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33c9658 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 | #!/usr/bin/env python3
"""Validate one bounded hosted-proof receipt against the public v1 contract."""
from __future__ import annotations
import argparse
import json
import math
import re
import stat
import sys
from collections.abc import Mapping, Sequence
from pathlib import Path
from typing import Any
ROOT = Path(__file__).resolve().parents[1]
SCHEMA_PATH = ROOT / "schemas" / "hosted-proof-receipt-v1.schema.json"
MAX_RECEIPT_BYTES = 16_384
MAX_SCHEMA_BYTES = 65_536
SUPPORTED_DIALECT = "https://json-schema.org/draft/2020-12/schema"
ANNOTATION_KEYWORDS = {"$id", "$schema", "description", "title"}
VALIDATION_KEYWORDS = {
"additionalProperties",
"const",
"enum",
"maximum",
"minimum",
"oneOf",
"pattern",
"properties",
"required",
"type",
}
class ReceiptValidationError(ValueError):
"""A bounded validation failure that never includes receipt values."""
class SchemaContractError(ReceiptValidationError):
"""The checked-in schema uses a contract this validator cannot enforce."""
def _unique_object(pairs: list[tuple[str, object]]) -> dict[str, object]:
value: dict[str, object] = {}
for name, item in pairs:
if name in value:
raise ReceiptValidationError("JSON contains a duplicate object member")
value[name] = item
return value
def _reject_nonstandard_number(_value: str) -> None:
raise ReceiptValidationError("JSON contains a non-standard number")
def _read_json(path: Path, *, maximum_bytes: int, label: str) -> object:
try:
metadata = path.lstat()
if not stat.S_ISREG(metadata.st_mode):
raise ReceiptValidationError(f"{label} must be a regular file")
with path.open("rb") as handle:
encoded = handle.read(maximum_bytes + 1)
except ReceiptValidationError:
raise
except OSError as error:
raise ReceiptValidationError(f"{label} could not be read") from error
if len(encoded) > maximum_bytes:
raise ReceiptValidationError(f"{label} exceeds its safe size bound")
try:
return json.loads(
encoded.decode("utf-8"),
object_pairs_hook=_unique_object,
parse_constant=_reject_nonstandard_number,
)
except ReceiptValidationError:
raise
except (UnicodeError, json.JSONDecodeError, RecursionError) as error:
raise ReceiptValidationError(f"{label} is not bounded UTF-8 JSON") from error
def _json_equal(left: object, right: object) -> bool:
if isinstance(left, bool) or isinstance(right, bool):
return type(left) is type(right) and left == right
if isinstance(left, (int, float)) and isinstance(right, (int, float)):
return left == right
return type(left) is type(right) and left == right
def _matches_type(value: object, expected: str) -> bool:
if expected == "object":
return isinstance(value, dict)
if expected == "string":
return isinstance(value, str)
if expected == "integer":
return (
isinstance(value, (int, float))
and not isinstance(value, bool)
and math.isfinite(value)
and (isinstance(value, int) or value.is_integer())
)
if expected == "number":
return (
isinstance(value, (int, float))
and not isinstance(value, bool)
and math.isfinite(value)
)
raise SchemaContractError("schema uses an unsupported type")
def _preflight_schema(schema: Mapping[str, Any], *, root: bool = False) -> None:
"""Reject schema drift anywhere before a receipt can select a branch."""
unknown = set(schema) - ANNOTATION_KEYWORDS - VALIDATION_KEYWORDS
if unknown:
raise SchemaContractError("schema uses an unsupported validation keyword")
for keyword in ANNOTATION_KEYWORDS & set(schema):
if not isinstance(schema[keyword], str):
raise SchemaContractError("schema has an invalid annotation")
if root and schema.get("$schema") != SUPPORTED_DIALECT:
raise SchemaContractError("schema uses an unsupported dialect")
if not root and "$schema" in schema:
raise SchemaContractError("schema has a nested dialect declaration")
expected_type = schema.get("type")
if expected_type is not None and expected_type not in {
"integer",
"number",
"object",
"string",
}:
raise SchemaContractError("schema uses an unsupported type")
branches = schema.get("oneOf")
if branches is not None:
if not isinstance(branches, list) or not branches:
raise SchemaContractError("schema has an invalid oneOf contract")
for branch in branches:
if not isinstance(branch, dict):
raise SchemaContractError("schema has an invalid oneOf branch")
_preflight_schema(branch)
properties = schema.get("properties")
required = schema.get("required")
additional = schema.get("additionalProperties")
has_object_contract = (
properties is not None
or required is not None
or "additionalProperties" in schema
)
if has_object_contract:
if (
expected_type != "object"
or not isinstance(properties, dict)
or not isinstance(required, list)
or additional is not False
or not all(isinstance(item, str) for item in required)
or len(required) != len(set(required))
):
raise SchemaContractError("schema has an invalid object contract")
for name, item_schema in properties.items():
if not isinstance(name, str) or not isinstance(item_schema, dict):
raise SchemaContractError("schema has an invalid property contract")
_preflight_schema(item_schema)
allowed = schema.get("enum")
if allowed is not None and (not isinstance(allowed, list) or not allowed):
raise SchemaContractError("schema has an invalid enum contract")
pattern = schema.get("pattern")
if pattern is not None:
if not isinstance(pattern, str) or expected_type != "string":
