Publish blockv2 ssz (#12636)

* wip produce block v2 ssz

* adding functions for ssz processing

* fixing linting

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

Co-authored-by: Radosław Kapka <rkapka@wp.pl>

* addressing review feedback

* fixing linting

---------

Co-authored-by: Radosław Kapka <rkapka@wp.pl>

network/BUILD.bazel

@@ -6,6 +6,7 @@ go_library(
         "auth.go",
         "endpoint.go",
         "external_ip.go",
+        "reader.go",
         "writer.go",
     ],
     importpath = "github.com/prysmaticlabs/prysm/v4/network",
@@ -25,6 +26,7 @@ go_test(
         "auth_test.go",
         "endpoint_test.go",
         "external_ip_test.go",
+        "reader_test.go",
     ],
     embed = [":go_default_library"],
     deps = [

network/reader.go

@@ -0,0 +1,51 @@
+package network
+
+import (
+	"net/http"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+// match a number with optional decimals
+var priorityRegex = regexp.MustCompile(`q=(\d+(?:\.\d+)?)`)
+
+// SszRequested takes a http request and checks to see if it should be requesting a ssz response.
+func SszRequested(req *http.Request) (bool, error) {
+	accept := req.Header.Values("Accept")
+	if len(accept) == 0 {
+		return false, nil
+	}
+	types := strings.Split(accept[0], ",")
+	currentType, currentPriority := "", 0.0
+	for _, t := range types {
+		values := strings.Split(t, ";")
+		name := values[0]
+		if name != jsonMediaType && name != octetStreamMediaType {
+			continue
+		}
+		// no params specified
+		if len(values) == 1 {
+			priority := 1.0
+			if priority > currentPriority {
+				currentType, currentPriority = name, priority
+			}
+			continue
+		}
+		params := values[1]
+
+		match := priorityRegex.FindAllStringSubmatch(params, 1)
+		if len(match) != 1 {
+			continue
+		}
+		priority, err := strconv.ParseFloat(match[0][1], 32)
+		if err != nil {
+			return false, err
+		}
+		if priority > currentPriority {
+			currentType, currentPriority = name, priority
+		}
+	}
+
+	return currentType == octetStreamMediaType, nil
+}

