JS Script to import transactions via GoCardless API

gcl-lunchMoney-bridge.mjs

import { createHash } from 'crypto';
import fs from 'fs/promises';
import axios from 'axios';
import { exit } from 'process';


// Get these from http://bankaccountdata.gocardless.com
let gclSecretId = "GoCardlessSecretID"
let gclSecretKey = "GoCardlessAccountKey"

// You can get this by creating a connection to your accounte
// See their docs on how to do it
// Warning: Requires CURL and command line (or similar)
let gclAccountId = "GoCardlessAccountID"

// Salt to hash external ID
let hashSalt = "GENERATE_YOUR_OWN"
let account_id = 0 // Account ID in LunchMoney
let lunchMoneyKey = "YOUR_LUNCH_MONEY_API_KEY";

function createDraft(tr) { 
    var notes = []
    var payee = null;
    var date = tr.bookingDate;
    if (tr.creditorName != null) {
        payee = tr.creditorName.trim()
        let location = tr.remittanceInformationUnstructured.replace(tr.creditorName, "").trim()
        var fxNote = null;
        if (tr.currencyExchange != null && tr.currencyExchange.length == 1) {
            let fxData = tr.currencyExchange[0];
            if (fxData.sourceCurrency != fxData.targetCurrency) {
                fxNote = "FX Rate: " + fxData.exchangeRate;
            }

            // Booking date is when the transaction was booked
            // Quotation Date is when the transaction (and FX exchange) happened.
            // This is filled also for same currency so we use it.
            if (fxData.quotationDate != null) {
                let dateParts = fxData.quotationDate.split("T")
                if (dateParts.length == 2) {
                    date = dateParts[0];
                }
            }
        }

        notes = [tr.proprietaryBankTransactionCode, tr.additionalInformation.trim(), location, fxNote]
    } else if (tr.debtorAccount != null) {
        payee = tr.remittanceInformationUnstructured
    }

    return { 
        date: date, 
        amount: tr.transactionAmount.amount, 
        currency: tr.transactionAmount.currency.toLowerCase(), 
        payee: payee, 
        asset_id: account_id,
        notes: notes.filter( x => x ).join(" – "),
        external_id: createHash('sha256').update(tr.transactionId).update(tr.bookingDate).update(hashSalt).digest('hex')
    } 
}

async function main() {
    let ccClient = axios.create({
        baseURL: "https://bankaccountdata.gocardless.com/api/v2/"
    });
    
    const lunchMoney = axios.create({
        baseURL: "https://dev.lunchmoney.app",
        headers: {
          "Authorization": `Bearer ${lunchMoneyKey}`
        }
    });
    let lastTransactions = (await lunchMoney.get("/v1/transactions", {
        params: {
            start_date: "1970-01-01",
            end_date: (new Date()).toISOString().split("T")[0],
            limit: 5,
            asset_id: account_id
        }
    })).data.transactions

    var knownTransactions = new Set(lastTransactions.map( x => x.external_id));
    let lastTransaction = lastTransactions[lastTransactions.length-1];
    var endpoint = `/accounts/${gclAccountId}/transactions/`
    var refDate = null;
    if (lastTransaction != null && lastTransaction.date != null) {
        endpoint += "?date_from="+lastTransaction.date;
        refDate = Date.parse(lastTransaction.date);
    } else {
        refDate = Date.parse("1970-01-01");
    }
    
    try {
        let ccClientAuthProm = ccClient.post("/token/new/", {
            secret_id: gclSecretId,
            secret_key: gclSecretKey
        });

        let authRes = (await ccClientAuthProm).data
        ccClient.defaults.headers.common["Authorization"] = `Bearer ${authRes.access}`

        let raw_t = await ccClient.get(endpoint);
        let t = raw_t.data;
        var draft = []

        for (const transaction of t.transactions.booked) {
            if (Date.parse(transaction.bookingDate) < refDate) { 
                continue;
            }
            let lm_tran = createDraft(transaction)
            if (!knownTransactions.has(lm_tran.external_id)) {
                draft.push(lm_tran)
                knownTransactions.add(lm_tran.external_id)
            }
        }
    } catch(e) {
        console.log(e);
        exit(1);
    }

    if (draft.length > 0) {
        // We reverse because GCL sends transactions in descending order
        // And lunch-money inserts in FIFO, so transactions with the same date will 
        // have an inverted display order
        let createTransPromise = lunchMoney.post("/v1/transactions", {
            transactions: draft.reverse(),
            apply_rules:true,
            debit_as_negative: true
          })
        let balance = (await ccClient.get(`/accounts/${gclAccountId}/balances/`)).data.balances
            .find((e) => e.balanceType == "closingBooked");

        let balanceAmount = ""
        if (balance.balanceAmount.amount[0] == "-") {
            balanceAmount = balance.balanceAmount.amount.substring(1);
        } else {
            balanceAmount = "-"+balance.balanceAmount.amount;
        }

        let updateBalance = await lunchMoney.put(`/v1/assets/${account_id}`, {
            balance: balanceAmount,
            balance_as_of: balance.referenceDate
        });

        console.log(await createTransPromise.data);
        console.log(updateBalance.data);
    }
}

main()