atproto relay implementation in zig
zlay.waow.tech
ensure tooBig: false on outgoing commit frames
some PDSes omit the tooBig field from commit events. the lexicon marks it
required, and consumers like hydrant reject frames without it.
resequenceFrame now detects #commit frames and injects tooBig: false when
the field is missing. non-commit frames are unaffected.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
+28
+28
src/broadcaster.zig
+28
src/broadcaster.zig
···
204
204
const header_end = header_result.consumed;
205
205
const payload_data = data[header_end..];
206
206
207
+
// check header type — commit frames need tooBig normalization
208
+
const is_commit = blk: {
209
+
const header_val = switch (header_result.value) {
210
+
.map => |entries| entries,
211
+
else => break :blk false,
212
+
};
213
+
for (header_val) |entry| {
214
+
if (std.mem.eql(u8, entry.key, "t")) {
215
+
const t = switch (entry.value) {
216
+
.text => |s| s,
217
+
else => break :blk false,
218
+
};
219
+
break :blk std.mem.eql(u8, t, "#commit");
220
+
}
221
+
}
222
+
break :blk false;
223
+
};
224
+
207
225
// decode payload map
208
226
const payload = cbor.decodeAll(allocator, payload_data) catch return null;
209
227
const old_entries = switch (payload) {
···
214
232
// rebuild map entries with seq replaced
215
233
var new_entries: std.ArrayListUnmanaged(cbor.Value.MapEntry) = .empty;
216
234
var found_seq = false;
235
+
var found_too_big = false;
217
236
for (old_entries) |entry| {
218
237
if (std.mem.eql(u8, entry.key, "seq")) {
219
238
new_entries.append(allocator, .{ .key = "seq", .value = .{ .unsigned = relay_seq } }) catch return null;
220
239
found_seq = true;
221
240
} else {
241
+
if (std.mem.eql(u8, entry.key, "tooBig")) found_too_big = true;
222
242
new_entries.append(allocator, entry) catch return null;
223
243
}
224
244
}
225
245
if (!found_seq) {
226
246
new_entries.append(allocator, .{ .key = "seq", .value = .{ .unsigned = relay_seq } }) catch return null;
247
+
}
248
+
// lexicon requires tooBig on #commit — some PDSes omit it, hydrant et al. reject the frame
249
+
if (is_commit and !found_too_big) {
250
+
new_entries.append(allocator, .{ .key = "tooBig", .value = .{ .boolean = false } }) catch return null;
227
251
}
228
252
229
253
const new_payload: cbor.Value = .{ .map = new_entries.items };
···
1420
1444
// other fields preserved
1421
1445
try std.testing.expectEqualStrings("did:plc:test123", p.getString("repo").?);
1422
1446
try std.testing.expectEqualStrings("3k2abc000000", p.getString("rev").?);
1447
+
// tooBig injected for commit frames missing it
1448
+
try std.testing.expectEqual(false, p.getBool("tooBig").?);
1423
1449
}
1424
1450
1425
1451
test "resequenceFrame preserves identity frame fields" {
···
1453
1479
try std.testing.expectEqual(@as(u64, 42), p.getUint("seq").?);
1454
1480
try std.testing.expectEqualStrings("did:plc:alice", p.getString("did").?);
1455
1481
try std.testing.expectEqualStrings("2024-01-15T10:30:00Z", p.getString("time").?);
1482
+
// tooBig NOT injected for non-commit frames
1483
+
try std.testing.expectEqual(@as(?bool, null), p.getBool("tooBig"));
1456
1484
}
1457
1485
1458
1486
test "encodeErrorFrame produces valid error frame CBOR" {