为什么我没有通过 id 获得一件商品？

Question

当我遵循路线时：'/gallery' 我从文件 './posts.json' 中获取所有项目并将它们显示在屏幕上。但是当我转向路线时：'/gallery/:id' 我想通过它的id 接收一件物品。但是我得到了数组的所有元素，就像在“/画廊”路线上一样。

告诉我我做错了什么，以及当我穿过路线时如何通过id 获取该项目：'/gallery/:id'

app.js：

const express = require('express');
const Database = require('./db');

const app = express();
const port = 3000;
const db = new Database();

app.use(express.json());

app.get('/gallery', (req, res) => {
    if (req.query.id) {
        const picture = db.read(req.query.id);
        picture.then(data => {
            res.send(data);
        })
    } else {
        const pictures = db.read();
        pictures.then(data => {
            res.send(data);
        })
    }
});

app.get('/gallery/:id', (req, res) => {
    const picture = db.read(req.query.id);
    if (!picture) {
        res.status(404);
        res.send();
    } else {
        picture.then(data => {
            res.send(data);
        })
    }
});

app.listen(port, () => {
    console.log(`Example app listening on port ${port}`)
});

db.js：

const fs = require('fs');
class Database {

    read (id) {
        return new Promise((resolve, reject) => {
            fs.readFile('./posts.json', 'utf-8', (err, data) => {
                if (err) {
                    reject(err)
                }else if(id) {
                    const formatePicture = JSON.parse(data);
                    const pictureId = formatePicture.find(p => p.id == parseInt(id));
                    resolve(pictureId)
                }
                else {
                    resolve(data)
                }
            })
        })
    }
}

module.exports = Database;

posts.json：

{
  "posts": [
    {
      "id": 1,
      "date": "2018-10-22T14:10:37.578Z",
      "title": "accusamus beatae ad facilis cum similique qui sunt",
      "url": "https://i.pinimg.com/originals/90/39/16/903916b9f0db6992f1a4b66ae3129fbe.jpg"
    },
    {
      "id": 2,
      "date": "2018-10-22T14:10:37.578Z",
      "title": "reprehenderit est deserunt velit ipsam",
      "url": "https://vignette.wikia.nocookie.net/okup/images/d/da/C683c20a5b0ae062b2325653f2fd3bdf.jpg/revision/latest?cb=20170131193210&path-prefix=da"
    }
      ]
}

Answer 1

在您的app.get('/gallery/:id') 中，我认为req.param 是您需要的，而不是 const picture = db.read(req.query.id);