pyjawk 0.1.0

Motivation

This program exists for fairly minor convenience, and mostly for my own use. Whenever I end up needing to quickly edit some json, I find myself opening a Python REPL, writing a bunch of obvious loading code to load in the json, work on it a little bit, and then dump it back out to the relevant file. Also, whenever I end up needing to inspect json from a web page, I either curl it to a file and then do the same, or use requests or something to pull it directly in a Python REPL so I can properly inspect it, or I pipe it through Python’s json.tool and less.

This is meant to supplant those use cases entirely for my own uses. If you find it inconvenient to repeatedly undergo the busy work associated with working with or inspecting json data, and especially if you are most familiar and comfortable with the stream-editing way of doing things or spending time in a REPL, this tool might make things a little more convenient for you.

Installation

pip install --user pyjawk

Use

The program is passed an input string either through stdin or a -i argument, and an output through -o or stdout. The document is put into a data object in the environment. -f arguments may pass in script files that are run first, and literal script chunks can be passed in as positional parameters. The data object is then serialized and output.

If -r / --repl is specified, instead of writing output after processing, the function to write to the output is registered in the environment as write, the arguments structure is registered as args, and a ptpython REPL is started up with the same environment.

Examples

Retroarch Playlists

If you had an issue with the way that RetroArch generates its playlist files for the Playstation (by default, it searches for .cue files, but not .bin), and had something like this in your directory, all playstation games:

Alpha.bin
Alpha.cue
Bravo.bin
Charlie.bin
Delta.bin
Delta.cue

You might end up with a playlist file like this:

{
  "version": "1.2",
  "default_core_path": "/home/user/.local/share/retroarch/cores/pcsx_rearmed_libretro.so",
  "default_core_name": "Sony - PlayStation (PCSX ReARMed)",
  "label_display_mode": 0,
  "right_thumbnail_mode": 0,
  "left_thumbnail_mode": 0,
  "items": [
    {
      "path": "/home/user/Roms/psx/Alpha.cue",
      "label": "Alpha",
      "core_path": "/home/user/.local/share/retroarch/cores/pcsx_rearmed_libretro.so",
      "core_name": "Sony - PlayStation (PCSX ReARMed)",
      "crc32": "00000000|crc",
      "db_name": "Sony - PlayStation.lpl"
    },
    {
      "path": "/home/user/Roms/psx/Delta.cue",
      "label": "Delta",
      "core_path": "/home/user/.local/share/retroarch/cores/pcsx_rearmed_libretro.so",
      "core_name": "Sony - PlayStation (PCSX ReARMed)",
      "crc32": "00000000|crc",
      "db_name": "Sony - PlayStation.lpl"
    }
  ]
}

If you want the file to just have the bins, you can easily scan the directory for these files and modify the json using this tool with this:

pyjawk -i 'Sony - PlayStation.lpl' -o 'Sony - PlayStation.lpl' 'from pathlib import Path' 'data["items"] = [{"path": str(path), "label": path.stem, "core_path": data["default_core_path"], "core_name": data["default_core_name"], "crc32": "00000000|crc", "db_name": "Sony - PlayStation.lpl"} for path in (Path.home() / "Roms" / "psx").iterdir() if path.suffix == ".bin"]'

That might look heavy up-front, but you can rewrite it as a script file:

from pathlib import Path
data["items"] = [{
      "path": str(path),
      "label": path.stem,
      "core_path": data["default_core_path"],
      "core_name": data["default_core_name"],
      "crc32": "00000000|crc",
      "db_name": "Sony - PlayStation.lpl",
} for path in (Path.home() / "Fast" / "Roms" / "psx").iterdir() if path.suffix == ".bin"]

and run it with pyjawk as so:

pyjawk -i 'Sony - PlayStation.lpl' -o 'Sony - PlayStation.lpl' -f script.py

Or instead load it into a repl to work on it in real time with this:

pyjawk -i 'Sony - PlayStation.lpl' -r

>>> args
Namespace(compact=0, files=[], input='Sony - PlayStation.lpl', no_input=False, output='-', repl=True, scripts=[])

>>> data['items'] = []

>>> write()
{
  "version": "1.2",
  "default_core_path": "/home/user/.local/share/retroarch/cores/pcsx_rearmed_libretro.so",
  "default_core_name": "Sony - PlayStation (PCSX ReARMed)",
  "label_display_mode": 0,
  "right_thumbnail_mode": 0,
  "left_thumbnail_mode": 0,
  "items": []
}

>>> args.compact = 2

>>> write()
{"version":"1.2","default_core_path":"/home/user/.local/share/retroarch/cores/pcsx_rearmed_libretro.so","default_core_name":"Sony - PlayStation (PCSX ReARMed)","label_display_mode":0,"right_thumbnail_mode":0,"left_thumbnail_mode":0,"items":[]}

>>> exit()

Just make sure you call write() in the repl, or nothing will be written.

Plans

Just to make this complete, I plan to add yaml and xml support to this toolkit (along with convenience console entrypoints pyxawk and pyyawk), plus whatever else people might find useful that makes sense (like msgpack, raw output, or printing and parsing as a Python expression).

I don’t plan to add too much to this, as I want it to be useful but also as lean and manageable as it possibly can be.