+		noncerest.RegisterQueryNonce,
 	}
 
 	for _, routeRegistrar := range routeRegistrars {

modules/nonce/rest/handlers.go

@@ -0,0 +1,72 @@
+package rest
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/gorilla/mux"
+	"github.com/spf13/viper"
+
+	"github.com/tendermint/basecoin"
+	"github.com/tendermint/basecoin/client/commands"
+	"github.com/tendermint/basecoin/client/commands/query"
+	"github.com/tendermint/basecoin/errors"
+	"github.com/tendermint/basecoin/modules/coin"
+	"github.com/tendermint/basecoin/modules/nonce"
+	"github.com/tendermint/basecoin/stack"
+	wire "github.com/tendermint/go-wire"
+	lightclient "github.com/tendermint/light-client"
+	"github.com/tendermint/tmlibs/common"
+)
+
+// doQueryNonce is the HTTP handlerfunc to query a nonce
+func doQueryNonce(w http.ResponseWriter, r *http.Request) {
+	args := mux.Vars(r)
+	signature := args["signature"]
+	actor, err := commands.ParseActor(signature)
+	if err != nil {
+		common.WriteError(w, err)
+		return
+	}
+	actor = coin.ChainAddr(actor)
+	key := nonce.GetSeqKey([]basecoin.Actor{actor})
+	key = stack.PrefixedKey(nonce.NameNonce, key)
+
+	prove := !viper.GetBool(commands.FlagTrustNode)
+
+	// query sequence number
+	data, height, err := query.Get(key, prove)
+	if lightclient.IsNoDataErr(err) {
+		err = fmt.Errorf("nonce empty for address: %q", signature)
+		common.WriteError(w, err)
+		return
+	} else if err != nil {
+		common.WriteError(w, err)
+		return
+	}
+
+	// unmarshal sequence number
+	var seq uint32
+	err = wire.ReadBinaryBytes(data, &seq)
+	if err != nil {
+		msg := fmt.Sprintf("Error reading sequence for %X", key)
+		common.WriteError(w, errors.ErrInternal(msg))
+		return
+	}
+
+	// write result to client
+	if err := query.FoutputProof(w, seq, height); err != nil {
+		common.WriteError(w, err)
+	}
+}
+
+// mux.Router registrars
+
+// RegisterQueryNonce is a mux.Router handler that exposes GET
+// method access on route /query/nonce/{signature} to query nonces
+func RegisterQueryNonce(r *mux.Router) error {
+	r.HandleFunc("/query/nonce/{signature}", doQueryNonce).Methods("GET")
+	return nil
+}
+
+// End of mux.Router registrars