I'm trying to get inputStream from request, but it's always empty. Any idea
how to get the contents of it? I'm trying to make a DataInputStream from it.
Are you uploading multipart requests? The request may have already been processed into a Spring MultipartRequest by Grails in which case you can use getFile() to get the upload contents.
If not, then request.inputStream should work fine.
cheers
Lee
For me it works when I request the controller method with "application/octet-stream" MIME and send some data within the request. Than in the controller I can simply do:
import org.apache.commons.io.IOUtils
def test() {
byte[] requestData = IOUtils.toByteArray(request.getInputStream())
}
That's it :-)
Related
Firstly, I know there are multiple posts related to this error but nothing is helping so far.
I am getting an error "Cannot redirect after HTTP headers have been sent." in my MVC razor application when I make a call to SomeController.
How do I fix this?
[HttpPost]
public ActionResult SomeController(Object abc)
{
Helper.somemethod("","excel");
return View(abc);//I tried this
return RedirectToAction("SomeController"); //I tried this also
}
public static void somemethod(string settocken, string filenames, List<Sample> samples)
{
//Extra logic for excel that uses List<Sample> to generate excel.
HttpContext.Current.Response.Clear();
HttpContext.Current.Response.Cookies.Add(new HttpCookie("downloadToken", settocken));
HttpContext.Current.Response.ContentType = "Application/x-msexcel";
HttpContext.Current.Response.AddHeader("Content-Disposition", String.Format("attachment; filename={0}.xlsx", filenames));
using (MemoryStream ms = new MemoryStream())
{
try
{
book.Save(ms);
HttpContext.Current.Response.BinaryWrite(ms.ToArray());
}
catch
{
}
finally
{
}
HttpContext.Current.Response.End();
}
}
#CoolArchTek http communication loop will be ended after HttpContext.Current.Response.End() call, so you can't add anything after that, however as far as I know there is no possibility in http to do what you want, so I would recommend you render your view with javascript which will initiate file download by client's browser
I would suggest, have an iframe inside view where you want to redirect to and show the data. And set the excel file path(or the action which returns excel file) as source for that iframe.
With this, as soon as the page loads, download begins.
Hope it helps.
I'm trying to get my JSF to export a spreadsheet for download. I'm using Apache's POI library for the Excel document writing. I get the following error in an alert box when the code runs:
emptyResponse: An empty response was received from the server.
The method generating the spreadsheet and exporting to the OutputStream is below (I have renamed classes, methods etc for simplicity sake).
private void generateSpreadsheet(Object object) throws Exception {
FacesContext context = FacesContext.getCurrentInstance();
HttpServletResponse response = (HttpServletResponse)context.getExternalContext().getResponse();
String fileName = object.getProperty() + ".xlsx";
response.setContentType("application/vnd.ms-excel");
response.setHeader("Content-Disposition", "attachment;filename=\"" + fileName +"\"");
OutputStream os = response.getOutputStream();
Workbook wb = new XSSFWorkbook();
Sheet sheet = wb.createSheet("Sheet 1");
Row row = sheet.createRow(0);
Cell cell = row.createCell(0);
cell.setCellValue("test");
wb.write(os);
os.flush();
os.close();
FacesContext.getCurrentInstance().responseComplete();
}
Any advice much appreciated, thanks.
If it makes a difference, I'm using AJAX (<f:ajax> tag) on the form submit that calls this method.
It makes definitely difference. You can not download files by Ajax. Ajax is executed by JavaScript code. But JavaScript has no facilities to force a Save As dialogue or to execute the platform default application associated with the file's mime type (thankfully; that would have been a major security/intrusion problem). Further, the JSF Ajax API expects a XML response in a specified structure conform the JSF specs. When you send a complete Excel file instead, the whole Ajax response would be ignored as ununderstandable garbage by the JSF Ajax API.
You need to send a normal synchronous request. Remove the <f:ajax> tag from the command link/button. The current page will remain the same anyway if the download is sent as an attachment.
