binary-tagged

Structurally tag binary serialisation stream.

Say you have:

data Record = Record
  { _recordFields  :: HM.HashMap Text (Integer, ByteString)
  , _recordEnabled :: Bool
  }
  deriving (Eq, Show, Generic)

instance Binary Record
instance HasStructuralInfo Record
instance HasSemanticVersion Record

then you can serialise and deserialise Record values with a structure tag by simply

encodeTaggedFile "cachefile" record
decodeTaggedFile "cachefile" :: IO Record

If structure of Record changes in between, deserialisation will fail early.

The overhead is next to non-observable, see a simple benchmark.

benchmarking encode/Binary
time                 362.6 μs   (361.2 μs .. 363.8 μs)

benchmarking encode/Tagged
time                 379.2 μs   (375.5 μs .. 382.2 μs)

benchmarking decode/Binary
time                 366.3 μs   (365.1 μs .. 368.1 μs)

benchmarking decode/Tagged
time                 367.6 μs   (367.0 μs .. 368.2 μs)