Blob API - invalid indicies should error instead of ignored (#13616)

* addressing ux issue when using API

* Update beacon-chain/rpc/eth/blob/handlers.go

Co-authored-by: Preston Van Loon <pvanloon@offchainlabs.com>

* Update beacon-chain/rpc/eth/blob/handlers.go

Co-authored-by: Preston Van Loon <pvanloon@offchainlabs.com>

* fixing tests

---------

Co-authored-by: Preston Van Loon <pvanloon@offchainlabs.com>

beacon-chain/rpc/eth/blob/handlers.go

@@ -1,6 +1,7 @@
 package blob
 
 import (
+	"fmt"
 	"net/http"
 	"net/url"
 	"strconv"
@@ -21,7 +22,11 @@ func (s *Server) Blobs(w http.ResponseWriter, r *http.Request) {
 	defer span.End()
 	var sidecars []*eth.BlobSidecar
 
-	indices := parseIndices(r.URL)
+	indices, err := parseIndices(r.URL)
+	if err != nil {
+		httputil.HandleError(w, err.Error(), http.StatusBadRequest)
+		return
+	}
 	segments := strings.Split(r.URL.Path, "/")
 	blockId := segments[len(segments)-1]
 
@@ -63,16 +68,19 @@ func (s *Server) Blobs(w http.ResponseWriter, r *http.Request) {
 }
 
 // parseIndices filters out invalid and duplicate blob indices
-func parseIndices(url *url.URL) []uint64 {
+func parseIndices(url *url.URL) ([]uint64, error) {
 	rawIndices := url.Query()["indices"]
 	indices := make([]uint64, 0, field_params.MaxBlobsPerBlock)
+	invalidIndices := make([]string, 0)
 loop:
 	for _, raw := range rawIndices {
 		ix, err := strconv.ParseUint(raw, 10, 64)
 		if err != nil {
+			invalidIndices = append(invalidIndices, raw)
 			continue
 		}
 		if ix >= field_params.MaxBlobsPerBlock {
+			invalidIndices = append(invalidIndices, raw)
 			continue
 		}
 		for i := range indices {
@@ -82,7 +90,11 @@ loop:
 		}
 		indices = append(indices, ix)
 	}
-	return indices
+
+	if len(invalidIndices) > 0 {
+		return nil, fmt.Errorf("requested blob indices %v are invalid", invalidIndices)
+	}
+	return indices, nil
 }
 
 func buildSidecarsResponse(sidecars []*eth.BlobSidecar) *structs.SidecarsResponse {

beacon-chain/rpc/eth/blob/handlers_test.go

@@ -7,6 +7,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"net/url"
+	"reflect"
 	"strings"
 	"testing"
 	"time"
@@ -27,10 +28,6 @@ import (
 	"github.com/prysmaticlabs/prysm/v5/testing/util"
 )
 
-func TestParseIndices(t *testing.T) {
-	assert.DeepEqual(t, []uint64{1, 2, 3}, parseIndices(&url.URL{RawQuery: "indices=100&indices=1&indices=2&indices=foo&indices=1&indices=3&bar=bar"}))
-}
-
 func TestBlobs(t *testing.T) {
 	params.SetupTestConfigCleanup(t)
 	cfg := params.BeaconConfig().Copy()
@@ -372,3 +369,46 @@ func TestBlobs(t *testing.T) {
 		require.Equal(t, len(writer.Body.Bytes()), 131932)
 	})
 }
+
+func Test_parseIndices(t *testing.T) {
+	tests := []struct {
+		name    string
+		query   string
+		want    []uint64
+		wantErr string
+	}{
+		{
+			name:  "happy path with duplicate indices within bound and other query parameters ignored",
+			query: "indices=1&indices=2&indices=1&indices=3&bar=bar",
+			want:  []uint64{1, 2, 3},
+		},
+		{
+			name:    "out of bounds indices throws error",
+			query:   "indices=6&indices=7",
+			wantErr: "requested blob indices [6 7] are invalid",
+		},
+		{
+			name:    "negative indices",
+			query:   "indices=-1&indices=-8",
+			wantErr: "requested blob indices [-1 -8] are invalid",
+		},
+		{
+			name:    "invalid indices",
+			query:   "indices=foo&indices=bar",
+			wantErr: "requested blob indices [foo bar] are invalid",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := parseIndices(&url.URL{RawQuery: tt.query})
+			if err != nil && tt.wantErr != "" {
+				require.StringContains(t, tt.wantErr, err.Error())
+				return
+			}
+			require.NoError(t, err)
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("parseIndices() got = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}