Swift-Blockchain-Server

Swift-Blockchain-API.swift

// Instance of blockchain
let blockchain = Blockchain()

// Create a new router
let router = Router()
router.all(middleware: BodyParser())

// Handle HTTP GET requests to /
router.get("/") {
    request, response, next in
    defer {next()}
    response.status(.OK)
    response.send("Welcome to Swift Blockchain")
}

router.get("/mine") {
    request, response, next in
    defer {next()}
    
    let last_block = blockchain.last_block
    let last_proof = last_block.proof
    let proof = blockchain.proofOfWork(last_proof: last_proof)
    
    // We must receive a reward for finding the proof.
    // The sender is "0" to signify that this node has mined a new coin.
    _ = blockchain.newTransaction(sender: "0", recipient: blockchain.node_identifier, amount: 1)
    
    // Forge the new Block by adding it to the chain
    let previous_hash = blockchain.hash(block: last_block)
    let block = blockchain.newBlock(previous_hash: previous_hash, proof: proof)
    
    struct ResponseData: Encodable {
        let message: String
        let index: Int64
        let transactions: [Transaction]
        let proof: Int64
        let previous_hash: String
    }
    let response_data = ResponseData(message: "New Block Foreged",
                                     index: block.index,
                                     transactions: block.transactions,
                                     proof: proof,
                                     previous_hash: previous_hash)
    response.status(.OK)
    response.send(response_data)
}

router.post("/transactions/new") {
    request, response, next in
    defer {next()}
    
    guard let body = request.body?.asJSON,
        let sender = body["sender"] as? String,
        let recipient = body["recipient"] as? String,
        let amount = body["amount"] as? Int64
        else {
            response.status(.badRequest)
            response.send("Missing values")
            return
    }
    let index = blockchain.newTransaction(sender: sender, recipient: recipient, amount: amount)
    struct ResponseData: Encodable {
        let message: String
    }
    let response_data = ResponseData(message: "Transaction will be added to Block \(index)")
    response.status(.created)
    response.send(response_data)
}


router.get("/chain") {
    request, response, next in
    defer {next()}
    struct ResponseData: Encodable {
        let chain: [Block]
        let length: Int
    }
    
    let response_data = ResponseData(chain: blockchain.chain, length: blockchain.chain.count)
    response.status(.OK)
    response.send(response_data)
}

router.post("/nodes/register") {
    request, response, next in
    defer {next()}
    
    guard let body = request.body?.asJSON,
        let nodes = body["nodes"] as? [String]
        else {
            response.status(.badRequest)
            response.send("Error: Please supply a valid list of nodes")
            return
    }
    
    for node in nodes {
        _ = blockchain.registerNode(address: node)
    }
    
    struct ResponseData: Encodable {
        let message: String
        let total_nodes: [String]
    }
    
    let response_data = ResponseData(message: "New nodes have been added", total_nodes: Array(blockchain.nodes))
    response.status(.created)
    response.send(response_data)
}

router.get("/nodes/resolve") {
    request, response, next in
    defer {next()}
    
    let replaced = blockchain.resolveConflicts()
    response.status(.OK)
    if replaced {
        struct ResponseData: Encodable {
            let message: String
            let new_chain: [Block]
        }
        let response_data = ResponseData(message: "Our chain was replaced", new_chain: blockchain.chain)
        response.send(response_data)
    } else {
        struct ResponseData: Encodable {
            let message: String
            let chain: [Block]
        }
        let response_data = ResponseData(message: "Our chain is authoritative", chain: blockchain.chain)
        response.send(response_data)
    }
}

// Add an HTTP server and connect it to the router
Kitura.addHTTPServer(onPort: 5000, with: router)

// Start the Kitura runloop (this call never returns)
Kitura.run()