Aeson Diff

This is a small library for working with changes to JSON documents. It includes a library and two executables in the style of diff(1) and patch(1).

Installing

The aeson-diff package is written in Haskell and can be installed using the Cabal package management tool.

For the command-line tools only, I recommend using Cabal's sandbox functionality to avoid installing the associated libraries globally on your system. This approach might look something like the following:

cd aeson-diff/
cabal sandbox init
cabal install --dependencies-only
cabal build
sudo mkdir -p /usr/local/bin
sudo cp dist/build/json-*/json-{diff,patch} /usr/local/bin/

If you want to use the library, use Cabal in a sandbox or not according to your preference.

cabal sandbox init
cabal sandbox install ~/Downloads/aeson-diff/

Usage

json-diff command

The json-diff command compares two JSON documents and extracts a patch describing the differences between the first document and the second.

Usage: json-diff [-j|--json] [-o|--output OUTPUT] FROM TO
Generate a patch between two JSON documents.

Available options:
    -h,--help                Show this help text
    -j,--json                Output patch in JSON.

json-patch command

The json-patch command applies a patch describing changes to be made to a JSON document.

Usage: json-patch [-j|--json] [-o|--output OUTPUT] PATCH FROM
Generate a patch between two JSON documents.

Available options:
  -h,--help                Show this help text
  -j,--json                Patch is in JSON format.
  -o,--output OUTPUT       Destination for patched JSON.
  PATCH                    Patch to apply.
  FROM                     JSON file to patch.

aeson-diff library

The aeson-diff library exports as single module: Data.Aeson.Diff. This exports diff and patch functions which do exactly what might be expected:

• diff :: Value -> Value -> Patch examines source and target JSON Values and constructs a new Patch describing the changes.

• patch :: Patch -> Value -> Value applies the changes in a Patch to a JSON Value.

For more complete information, see the documentation.