raise SchemaContractError("schema has an invalid string pattern")
try:
re.compile(pattern)
except re.error as error:
raise SchemaContractError("schema has an invalid string pattern") from error
minimum = schema.get("minimum")
maximum = schema.get("maximum")
if minimum is not None or maximum is not None:
if expected_type not in {"integer", "number"}:
raise SchemaContractError("schema has an invalid numeric bound")
for bound in (minimum, maximum):
if bound is not None and not _matches_type(bound, "number"):
raise SchemaContractError("schema has an invalid numeric bound")
if minimum is not None and maximum is not None and minimum > maximum:
raise SchemaContractError("schema has inconsistent numeric bounds")
def _validate(value: object, schema: Mapping[str, Any], path: str = "receipt") -> None:
unknown = set(schema) - ANNOTATION_KEYWORDS - VALIDATION_KEYWORDS
if unknown:
raise SchemaContractError("schema uses an unsupported validation keyword")
branches = schema.get("oneOf")
if branches is not None:
if not isinstance(branches, list) or not branches:
raise SchemaContractError("schema has an invalid oneOf contract")
matches = 0
for branch in branches:
if not isinstance(branch, dict):
raise SchemaContractError("schema has an invalid oneOf branch")
try:
_validate(value, branch, path)
except SchemaContractError:
raise
except ReceiptValidationError:
continue
matches += 1
if matches != 1:
raise ReceiptValidationError("receipt does not match exactly one v1 shape")
expected_type = schema.get("type")
if expected_type is not None and not isinstance(expected_type, str):
raise SchemaContractError("schema has an invalid type contract")
if isinstance(expected_type, str) and not _matches_type(value, expected_type):
raise ReceiptValidationError(f"{path} has the wrong JSON type")
if "const" in schema and not _json_equal(value, schema["const"]):
raise ReceiptValidationError(f"{path} does not match its required value")
allowed = schema.get("enum")
if allowed is not None and not isinstance(allowed, list):
raise SchemaContractError("schema has an invalid enum contract")
if isinstance(allowed, list) and not any(_json_equal(value, item) for item in allowed):
raise ReceiptValidationError(f"{path} is not an allowed value")
pattern = schema.get("pattern")
if pattern is not None:
if not isinstance(pattern, str) or not isinstance(value, str):
raise SchemaContractError("schema has an invalid string pattern")
try:
matches_pattern = re.fullmatch(pattern, value) is not None
except re.error as error:
raise SchemaContractError("schema has an invalid string pattern") from error
if not matches_pattern:
raise ReceiptValidationError(f"{path} does not match its required format")
if "minimum" in schema or "maximum" in schema:
if not _matches_type(value, "number"):
raise ReceiptValidationError(f"{path} has the wrong JSON type")
minimum = schema.get("minimum")
maximum = schema.get("maximum")
if minimum is not None and not _matches_type(minimum, "number"):
raise SchemaContractError("schema has an invalid minimum")
if maximum is not None and not _matches_type(maximum, "number"):
raise SchemaContractError("schema has an invalid maximum")
if minimum is not None and value < minimum:
raise ReceiptValidationError(f"{path} is below its allowed bound")
if maximum is not None and value > maximum:
raise ReceiptValidationError(f"{path} is above its allowed bound")
properties = schema.get("properties")
required = schema.get("required")
if properties is not None or required is not None or schema.get("additionalProperties") is False:
if not isinstance(value, dict) or not isinstance(properties, dict):
raise SchemaContractError("schema has an invalid object contract")
if not isinstance(required, list) or not all(isinstance(item, str) for item in required):
raise SchemaContractError("schema has an invalid required-field contract")
missing = set(required) - set(value)
if missing:
raise ReceiptValidationError("receipt is missing a required field")
if schema.get("additionalProperties") is False and set(value) - set(properties):
raise ReceiptValidationError("receipt contains an unexpected field")
for name, item_schema in properties.items():
if not isinstance(name, str) or not isinstance(item_schema, dict):
raise SchemaContractError("schema has an invalid property contract")
if name in value:
_validate(value[name], item_schema, f"{path}.{name}")
def validate_receipt(receipt: object, schema: object) -> None:
if not isinstance(schema, dict):
raise SchemaContractError("schema root must be an object")
_preflight_schema(schema, root=True)
_validate(receipt, schema)
def main(argv: Sequence[str] | None = None) -> int:
parser = argparse.ArgumentParser(
description="validate one local Lumi Eggcracker hosted-proof receipt against v1"
)
parser.add_argument("receipt", type=Path, help="path to one JSON receipt object")
arguments = parser.parse_args(argv)
try:
schema = _read_json(SCHEMA_PATH, maximum_bytes=MAX_SCHEMA_BYTES, label="schema")
receipt = _read_json(
arguments.receipt,
maximum_bytes=MAX_RECEIPT_BYTES,
label="receipt input",
)
validate_receipt(receipt, schema)
except ReceiptValidationError as error:
print(f"INVALID hosted-proof receipt v1: {error}", file=sys.stderr)
return 1
print("VALID hosted-proof receipt v1")
return 0
if __name__ == "__main__":
raise SystemExit(main())
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