cosmos-sdk/x/nft/handler.go

package nft

import (
	"fmt"

	abci "github.com/tendermint/tendermint/abci/types"

	sdk "github.com/cosmos/cosmos-sdk/types"
	"github.com/cosmos/cosmos-sdk/x/nft/internal/keeper"
	"github.com/cosmos/cosmos-sdk/x/nft/internal/types"
)

// GenericHandler routes the messages to the handlers
func GenericHandler(k keeper.Keeper) sdk.Handler {
	return func(ctx sdk.Context, msg sdk.Msg) sdk.Result {
		switch msg := msg.(type) {
		case types.MsgTransferNFT:
			return HandleMsgTransferNFT(ctx, msg, k)
		case types.MsgEditNFTMetadata:
			return HandleMsgEditNFTMetadata(ctx, msg, k)
		case types.MsgMintNFT:
			return HandleMsgMintNFT(ctx, msg, k)
		case types.MsgBurnNFT:
			return HandleMsgBurnNFT(ctx, msg, k)
		default:
			errMsg := fmt.Sprintf("unrecognized nft message type: %T", msg)
			return sdk.ErrUnknownRequest(errMsg).Result()
		}
	}
}

// HandleMsgTransferNFT handler for MsgTransferNFT
func HandleMsgTransferNFT(ctx sdk.Context, msg types.MsgTransferNFT, k keeper.Keeper,
) sdk.Result {

	nft, err := k.GetNFT(ctx, msg.Denom, msg.ID)
	if err != nil {
		return err.Result()
	}
	// update NFT owner
	nft.SetOwner(msg.Recipient)
	// update the NFT (owners are updated within the keeper)
	err = k.UpdateNFT(ctx, msg.Denom, nft)
	if err != nil {
		return err.Result()
	}

	ctx.EventManager().EmitEvents(sdk.Events{
		sdk.NewEvent(
			types.EventTypeTransfer,
			sdk.NewAttribute(types.AttributeKeyRecipient, msg.Recipient.String()),
			sdk.NewAttribute(types.AttributeKeyDenom, msg.Denom),
			sdk.NewAttribute(types.AttributeKeyNFTID, msg.ID),
		),
		sdk.NewEvent(
			sdk.EventTypeMessage,
			sdk.NewAttribute(sdk.AttributeKeyModule, types.AttributeValueCategory),
			sdk.NewAttribute(sdk.AttributeKeySender, msg.Sender.String()),
		),
	})
	return sdk.Result{Events: ctx.EventManager().Events()}
}

// HandleMsgEditNFTMetadata handler for MsgEditNFTMetadata
func HandleMsgEditNFTMetadata(ctx sdk.Context, msg types.MsgEditNFTMetadata, k keeper.Keeper,
) sdk.Result {

	nft, err := k.GetNFT(ctx, msg.Denom, msg.ID)
	if err != nil {
		return err.Result()
	}

	// update NFT
	nft.EditMetadata(msg.TokenURI)
	err = k.UpdateNFT(ctx, msg.Denom, nft)
	if err != nil {
		return err.Result()
	}

	ctx.EventManager().EmitEvents(sdk.Events{
		sdk.NewEvent(
			types.EventTypeEditNFTMetadata,
			sdk.NewAttribute(types.AttributeKeyDenom, msg.Denom),
			sdk.NewAttribute(types.AttributeKeyNFTID, msg.ID),
			sdk.NewAttribute(types.AttributeKeyNFTTokenURI, msg.TokenURI),
		),
		sdk.NewEvent(
			sdk.EventTypeMessage,
			sdk.NewAttribute(sdk.AttributeKeyModule, types.AttributeValueCategory),
			sdk.NewAttribute(sdk.AttributeKeySender, msg.Sender.String()),
		),
	})
	return sdk.Result{Events: ctx.EventManager().Events()}
}

// HandleMsgMintNFT handles MsgMintNFT
func HandleMsgMintNFT(ctx sdk.Context, msg types.MsgMintNFT, k keeper.Keeper,
) sdk.Result {

	nft := types.NewBaseNFT(msg.ID, msg.Recipient, msg.TokenURI)
	err := k.MintNFT(ctx, msg.Denom, &nft)
	if err != nil {
		return err.Result()
	}

	ctx.EventManager().EmitEvents(sdk.Events{
		sdk.NewEvent(
			types.EventTypeMintNFT,
			sdk.NewAttribute(types.AttributeKeyRecipient, msg.Recipient.String()),
			sdk.NewAttribute(types.AttributeKeyDenom, msg.Denom),
			sdk.NewAttribute(types.AttributeKeyNFTID, msg.ID),
			sdk.NewAttribute(types.AttributeKeyNFTTokenURI, msg.TokenURI),
		),
		sdk.NewEvent(
			sdk.EventTypeMessage,
			sdk.NewAttribute(sdk.AttributeKeyModule, types.AttributeValueCategory),
			sdk.NewAttribute(sdk.AttributeKeySender, msg.Sender.String()),
		),
	})
	return sdk.Result{Events: ctx.EventManager().Events()}

}

// HandleMsgBurnNFT handles MsgBurnNFT
func HandleMsgBurnNFT(ctx sdk.Context, msg types.MsgBurnNFT, k keeper.Keeper,
) sdk.Result {

	_, err := k.GetNFT(ctx, msg.Denom, msg.ID)
	if err != nil {
		return err.Result()
	}

	// remove  NFT
	err = k.DeleteNFT(ctx, msg.Denom, msg.ID)
	if err != nil {
		return err.Result()
	}

	ctx.EventManager().EmitEvents(sdk.Events{
		sdk.NewEvent(
			types.EventTypeBurnNFT,
			sdk.NewAttribute(types.AttributeKeyDenom, msg.Denom),
			sdk.NewAttribute(types.AttributeKeyNFTID, msg.ID),
		),
		sdk.NewEvent(
			sdk.EventTypeMessage,
			sdk.NewAttribute(sdk.AttributeKeyModule, types.AttributeValueCategory),
			sdk.NewAttribute(sdk.AttributeKeySender, msg.Sender.String()),
		),
	})
	return sdk.Result{Events: ctx.EventManager().Events()}
}

// EndBlocker is run at the end of the block
func EndBlocker(ctx sdk.Context, k keeper.Keeper) []abci.ValidatorUpdate {
	return nil
}