Returning an exe file from server and downloading on client via browser

Question

I am trying to send an exe file from the server to the client. The file contents come in the form of byte array. Then i am trying to recreate the .exe file on the client machine again. On server side I am returning file contents as ' application/octet-stream ', 'Content':bytearray

I am using an ajax call of following type to get file contents.

$.ajax({
type : 'POST',
url : 'https://myurl,
cache : false,
success : function(data) {
var myBlob = new Blob([data], { type: "application/octet-stream" });
              var uri = (window.URL || window.webkitURL).createObjectURL(myBlob);

              // var outputFile = window.prompt("Saving .log file of rows from different modalities") || 'export';
                var  outputFile = "utility"+ '.exe'
               var downloadLink = document.createElement("a");
               downloadLink.href = uri;
               downloadLink.download =outputFile;

               document.body.appendChild(downloadLink);
               downloadLink.click();
               document.body.removeChild(downloadLink); 
cnt++;
/* }); */
},

error : (function(message) {
debugger;
console.log('message ' +message)
}),

statusCode : {
404 : function() {
alert("page not found");
}
}
}); 

But when the file gets downloaded the size of the file is big. for ex original file 192kbs downloaded file 320 kbs Also I am getting the following exception after running the exe: The version of file is not compatible with version of windows you are running on 32/64

Please if anybody can help resolve this issue

The following is the server side code to return exe file contents

    //The context with which all SDK operations are performed.
Context context = Context.create();
String modelnumber = parameters.modelnumber;
String siteid=parameters.siteid;
def b;
try{

JSONArray arr=new  JSONArray();
    ModelFinder mf = new ModelFinder(context);
    mf.setName(modelnumber)

    Model m=mf.find();
    if(m!=null)
    {
        DeviceFinder df = new DeviceFinder(context);
        df.setModel(m)
        df.setSerialNumber(siteid)
        Device dev=df.find()
        if(dev!=null)

        {
            UploadedFileFinder  filefinder=new UploadedFileFinder(context)
            filefinder.setDevice(dev)
            filefinder.setFilename("/remote/notepad.exe")
            UploadedFile temp=filefinder.find()
            if(temp!=null)
            {
                    File f=temp.extractFile();
                    arr[0]=f.text
                    b=f.getBytes() 

            }
        }

    }

    return ['Content-Type': 'application/binary', 'Content':b];
    }
    catch(Exception e)
    {       return ['Content-Type': 'application/text', 'Content':e.getMessage()];
    }

Answer 1

I have solved the problem in following manner: Server side code:

JSONArray arr=new JSONArray() 
def bytes=file.getBytes()
                arr.add(bytes)

                return ['Content-Type': 'application/json', 'Content': arr];
            }

> Client side code:

value3 comes from ajax which is a byte array

      var arr =value3
                  var byteArray = new Uint8Array(arr);
                  var a = window.document.createElement('a');

                  a.href = window.URL.createObjectURL(new Blob([byteArray], { type: 'application/octet-stream' }));
                  a.download ="Utility.exe";

                  // Append anchor to body.
                  document.body.appendChild(a)
                  a.click();


                  // Remove anchor from body
                  document.body.removeChild(a)