network/reader_test.go

@@ -0,0 +1,99 @@
+package network
+
+import (
+	"fmt"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/prysmaticlabs/prysm/v4/testing/assert"
+	"github.com/prysmaticlabs/prysm/v4/testing/require"
+)
+
+func TestSSZRequested(t *testing.T) {
+	t.Run("ssz_requested", func(t *testing.T) {
+		request := httptest.NewRequest("GET", "http://foo.example", nil)
+		request.Header["Accept"] = []string{octetStreamMediaType}
+		result, err := SszRequested(request)
+		require.NoError(t, err)
+		assert.Equal(t, true, result)
+	})
+
+	t.Run("ssz_content_type_first", func(t *testing.T) {
+		request := httptest.NewRequest("GET", "http://foo.example", nil)
+		request.Header["Accept"] = []string{fmt.Sprintf("%s,%s", octetStreamMediaType, jsonMediaType)}
+		result, err := SszRequested(request)
+		require.NoError(t, err)
+		assert.Equal(t, true, result)
+	})
+
+	t.Run("ssz_content_type_preferred_1", func(t *testing.T) {
+		request := httptest.NewRequest("GET", "http://foo.example", nil)
+		request.Header["Accept"] = []string{fmt.Sprintf("%s;q=0.9,%s", jsonMediaType, octetStreamMediaType)}
+		result, err := SszRequested(request)
+		require.NoError(t, err)
+		assert.Equal(t, true, result)
+	})
+
+	t.Run("ssz_content_type_preferred_2", func(t *testing.T) {
+		request := httptest.NewRequest("GET", "http://foo.example", nil)
+		request.Header["Accept"] = []string{fmt.Sprintf("%s;q=0.95,%s;q=0.9", octetStreamMediaType, jsonMediaType)}
+		result, err := SszRequested(request)
+		require.NoError(t, err)
+		assert.Equal(t, true, result)
+	})
+
+	t.Run("other_content_type_preferred", func(t *testing.T) {
+		request := httptest.NewRequest("GET", "http://foo.example", nil)
+		request.Header["Accept"] = []string{fmt.Sprintf("%s,%s;q=0.9", jsonMediaType, octetStreamMediaType)}
+		result, err := SszRequested(request)
+		require.NoError(t, err)
+		assert.Equal(t, false, result)
+	})
+
+	t.Run("other_params", func(t *testing.T) {
+		request := httptest.NewRequest("GET", "http://foo.example", nil)
+		request.Header["Accept"] = []string{fmt.Sprintf("%s,%s;q=0.9,otherparam=xyz", jsonMediaType, octetStreamMediaType)}
+		result, err := SszRequested(request)
+		require.NoError(t, err)
+		assert.Equal(t, false, result)
+	})
+
+	t.Run("no_header", func(t *testing.T) {
+		request := httptest.NewRequest("GET", "http://foo.example", nil)
+		result, err := SszRequested(request)
+		require.NoError(t, err)
+		assert.Equal(t, false, result)
+	})
+
+	t.Run("empty_header", func(t *testing.T) {
+		request := httptest.NewRequest("GET", "http://foo.example", nil)
+		request.Header["Accept"] = []string{}
+		result, err := SszRequested(request)
+		require.NoError(t, err)
+		assert.Equal(t, false, result)
+	})
+
+	t.Run("empty_header_value", func(t *testing.T) {
+		request := httptest.NewRequest("GET", "http://foo.example", nil)
+		request.Header["Accept"] = []string{""}
+		result, err := SszRequested(request)
+		require.NoError(t, err)
+		assert.Equal(t, false, result)
+	})
+
+	t.Run("other_content_type", func(t *testing.T) {
+		request := httptest.NewRequest("GET", "http://foo.example", nil)
+		request.Header["Accept"] = []string{"application/other"}
+		result, err := SszRequested(request)
+		require.NoError(t, err)
+		assert.Equal(t, false, result)
+	})
+
+	t.Run("garbage", func(t *testing.T) {
+		request := httptest.NewRequest("GET", "http://foo.example", nil)
+		request.Header["Accept"] = []string{"This is Sparta!!!"}
+		result, err := SszRequested(request)
+		require.NoError(t, err)
+		assert.Equal(t, false, result)
+	})
+}

network/writer.go

@@ -10,6 +10,11 @@ import (
 	log "github.com/sirupsen/logrus"
 )
 
+const (
+	jsonMediaType        = "application/json"
+	octetStreamMediaType = "application/octet-stream"
+)
+
 // DefaultErrorJson is a JSON representation of a simple error value, containing only a message and an error code.
 type DefaultErrorJson struct {
 	Message string `json:"message"`
@@ -18,13 +23,23 @@ type DefaultErrorJson struct {
 
 // WriteJson writes the response message in JSON format.
 func WriteJson(w http.ResponseWriter, v any) {
-	w.Header().Set("Content-Type", "application/json")
+	w.Header().Set("Content-Type", jsonMediaType)
 	w.WriteHeader(http.StatusOK)
 	if err := json.NewEncoder(w).Encode(v); err != nil {
 		log.WithError(err).Error("Could not write response message")
 	}
 }
 
+// WriteSsz writes the response message in ssz format
+func WriteSsz(w http.ResponseWriter, respSsz []byte, fileName string) {
+	w.Header().Set("Content-Length", strconv.Itoa(len(respSsz)))
+	w.Header().Set("Content-Type", octetStreamMediaType)
+	w.Header().Set("Content-Disposition", "attachment; filename="+fileName)
+	if _, err := io.Copy(w, io.NopCloser(bytes.NewReader(respSsz))); err != nil {
+		log.WithError(err).Error("could not write response message")
+	}
+}
+
 // WriteError writes the error by manipulating headers and the body of the final response.
 func WriteError(w http.ResponseWriter, errJson *DefaultErrorJson) {
 	j, err := json.Marshal(errJson)