React+react-dropzone+node.js实现图片上传的示例代码
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2022-09-08 20:46:29
本文将会用typescript+react+react-dropzone+express.js实现前后端上传图片。当然是用typescript需要提前下载相应的模块,在这里...
本文将会用typescript+react+react-dropzone+express.js实现前后端上传图片。当然是用typescript需要提前下载相应的模块,在这里就不依依介绍了。
第一步,配置tsconfig.js
"compileroptions": { "outdir": "./public/", "sourcemap": true, "noimplicitany": true, "module": "commonjs", "target": "es5", "jsx": "react" , "noimplicitany": false, "suppressimplicitanyindexerrors": true }, "files": [ "./views/home/main.tsx" ], "exclude": [ "node_modules" ] }
2.配置webpack
var path = require('path'); var webpack = require('webpack'); var extracttextplugin = require("extract-text-webpack-plugin"); var htmlwebpackplugin = require('html-webpack-plugin'); var title = { home: '首页', } module.exports = { entry: { home: [ 'babel-polyfill', './views/home/main.tsx' ], common: ['react','babel-polyfill'] }, output: { path: path.join(__dirname, 'views/wap'), filename: '[name].js', chunkfilename: '[id].build.js?[chunkhash]', publicpath: '/views/wap/', }, module: { loaders: [ { test: /\.tsx?$/, loader: 'ts-loader' }, { test: /\.(less|css)$/, loader: extracttextplugin.extract('style', 'css!less'), }, { test:/\.(js|jsx)?$/, loader:'babel', exclude:/node_modules/, query:{compact:false,presets:['es2015','react','stage-0','stage-1','stage-2']} }, { test: /\.(png|jpg|gif)?$/, loaders: ['url?limit=8192&name=[name]_[sha512:hash:base64:7].[ext]'], }, { test: /\.(eot|woff|ttf|svg)$/, loader: 'file?limit=81920&name=[name]_[sha512:hash:base64:7].[ext]' }, ] }, resolve: { root: ['node_modules'], extensions: ['', '.js', '.jsx', '.html', '.json','.ts', '.tsx'], modulesdirectories: ['node_modules'], alias: {} }, externals: {}, plugins: [ new webpack.defineplugin({ 'process.env.node_env': '"production"' }), new webpack.hotmodulereplacementplugin(), new extracttextplugin('[name].[contenthash:20].css'), new webpack.optimize.uglifyjsplugin({ compress: {warnings: false} }), new webpack.optimize.commonschunkplugin('common', 'common.js'), new htmlwebpackplugin( { title: "", template: path.join(path.resolve(__dirname),'views/wap/myapp.html'), //模板文件 inject:'body', hash:true, //为静态资源生成hash值 minify:{ //压缩html文件 removecomments:false, //移除html中的注释 collapsewhitespace:false //删除空白符与换行符 } } ) ] };
3.react-dropzone
import * as dropzone from 'react-dropzone'; <dropzone accept="image/jpeg, image/png" ondrop={(accepted, rejected) => { this.setstate({ accepted, rejected });this.drop(accepted[0].preview) }} style={{width:"100%",height:"120px",background:"#f2f2f2","padding-top":'90px',"cursor":"pointer","box-sizing":"content-box"}} > </dropzone>
accept:表示图片的接受类型
ondrop代表图片加载以后触发
accepted:表示加载图片成功后相关信息,打印出来如下:
rejected:表示加载图片失败后,相关信息:
4.图片处理、上传
新建一个drop方法在触发ondrop后。
drop(src : any) : any{ const that = this; let img = src; let image = new image(); image.crossorigin = 'anonymous'; image.src = img; image.onload = function(){ let base64 = that.getbase64image(image); that.uploadimg({imgdata:base64}) } }
在这里我们使用base64传递,所以我们需要把图片转成base64,定义getbase64image处理
getbase64image(img :any) : string { let canvas = document.createelement("canvas"); canvas.width = img.width; canvas.height = img.height; let ctx = canvas.getcontext("2d"); ctx.drawimage(img, 0, 0, img.width, img.height); let ext = img.src.substring(img.src.lastindexof(".")+1).tolowercase(); let dataurl = canvas.todataurl("image/"+ext); return dataurl; }
最终返回的是处理后图片的地址,然后上传
async uploadimg(params : object) : promise<any>{ let res = await axios.post('http://localhost:3000/uploadimg',params); }
5.node部分
router/index.js
var express = require('express'); var router = express.router(); var rf = require('fs'); var setimg = require('./controller/uploadimg'); var setimg = new setimg; router.post('/uploadimg',setimg.setuploadimg); module.exports = router;
./controller/uploadimg.js
var rf = require('fs'); class setimg { setuploadimg(req, res, next) { let imgdata = req.body.imgdata; let base64data = imgdata.replace(/^data:image\/\w+;base64,/, ""); let databuffer = new buffer(base64data, 'base64'); let timer = number( new date() ); rf.writefile("views/images/artcover"+timer+".png",databuffer, function(err) { if(err) { res.json({"code":400,"verson":false,"msg":err}); }else { res.json({"code":100,"verson":true,"url":"views/src/common/images/artcover/"+timer+".png"}); } }); } } module.exports = setimg;
拿到图片后先进行格式转换,然后将图片写入到本地,返回图片路径。
import * as react from 'react'; import * as reactdom from 'react-dom'; import * as dropzone from 'react-dropzone'; import * as axios from 'axios'; import './main.less'; declare var document; declare var image; class imgupload extends react.component<any,any> { constructor(){ super() this.state = { accepted: [], rejected: [] } } public drop(src : any) : any{ const that = this; let img = src; let image = new image(); image.crossorigin = 'anonymous'; image.src = img; image.onload = function(){ let base64 = that.getbase64image(image); console.log(base64) that.uploadimg({imgdata:base64}) } } //转base64 public getbase64image(img :any) : string { let canvas = document.createelement("canvas"); canvas.width = img.width; canvas.height = img.height; let ctx = canvas.getcontext("2d"); ctx.drawimage(img, 0, 0, img.width, img.height); let ext = img.src.substring(img.src.lastindexof(".")+1).tolowercase(); let dataurl = canvas.todataurl("image/"+ext); return dataurl; } public async uploadimg(params : object) : promise<any>{ let res = await axios.post('http://localhost:3000/uploadimg',params); } render(){ const that = this; let imgs; if(this.state.accepted.length > 0){ imgs = ( <ul> {this.state.accepted.map( (f) => { return <img key={f.name} src={f.preview} /> })} </ul> ) } return ( <div> <div classname="wrap"> <dropzone accept="image/jpeg, image/png" ondrop={(accepted, rejected) => { console.log(accepted);console.log(rejected);this.setstate({ accepted, rejected });this.drop(accepted[0].preview) }} style={{width:"100%",height:"120px",background:"#f2f2f2","padding-top":'90px',"cursor":"pointer","box-sizing":"content-box"}} > <p classname="upload">请添加主题图片</p> </dropzone> </div> <div classname="show">{imgs} </div> </div> ) } } reactdom.render( <imgupload />, document.getelementbyid('app') )
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持。
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