Backend implementation using adonis.js framework for Lightning Network withdrawals straight to wallet using LNURL

lnurl-withdrawal.js

const Logger = use('Logger')
const bech32 = require('bech32')
const Hash = use('Hash')
const lnService = require('ln-service')

const NonceHashMap = {};
const k1HashMap = {};

async requestWithdrawal ({auth, response}) {
    try{
        if (auth.user.unique_id){
            // create random nonce for the user
            const nonce = Math.floor(Math.random() * 1000000) // TODO: stronger source of randomness

            // add item to hashmap
            NonceHashMap[Hash.make(nonce)] = auth.user.id 
                
            return response.json({
                data: bech32.encode('LNURL', "https://satoshis.games/withdrawal/confirmation?q="+nonce).toLocaleUpperCase()
            })
        }
    }catch(error){
        Logger.error(error)
        return response.json({error})
    }
}

async confirmWithdrawal ({response, request}) {
        
        const { q } = request.all()

        if (Hash.make(q) in NonceHashMap){

            const existingUserId = NonceHashMap[Hash.make(q)]

            delete NonceHashMap[Hash.make(q)]; // Invalidate a QR

            const secondLevelNonce = Math.floor(Math.random() * 1000000) // TODO: stronger source of randomness

            // k1HashMap[Hash.make(k1)] = Hash.make(auth.user.id)
            k1HashMap[Hash.make(secondLevelNonce)] = existingUserId

            return response.json({
                callback = "https://satoshis.games/withdrawal/execute",
                k1 = secondLevelNonce,
                maxWithdrawable = 2000, // msat
                defaultDescription = "withdraw from satoshis.games",
                tag = "withdrawRequest",
            })
        }
}

async executeWithrawal ({request}) {
        
        const { k1 } = request.all() 

        const { pr } = request.all()

        if (Hash.make(k1) in k1HashMap){

            const existingUserId = k1HashMap[Hash.make(k1)]

            delete k1HashMap[Hash.make(k1)];
            this.makePayment({pr})
            
            response.ok()
        } else {
        return json({ status: "ERROR", reason: "Second level nonce not found" })
        }
    }

    async makePayment ({pr}) {
        try {
            const lnd = await LndService.getLndInstance()

            // Payment to encoded invoice request
            await lnService.pay({
                lnd,
                request: pr
            },  (error, result) => {
                Logger.info(result)
                Logger.error('Error:', error)
            })
        }catch(error){
            Logger.error(error)
        }
    }