add support for gRPC GetTransaction() (mined tx)

common/darkside.go

@@ -2,6 +2,7 @@ package common
 
 import (
 	"bufio"
+	"bytes"
 	"encoding/hex"
 	"encoding/json"
 	"errors"
@@ -253,7 +254,7 @@ func darksideRawRequest(method string, params []json.RawMessage) (json.RawMessag
 
 	case "getrawtransaction":
 		// Not required for minimal reorg testing.
-		return nil, errors.New("not implemented yet")
+		return darksideGetRawTransaction(params)
 
 	case "sendrawtransaction":
 		var rawtx string
@@ -272,3 +273,35 @@ func darksideRawRequest(method string, params []json.RawMessage) (json.RawMessag
 		return nil, errors.New("there was an attempt to call an unsupported RPC")
 	}
 }
+
+func darksideGetRawTransaction(params []json.RawMessage) (json.RawMessage, error) {
+	// remove the double-quotes from the beginning and end of the hex txid string
+	txbytes, err := hex.DecodeString(string(params[0][1 : 1+64]))
+	if err != nil {
+		return nil, errors.New("-9: " + err.Error())
+	}
+	// Linear search for the tx, somewhat inefficient but this is test code
+	// and there aren't many blocks. If this becomes a performance problem,
+	// we can maintain a map of transactions indexed by txid.
+	for _, b := range state.blocks {
+		block := parser.NewBlock()
+		rest, err := block.ParseFromSlice(b)
+		if err != nil {
+			// this would be strange; we've already parsed this block
+			return nil, errors.New("-9: " + err.Error())
+		}
+		if len(rest) != 0 {
+			return nil, errors.New("-9: block serialization is too long")
+		}
+		for _, tx := range block.Transactions() {
+			if bytes.Equal(tx.GetDisplayHash(), txbytes) {
+				reply := struct {
+					Hex    string `json:"hex"`
+					Height int    `json:"height"`
+				}{hex.EncodeToString(tx.Bytes()), block.GetHeight()}
+				return json.Marshal(reply)
+			}
+		}
+	}
+	return nil, errors.New("-5: No information available about transaction")
+}

frontend/service.go

@@ -170,14 +170,18 @@ func (s *LwdStreamer) GetTransaction(ctx context.Context, txf *walletrpc.TxFilte
 			common.Log.Errorf("GetTransaction error: %s", rpcErr.Error())
 			return nil, errors.New((strings.Split(rpcErr.Error(), ":"))[0])
 		}
-		var txinfo interface{}
+		var txinfo struct {
+			Hex    string
+			Height int
+		}
 		err := json.Unmarshal(result, &txinfo)
 		if err != nil {
 			return nil, err
 		}
-		txBytes := txinfo.(map[string]interface{})["hex"].(string)
-		txHeight := txinfo.(map[string]interface{})["height"].(float64)
-		return &walletrpc.RawTransaction{Data: []byte(txBytes), Height: uint64(txHeight)}, nil
+		return &walletrpc.RawTransaction{
+			Data:   []byte(txinfo.Hex),
+			Height: uint64(txinfo.Height),
+		}, nil
 	}
 
 	if txf.Block != nil && txf.Block.Hash != nil {