Encode one Protocol Buffers message

Encodes a named list as one message of type type, the inverse of proto_decode(): every value proto_decode() returns encodes back to the same message.

Usage

proto_encode(
  x,
  type,
  pool,
  deterministic = TRUE,
  unknown = TRUE,
  check_required = TRUE,
  extra = c("error", "ignore")
)

Arguments

x

A named list, one element per field. For a well-known type with an R scalar form (Timestamp, Duration, wrappers), that scalar.

type

The message type's full name, such as "pkg.Message".

pool

A pool from proto_pool() holding type.

deterministic

Whether to encode deterministically: map entries sorted by key, so equal values always give equal bytes.

unknown

Whether to write back unknown fields kept by proto_decode(unknown = "keep") in a proto_unknown attribute.

check_required

Whether a missing proto2 required field is an error.

extra

"error" to refuse names the type does not define, "ignore" to skip them.

Value

A raw vector.

Details

Each element is a field, by its name, or an extension, by its full name in brackets ("[pkg.ext]"). An element that is NULL or NA leaves its field unset, as does a field the list leaves out. Values take the R forms proto_decode() gives them, and also:

• integer kinds: integers, or doubles that are whole and in range; 64-bit kinds also decimal strings, which are exact;

• enums: factors, value names, or numbers (a closed enum accepts only the numbers it defines);

• Timestamp: POSIXct or seconds since the epoch (not a Date, whose number is days: convert it with as.POSIXct()); Duration: difftime or seconds; a wrapper: its value;

• strings: valid UTF-8, or in an encoding R translates to it;

• Value: NULL, a logical, number or string, a named list (a Struct), or an unnamed list or vector (a ListValue).

bytes fields take raw vectors (a list of them when repeated).

See also

zuproto-conditions for the errors it raises; each one about a value carries path, the field at fault, such as "points[2].x".

Examples

pool <- proto_pool()
proto_encode(42L, "google.protobuf.Int32Value", pool)
#> [1] 08 2a
when <- as.POSIXct("2026-10-25 12:00:00", tz = "UTC")
raw <- proto_encode(when, "google.protobuf.Timestamp", pool)
proto_decode(raw, "google.protobuf.Timestamp", pool)
#> [1] "2026-10-25 12:00:00 UTC"