url转base64

`var http = require('http');

var url = 'http://172.31.228.15:8081/images/28a3b451f81986184a86281a4aed2e7389d4e6a0.jpg';

http.get(url, (res) => {

var chunks = [];
var size = 0;
res.on('data', (res) => {
    console.log(res);
    chunks.push(res);
    size += res.length;
});
res.on('end', function(err) {
    var data = Buffer.concat(chunks, size);
    var base64Img = data.toString('base64');
    console.log(`data:image/png;base64,${base64Img}`);
});

});`

本地图片转base64

`var fs = require('fs');

fs.readFile('./public/images/aaa.jpg', (err, res) => {

if (err) {
    return console.error(err);
};
var base64str = res.toString('base64');
console.log('data:image/png;base64,', base64str);

}) `