PHP使用phantomjs导出网址的图片，并使用proc_open输出到浏览器

1. phantomjs部分,保存为capture.js

用法:
phantomjs export.js http://www.bugshoot.cn png 5000 225*1364

"use strict";
var page = require('webpage').create(),
    system = require('system'),
    address, output, size, pageWidth, pageHeight;

if (system.args.length < 3 || system.args.length > 5) {
    console.log('Usage:\tphantomjs capture.js URL filename [paperwidth*paperheight] [cookies] [zoom]');
    console.log('Cookies: key=value;key=value')
    console.log('Eg1:\n\t// 生成图片为 ifmicro.png, 并且大小为宽1820px, 高1920px')
    console.log('\tphantomjs capture.js http://www.bugshoot.cn/ ifmicro.png 1920px*1920px');
    console.log('Eg2:\n\t// 生成图片为 ifmicro.jpg, 并且大小为宽1820px, 高1920*3/4px')
    console.log('\tphantomjs capture.js http://www.bugshoot.cn/ ifmicro.png 1920px');
    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[3].substr(-2) === "px") {
        size = system.args[3].split('*');
        if (size.length === 2) {
            pageWidth = parseInt(size[0], 10);
            pageHeight = parseInt(size[1], 10);
            page.viewportSize = { width: pageWidth, height: pageHeight };
            page.clipRect = { top: 0, left: 0, width: pageWidth, height: pageHeight };
        } else {
            console.log("size:", system.args[3]);
            pageWidth = parseInt(system.args[3], 10);
            pageHeight = parseInt(pageWidth * 3/4, 10); // it's as good an assumption as any
            console.log ("pageHeight:",pageHeight);
            page.viewportSize = { width: pageWidth, height: pageHeight };
        }
    }

    if (system.args.length > 4) {
      var cookiesArr = system.args[4].split(";");
      var cookiesJson = {};
      for (var i=0; ivar tempCookie = cookiesArr[i].split('=');
        cookiesJson[tempCookie[0].trim()] = tempCookie[1].trim()
                phantom.addCookie({
                    name: tempCookie[0].trim(),
                    value: tempCookie[1].trim(),
                    domain: 'www.bugshoot.cn'
                })
      }
            console.log(phantom.cookies)
    }

    if (system.args.length > 5) {
        page.zoomFactor = system.args[5];
    }

    page.open(address, function (status) {
        if (status !== 'success') {
            console.log('Unable to load the address!');
            phantom.exit(1);
        } else {
            window.setTimeout(function () {
                page.render(output);
                phantom.exit();
            }, 2500);
        }
    });
}

2.PHP部分。

思路是执行上述的shell操作，然后把接收到的数据作为PNG文件返回给浏览器。这里使用proc_open函数，相比system``exec等函数，优点是输入、输出、错误流是分开的。代码：

        set_time_limit(0);
        #关掉缓存，否则返回的内容会先打内存，大小会受脚本运行内存限制
        ob_implicit_flush(true);
        ob_end_flush();
        header('Content-Disposition:  attachment;  filename=summary.png'  );
        #header('Content-Length:' . $api_result['detail']['size']);
        header('Content-Description: File Transfer');
        header('Content-Type: application/octet-stream');
        header('Content-Transfer-Encoding: binary');
        header('Expires: 0');
        header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
        header('Pragma: public');

        $command = 'phantomjs export.js '. \Yii::$app->params['CALLBACKURL'] .'export/post-data?md5=' . $md5 . '/#/'. $url.' png 5000 ' . $height .'*' . $width;
        $descriptorSpec = array(
            0 => array("pipe", "r"),#shell标准输入流
            1 => array("pipe", "w"),#标准输出流
            2 => array("pipe", "w")#错误流
        );
        $process = proc_open($command, $descriptorSpec, $pipes);
        $flag = 1;
        $text = '';
        if (is_resource($process)) {
            while (!feof($pipes[1])) {
                if($flag)
                {
                 fgets($pipes[1],strlen('data:image/png;base64,')+1);#去掉头
                    $flag = 0;
                }
                else{
                    $text .=  fgets($pipes[1], 1024);
                }
            }
            echo base64_decode($text);#由于phantomjs直接输出png binary格式的api没有实现，需要从base64转换
            fclose($pipes[1]);
            proc_close($process);
        }
        exit;