File: zj.py 1 #!/usr/bin/python3 2 3 # The MIT License (MIT) 4 # 5 # Copyright © 2024 pacman64 6 # 7 # Permission is hereby granted, free of charge, to any person obtaining a copy 8 # of this software and associated documentation files (the “Software”), to deal 9 # in the Software without restriction, including without limitation the rights 10 # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 11 # copies of the Software, and to permit persons to whom the Software is 12 # furnished to do so, subject to the following conditions: 13 # 14 # The above copyright notice and this permission notice shall be included in 15 # all copies or substantial portions of the Software. 16 # 17 # THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 18 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 19 # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 20 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 21 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 22 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 23 # SOFTWARE. 24 25 26 # zj [keys/indices...] 27 # 28 # Zoom Json digs into a subset of valid JSON input, using the given mix of 29 # keys and array-indices, either 0-based or negative. 30 31 32 from json import load, dump 33 from sys import argv, exit, stderr, stdin, stdout 34 from typing import Any, List 35 36 37 # info is the help message shown when asked to 38 info = ''' 39 zj [keys/indices...] 40 41 Zoom Json digs into a subset of valid JSON input, using the given mix of 42 keys and array-indices, either 0-based or negative. 43 '''.strip() 44 45 # handle standard help cmd-line options, quitting right away in that case 46 if len(argv) == 2 and argv[1] in ('-h', '--h', '-help', '--help'): 47 print(info, file=stderr) 48 exit(0) 49 50 51 def zoom(data: Any, keys: List[str]) -> Any: 52 '''Dig into the value given, using the keys given.''' 53 54 for k in keys: 55 if isinstance(data, dict): 56 data = data[k] 57 continue 58 59 if isinstance(data, list): 60 try: 61 i = int(k) 62 except: 63 raise Exception(f'can\'t index an array with {k}') 64 data = data[i] 65 continue 66 67 raise ValueError(f'current top-level value isn\'t indexable') 68 69 return data 70 71 72 try: 73 stdout.reconfigure(newline='\n', encoding='utf-8') 74 data = zoom(load(stdin.buffer), argv[1:]) 75 dump(data, stdout, indent=2, allow_nan=False, separators=(', ', ': ')) 76 stdout.write('\n') 77 except (BrokenPipeError, KeyboardInterrupt): 78 # quit quietly, instead of showing a confusing error message 79 stderr.flush() 80 stderr.close() 81 except Exception as e: 82 print(f'\x1b[31m{e}\x1b[0m', file=stderr) 83 exit(1)