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
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"compilerOptions": {
"outDir": "./public/","sourceMap": true,"noImplicitAny": true,"module": "commo
njs","target": "es5","jsx": "react","noImplicitAny": false,"suppressImplicitAnyIndexErrors": true
},"files": [ "./views/home/main.tsx" ],"exclude": [
"node_modules"
]
}
2.配置webpack
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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
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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"}} >
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：
新建一个drop方法在触发onDrop后。
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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
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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,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
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async upLoadImg(p
arams : object) : Promise
{
let res = await axios.post('http://localhost:3000/upLoadImg',params);
}
5.node部分
router/index.js
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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
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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。
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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,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{
let res = await axios.post('http://localhost:3000/upLoadImg',params);
}
render(){
const that = this;
let imgs;
if(this.state.accepted.length > 0){
imgs = (
{this.state.accepted.map( (f) => {
return 
})}
)
}
return (
{ console.log(accepted);console.log(rejected);this.setState({ accepted,rejected });this.drop(accepted[0].preview) }}
style={{width:"100%","
Box-sizing":"content-
Box"}}
>
添加主题图片
)
}
}
ReactDom.render(
,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编程之家。
