JavaScript implements decompression and viewing of zip files on the web page

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JavaScript implements decompression and viewing of zip files on the web page_javascript skills

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May 16, 2016 pm 03:25 PM

javascript

WEB front-end decompression ZIP package

What is the use of web front-end to decompress zip files:

If we only consider standard browsers, the server only needs to transmit the compressed package to the client, which saves bandwidth and transmission time, which sounds very impressive;

If there is a lot of front-end code and contains large pictures, then various data such as js, css, jpg and png can be packaged into zip through the server and sent to the browser. The browser is responsible for decompression. CSS practical dynamics Generate and insert into the dom, js is also directly executed using globalEval, various jpg or png image files are converted from blob streams into images, and directly inserted into the browser;

HTML5 supports reading Blobs (binary large objects, file files also inherit Blobs) and converts them into image streams or text streams or other stream formats. This is why browsers can read "application/zip" files. ;

To decompress zip files in the browser, you need to introduce four js, because UnZipArchive.js depends on zip.js, mime-type.js and jquery.js. The test demo is as follows:

<!DOCTYPE html>
<html>
<head lang="en">
 <meta charset="UTF-8">
 <title></title>
 <script src="http://gildas-lormeau.github.io/zip.js/demos/zip.js"></script>
 <script src="http://gildas-lormeau.github.io/zip.js/demos/mime-types.js"></script>
 <script src="http://apps.bdimg.com/libs/jquery/1.9.0/jquery.js"></script>
 <script src="http://files.cnblogs.com/files/diligenceday/UnZipArchive.js"></script>
</head>
<body>
<h2>
 demo
</h2>
<div>
 <input type="file" id="file">
</div>
<ul id="dir">

</ul>
<script>
 $("#file").change(function (e) {
  var file = this.files[0];
  window.un = new UnZipArchive( file );
  un.getData( function() {
   //获取所以的文件和文件夹列表;
   var arr = un.getEntries();
   //拼接字符串
   var str = "";
   for(var i=0; i<arr.length; i++ ) {
    //点击li的话直接下载文件;
    str += "<li onclick=download('"+arr[i]+"')>"+arr[i]+"</li>"
   };
   $("#dir").html( str );
  });
 });
 var download = function ( filename ) {
  un.download( filename );
 };
</script>
</body>
</html>

UnzioarichiveJS is encapsulated by itself. If you have any questions, please feedback in time

Complete DEMO of decompressing ZIP compressed package

<!DOCTYPE html>
<html>
<head lang="en">
 <meta charset="UTF-8">
 <title></title>
 <script src="http://gildas-lormeau.github.io/zip.js/demos/zip.js"></script>
 <script src="http://gildas-lormeau.github.io/zip.js/demos/mime-types.js"></script>
 <script src="http://apps.bdimg.com/libs/jquery/1.9.0/jquery.js"></script>
 <style>
  code{
   display: block;
   padding: 10px;
   background: #eee;
  }
 </style>
</head>
<body>
<div>
 <h1>
  兼容性
 </h1>
 <div>
  <p>
   zip.js可以在所有的chrome浏览器和firefox浏览器中运行， 可以在safari6和IE10，以及IE10以上运行;
  </p>
  <p>
   如果要在IE9和safari中运行需要两个设置：
  </p>
  <code>
   1：zip.useWebWorkers == false
  </code>
  <code>
   2：并引用这个JS:https://bitbucket.org/lindenlab/llsd/raw/7d2646cd3f9b/js/typedarray.js
  </code>
 </div>

 <h2>
  demo
 </h2>
 <div>
  <input type="file" id="file">
 </div>
 <ul id="dir">

 </ul>
 <script>
  $("#file").change(function (e) {
   var file = this.files[0];
   window.un = new UnZipArchive( file );
   un.getData( function() {
    var arr = un.getEntries();
    var str = "";
    for(var i=0; i<arr.length; i++ ) {
     str += "<li onclick=download('"+arr[i]+"')>"+arr[i]+"</li>"
    };
    $("#dir").html( str );
   });
  });
  var download = function ( filename ) {
   un.download( filename );
  };
 </script>
</div>
<script>
 zip.workerScriptsPath = "http://gildas-lormeau.github.io/zip.js/demos/";
 /**
  * @desc 解压缩文件的类;
  * @return UnZipArchive 的实例;
  * */
 var UnZipArchive = function( blob ) {
  if( !blob ) {
   alert("参数不正确, 需要一个Blob类型的参数");
   return ;
  };
  if( !(blob instanceof Blob) ) {
   alert("参数不是Blob类型");
   return ;
  };

  function noop() {};
  this.entries = {};
  this.zipReader = {};
  var _this = this;
  this.length = 0;
  this.onend = noop;
  this.onerror = noop;
  this.onprogress = noop;
  //创建一个延迟对象;
  var def = this.defer = new $.Deferred();
  zip.createReader( new zip.BlobReader( blob ), function(zipReader) {
   _this.zipReader = zipReader;
   zipReader.getEntries(function(entries) {
    _this.entries = entries;
    //继续执行队列;
    def.resolve();
   });
  }, this.error.bind(_this) );
 };

 /**
  * @desc 把blob文件转化为dataUrl;
  * */
 UnZipArchive.readBlobAsDataURL = function (blob, callback) {
  var f = new FileReader();
  f.onload = function(e) {callback( e.target.result );};
  f.readAsDataURL(blob);
 };

 $.extend( UnZipArchive.prototype, {
  /**
   * @desc 获取压缩文件的所有入口;
   * @return ArrayList;
   * */
  "getEntries" : function() {
   var result = [];
   for(var i= 0, len = this.entries.length ; i<len; i++ ) {
    result.push( this.entries[i].filename );
   }
   return result;
  },

  /**
   * @desc 获取文件Entry;
   * @return Entry
   * */
  "getEntry" : function ( filename ) {
   var entrie;
   for(var i= 0, len = this.entries.length ; i<len; i++ ) {
    if( this.entries[i].filename === filename) {
     return this.entries[i];
    };
   }
  },

  /**
   * @desc 下载文件
   * @param filename;
   * @return void;
   * */
  "download" : function ( filename , cb , runoninit) {
   var _this = this;
   this.defer = this.defer.then(function() {
    var def = $.Deferred();
    if(!filename) return ;
    if(runoninit) {
     return runoninit();
    };
    var entry = _this.getEntry( filename );
    if(!entry)return;
    entry.getData(new zip.BlobWriter(zip.getMimeType(entry.filename)), function(data) {
     if( !cb ) {
      UnZipArchive.readBlobAsDataURL(data, function( dataUrl ) {
       var downloadButton = document.createElement("a"),
         URL = window.webkitURL || window.mozURL || window.URL;
       downloadButton.href = dataUrl;
       downloadButton.download = filename;
       downloadButton.click();
       def.resolve( dataUrl );
       _this.onend();
      });
     }else{
      cb( data );
      def.resolve( data );
     }
    });
    return def;
   });
  },

  /**
   * @desc 获取对应的blob数据;
   * @param filename 文件名;
   * @param callback回调, 参数为 blob;
   * @desc 或者可以直接传一个函数作为zip解压缩完毕的回调;
   * */
  "getData" : function ( filename, fn ) {
   if( typeof filename === "string") {
    this.download(filename, function( blob ) {
     fn&&fn( blob );
    });
   }else if( typeof filename === "function") {
    this.download("test", null, function( blob ) {
     filename();
    });
   };
  },

  "error" : function() {
   this.onerror( this );
   throw new Error("压缩文件解压失败");
  }
 });

</script>
</body>
</html>

But browser compatibility is a big problem;

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