From b42410ea8029e18d7c1cf92e10f07eb01390db2d Mon Sep 17 00:00:00 2001
From: Tony Stark <ironman0x7b2@protonmail.com>
Date: Fri, 1 Mar 2019 01:10:32 +0530
Subject: [PATCH] Added custom querier

---
 x/auth/keeper.go  | 21 +++++++++++-------
 x/auth/querier.go | 54 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+), 8 deletions(-)
 create mode 100644 x/auth/querier.go

diff --git a/x/auth/keeper.go b/x/auth/keeper.go
index 3727981cf..9476029a1 100644
--- a/x/auth/keeper.go
+++ b/x/auth/keeper.go
@@ -10,17 +10,22 @@ import (
 	"github.com/cosmos/cosmos-sdk/x/params"
 )
 
-var (
-	// AddressStoreKeyPrefix prefix for account-by-address store
-	AddressStoreKeyPrefix = []byte{0x01}
-
-	globalAccountNumberKey = []byte("globalAccountNumber")
-
+const (
 	// StoreKey is string representation of the store key for auth
 	StoreKey = "acc"
 
 	// FeeStoreKey is a string representation of the store key for fees
 	FeeStoreKey = "fee"
+
+	// QuerierRoute is the querier route for acc
+	QuerierRoute = StoreKey
+)
+
+var (
+	// AddressStoreKeyPrefix prefix for account-by-address store
+	AddressStoreKeyPrefix = []byte{0x01}
+
+	globalAccountNumberKey = []byte("globalAccountNumber")
 )
 
 // AccountKeeper encodes/decodes accounts using the go-amino (binary)
@@ -193,7 +198,7 @@ func (ak AccountKeeper) GetNextAccountNumber(ctx sdk.Context) uint64 {
 	return accNumber
 }
 
-//-----------------------------------------------------------------------------
+// -----------------------------------------------------------------------------
 // Params
 
 // SetParams sets the auth module's parameters.
@@ -207,7 +212,7 @@ func (ak AccountKeeper) GetParams(ctx sdk.Context) (params Params) {
 	return
 }
 
-//-----------------------------------------------------------------------------
+// -----------------------------------------------------------------------------
 // Misc.
 
 func (ak AccountKeeper) decodeAccount(bz []byte) (acc Account) {
diff --git a/x/auth/querier.go b/x/auth/querier.go
new file mode 100644
index 000000000..5b40bcbf3
--- /dev/null
+++ b/x/auth/querier.go
@@ -0,0 +1,54 @@
+package auth
+
+import (
+	"fmt"
+
+	abci "github.com/tendermint/tendermint/abci/types"
+
+	"github.com/cosmos/cosmos-sdk/codec"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+)
+
+// query endpoints supported by the auth Querier
+const (
+	QueryAccount = "account"
+)
+
+// creates a querier for auth REST endpoints
+func NewQuerier(keeper AccountKeeper) sdk.Querier {
+	return func(ctx sdk.Context, path []string, req abci.RequestQuery) ([]byte, sdk.Error) {
+		switch path[0] {
+		case QueryAccount:
+			return queryAccount(ctx, req, keeper)
+		default:
+			return nil, sdk.ErrUnknownRequest("unknown auth query endpoint")
+		}
+	}
+}
+
+// defines the params for query: "custom/acc/account"
+type QueryAccountParams struct {
+	Address sdk.AccAddress
+}
+
+func NewQueryAccountParams(addr sdk.AccAddress) QueryAccountParams {
+	return QueryAccountParams{
+		Address: addr,
+	}
+}
+
+func queryAccount(ctx sdk.Context, req abci.RequestQuery, keeper AccountKeeper) ([]byte, sdk.Error) {
+	var params QueryAccountParams
+	if err := keeper.cdc.UnmarshalJSON(req.Data, &params); err != nil {
+		return nil, sdk.ErrInternal(fmt.Sprintf("failed to parse params: %s", err))
+	}
+
+	account := keeper.GetAccount(ctx, params.Address)
+
+	bz, err := codec.MarshalJSONIndent(keeper.cdc, account)
+	if err != nil {
+		return nil, sdk.ErrInternal(sdk.AppendMsgToErr("could not marshal result to JSON", err.Error()))
+	}
+
+	return bz, nil
+}