chess.com API 没有带回一些请求

Question

所以我对全栈很陌生，一直在做一个小的 vanilla js 项目来制作一个网站，该网站调用我运行调用 chess.com api 的服务器，例如检索所有 elo 评分为：

https://api.chess.com/pub/player/${username}/stats

所以我在 node-js 中进行了后端调用：

const fetch = require('node-fetch');

exports.getChessManStats = () => {
   return (req, res) => {
    res.set('Access-Control-Allow-Origin', '*');
    const username = req.param('username');
    console.log(req.param('username'));
    fetch(`https://api.chess.com/pub/player/${username}/stats`)
    .then(res2 => res2.json() )
    .then(chessManData => {
        res.json({  
            daily: chessManData.chess_daily.last.rating,
            rapid: chessManData.chess_rapid.last.rating,
            blitz: chessManData.chess_blitz.last.rating,
            bullet: chessManData.chess_bullet.last.rating,
        })
    })
    .catch(err => console.log(err));
   } 
};

代码然后运行s with express on the main.js with:

const app = express();
app.get('/getRating',chessManController.getChessManStats());

显然后来我打电话给 app.listen(3000) .

然后在前端我做了一个调用这个函数的按钮:

const makeUserStats = () => {
const username = document.getElementById('username').value;//id=username is type input
document.getElementById('rating').innerHTML = `Searching`; //making the rating div into 'searching'
console.log(`http://localhost:3000/getRating?username=${username}`)//just seeing the sting I send
fetch(`http://localhost:3000/getRating?username=${username}`)
.then(rating => {
    document.getElementsByClassName('statButton').disabled = true;//disabling buttons until the data arrives
    console.log('got json');
    return rating.json();
})
.catch(err => console.log(err))//looking for errors
.then((userRating => {
    window.userRating = userRating;//saving the stats globaly to use in other buttons
    window.user = username;
}))
.then(() => {
    document.getElementsByClassName('statButton').disabled = false;//enabling the buttons again
    document.getElementById('rating').innerHTML = `${window.user} rating is:`; 
})
}

现在，当我按下按钮时，它可以使用一些用户名和一些不使用的用户名。 YoniRamot（我的）有效，hikaru（职业玩家）有效，atomicstew（朋友）无效，idobl（朋友）无效。奇怪的是它不会捕获任何错误，只是等待它永远不会得到的答案。但是如果你去 api 它们都存在：

https://api.chess.com/pub/player/yoniramot/stats -- mine

https://api.chess.com/pub/player/hikaru/stats --proplayer

https://api.chess.com/pub/player/atomicstew/stats --friend

https://api.chess.com/pub/player/idobl/stats --friend

后台控制台显示：

atomicstew
TypeError: Cannot read property 'last' of undefined
    at C:\Users\Yonatan\Desktop\coding\training\intermediateChess\backend\controllers\chessStats.js:12:45
    at processTicksAndRejections (internal/process/task_queues.js:93:5)

意味着后端获取了用户名，但出于某种原因在 api 中找不到它。

请帮帮我，我的脑袋现在乱七八糟。

-编辑 1-

所以我在发送带有数据的 res 之前添加了一个控制台日志，它打印了：

atomicstew
{
  chess_rapid: {
    last: { rating: 1228, date: 1612114999, rd: 28 },
    best: {
      rating: 1265,
      date: 1611786478,
      game: 'https://www.chess.com/live/game/6380128206'
    },
    record: { win: 233, loss: 202, draw: 19 }
  },
  chess_blitz: {
    last: { rating: 902, date: 1611928398, rd: 50 },
    best: {
      rating: 1010,
      date: 1609882454,
      game: 'https://www.chess.com/live/game/6297568401'
    },
    record: { win: 26, loss: 24, draw: 4 }
  },
  fide: 0,
  tactics: {
    highest: { rating: 1659, date: 1609635730 },
    lowest: { rating: 387, date: 1608148134 }
  },
  lessons: {},
  puzzle_rush: {}
}
TypeError: Cannot read property 'last' of undefined
    at C:\Users\Yonatan\Desktop\coding\training\intermediateChess\backend\controllers\chessStats.js:13:45
    at processTicksAndRejections (internal/process/task_queues.js:93:5)

我调用的引用就在那里，所以我仍然卡住了。

-编辑 2-

我没有意识到，如果玩家不玩某种游戏模式，那么 api 就不会持有该值。如果没有数据，如何将数据整齐地保存为 0 或 null，有什么想法吗？

Answer 1

问题出在以下代码块中，您在其中尝试访问不同属性的 last 字段作为响应：

res.json({  
      daily: chessManData.chess_daily.last.rating,
      rapid: chessManData.chess_rapid.last.rating,
      blitz: chessManData.chess_blitz.last.rating,
      bullet: chessManData.chess_bullet.last.rating,
})

我快速查看了以下 API 的回复，但它没有 chess_daily 和 chess_bullet 属性。

https://api.chess.com/pub/player/atomicstew/stats

由于您正在尝试访问 chessManData.chess_daily.last.rating 并且 chess_daily 不存在于 chessManData 中，您将获得 .last.

的异常

为了修复它，您可以通过以下方式替换上面的块：

res.json({  
     daily: chessManData.chess_daily && chessManData.chess_daily.last ? chessManData.chess_daily.last.rating : null, // replace null with appropriate default value for rating
     rapid: chessManData.chess_rapid && chessManData.chess_rapid.last ? chessManData.chess_rapid.last.rating : null,
     blitz: chessManData.chess_blitz && chessManData.chess_blitz.last ? chessManData.chess_blitz.last.rating : null,
     bullet: chessManData.chess_bullet && chessManData.chess_bullet.last ? chessManData.chess_bullet.last.rating : null,
})

chess.com API 没有带回一些请求

chess.com API does'nt bring back some requests

javascript

node.js

frontend

backend

chess