JSON – Haskell – Aelve Guide

waargonaut

2018-12-18T22:53:55Z

waargonaut (Hackage)

Flexible, precise, and efficient JSON decoding/encoding library. This package provides a plethora of tools for decoding, encoding, and manipulating JSON data.

Pros

Fully RFC compliant

Encoders and Decoders are values, they are not tied to a typeclass and as such you are not tied to a single interpretation of how a particular type "should" be handled

No information is discarded on parsing

Cons

Requires slightly more code than automatically derived typeclass based approaches

aeson-parsec-picky

2016-05-11T16:07:05Z

aeson-parsec-picky (Hackage)

A JSON parser written in Parsec, can be used instead of the default Aeson parser. Intended for use with human-written JSON (config files, etc) – unlike Aeson's parser, it reports error positions, which is pretty useful.

Pros

Compatible with aeson.

Cons

Slower than the default aeson parser.

Disallows trailing spaces, which isn't good if you simply wanted a parser that would be the same as Aeson's parser but with better error reporting.

buffer-builder

2016-05-11T15:29:38Z

buffer-builder (Hackage)

Another fast JSON builder.

Pros

Cons

Ecosystem

buffer-builder-aeson

json-incremental-decoder

2016-05-11T15:29:29Z

json-incremental-decoder (Hackage)

Another incremental decoder.

Pros

Cons

json-encoder

2016-05-11T15:29:19Z

json-encoder (Hackage)

A fast JSON builder.

Pros

Cons

json-stream

2016-05-11T10:37:05Z

json-stream (Hackage)

A fast decoder that tries to do the least amount of work possible (e.g. it skips parsing of unnecessary fields, etc) and can even parse certain JSON structures using constant space.

Pros

Compatible with aeson.

Cons

Sometimes doesn't tell you when the JSON is malformed (this is by design, tho).

highjson

2016-05-11T10:19:53Z

highjson (Hackage)

A fast library that tries to require less boilerplate than aeson (and provides a different parsing model). Use at your own risk.

Pros

As fast as Aeson (benchmarks).

The same declaration is used to convert to/from JSON – there's no need to write separate ToJSON and FromJSON instances and worry about them accidentally going out of sync.

Cons

The library is still work in progress.

There are some examples, but not much documentation.

aeson

2016-04-14T09:44:48Z

aeson (Hackage)

Haskell's de-facto standard JSON parsing library.

Pros

Widely used and actively developed.

Fast.

Cons

Can be rather complicated/non-intuitive to use.

Ecosystem

Alternative instance generators: json-autotype (automatically generates types/instances from JSON files), generic-aeson (generates more idiomatic instances than aeson's generic derivation),
Schemas: json-schema (unrelated to json-schema.org), hjsonschema (an implementation of the json-schema.org standard)
Bidirectional parsing (when the same declaration is used to convert to/from JSON): codec (there are other libraries, such as roundtrip-aeson, JsonGrammar, and aeson-applicative, but they all don't work with recent GHC)
Lens integration: lens-aeson and microlens-aeson (don't use aeson-lens, it's deprecated)
Alternative parsers: aeson-parsec-picky (an alternative parser that reports error positions; described further in this category), json-stream (an incremental fast parser that can skip what it doesn't need to parse)
Utils: aeson-casing (makes it easier to implement different casing variants like snake_case or PascalCase for field names), aeson-extra (just a grab bag of utils), json-extra (another grab bag of utils), aeson-prefix (makes all keys hierarchical), aeson-filthy (working with booleans encoded as “on”/“yes”/etc, case-insensitive keys, and double-encoded JSON)
Various stuff: aeson-pretty (pretty-prints JSON), aeson-qq (lets you embed JSON values in Haskell source more conveniently than you might've done with object and .=), aeson-diff (diffs two JSON documents), aeson-better-errors (gives better conversion errors)
Instances, etc: pipes-aeson, binary-orphans (instances for Binary)

JSON – Haskell – Aelve Guide

waargonaut

waargonaut (Hackage)

Pros

Cons

aeson-parsec-picky

aeson-parsec-picky (Hackage)

Pros

Cons

buffer-builder

buffer-builder (Hackage)

Pros

Cons

Ecosystem

json-incremental-decoder

json-incremental-decoder (Hackage)

Pros

Cons

json-encoder

json-encoder (Hackage)

Pros

Cons

json-stream

json-stream (Hackage)

Pros

Cons

highjson

highjson (Hackage)

Pros

Cons

aeson

aeson (Hackage)

Pros

Cons

Ecosystem

Notes

Links