canonical_json

Description:

canonical json

Canonical JSON Encoder/Decoder #
This package provides an encoder and decoder for encoding/decoding
canonical JSON. The canonical JSON format does not support floating-point
numbers and the decoder validates that the value is indeed a canonically encoded
JSON value.
Disclaimer: This is not an officially supported Google product.
Example #
import 'package:canonical_json/canonical_json.dart';
void main() {
// Encode a message
final bytes = canonicalJson.encode({
'from': 'alice',
'message': 'Hi Bob',
});
final hash = sha256(bytes); // using a sha256 from some library...
// Decode message
try {
final msg = canonicalJson.decode(bytes);
if (!fixedTimeEqual(sha256(canonicalJson.encode(msg)), bytes)) {
print('Expected a different hash!');
}
print(msg['message']);
} on InvalidCanonicalJsonException {
print('Message was not canonical JSON!');
}
}
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Canonical JSON Format #

Integers are encoded without leading zeros.
Floating point numbers are not permitted.
Map keys appear in sorted by byte values.
Whitespace is not permitted (outside of strings).
Only allow escape sequences in strings are \\ and \".
Strings must be valid UTF-8 in Unicode Normalization Form C.

This follows the rules outlined in canoncial JSON, with the deviation that
this package requires strings to be encoded as valid UTF-8 in
Unicode Normalization Form C rather than arbitrary
byte values. This is only recommended by canoncial JSON, but this library
takes the opinion that binary values should be encoded.
See Also #

Specification of canoncial JSON used by this package.
Discusson of alternative canonicalization formats for JSON.
Specification of JSON in RFC 8259