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BETTERZON-73: Adding API endpoint that returns the lowest non-amazon prices for a given list of product ids (#32)

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Patrick 2021-04-29 09:41:11 +02:00 committed by GitHub
parent 9e9b442f35
commit f7c045b5a3
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2 changed files with 95 additions and 11 deletions
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19
Backend/src/models/prices/prices.router.ts
View File

@ -82,6 +82,25 @@ pricesRouter.get('/bestDeals/:amount', async (req: Request, res: Response) => {
}
});
// GET prices/byProduct/list/[]
pricesRouter.get('/byProduct/list/:ids', async (req: Request, res: Response) => {
const productIds: [number] = JSON.parse(req.params.ids);
if (!productIds) {
res.status(400).send('Missing parameters.');
return;
}
try {
const prices: Prices = await PriceService.findListByProducts(productIds);
res.status(200).send(prices);
} catch (e) {
res.status(404).send(e.message);
}
});
// POST items/
// pricesRouter.post('/', async (req: Request, res: Response) => {

87
Backend/src/models/prices/prices.service.ts
View File

@ -195,7 +195,6 @@ export const getBestDeals = async (amount: number): Promise<Prices> => {
let allPrices: Record<number, Price[]> = {};
// Get newest prices for every product at every vendor
const rows = await conn.query(
'WITH summary AS (\n' +
' SELECT p.product_id,\n' +
@ -222,10 +221,11 @@ export const getBestDeals = async (amount: number): Promise<Prices> => {
}
// Iterate over all prices to find the products with the biggest difference between amazon and other vendor
let deals = [];
for (let productId in Object.keys(allPrices)) {
if (allPrices[productId]) {
let pricesForProd = allPrices[productId];
let deals: Price[] = [];
Object.keys(allPrices).forEach(productId => {
if (allPrices[parseInt(productId)]) {
let pricesForProd = allPrices[parseInt(productId)];
// Get amazon price and lowest price from other vendor
let amazonPrice = {} as Price;
@ -234,6 +234,7 @@ export const getBestDeals = async (amount: number): Promise<Prices> => {
if (price.vendor_id === 1) {
amazonPrice = price;
} else {
// If there is no lowest price yet or the price of the current iteration is lower, set / replace it
if (!lowestPrice.price_in_cents || lowestPrice.price_in_cents > price.price_in_cents) {
lowestPrice = price;
}
@ -245,25 +246,25 @@ export const getBestDeals = async (amount: number): Promise<Prices> => {
'product_id': lowestPrice.product_id,
'vendor_id': lowestPrice.vendor_id,
'price_in_cents': lowestPrice.price_in_cents,
'timestamp' :lowestPrice.timestamp,
'timestamp': lowestPrice.timestamp,
'amazonDifference': (amazonPrice.price_in_cents - lowestPrice.price_in_cents),
'amazonDifferencePercent': ((1 - (lowestPrice.price_in_cents / amazonPrice.price_in_cents)) * 100),
};
// Push only deals were the amazon price is actually higher
if(deal.amazonDifferencePercent > 0) {
deals.push(deal);
if (deal.amazonDifferencePercent > 0) {
deals.push(deal as Price);
}
}
}
});
// Sort to have the best deals on the top
deals.sort((a, b) => a.amazonDifferencePercent < b.amazonDifferencePercent ? 1 : -1);
deals.sort((a, b) => a.amazonDifferencePercent! < b.amazonDifferencePercent! ? 1 : -1);
// Return only as many records as requested or the maximum amount of found deals, whatever is less
let maxAmt = Math.min(amount, deals.length);
for (let dealIndex = 0; dealIndex < maxAmt; dealIndex++){
for (let dealIndex = 0; dealIndex < maxAmt; dealIndex++) {
//console.log(deals[dealIndex]);
priceRows.push(deals[dealIndex] as Price);
}
@ -280,6 +281,70 @@ export const getBestDeals = async (amount: number): Promise<Prices> => {
return priceRows;
};
/**
* Get the lowest, latest, non-amazon price for each given product
* @param ids the ids of the products
*/
export const findListByProducts = async (productIds: [number]): Promise<Prices> => {
let conn;
let priceRows: Price[] = [];
try {
conn = await pool.getConnection();
let allPrices: Record<number, Price[]> = {};
// Get newest prices for every given product at every vendor
const rows = await conn.query(
'WITH summary AS (\n' +
' SELECT p.product_id,\n' +
' p.vendor_id,\n' +
' p.price_in_cents,\n' +
' p.timestamp,\n' +
' ROW_NUMBER() OVER(\n' +
' PARTITION BY p.product_id, p.vendor_id\n' +
' ORDER BY p.timestamp DESC) AS rk\n' +
' FROM prices p' +
' WHERE p.product_id IN (?)' +
' AND p.vendor_id != 1)\n' +
'SELECT s.*\n' +
'FROM summary s\n' +
'WHERE s.rk = 1', [productIds]);
// Write returned values to allPrices map with product id as key and a list of prices as value
for (let row in rows) {
if (row !== 'meta') {
if (!allPrices[parseInt(rows[row].product_id)]) {
allPrices[parseInt(rows[row].product_id)] = [];
}
allPrices[parseInt(rows[row].product_id)].push(rows[row]);
}
}
// Iterate over all products to find lowest price
Object.keys(allPrices).forEach(productId => {
if (allPrices[parseInt(productId)]) {
let pricesForProd = allPrices[parseInt(productId)];
// Sort ascending by price so index 0 has the lowest price
pricesForProd.sort((a, b) => a.price_in_cents > b.price_in_cents ? 1 : -1);
// Push the lowest price to the return list
priceRows.push(pricesForProd[0]);
}
});
} catch (err) {
throw err;
} finally {
if (conn) {
conn.end();
}
}
return priceRows;
};
// export const create = async (newItem: Product): Promise<void> => {
// let conn;
// try {