Nodejs+express+mysql simple blog building

Refer to the learning video     Reference resources up Video learning

establish gitee Warehouse

gitee Official website --------- New warehouse （ Upper right corner + Number ）------- Adjust the basic information to create -------- Go back to the location where you want to create the file , Right click git bash here------ according to gitee The prompt command on ------- notice gitee Successfully created on  

Local environment construction

initialization

npm init -y

download express mysql

npm i express mysql -D

establish app.js And carry out basic configuration

const express = require("express");
const app = express();
app.get("/login", (req, res) => {
    res.send({
        status: 0,
        message: " The request is successful ！",
        data: [
            { id: 1, name: ' Zhang San ', age: 23 },
            { id: 2, name: ' Li Si ', age: 22 },
            { id: 2, name: ' Wang Wu ', age: 25 },
        ]
    });
    res.end();
})
app.listen(3000, () => {
    console.log(" Server turned on  http://localhost:3000")
});

Opening service

node app.js

Check whether the browser input is successfully configured http://localhost:3000 Check for data

The request is successful

  Routing jump encapsulation

newly build pages Catalog ----- New under the directory index.html  login.html Give me something

Routing configuration app.js adopt fs introduce html file ( Modify and add app.js by ）

const express = require("express");
const app = express();
const fs = require("fs");
app.get("/", (req, res) => {
    fs.readFile("pages/index.html", (err, data) => {
        if (!err) {
            res.end(data);
        } else {
            console.log(err);
        }

    })
})
app.get("/toLogin", (req, res) => {
    fs.readFile("pages/login.html", (err, data) => {
        if (!err) {
            res.end(data);
        } else {
            console.log(err);
        }

    })
})
app.listen(3000, () => {
    console.log(" Server turned on  http://localhost:3000")
});

open localhost:3000 The default index.html 

Input localhost:3000/toLogin The default login.html page

Page route encapsulation

Because the imported file code is highly similar , So build util.js file , Put the public method here , Optimize the code

const fs = require("fs");
module.exports = {
    read: (url) => {
        return new Promise((resolve, rejects) => {
            fs.readFile(url, (err, data) => {
                if (!err) {
                    resolve(data);
                } else {
                    console.log(err);
                    rejects(err);
                }
            })
        })
    }
}

app.js by ：

const express = require("express");
const app = express();
const fs = require("fs");
const util = require("./util");
app.get("/", (req, res) => {
    util.read("pages/index.html").then((data) => {
        res.end(data);
    })
})
app.get("/toLogin", (req, res) => {
    util.read("pages/login.html").then((data) => {
        res.end(data);
    })
})
app.listen(3000, () => {
    console.log(" Server turned on  http://localhost:3000")
});

Successful visit , Route encapsulation succeeded

Connect mysql database

configure connections , For example, request /getList Get the database data , There's something wrong here bug Can't connect , Finally, the configuration is modified

db_config The properties inside are configured according to their own

// Database operation 
app.get("/getList", (err, res) => {

    const db_config = {
        host: "localhost",
        user: "root",
        password: "123456",
        port: "3306",
        database: "blog"
    }
    let connect = mysql.createConnection(db_config);
    // Start linking databases 
    connect.connect(function(er) {
        if (er) {
            console.log(`mysql The connection fails : ${er}!`);
        } else {
            console.log("mysql Successful connection !");
        }
    });
    // Basic query statements 
    let sqlQuery = "select * from t_user";
    connect.query(sqlQuery, function(e, result) {
        if (e) {
            console.log(`SQL error: ${e}!`);
        } else {
            console.log(result);
            res.send(JSON.parse(JSON.stringify(result)));
            closeMysql(connect);
        }
    });
    // Close after successful query mysql
    function closeMysql(connect) {
        connect.end((err) => {
            if (err) {
                console.log(`mysql Close the failure :${err}!`);
            } else {
                console.log('mysql Closed successfully !');
            }
        });
    }

});

But it's too troublesome to need everyone , So we build a db.js Special configuration database

const mysql = require("mysql");
const db_config = {
    host: "localhost",
    user: "root",
    password: "123456",
    port: "3306",
    database: "blog"
}
exports.db = (sql, sqlParams) => {
    return new Promise((resolve, reject) => {
        let connect = mysql.createConnection(db_config);
        // Start linking databases 
        connect.connect(function(er) {
            if (er) {
                console.log(`mysql The connection fails : ${er}!`);
            } else {

                console.log("mysql Successful connection !");
            }
        });

        connect.query(sql, sqlParams, function(e, result) {
            if (e) {
                reject(e)
                console.log(`SQL error: ${e}!`);
            } else {
                console.log(result);
                resolve(result)
                closeMysql(connect);
            }
        });
        // Close after successful query mysql
        function closeMysql(connect) {
            connect.end((err) => {
                if (err) {
                    console.log(`mysql Close the failure :${err}!`);
                } else {
                    console.log('mysql Closed successfully !');
                }
            });
        }

    })
}

At this time app.js

const express = require("express");
const app = express();
const { db } = require("./db");
const util = require("./util");
app.get("/", (req, res) => {
    util.read("pages/index.html").then((data) => {
        res.end(data);
    })
});
app.get("/toLogin", (req, res) => {
    util.read("pages/login.html").then((data) => {
        res.end(data);
    })
});
// Database operation 
app.get("/getList", (err, res) => {
    const sql = "select * from t_user";
    const sqlParams = null;
    db(sql, sqlParams).then((data) => {
        res.send(data);
    })
});
//  Add database user operations 
// Database operation 
app.get("/addList", (err, res) => {

    const sql = "insert into t_user set ?";
    const sqlParams = { id: 7, name: 'lld', age: 14, sex: 0 };
    db(sql, sqlParams).then((data) => {
        res.send(data);
    })
});

app.listen(3001, () => {
    console.log(" Server turned on  http://localhost:3001")
});

Static resource allocation

Create a new file in the root directory static

static Under the new css js upload Catalog    

css newly build index.css file

To configure stay app.js in

app.use('/static', express.static(__dirname + '/static')); // Static files 

stay index.html Call in

 <link rel="stylesheet" href="static/css/index.css">

Then you can see that the effect is successfully introduced

Data persistence module separation

  The actions under different paths may be the same , For example, you need to query the database for the mobile phone before logging in or registering the path , So it is convenient for you, me and him to package the module .