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Retrieving your metadata

Overview​

There are many ways to retrieve metadata stored in the Cardano blockchain. This article discusses the different components and ways that can help us retrieve all kinds of blockchain data.

Blockfrost​

Blockfrost provides an API to access the Cardano blockchain fast and easily.

To retrieve metadata using Blockfrost, we call a specific endpoint for transaction metadata that they provide.

Query 1337 Metadata 

curl -H 'project_id: <api_key>' https://cardano-mainnet.blockfrost.io/api/v0/metadata/txs/labels/1337 | jq

You should see something like this:

[
  {
    "tx_hash": "a54d000ad56cf5b4afe769b5d74b51a5817dc44102c7f8286887e28bf257a2fd",
    "json_metadata": "gimbalabs-poc"
  },
  {
    "tx_hash": "b26cc2323d6212a0396fa4ddb35578648853ef769e2e427d92019d50163f636a",
    "json_metadata": "go build"
  }
]

In this example, we query the Cardano Mainnet for any metadata under the key 1337. We see a few of the many metadata that is already inserted into the Cardano blockchain under that key. It is now up to your implementation how you want to cache and sort through all the data that lives on-chain. Blockfrost provides paging and ordering parameters.

Please visit their official documentation to know more.

cardano-db-sync​

@TODO

cardano-graphql​

@TODO

cardano-wallet​

note

This Section assumes that you have basic understanding of cardano-wallet, how to use it and that you have installed it into your system. Otherwise we recommend reading Installing cardano-node, Running cardano-node and Exploring Cardano Wallets guides first.

This guide also assumes that you have cardano-node and cardano-wallet running in the background and connected to the testnet network.

To retrieve all the Metadata for the transactions of a selected Wallet you just need to query the wallet transections, passing as filter '.[].metadata'

curl --url 'http://localhost:1337/v2/wallets/41263958f6668e06190be661900f7129be78d583/transactions' | jq '.[].metadata'

It is important to note that the 41263958f6668e06190be661900f7129be78d583 string is actually the wallet.id of a previously generated wallet.

The JSON returning all Wallet Transactions Metadata will have some format like below (considering the Metadata created for these transactions has these values):

{
  "1337": {
    "map": [
      {
        "k": {
          "string": "name"
        },
        "v": {
          "string": "hello world"
        }
      },
      {
        "k": {
          "string": "completed"
        },
        "v": {
          "int": 0
        }
      }
    ]
  }
}

A similar command may be used to retrieve the Metadata of a single transaction.

curl --url 'http://localhost:1338/v2/wallets/41263958f6668e06190be661900f7129be78d583/transactions/fab2e2a42b465d0f86452521521a2853597a58d31c5b29663b7e615cd2b2eb47' | jq '.metadata'

41263958f6668e06190be661900f7129be78d583 string is actually the wallet.id of a previously generated wallet.

fab2e2a42b465d0f86452521521a2853597a58d31c5b29663b7e615cd2b2eb47 string is the transaction.id.

The JSON returning the single Transaction Metadata will have some format like below (considering the Metadata created for these transactions has these values):

{
  "1337": {
    "map": [
      {
        "k": {
          "string": "name"
        },
        "v": {
          "string": "hello world"
        }
      },
      {
        "k": {
          "string": "completed"
        },
        "v": {
          "int": 0
        }
      }
    ]
  }
}

Ogmios​

@TODO