BCSwiftEsplora

A pure Swift interface to the Esplora block explorer REST API.

Takes full advantage of Swift 5.5's concurrency architecture.

Building

Add to your project like any other Swift Package.

Usage

See the unit tests for examples of every API call.

import Esplora

/// Find the last transaction in the latest block and print the addresses of its outputs.
func testEsplora() async throws {
    // Instantiate the API.
    let esplora = Esplora(host: "blockstream.info")
    
    // Get the current blockchain height.
    let blockHeight = try await esplora.currentBlockHeight()
    print(blockHeight)
    // 720712
    
    // Get the hash (ID) of the most recent block.
    let latestBlockHash = try await esplora.blockHash(at: blockHeight)
    print(latestBlockHash.hex)
    // 000000000000000000054fa746a7a19ba190f5dacad05087c8dfc725ff1f6ef8
    
    // Get the time the latest block was added.
    let latestBlock = try await esplora.block(hash: latestBlockHash)
    print(latestBlock.timestamp)
    // 2022-01-28 07:12:51 +0000
    
    // Get the IDs of all the transactions in the block
    let latestBlockTXIDs = try await esplora.blockTransactionIDs(hash: latestBlockHash)
    // Extract the ID of the last transaction in the block
    let latestTXID = latestBlockTXIDs.last!
    print(latestTXID.hex)
    // b10f61f106284c626d2d9bbc874c1d3e723cdacbaa508338b219620457dc7b52
    
    // Get the transaction and print all of its output addresses
    let tx = try await esplora.transaction(txid: latestTXID)
    let txAddresses = tx.outputs.compactMap { \$0.scriptPubKeyAddress }
    print(txAddresses)
    // ["bc1qm34lsc65zpw79lxes69zkqmk6ee3ewf0j77s3h", "bc1qslxt46qzcp0uqeq09wnhfz7cxeepvmgysqt2ve"]
}

/// Print the estimated fee in number of satoshis/vB needed to confirm a transaction within the next 3 blocks.
func testFeeEstimate() async throws {
    let esplora = Esplora(host: "blockstream.info")
    let estimates = try await esplora.feeEstimates()
    print(estimates[3]!)
    // 5.074
}