tf2wikipricing/src/background/background.ts

chrome.runtime.onMessage.addListener(
  function(request, sender, sendResponse) {
    if (request.contentScriptQuery == "queryExchangeRates") {
      const url = "https://open.er-api.com/v6/latest/USD";
      fetch(url)
          .then(response => response.json())
          .then(json => sendResponse(json))
          .catch(error => {
            console.error("Failed to get exchange rates", error);
          })
      return true;
    }
})

chrome.runtime.onMessage.addListener(
  function(request, sender, sendResponse) {
    if (request.contentScriptQuery == "querySchema") {
      const url = "https://raw.githubusercontent.com/danocmx/node-tf2-static-schema/master/static/items.json";
      fetch(url)
          .then(response => response.json())
          .then(json => sendResponse(json))
          .catch(error => {
            console.error("Failed to get schema", error);
          })
      return true;
    }
  }
);

class PricesResponse {
  keys: number
  metal: number
}

async function priceUsingPricedb(sku: string, retries: number = 3): Promise<PricesResponse> {
  const url = `https://pricedb.io/api/item/${encodeURIComponent(sku)}`;
  const response = await fetch(url, {
    method: 'get',
    headers: {
      'Accept': 'application/json',
    }
  })
  if (response.status === 404 && sku.includes(';') && !sku.includes(';uncraftable')) {
    const quality: number = parseInt(sku.split(';')[1], 10);
    if(quality === 6) {
      // Try uncraftable variant if unique weapon
      return priceUsingPricedb(sku + ';uncraftable');
    }
  }
  if(response.status === 429) {
    // Happens if we send too many requests (rate limit: 180 req/min)
    // Retry after a few seconds
    if(retries >= 0) {
      console.log(`Rate limit exceeded, trying again after 1 second, ${retries} retries left`)
      await new Promise(resolve => setTimeout(resolve, 1000));
      return priceUsingPricedb(sku, retries - 1);
    } else {
      throw new Error(`Rate limit exceeded, stopping`)
    }
  }
  if (!response.ok) {
    throw new Error(`Pricing request for ${sku} failed with status code: ${response.status}`);
  }
  const data = await response.json();
  const prices = new PricesResponse();
  prices.keys = data.sell.keys
  prices.metal = data.sell.metal
  return prices;
}

chrome.runtime.onMessage.addListener(
  function(request, sender, sendResponse) {
    if (request.contentScriptQuery == "priceSKU") {
      const sku: string = request.sku
      priceUsingPricedb(sku)
      .then((response) => sendResponse(response))
      .catch(error => {
        console.error(`Received "${error}" error while pricing ${sku} using pricedb.io`)
        sendResponse(null);
        return false;
      })
    }
    return true;
  }
);