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# Python + Flask 虛擬美國股票交易網站 Part6 （股價來源 ）
###### tags: `CS50` `Python` `Flask`

## 前言
登入網站後第一件要做的事就是趕快炒股，所以能拿到即時股價是很重要的，CS50課程中介紹了[IEX](https://iexcloud.io/) 這個工具可以讓我們使用它的API查價。IEX API會用json格式傳回所需的數據

例如查詢NFLX

{  
   "symbol": "NFLX",
   "companyName": "Netflix, Inc.",
   "primaryExchange": "NASDAQ",
   "calculationPrice": "close",
   "open": 317.49,
   "openTime": 1564752600327,
   "close": 318.83,
   "closeTime": 1564776000616,
   "high": 319.41,
   "low": 311.8,
   "latestPrice": 318.83,
   "latestSource": "Close",
   "latestTime": "August 2, 2019",
   "latestUpdate": 1564776000616,
   "latestVolume": 6232279,
   "iexRealtimePrice": null,
   "iexRealtimeSize": null,
   "iexLastUpdated": null,
   "delayedPrice": 318.83,
   "delayedPriceTime": 1564776000616,
   "extendedPrice": 319.37,
   "extendedChange": 0.54,
   "extendedChangePercent": 0.00169,
   "extendedPriceTime": 1564876784244,
   "previousClose": 319.5,
   "previousVolume": 6563156,
   "change": -0.67,
   "changePercent": -0.0021,
   "volume": 6232279,
   "iexMarketPercent": null,
   "iexVolume": null,
   "avgTotalVolume": 7998833,
   "iexBidPrice": null,
   "iexBidSize": null,
   "iexAskPrice": null,
   "iexAskSize": null,
   "marketCap": 139594933050,
   "peRatio": 120.77,
   "week52High": 386.79,
   "week52Low": 231.23,
   "ytdChange": 0.18907500000000002,
   "lastTradeTime": 1564776000616
}

## 設定IEX API

### vfinance/utils.py

def lookup(symbol):
    """Look up quote for symbol."""

    # Contact API
    try:
        api_key = os.environ.get("API_KEY")
        response = requests.get(f"https://cloud-sse.iexapis.com/stable/stock/{urllib.parse.quote_plus(str(symbol))}/quote?token={api_key}")
        response.raise_for_status()
    except requests.RequestException:
        flash("Please set API_KEY", 'danger')
        return None

    # Parse response
    try:
        quote = response.json()
        return {
            "name": quote["companyName"],
            "price": float(quote["latestPrice"]),
            "symbol": quote["symbol"],
            "change": quote["change"],
            "changePercent": quote["changePercent"],
            "volume": quote["volume"],
            "week52High": quote["week52High"],
            "week52Low": quote["week52Low"],
            "open" :quote["open"],
            "high" :quote['high'],
            "low" : quote["low"]
        }
    except (KeyError, TypeError, ValueError):
        return None

在這之前要去[IEX](https://iexcloud.io/) 註冊登入並拿到API Token，然後在執行程式之前先執行

export API_KEY=YOUR TOKEN

之後就可以利用回傳回來的json格式拿到所需要的數據，例如要股價的話就輸入

quote = lookup(AMZN)
stock_price = quote['price']