mirror of
https://github.com/simplex-chat/simplexmq.git
synced 2026-06-08 17:22:16 +00:00
Evgeny @ SimpleX Chat
22 lines
1.2 KiB
Markdown
22 lines
1.2 KiB
Markdown
# Simplex.Messaging.Parsers
|
|
|
|
> Attoparsec helpers and Aeson JSON encoding options.
|
|
|
|
**Source**: [`Parsers.hs`](../../../../src/Simplex/Messaging/Parsers.hs)
|
|
|
|
## sumTypeJSON (platform-dependent JSON encoding)
|
|
|
|
On Darwin with the `swiftJSON` CPP flag, `sumTypeJSON` uses `ObjectWithSingleField` encoding with tag `"_owsf"`. On all other platforms, it uses `TaggedObject` encoding with `"type"` / `"data"` keys.
|
|
|
|
This means the same Haskell type produces **different JSON** on macOS/iOS vs Linux. Cross-platform JSON interchange must use `taggedObjectJSON` or `singleFieldJSON` directly, not `sumTypeJSON`.
|
|
|
|
The `_owsf` tag enables Swift clients to convert between the two encodings — it's a marker that the value was encoded as ObjectWithSingleField rather than TaggedObject.
|
|
|
|
## parseE vs parseE'
|
|
|
|
`parseE` requires full input consumption (`endOfInput`). `parseE'` does not — it succeeds if the parser matches a prefix. Using `parseE'` where `parseE` is needed silently ignores trailing input.
|
|
|
|
## base64P
|
|
|
|
Parses standard base64 (`+` and `/`), not base64url (`-` and `_`). Contrast with `base64urlP` in [Simplex.Messaging.Encoding.String](./Encoding/String.md) which parses URL-safe base64.
|