// ==UserScript==
// @name        Allegro.pl - convert prices to EUR
// @namespace   Violentmonkey Scripts
// @match       https://allegro.pl/oferta/*
// @match       https://allegro.pl/uzytkownik/*
// @match       https://allegro.pl/listing
// @match       https://allegro.pl/produkt/*
// @match       https://allegro.pl/kategoria/*
// @run-at      document-idle
// @grant       none
// @version     1.3
// @author      -
// @description 1/16/2022, 1:31:29 AM - Convert prices to EUR. You have to get a free API key from https://free.currencyconverterapi.com/ in order to use this script. The first time you use it on allegro, you will receive a prompt for the API key. It will keep prompting until you provide a valid key. If you don't want to see the prompt, turn off the script.
// ==/UserScript==
// set debug to true to see log messages from this script.
const debug = true
const messageTitle = "Allegro.pl convert to EUR greasemonkey script:"
// log stuff to console with a banner but only if debugging is turned on in the script
function log(...arguments) {
if (debug) console.log(messageTitle, ...arguments)
}
// create an Euro price string based on found parts of price in PLN.
function pricePlnToEur(conversionRate, match1, match2) {
const priceStr = "".concat(match1.replace(/\ /g, ''), match2)
const priceGrosze = parseInt(priceStr) // price expressed as an integer amount of Grosz
const priceCents = Math.round(priceGrosze * conversionRate) // price expressed as an integer amount of Cents. Round to nearest (i.e. 16.5 -> 17)
const priceCentsStr = priceCents.toString() // string version of price expressed as an integer amount of Cents
const priceEurStr = priceCentsStr.slice(0, -2) // whole Euros
const priceCentsFracStr = priceCentsStr.slice(-2) // Cents after decimal point
const priceEurStrFull = "".concat(priceEurStr.padStart(1, "0"), ".", priceCentsFracStr.padStart(2, "0")) // price in Euro expressed as string. the padding is to prevent prices like 1 cent or 44 cents from showing up with necessary leading zeros.
return priceEurStrFull
}
// xpath might be "deprecated", but it's still the only thing that can search by text.
function getElementsByXPath(xpath, parent)
{
let r###lts = [];
let query = document.evaluate(xpath, parent || document,
null, XPathR###lt.ORDERED_NODE_SNAPSHOT_TYPE, null);
for (let i = 0, length = query.snapshotLength; i < length; ++i) {
r###lts.push(query.snapshotItem(i));
}
return r###lts;
}
// register a listener that adds Euro prices. Note that it must be idempotent: if it is successfully run twice on the same element, it shouldn't add the prices twice, only once.
function registerListener(callback) {
callback()
document.addEventListener('scroll', callback) // needed because when you run the callback items that are off screen will not be processed
const observer = new MutationObserver(callback) // eg used for going to the next page of r###lts
observer.observe(document, { attributes: true, childList: true, subtree: true })
// used for when the tab was in the background and now becomes visible. This is important because sometimes dom modifications to background tabs just fail. I don't know if it's because of allegro, or if it's the browsers optimizing this stuff away, but doing this - performing a pass once the tab becomes visible - helps.
document.addEventListener('visibilitychange', function(event) {
if (document.visibilityState === "visible") callback()
})
}
// check if the span has already been added to prevent adding it multiple times
function addChildOnce(parent, newChild, searchClass) {
var alreadyAttached = false
siblings = parent.childNodes
siblings.forEach(function (sibling) {
if (sibling.classList.contains(searchClass)) {
alreadyAttached = true
}
})
if (!alreadyAttached) {
parent.appendChild(newChild) // add span that contains euro price
}
}
async function main() {
// We can only await inside an async function, so the whole script has to be an async function.
// I'm not indenting this function because it is the whole file.
storage = window.localStorage
const forexApiBase = "https://free.currconv.com/api/v7/convert"
const forexApi = "".concat(forexApiBase, "?q=PLN_EUR&compact=ultra&apiKey=")
// If the foreign exchange api key is not present, request it from the user, and save it in storage.
if(storage.getItem("forexApiKey") === null) {
const newForexApiKey = prompt("".concat(messageTitle, "Please enter API Key. You can request it for free from https://free.currencyconverterapi.com/"), "")
const apiCallValidate = "".concat(forexApi, newForexApiKey)
log("about to create the following request to validate the API key: ", apiCallValidate)
// validate the key
fetch(apiCallValidate).then(function(response) {
if (response.status !== 200) {
// Apparently errors >= 400 do not count to trigger onerror
throw new Error("Response HTTP code not 200 during api key validation") // fixme: use a typed error
}
storage.setItem("forexApiKey", newForexApiKey)
}).catch(function(error) {
alert("".concat(messageTitle, "Error performing API request. Is the key correct?"))
log("Error performing API request. Is the key correct?")
log(error)
})
}
// get the api key from storage and convert the prices.
const forexApiKey = storage.getItem("forexApiKey")
if(forexApiKey !== null) {
// perform actual call with the api key
apiCall = "".concat(forexApi, forexApiKey)
log("about to create the following request to get the conversion rate: ", apiCall)
fetch(apiCall).then(function(response) {
if (response.status !== 200) {
// Apparently errors >= 400 do not count to trigger onerror
throw new Error("Response HTTP code not 200 during API call") // fixme: use a typed error
}
return response.json()
}).then(function(data) {
// convert stuff
log("found conversion rate: ", data["PLN_EUR"])
// find the price:
// which page are we on?
const loc = window.location.toString()
// item page
if(loc.startsWith("https://allegro.pl/oferta/")) {
log("detected item page.")
