Question

i have the following situation :
i have to create files dynamically , the user agent send data to the server via ajax in this way :

$("#generateButton").live("click",function(){
dateLimite = $("#dateLimite").val();
 $.ajax({
   type    : "POST",
   url     : "../generateFile.do",
   data    : { fileName: "demandeExplication",
   nbrParam: "3",
   param1:"<%=agent.getPrenomAgentArabe()+" "+agent.getNomAgentArabe()%>",
   param2:"<%=descriptionActe%>",
   param3:dateLimite,
   },
   dataType: "html",

}).done(function(data) {
$("#test").empty().append(data);
  fileName = $("#test").find("input").val();
$.fileDownload('http://localhost:8080/gestionRH/fiches/temp/'+fileName);

});
});

the server process this data with an action that create a file dynamicaly :

public class GenerateFile extends Action
{ 



public ActionForward execute(ActionMapping mapping, ActionForm form,
        HttpServletRequest request, HttpServletResponse response) throws IOException {
    String fileName = request.getParameter("fileName");
    Integer nbrParam = Integer.parseInt(request.getParameter("nbrParam"));
    String[] valueParam = new String[nbrParam+1];
    for(int i =1;i<=nbrParam;i++)
    {  System.out.println(request.getParameter("param"+i));
        valueParam[i]=request.getParameter("param"+i);
    }
    FileInputStream in = new FileInputStream("C:\\Users\\free\\Desktop\\myworkspace\\gestionRH\\WebRoot\\fiches\\"+fileName+".doc");
    POIFSFileSystem fs = new POIFSFileSystem(in);
    HWPFDocument doc = new HWPFDocument(fs);
    Range r = doc.getRange();
    for(int i=1;i<=nbrParam;i++)
    {   System.out.println("<param"+i+">");
        System.out.println(valueParam[i]);
        r.replaceText("<param"+i+">", valueParam[i]);
    }


    File frr = new File("C:\\Users\\free\\Desktop\\myworkspace\\gestionRH\\WebRoot\\fiches\\temp");
    File temp = File.createTempFile("monfile",".doc",frr);
    FileOutputStream out = new FileOutputStream(temp);
    doc.write(out);
    out.close();
    in.close();
    request.setAttribute("fileName", temp.getName());
    return mapping.findForward("fileName");
}
}

i use a this plugin to do the download : http://johnculviner.com/category/jQuery-File-Download.aspx

i get an error download !
which i don’t get with already existing files , or when i trigger the download after some time with this code :

function timeout_trigger() {    

fileName = $(“#test”).find(“input”).val();
}

wich i use it in this way :

......}).done(function(data) {
setTimeout("timeout_trigger()",7000);
});

and this second solution is not always working , so i must solve this problem.
why already existing files are downloaded with no problems and recently created show errors on download ?

Answer 1

That’s probably because the file hasn’t been uploaded, yet. With AJAX, the file is uploaded in the background. That takes time. The server code is triggered only after the whole file has been uploaded (it wouldn’t want to operate on a partial file).

So what you need is a way to ask “Is there an upload for this in progress?”. When I had the same problem, I sent several AJAX requests. The first one would create a status object in the session where I would record the file name.

When querying for the file, I’d look at that status object to see whether the upload was complete and return the status.

There are also ways to hook into the upload process; when you do that, you can even add a “percentage uploaded” to the status object.