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几乎所有的项目涉及到报表或者合同处理等，都会跟PDF打交道。

node.js中，用的比较多的是html-pdf，每周下载量达到8万多，是比较多了。

这款工具的特点是不光可以通过代码调用API生成pdf，还提供命令行工具html-pdf来将html文件转换成pdf文件。

接下来，我们看一下html-pdf的安装使用。

html-pdf 安装

 npm install -g html-pdf

由于html-pdf是基于phantomjs的，所以在安装过程中会自动下载phantomjs。

html-pdf命令行

html-pdf test/businesscard.html businesscard.pdf

直接运行html-pdf加上源html文件，后面加上pdf文件名就可以生成pdf文件。

创建PDF文件，代码示例

//引入fs, html-pef模块
var fs = require('fs');
var pdf = require('html-pdf');
//读取html文件
var html = fs.readFileSync('./test/businesscard.html', 'utf8');
//参数options, 将PDF format设为letter, 如果是A4,直接将下面代码中的letter换成A4即可
var options = { format: 'Letter' };

//创建pdf文件
pdf.create(html, options).toFile('./businesscard.pdf', function(err, res) {
  if (err) return console.log(err);
  console.log(res); // { filename: '/app/businesscard.pdf' }
});

相关API

var pdf = require('html-pdf');
pdf.create(html).toFile([filepath, ]function(err, res){
  console.log(res.filename);
});

pdf.create(html).toStream(function(err, stream){
  stream.pipe(fs.createWriteStream('./foo.pdf'));
});

pdf.create(html).toBuffer(function(err, buffer){
  console.log('This is a buffer:', Buffer.isBuffer(buffer));
});

HTML中的header 和footer可以直接读出

html-pdf 可以将html中的header和footer读出。只要是id为pageHeader或者pageFooter的都可以被识别出来。

<div id="pageHeader">Default header</div>
<div id="pageHeader-first">Header on first page</div>
<div id="pageHeader-2">Header on second page</div>
<div id="pageHeader-3">Header on third page</div>
<div id="pageHeader-last">Header on last page</div>
...
<div id="pageFooter">Default footer</div>
<div id="pageFooter-first">Footer on first page</div>
<div id="pageFooter-2">Footer on second page</div>
<div id="pageFooter-last">Footer on last page</div>

关于参数options

在调用API pdf.create(html, options).toFile()创建PDF时，这里面的参数options相当强大，可以传很多数据。包括之前说的A4格式。

config = {

  // Export options
  "directory": "/tmp",       // The directory the file gets written into if not using .toFile(filename, callback). default: '/tmp'

  // Papersize Options: http://phantomjs.org/api/webpage/property/paper-size.html
  "height": "10.5in",        // allowed units: mm, cm, in, px
  "width": "8in",            // allowed units: mm, cm, in, px
  - or -
  "format": "Letter",        // allowed units: A3, A4, A5, Legal, Letter, Tabloid
  "orientation": "portrait", // portrait or landscape

  // Page options
  "border": "0",             // default is 0, units: mm, cm, in, px
  - or -
  "border": {
    "top": "2in",            // default is 0, units: mm, cm, in, px
    "right": "1in",
    "bottom": "2in",
    "left": "1.5in"
  },

  paginationOffset: 1,       // Override the initial pagination number
  "header": {
    "height": "45mm",
    "contents": '<div style="text-align: center;">Author: Marc Bachmann</div>'
  },
  "footer": {
    "height": "28mm",
    "contents": {
      first: 'Cover page',
      2: 'Second page', // Any page number is working. 1-based index
      default: '<span style="color: #444;">{{page}}</span>/<span>{{pages}}</span>', // fallback value
      last: 'Last Page'
    }
  },


  // Rendering options
  "base": "file:///home/www/your-asset-path", // Base path that's used to load files (images, css, js) when they aren't referenced using a host

  // Zooming option, can be used to scale images if `options.type` is not pdf
  "zoomFactor": "1", // default is 1

  // File options
  "type": "pdf",             // allowed file types: png, jpeg, pdf
  "quality": "75",           // only used for types png & jpeg

  // Script options
  "phantomPath": "./node_modules/phantomjs/bin/phantomjs", // PhantomJS binary which should get downloaded automatically
  "phantomArgs": [], // array of strings used as phantomjs args e.g. ["--ignore-ssl-errors=yes"]
  "script": '/url',           // Absolute path to a custom phantomjs script, use the file in lib/scripts as example
  "timeout": 30000,           // Timeout that will cancel phantomjs, in milliseconds

  // Time we should wait after window load
  // accepted values are 'manual', some delay in milliseconds or undefined to wait for a render event
  "renderDelay": 1000,

  // HTTP Headers that are used for requests
  "httpHeaders": {
    // e.g.
    "Authorization": "Bearer ACEFAD8C-4B4D-4042-AB30-6C735F5BAC8B"
  },

  // To run Node application as Windows service
  "childProcessOptions": {
    "detached": true
  }

  // HTTP Cookies 
  "httpCookies": [
    // e.g.
    {
      "name": "Valid-Cookie-Name", // required
      "value": "Valid-Cookie-Value", // required
      "domain": "localhost",
      "path": "/foo", // required
      "httponly": true,
      "secure": false,
      "expires": (new Date()).getTime() + (1000 * 60 * 60) // e.g. expires in 1 hour
    }
  ]

}