5. 文件上传下载与 db数据库

文件上传

formidable

multer

npm i formidable multer

如何使用见： https://www.npmjs.com/

util.inspect 自己查

文件上传：表单必须有2个东西

1、enctyp="multipart/form-data"

2、method="post"

文件下载：

res.download(__filename);

formidable

server1.js

var http = require("http");

var formidable = require("formidable");

var fs = require("fs");

var path = require("path");

http.createServer(function(req,res){

	console.log(req.url);

	if(req.url == "/upload"){

		var form = new formidable.IncomingForm();

		form.uploadDir = "upload";

		form.parse(req, function(err, fields, files) {

			console.log(fields, files);

			var oFile = files.f1;

			var oldPath = oFile.path;

			var newName = oldPath + oFile.name;

			fs.rename(oldPath,newName,function(err){

				res.writeHead(200,{'Content-Type':'text/html;charset=utf-8'});//设置response编码为utf-8

				if(err){

					res.end("上传失败");

				} else {

					res.end("上传成功");

				}

			});

		});

	}

}).listen(9000);

form.html

<!doctype html>

<html>

<head>

<meta charset="utf-8">

<title>无标题文档</title>

</head>

<body>

<form action="http://localhost:9000/upload" enctype="multipart/form-data" method="post">

	<input type="text" name="user" value="aaa" /> <br /><br />

	<input type="file" name="f1" value="" /> <br /><br />

	<input type="submit"/>

</form>

</body>

</html>

res:

$ node server

/upload

{ user: 'aaa' } { f1:

   File {

     domain: null,

     _events: {},

     _eventsCount: 0,

     _maxListeners: undefined,

     size: 5,

     path: 'upload\\upload_df6a908be04c7a08d5406784cfbcb468',

     name: 'test.txt',

     type: 'text/plain',

     hash: null,

     lastModifiedDate: 2018-07-13T12:55:25.753Z,

     _writeStream:

      WriteStream {

        _writableState: [Object],

        writable: false,

        domain: null,

        _events: {},

        _eventsCount: 0,

        _maxListeners: undefined,

        path: 'upload\\upload_df6a908be04c7a08d5406784cfbcb468',

        fd: null,

        flags: 'w',

        mode: 438,

        start: undefined,

        autoClose: true,

        pos: undefined,

        bytesWritten: 5,

        closed: true } } }

server.js

var express = require("express");

var multer = require("multer");

var fs = require("fs");

var app = express();

app.listen(9000);

app.use(express.static("www"));

app.use(express.urlencoded({extended:false}));

//文件上传中间件

var multerMiddleware = multer().any();

app.use(multerMiddleware);

app.use("/upload",function(req,res){

	console.log(req.files);

	var oFile = req.files[0];

	var path = "upload/"+ oFile.originalname;

	var buf = oFile.buffer;

	fs.writeFileSync(path,buf);

});

res:

$ node server2

[ { fieldname: 'f1',

    originalname: 'test.txt',

    encoding: '7bit',

    mimetype: 'text/plain',

    buffer: <Buffer 36 36 36 36 36>,

    size: 5 } ]

文件下载download

var express = require("express");

var app = express();

app.listen(9000);

app.use("/download",function(req,res){

	res.download(__filename);//下载自己

});

res:

db数据库

mysql与 mongodb

1.mysql

npm i mysql 驱动

连接数据库

var db = mysql.createConnection({

	host,user,password,database

});

操作数据库:

db.query(sql,fn(err,data){...});

关闭数据库:

db.end(); 不是close();

//查询

select * from user_table;

select * from user_table where username="aaa" and password="123";

插入

insert into user_table(username,password) values("aaa","123");

2.mongodb

     mysql            mongodb —— json

    关系型数据库     非关系型数据库

库   database         database

表    table          collection集合

行    row            document文档

列    col            field属性

安装目录： C:\Program Files\MongoDB\Server\3.3\bin

mongod 服务器端

mongo 客户端

配置环境变量：

;C:\Program Files\MongoDB\Server\3.3\bin

执行:

mongod --dbpath C:\data\db  默认的配置  以后启动 mogod

mongod --dbpath C:\mongoData 每次启动服务器必须带上完整路径

常用命令：

show dbs显示所有数据 —— 只显示有数据的库名称 show databases

db 查看用户当前所在的数据库

use 切换数据库、创建数据库

插入数据

db.user.insert({a:1}); 包括创建表和插入数据

db.user.insertOne( { x: 1 } );

db.user.find();

db.user.find({x:1});

select * from user_table where x="1"

use 20180713

db.user_table.insert({username:"aaa",password:"123",age:1});

db.user_table.insert({username:"aaa1",password:"123",age:18});

db.user_table.insert({username:"aaa2",password:"123",age:30});

db.user_table.insert({username:"aaa3",password:"123",age:60});

db.user_table.find({},{username:0/1,"_id":0});

select password from user_table

db.getCollection("user_table").find();

db.user_table.find().pretty() 美化json

show collections 查询当前库里面所有的表

db.user_table.find( { age: { $gt: 18 } } ,{"_id":0}) >

db.user_table.find( { age: { $gte: 18 } } ,{"_id":0}) >=

db.user_table.find( { age: { $lt: 18 } } ,{"_id":0}) <

db.user_table.find( { age: { $lte: 18 } } ,{"_id":0}) <=

db.user_table.find( {age:{ $gt: 18, $lt: 60 }},{"_id":0}) >18 <60

db.user_table.find({},{"_id":0}).sort( { age: -1 } ); 1 -1

1 :降序 desc

-1：升序 asc

db.user_table.find({},{"_id":0}).limit(2)

