如何为 SQL 服务器数据的多个获取请求设置 API 服务器？

Question

我是 React 新手，我想设置一个 API 服务器来获取 SQL 服务器数据，我想向 API 发送多个获取请求服务器。

我试过 promise.all 方法，但在第二次提取请求时总是失败。使它工作的唯一方法是嵌套请求 through.then，但我不想这样做，因为获取请求的数量各不相同。

这是我的代码：

Promise.all([
//the number of requests varied
    fetch('http://localhost:8080/api/report/favorite/check/1/1').then(value => value.json()),
    fetch('http://localhost:8080/api/report/favorite/check/1/4').then(value => value.json())
    ])
    .then((value) => {
        //I always get EALREADYCONNECTING error here from 2nd request and on
        console.log(value)
    })
    .catch((err) => {
        console.log(err);
    });

问题是否出在API服务器配置上？

//Initializing node modules
var express = require("express");
var bodyParser = require("body-parser");
var sql = require("mssql");
var app = express(); 

// Body Parser Middleware
app.use(bodyParser.json()); 

//CORS Middleware
app.use(function (req, res, next) {
//Enabling CORS 
res.header("Access-Control-Allow-Origin", "*");
res.header("Access-Control-Allow-Methods", "GET,HEAD,OPTIONS,POST,PUT");
res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, contentType,Content-Type, Accept, Authorization");
next();
});

//Setting up server
var server = app.listen(process.env.PORT || 8080, function () {
var port = server.address().port;
console.log("App now running on port", port);
});

var connPool = new sql.ConnectionPool({
    user: 'someuser',
    password: 'somepassword',
    server: 'some\thing',
    database: 'somedb',
    port: 12345
});

//Function to connect to database and execute query
var executeQuery = function(res, query){
connPool.connect().then(function () {
    // create request object
    var request = new sql.Request(connPool);
    // query to the database
    request.query(query).then(function (recordset) {
        res.send(recordset)
        connPool.close();
    })
    .catch(function (err) {
        console.log("Error while querying database :- " + err);
        res.send(err)
        connPool.close();
    });
})
.catch(function (err) {
    console.log("Error while connecting database :- " + err);
    res.send(err);
});
}

//GET API
app.get("/api/report/favorite/check/:userid/:reportid", function(req, res){
    var query = "EXEC rpt.proc_ReportFavoriteCheck " + req.params.userid + ", " + req.params.reportid;
    executeQuery (res, query);
});

我尝试了这里描述的几种方法，但我无法使它起作用：

How to finish Fetch data completely and assign it to component state before proceeding further in componentDidMount React?

Answer 1

通过更改我的 API 服务器配置解决了这个问题：

var executeQuery = async function(res, query){
    const pool = new sql.ConnectionPool(dbConfig);
    pool.on('error', err => {
        console.log('sql errors ', err);
    });

    try {
        await pool.connect();
        let result = await pool.request().query(query);
        console.log('success')
        res.send(result);
        return {success: result};
    } catch (err) {
        console.log('error')
        console.log(err)
        res.send(err);
        return {err: err};
    } finally {
        pool.close();
    }
}

如何为 SQL 服务器数据的多个获取请求设置 API 服务器？

How to set up API server for multiple fetch requests of SQL Server data?

sql-server

reactjs

fetch-api