后端导出svg为png到前端, image.js为express路由，rasterize.js为phantomjs运行文件，client.js为前端发送请求生成png文件请求的代码

client.js

var chart = highchart(this.el, opts).highcharts();
var svg = chart.getSVG();
request
  .post('/image')
  .send({
    xml: svg
  })
  .set('Accept', 'application/json')
  .end(function(err, res) {
    if(err) throw err;
    if(res.error) throw new Error(res.error.status);
    window.open('/image/' + res.body.name);
  })

image.js

var express = require('express');
var childProcess = require('child_process');
var phantomjs = require('phantomjs');
var fs = require ('fs');
var path = require ('path');
var tmp = require ('tmp');
var binPath = phantomjs.path;

var app = module.exports = express();

app.post('/image', function(req, res, next) {
  //xml is the svg string posted in field xml
  var xml = req.body.xml;
  var str = '<?xml version="1.0" encoding="UTF-8" standalone="no"?>\n' + xml;
  tmp.file({
    template: path.join(__dirname, 'tmp/tmp-XXXXXXXX.svg')
  }, function (err, filePath, fd) {
    if (err) return next(err);
    var target = filePath.replace(/\.svg$/, '.png');
    fs.writeFile(filePath, str, function(err) {
      if(err) return next(err);
      var childArgs = [ path.join(__dirname, 'rasterize.js'), filePath, target];
      childProcess.execFile(binPath, childArgs, function(err, stdout, stderr) {
        if(err) return next(err);
        res.json({
          name: path.basename(target)
        })
      })
    })
  });
})

app.get('/image/:filename', function(req, res, next) {
  var fileName = req.params.filename;
  var filePath = path.join(__dirname, 'tmp', fileName);
  res.download(filePath, function(err) {
    if(err) return next(err);
  })
})

rasterize.js

var page = require('webpage').create(),
    system = require('system'),
    address, output, size;

if (system.args.length < 3 || system.args.length > 5) {
    console.log('Usage: rasterize.js URL filename [paperwidth*paperheight|paperformat] [zoom]');
    console.log('  paper (pdf output) examples: "5in*7.5in", "10cm*20cm", "A4", "Letter"');
    phantom.exit(1);
} else {
    address = system.args[1];
    output = system.args[2];
    page.viewportSize = { width: 600, height: 600 };
    if (system.args.length > 3 && system.args[2].substr(-4) === ".pdf") {
        size = system.args[3].split('*');
        page.paperSize = size.length === 2 ? { width: size[0], height: size[1], margin: '0px' }
                                           : { format: system.args[3], orientation: 'portrait', margin: '1cm' };
    }
    if (system.args.length > 4) {
        page.zoomFactor = system.args[4];
    }
    page.open(address, function (status) {
        if (status !== 'success') {
            console.log('Unable to load the address!');
            phantom.exit();
        } else {
            window.setTimeout(function () {
                page.render(output);
                phantom.exit();
            }, 200);
        }
    });
}

ubuntu下需要执行sudo apt-get install xfonts-wqy解决乱码问题

hi，我觉得如果没有这种导出的需求的话，就根本没必要把这些东西放在后端做。
比如复杂的svg绘图。