db.user_table.find({},{"_id":0}).limit(2).skip(0)

limit(pageSize).skip(beginIndex);

beginIndex = pageSize*(pageNo-1)

pageSize 2条

pageNo   beginIndex

  1         0

  2         2

  3         4

  4         6

11条数据每页2条一共几页? Math.ceil(total/pageSize);

db.user_table.count();

db.collection.insert()

db.collection.insertOne() 同 insert

db.collection.insertMany([ <document 1> , <document 2>, ... ])

db.user_table.insertMany([

			{username:"xxx1",password"xxx1",age:1},

			{username:"xxx2",password"xxx2",age:2},

			{username:"xxx3",password"xxx3",age:3}

]);

db.user_table.insertMany([

			{username:"xxx1",password:"xxx1",age:1},

			{username:"xxx2",password:"xxx2",age:2},

			{username:"xxx3",password:"xxx3",age:3}

]);

db.user_table.insert([

			{username:"xxx11",password:"xxx1",age:1},

			{username:"xxx22",password:"xxx2",age:2},

			{username:"xxx33",password:"xxx3",age:3}

]);

update

$set：修改或者添加

db.user_table.update(

   { username: "aaa" },

   {

     $set: {username: "AAA", password: "AAA",age: 100}

   }

)

db.user_table.update( { username: "AAA" }, { $unset: { password: 1 } } )

$unset 删除属性

db.user_table.find({},{"_id":0}); 

db.user_table.update(

   { username: "aaa1" },

   { $set: { username : "AAA1" } },

   { multi: true}  可以修改多条数据 默认是false

)

db.user_table.updateOne(

    { username: "aaa3" },

    { $set: { username : "AAA3" } }

);

db.user_table.updateMany(

    { username: "aaa2" },

    { $set: { username : "AAA2" } }

);

删除没有delete 用remove

db.user_table.deleteOne( { "_id" : ObjectId("5b48548b86ffbcc901fc4ac2") } );

db.user_table.deleteOne( { "age" : {$gte:1}} );

db.user_table.deleteMany( { "age" : {$gte:1}} );

db.user_table.remove( { "age" : {$gte:1}} );

db.user_table.remove( { "age" : {$gte:1}},{justOne:true} );

justOne:true 只删除一条默认false删除所有

注意：必须在cmd环境下运行

https://stackoverflow.com/questions/47282119/mongo-export-syntaxerror-missing-before-statement-shell114

导入数据：

mongoimport --db 20180713 --collection user_table --drop --file xxx.txt

导出数据

mongoexport --db 20180713 --collection user_table --out xxx.txt

xxx.txt

{username:"xxx1",password:"xxx1",age:1}

{username:"xxx2",password:"xxx2",age:2}

{username:"xxx3",password:"xxx3",age:3}

mongodb&& node

npm i mongodb

使用方法：https://www.npmjs.com/package/mongodb

mongodb浏览器的可视化

adminMongo https://github.com/mrvautin/adminMongo

mongoose:

mongodb/mongoose

DOM 文档对象模型

ODM 对象文档模型

npm i mongoose

https://www.npmjs.com/package/mongoose

http://mongoosejs.com/

db.js

var mongoose = require('mongoose');

var Schema = mongoose.Schema;

mongoose.connect('mongodb://localhost/20180716');

//定义表结构的数据类型

var userSchema = new Schema({

	user:String,

	pass:String

});

//定义表 表结构都会带s,只能有一个s    控制台查询:db.user_tables.find();

var UserModel = mongoose.model('user_table', userSchema);

//创建数据  行 document

var oUser = new UserModel({user:"bbb"});

oUser.pass = "123";

//db.user_table.insert(document);

//插入

oUser.save(function (err, result) {

  	console.log(err, result);

	//查询

	//find

	UserModel.find(function (err, data) {

		console.log(err, data);

	})

});

res:

$ node db.js

(node:9996) DeprecationWarning: current URL string parser is deprecated, and wil

l be removed in a future version. To use the new parser, pass option { useNewUrl

Parser: true } to MongoClient.connect.

null { _id: 5b4c780013c2a1270cd6c0fd,

  user: 'bbb',

  pass: '123',

  __v: 0 }

null [ { _id: 5b4c76c859b0432a1c4e0626,

    user: 'bbb',

    pass: '123',

    __v: 0 },

  { _id: 5b4c780013c2a1270cd6c0fd,

    user: 'bbb',

    pass: '123',

    __v: 0 } ]

db2.js

连接成功测试

/*var mongoose = require('mongoose');

var Schema = mongoose.Schema;

mongoose.connect('mongodb://localhost/716');

var db = mongoose.connection;

db.on('error', function() {

  console.log("连接失败");

});

db.once('open', function() {

  console.log("连接已经建立");

});*/

//或者

/*var mongoose = require('mongoose');

mongoose.connect('mongodb://localhost/20180716',function(err) {

  	if(err){

		console.log("连接失败");

	} else {

		console.log("连接已经建立");

	}

});*/

res:

$ node db2

(node:11436) DeprecationWarning: current URL string parser is deprecated, and wi

ll be removed in a future version. To use the new parser, pass option { useNewUr

lParser: true } to MongoClient.connect.

连接已经建立

心中那自由的世界,如此的清澈高远!