!feat(api/gateway): return txdata from submitPFB if it is present (#2329

)

## Overview

Closes #2328

api/gateway/state.go

@@ -148,17 +148,23 @@ func (h *Handler) handleSubmitPFB(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// perform request
-	txResp, err := h.state.SubmitPayForBlob(r.Context(), fee, req.GasLimit, []*apptypes.Blob{blob})
-	if err != nil {
+	txResp, txerr := h.state.SubmitPayForBlob(r.Context(), fee, req.GasLimit, []*apptypes.Blob{blob})
+	if txerr != nil && txResp == nil {
+		// no tx data to return
 		writeError(w, http.StatusInternalServerError, submitPFBEndpoint, err)
-		return
 	}
-	resp, err := json.Marshal(txResp)
+
+	bs, err := json.Marshal(&txResp)
 	if err != nil {
 		writeError(w, http.StatusInternalServerError, submitPFBEndpoint, err)
 		return
 	}
-	_, err = w.Write(resp)
+
+	// if error returned, change status from 200 to 206
+	if txerr != nil {
+		w.WriteHeader(http.StatusPartialContent)
+	}
+	_, err = w.Write(bs)
 	if err != nil {
 		log.Errorw("writing response", "endpoint", submitPFBEndpoint, "err", err)
 	}

api/gateway/state_test.go

@@ -0,0 +1,48 @@
+package gateway
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/golang/mock/gomock"
+	"github.com/stretchr/testify/require"
+
+	stateMock "github.com/celestiaorg/celestia-node/nodebuilder/state/mocks"
+	"github.com/celestiaorg/celestia-node/state"
+)
+
+func TestHandleSubmitPFB(t *testing.T) {
+	ctrl := gomock.NewController(t)
+	mock := stateMock.NewMockModule(ctrl)
+	handler := NewHandler(mock, nil, nil, nil)
+
+	t.Run("partial response", func(t *testing.T) {
+		txResponse := state.TxResponse{
+			Height:    1,
+			TxHash:    "hash",
+			Codespace: "codespace",
+			Code:      1,
+		}
+		// simulate core-app err, since it is not exported
+		timedErr := errors.New("timed out waiting for tx to be included in a block")
+		mock.EXPECT().SubmitPayForBlob(gomock.Any(), gomock.Any(), gomock.Any(), gomock.Any()).
+			Return(&txResponse, timedErr)
+
+		bs, err := json.Marshal(submitPFBRequest{})
+		require.NoError(t, err)
+		httpreq := httptest.NewRequest("GET", "/", bytes.NewReader(bs))
+		respRec := httptest.NewRecorder()
+		handler.handleSubmitPFB(respRec, httpreq)
+
+		var resp state.TxResponse
+		err = json.NewDecoder(respRec.Body).Decode(&resp)
+		require.NoError(t, err)
+
+		require.Equal(t, http.StatusPartialContent, respRec.Code)
+		require.Equal(t, resp, txResponse)
+	})
+}