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JSON

General structs​

All on-chain types have to/from JSON support. The vast majority is auto-generated but some have custom logic e.g. Url, Ipv4, BigInteger, etc.

WASM​

In WASM JSON conversions are exposed by .to_json() and .from_json() methods on all supported wrappers. There is also a to_js_value().

let txInJson = "{\"transaction_id\":\"0fba1404ed9b82b41938ba2e8bda7bec8cce813fb7e7cd7692b43caa76fe891c\",\"index\":3}";

let txIn = CML.TransactionInput.from_json(txInJson);

console.log(`txIn JSON: ${txIn.to_json()}`);

Rust​

JSON conversions are exposed in rust via the serde::Serialize and serde::Deserialize traits together with serde_json.

example:

let tx_in_json = "{\"transaction_id\":\"0fba1404ed9b82b41938ba2e8bda7bec8cce813fb7e7cd7692b43caa76fe891c\",\"index\":3}";

// from JSON using serde_json::from_str() - note the type annotations
let tx_in: TransactionInput = serde_json::from_str(tx_in_json).unwrap();

// to JSON using serde_json::to_string() - use to_string_pretty() if you want more human-readable formatting
println!("tx_in JSON: {}", serde_json::to_string(&tx_in).unwrap());

Metadata​

Metadata, on top of the generic API mentioned above, has specific JSON functionality for compatability with cardano-node.

There are three formats on MetadataJsonSchema. NoConversions is the stricted, stricter than cardano-node and only converts when there are no implicit conversions at all. BasicConversions is the node's TxMetadataJsonNoSchema and DetailedSchema its TxMetadataJsonDetailedSchema. See MetadataJsonSchema for more info on the schema.

let basic_json = "{\"0x8badf00d\": \"0xdeadbeef\",\"9\": 5,\"obj\": {\"a\":[{\"5\": 2},{}]}}";
let metadatum = CML.encode_json_str_to_metadatum(basic_json, CML.MetadataJsonSchema.BasicConversions);
console.log(`detailed json: ${CML.decode_metadatum_to_json_str(metadatum, CML.MetadataJsonSchema.DetailedSchema)}`);
// OUTPUT:
// detailed json: {"map":[{"k":{"bytes":"8badf00d"},"v":{"bytes":"deadbeef"}},{"k":{"int":9},"v":{"int":5}},{"k":{"string":"obj"},"v":{"map":[{"k":{"string":"a"},"v":{"list":[{"map":[{"k":{"int":5},"v":{"int":2}}]},{"map":[]}]}}]}}]}

Plutus Datums​

Plutus datums also have additional cardano-node JSON support. Remember that Plutus has no String datum so the strings there will be converted to utf8 bytes. See CardanoNodePlutusDatumSchema for more info on the schema.

let basic_json = "{ \"100\": [ { \"x\": \"0\", \"y\": 1 } ], \"foo\": \"0x0000baadf00d0000cafed00d0000deadbeef0000\" }";
let datum = CML.encode_json_str_to_plutus_datum(basic_json, CML.CardanoNodePlutusDatumSchema.BasicConversions);
console.log(`detailed json: ${CML.decode_plutus_datum_to_json_str(datum, CML.CardanoNodePlutusDatumSchema.DetailedSchema,
)}`);
// OUTPUT:
// detailed json: {"map":[{"k":{"int":100},"v":{"list":[{"map":[{"k":{"bytes":"78"},"v":{"bytes":"30"}},{"k":{"bytes":"79"},"v":{"int":1}}]}]}},{"k":{"bytes":"666f6f"},"v":{"bytes":"0000baadf00d0000cafed00d0000deadbeef0000"}}]}