// convert item price
function attachEurToMainPrice() {
const list = document.querySelectorAll('[aria-label^="cena "]') // ^= means "begins with".
log("found the following elements:", list)
if (list.length !== 1) {
const elmErr = "Found too many or no elements when searching for price. Aborting."
log(elmErr)
throw new Error("".concat(messageTitle, " ", elmErr)) // fixme: use a typed error
}
const priceDiv = list[0]
const priceLabel = priceDiv.attributes["aria-label"].value
const matches = priceLabel.match(/^cena ([0-9]{1,3}(?:\ [0-9]{3})*)\.([0-9]{2}) zł$/) // note the decimal point is a comma on the listing page and a period on the item page. The regex means that you have 1-3 digits, then maybe (a space and 3 digits) repeated.
priceEurStrFull = pricePlnToEur(data["PLN_EUR"], matches[1], matches[2])
const priceEurSpan = document.createElement('span')
priceEurSpan.textContent = "".concat("\u00a0=\u00a0", priceEurStrFull, "\u00a0EUR")
priceEurSpan.classList.add("priceEur") // used to check if this span has already been added
log("priceDiv:", priceDiv)
addChildOnce(priceDiv, priceEurSpan, "priceEur")
}
registerListener(attachEurToMainPrice)
// convert prices of carousel items
function attachEurToCarousel() {
carouselSpans = getElementsByXPath("//div[contains(@class, 'carousel-item')]/div/ul/li/span/span[contains(text(),' zł')]/..")
log("carouselSpans:", carouselSpans)
carouselSpans.forEach(function(priceSpan) {
log("priceSpan:", priceSpan)
if (!priceSpan.classList.contains("priceEur")) { // priceEur would mean it's already an Euro price we placed
const matches =  priceSpan.innerText.match(/^([0-9]{1,3}(?:\ [0-9]{3})*),([0-9]{2}) zł$/) // note the decimal point is a comma
priceEurStrFull = pricePlnToEur(data["PLN_EUR"], matches[1], matches[2])
const priceEurSpan = document.createElement('span')
priceSpan.classList.forEach(function(cls) {
priceEurSpan.classList.add(cls)
})
priceEurSpan.classList.add("priceEur") // used to check if this span has already been added
priceEurSpan.textContent = "".concat(priceEurStrFull, "\u00a0EUR")
priceSpan.parentNode.replaceChild(priceEurSpan, priceSpan) // we don't leave the original price in since there's no space left.
}
})
}
registerListener(attachEurToCarousel)
// listing page
} else if (loc.startsWith("https://allegro.pl/uzytkownik/")
|| loc.startsWith("https://allegro.pl/listing")
|| loc.startsWith("https://allegro.pl/produkt")
|| loc.startsWith("https://allegro.pl/kategoria")
) {
log("detected listing page.")
function attachEurToListings() {
list = document.querySelectorAll('[aria-label$=" zł aktualna cena"]') // $= means "ends with".
log("found the following elements:", list)
list.forEach(function(priceSpan) {
const priceLabel = priceSpan.attributes["aria-label"].value
const matches = priceLabel.match(/^([0-9]{1,3}(?:\ [0-9]{3})*),([0-9]{2}) zł aktualna cena$/) // note the decimal point is a comma on the listing page and a period on the item page. The regex means that you have 1-3 digits, then maybe (a space and 3 digits) repeated.
priceEurStrFull = pricePlnToEur(data["PLN_EUR"], matches[1], matches[2])
const priceEurSpan = document.createElement('span')
priceEurSpan.textContent = "".concat("\u00a0=\u00a0", priceEurStrFull, "\u00a0EUR")
priceSpan.classList.forEach(function(cls) {
priceEurSpan.classList.add(cls)
})
priceEurSpan.classList.add("priceEur") // used to check if this span has already been added
priceDiv = priceSpan.parentNode
addChildOnce(priceDiv, priceEurSpan, "priceEur")
})
}
registerListener(attachEurToListings)
}
}).catch(function(error) {
// fixme: make this better
log("Error performing API request. Is the key correct?")
log(error)
})
}
}
var runMainOnce = (function() {
var executed = false
return function() {
if (!executed) {
executed = true
main()
}
}
})()
// Execute the code in one of two ways...
// This event runs when we switch into a tab that just loaded.
document.addEventListener('visibilitychange', function(event) {
if (document.visibilityState === "visible") {
runMainOnce()
}
})
// This code runs if the tab is visible while it's loading.
if (document.visibilityState === "visible") {
runMainOnce()
}