Is it possible to get info from a file on the clie

问题:

I am allowing my users to upload mp3 files just so I can read the metadata and extract the Song Title and Singer Name.

At the moment I am uploading the file and using getId to read the meta data. The upload of course takes a lot of resources and bandwidth. And it seems kind of wasteful to upload the mp3s since all I need are 2 pieces of information and I won't even be doing anything with the file itself. So I delete it afterwards.

Is it possible to get these 2 pieces of information on the client side without copying the file to my server?

回答1:

you can only do this in HTML5 compliant browsers that implemented the FileReader interface (Firefox, Chrome, IE10, Safari 5.1+, not sure about Opera).

You basically use FileReader to get the contents of your file into memory and then manually scan (in client-side javascript) for the MP3 tags you want.

回答2:

You can only get information from a client-side file by either uploading it and processing it on the server (which you don't want to do), or distributing a client that will process the file on the client-side and upload just the pertinent information. Option 2 requires you develop (or co-opt) a client application, and distribute it.

回答3:

Like this you mean: Working demo http://jsfiddle.net/9pfLJ/

Good link: http://jquerybyexample.blogspot.com/2012/03/how-to-check-file-size-before-uploading.html

http://www.aibn.com/help/Learn/mimetypes.html

Hope it helps your cause :) , rest feel free to play around with the demo.

P.S. - in the demo it will alert the file name as well.

code

$(document).ready(function() {
   $("#flUpload").change(function () 
   { 
     var iSize = ($("#flUpload")[0].files[0].size / 1024); 

     alert("Name of file ===> " + $("#flUpload")[0].files[0].name);

     if (iSize / 1024 > 1) 
     { 
        if (((iSize / 1024) / 1024) > 1) 
        { 
            iSize = (Math.round(((iSize / 1024) / 1024) * 100) / 100);
            $("#lblSize").html( iSize + "Gb"); 
        }
        else
        { 
            iSize = (Math.round((iSize / 1024) * 100) / 100)
            $("#lblSize").html( iSize + "Mb"); 
        } 
     } 
     else 
     {
        iSize = (Math.round(iSize * 100) / 100)
        $("#lblSize").html( iSize  + "kb"); 
     }    
  }); 
});​