Understanding Midnight Outputs with Bulletin Board Example

Technical Questions
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1

I’m trying to learn what a lot of my outputs mean and what I’m supposed to do with the Midnight examples. I’m trying to decode events from a transaction using the bulletin board message example. This is the output for midnight_jsonBlock:

{
  "header": {
    "parentHash": "0x510648386c58ef1708039ffa029c7190c3b9465ef353c71fa3c39238b3350aec",
    "number": "0x10058d",
    "stateRoot": "0xe5c8c262d30cdf5d1ccba5972215c2fc02fdd7a082786d22b30614474ad8bfa2",
    "extrinsicsRoot": "0x4b7734a2ed077627627b4b9e157ea67a10771953fb24ff9097691029cd984699",
    "digest": {
      "logs": [
        "0x066175726120437c531100000000",
        "0x066d637368800ecc42452b12e66f832bb3decbd0b037b4e64db200fc74a8c1e09332b5b9892d",
        "0x044d4e535610401f0000",
        "0x056175726101019abc9c89e5c1e4c7832d84eec88f86f4f17c93860b8147b65000786aad26a728f8795c7b1260e9d874244b142f7e44fd6514f65ab5a753b8c71bf2778194018e"
      ]
    }
  },
  "body": [
    {
      "Timestamp": 1744103826000
    },
    "UnknownTransaction",
    {
      "MidnightTransaction": {
        "tx": {
          "tx_hash": "a59dbdd6313e416cc565c434f31fdc2ab8a9a13262831fe94407e8bcf36a2e16",
          "operations": [
            {
              "Call": {
                "address": "020200f00c70fcf64e574b6b43a274c9bf3bcc9106ba7ac45268a8dccb8ddf1c4cd601",
                "entry_point": "706f7374"
              }
            },
            "GuaranteedCoins"
          ],
          "identifiers": [
            "0000000010168cb7a3d87b14e371a6dc1a8312827c90ae60ae07285cd0a1f95b93f13cb08c4f4f937d1c65a6aa18eb7232277e2dedffbfcc7165329c",
            "000000000b69187d4b2fff941dd85a8bd5b70820c3d6f90aa55d01de466f71dc21e9c39f6b6534a25cbe789f0c1f517da6f8de94c60872148c76860a",
            "0000000014c971d9e513c201c2405a4439cd3bbbdbfe73879d98a57751413422166154d0eadbb4436dd51da52f50a19467107a5989269418fb446384"
          ]
        }
      }
    }
  ],
  "transactions_index": [
    [
      "0xa59dbdd6313e416cc565c434f31fdc2ab8a9a13262831fe94407e8bcf36a2e16",
      "0x0203000000000003000100000064ccf66b098..."
    ]
  ]
}
  1. Am I supposed to call midnight_decodeEvents with the identifiers inside MidnightTransaction.tx?
  2. What do these identifiers represent?
  3. Should I expect an empty array if the contract doesn’t emit any events (which is the case when I use identifiers from the above question)
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2
  1. Identifiers in the MidnightTransaction.tx object are not directly related to events, so no, you do not need to call them with identifiers.
  2. Identifiers represent transaction-specific elements related to zero-knowledge proofs and transaction validity.
  3. The bulletin board example does not emit events, so an empty array should be expected behavior.
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