Blockchain Interactions

Query and mutate Flow blockchain

Make sure you have set the configuration in Getting Started first.

We are assuming you have read the Scripts Documentation before this, as transactions are sort of scripts with more required things.

There are two different operations to interact with Flow blockchain:

1. Query: Send arbitrary Cadence scripts to the chain and receive decoded values. Can be performed without user login

2. Mutate: Use transaction to send Cadence code with specify authorizer to perform permanently state changes on chain. Must be performed after user logged in

Query

// Pass your Cadence script as a parameter
when (val result = Fcl.query(script)) {
    is Result.Success -> {
        val queryResult = result.value.toString()
    }
    is Result.Failure -> {
        // Handle error
    }
}

Mutate

when (val result = Fcl.mutate(
    cadence = script,
    arguments = args, 
    limit = 300u,
    authorizers = listOf(FlowAddress(userAddress)
)) {
    is Result.Success -> {
        val transactionId = result.value
    }
    is Result.Failure -> {
        // Handle error
    }
}