Show Structure

1"""Show JSON keys and types without values. Reads from stdin or a file argument."""
2
3import json
4import sys
5
6from _common import unwrap_text_envelope
7
8
9def structure(obj, depth=0, max_depth=3):
10    indent = "  " * depth
11    if depth > max_depth:
12        print(f"{indent}...")
13        return
14    if isinstance(obj, dict):
15        for k, v in obj.items():
16            if isinstance(v, dict):
17                print(f"{indent}{k}: {{...}} ({len(v)} keys)")
18                structure(v, depth + 1, max_depth)
19            elif isinstance(v, list):
20                print(f"{indent}{k}: [...] ({len(v)} items)")
21                if v:
22                    structure(v[0], depth + 1, max_depth)
23            elif isinstance(v, str):
24                print(f"{indent}{k}: str[{len(v)}]")
25            else:
26                print(f"{indent}{k}: {v}")
27    elif isinstance(obj, list):
28        print(f"{indent}[{len(obj)} items]")
29        if obj:
30            structure(obj[0], depth + 1, max_depth)
31
32
33if len(sys.argv) > 1:
34    with open(sys.argv[1]) as f:
35        data = unwrap_text_envelope(json.load(f))
36else:
37    data = unwrap_text_envelope(json.load(sys.stdin))
38structure(data)