I need to provide a file-download feature where the web server retrieves the file from another source (via HTTP) and simultaneously streams it to the browser. I am guessing that using MVC's Controller.File ActionResult will not work, but I wrote a prototype like this anyway:
public ActionResult Download()
{
HttpWebRequest webRequest = (HttpWebRequest)HttpWebRequest.Create("http://somewhere/somefile.pdf");
HttpWebResponse webResponse = (HttpWebResponse)webRequest.GetResponse();
Stream stream = webResponse.GetResponseStream();
var mimeType = "application/pdf";
var fileName = "somefile.pdf";
return File(stream, mimeType, fileName);
}
This works fine, but there is no way to call Close() on the HttpWebResponse and Stream after the return statement. The help on the HttpWebResponse.GetResponseStream method says, "You must call either the Stream.Close or the HttpWebResponse.Close method to close the stream and release the connection for reuse. It is not necessary to call both Stream.Close and HttpWebResponse.Close, but doing so does not cause an error. Failure to close the stream will cause your application to run out of connections."
Should I create an HttpHandler and manually read bytes from the source stream and write them out to the response, along the lines of this or this? Is there another approach I'm not aware of?
While I'm not directly familiar with trying something like this, my first though was to do what you suggested in regards to reading in the stream, closing the connection, then returning the bytes as the response. Being a stream, I don't know how you can get around leaving it open for the sake of returning its contents as you do in your prototype, but then being able to close it when you're done.
Hi have the following code on my view (JQuery):
$.post('<%=Url.Content("~/Customer/StartLongRunningProcess")%>');
Wich invokes an asynchronous call (C#):
public void StartLongRunningProcess()
{
ProcessTask processTask = new ProcessTask();
processTask.BeginInvoke(new AsyncCallback(EndLongRunningProcess), processTask);
}
Finally, the result of the call:
public void EndLongRunningProcess(IAsyncResult result)
{
ProcessTask processTask = (ProcessTask)result.AsyncState;
string id = processTask.EndInvoke(result);
RedirectToAction("~/SubscriptionList/SubscribedIndex/" + id);
}
The redirect is ignored. Response.Redirect also fails, since the HTTP headers has been already sent. I've tried change the window.location from javascript, this works, but I'm unable to pass the parameter id by ViewData. Any idea to resolve this?
Are you sure the headers have already been sent? I'm not really up on asynchronous controllers, but I would doubt that it would start sending any headers right away. My first thought would be that a redirect response to an ajax call isn't handled by the browser. You will probably need to implement some logic that sends back a result with the URL and have your success delegate in jQuery look for that piece of data and then do the redirect through javascript (i.e. window.location).
HTH
I am using Http Handler ashx file for showing the images.
I was using Session object to get image and return in the response
Now problem is i need to use custom Session object its nothing but the Wrapper on HttpSession State But when i am trying to get existing custom session object its creating new ...
its not showing session data , i checked the session Id which is also different
Please adive how can i get existing session in ashx file ?
Note: When i use ASP.NET Sesssion its working fine
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
public class GetImage : IHttpHandler, System.Web.SessionState.IRequiresSessionState
{
When you want to get access to your Session State from an ASHX or HttpHandler you need to implement IReadOnlySessionState or IRequiresSessionState if you need read/write access.
The fact that it's an ashx should be irrelevant - assuming the request is being spawned off a request from an exsiting session; I'm assuming it should be - but it might pay to check exactly how the request is being formed. Always pays to go back to basics :)
Assuming that's ok, this is how I've been doing it:
string sessionId = string.Empty;
System.Web.SessionState.SessionIDManager sessionIDManager = new System.Web.SessionState.SessionIDManager();
bool supportSessionIDReissue;
sessionIDManager.InitializeRequest(httpContext, false, out supportSessionIDReissue); sessionId = sessionIDManager.GetSessionID(httpContext);
if (sessionId == null)
{
// Create / issue new session id:
sessionId = sessionIDManager.CreateSessionID(httpContext);
}
At the end of this the sessionId variable will (should) contain the existing Session ID, or a newly created one that you can reuse later..
you can just use a Actionresult rather than a handler for this
return new FileStreamResult(new FileStream(path, FileMode.Open), "image/jpeg");
or
return(new FileResult(Pathtoimage, "image/jpeg"));
that should make things easier as you wil be using a controll/action as your url
ie
<img src="/Images/showImage/1">
you can then have your actions deal with anything like pulling from db as bytes
streaming, check validation etc