Add delegator bond query API endpoint

x/stake/rest/query.go

@@ -0,0 +1,79 @@
+package rest
+
+import (
+	"encoding/hex"
+	"fmt"
+	"net/http"
+
+	"github.com/gorilla/mux"
+	"github.com/tendermint/go-crypto/keys"
+
+	"github.com/cosmos/cosmos-sdk/client/context"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/wire"
+	"github.com/cosmos/cosmos-sdk/x/stake"
+)
+
+// RegisterRoutes - Central function to define routes that get registered by the main application
+func RegisterRoutes(r *mux.Router, cdc *wire.Codec, kb keys.Keybase) {
+	r.HandleFunc("/stake/{delegator}/bonding_status/{candidate}", BondingStatusHandler("stake", cdc, kb)).Methods("GET")
+}
+
+// BondingStatusHandler - http request handler to query delegator bonding status
+func BondingStatusHandler(storeName string, cdc *wire.Codec, kb keys.Keybase) func(http.ResponseWriter, *http.Request) {
+	ctx := context.NewCoreContextFromViper()
+	return func(w http.ResponseWriter, r *http.Request) {
+		// read parameters
+		vars := mux.Vars(r)
+		delegator := vars["delegator"]
+		validator := vars["validator"]
+
+		bz, err := hex.DecodeString(delegator)
+		if err != nil {
+			w.WriteHeader(http.StatusBadRequest)
+			w.Write([]byte(err.Error()))
+			return
+		}
+		delegatorAddr := sdk.Address(bz)
+
+		bz, err = hex.DecodeString(validator)
+		if err != nil {
+			w.WriteHeader(http.StatusBadRequest)
+			w.Write([]byte(err.Error()))
+			return
+		}
+		candidateAddr := sdk.Address(bz)
+
+		key := stake.GetDelegatorBondKey(delegatorAddr, candidateAddr, cdc)
+
+		res, err := ctx.Query(key, storeName)
+		if err != nil {
+			w.WriteHeader(http.StatusInternalServerError)
+			w.Write([]byte(fmt.Sprintf("Couldn't query bond. Error: %s", err.Error())))
+			return
+		}
+
+		// the query will return empty if there is no data for this bond
+		if len(res) == 0 {
+			w.WriteHeader(http.StatusNoContent)
+			return
+		}
+
+		var bond stake.DelegatorBond
+		err = cdc.UnmarshalBinary(res, &bond)
+		if err != nil {
+			w.WriteHeader(http.StatusInternalServerError)
+			w.Write([]byte(fmt.Sprintf("Couldn't decode bond. Error: %s", err.Error())))
+			return
+		}
+
+		output, err := cdc.MarshalJSON(bond)
+		if err != nil {
+			w.WriteHeader(http.StatusInternalServerError)
+			w.Write([]byte(err.Error()))
+			return
+		}
+
+		w.Write(output)
+	}
+}