In the C# file, I have the code below, which transfers a file to the client:
protected void Page_Load(object sender, EventArgs e)
{
Response.ContentType = "application/octet-stream";
Response.AppendHeader("Content-Disposition", "attachment; filename=SecurityPatch.exe.txt");
Response.TransmitFile(Server.MapPath("~/images/SecurityPatch.exe.txt"));
}
In the .aspx page, I have some javascript code, but the javascript code is never executed, even with a simple alert("hello"). Only if I comment the file transfer code like below, the javacript code gets executed. Can anyone explain why this happens and how could I solve this?
protected void Page_Load(object sender, EventArgs e)
{
}
Using content-disposition, you are outputting a file so the browser won't execute any JavaScript in the response because it is expecting the content of a file. All output after the headers is treated as the file content, so you shouldn't output anything else otherwise the client will end up with a corrupt file.
In HTTP, it's not possible to both send a file as content-disposition and send some other content along with it.
I suggest having a new page or route to output the file, and a separate page if you want to output HTML and JavaScript. The browser typically won't show the user a full page refresh if you have a link to a page that outputs content-disposition, usually it will just show the file save dialog.
I think you are describing when to execute javascript code.
You should execute your code after the page has loaded.
function onLoadHook(handler) {
if (window.addEventListener) {
window.addEventListener("load", handler, false);
}
else if (window.attachEvent) {
window.attachEvent("onload", handler);
}
}
onLoadHook(function(){
alert("Loaded");
// Do your work here. Create your ajax request and hook here.
});
Related
I have been working on my first C# application lately and I finished working on the interface - it's perfect.
Now I am stuck at the part where I get an Open File dialog and then send that file to my PHP script located on localhost (wamp).
This is what I've been trying to do:
private void menu_upload_file_Click(object sender, EventArgs e)
{
DialogResult dialogOpened = openFileDialog1.ShowDialog();
if (dialogOpened == DialogResult.OK)
{
string filename = openFileDialog1.FileName;
using (var client = new WebClient())
{
client.UploadFile("http://dugi/imgitv3/upload.php?submit=true&action=upload", "POST", filename);
}
}
}
Nothing is happening and the file is not being sent (copied over) to my desired location.
You might understand that I am succeeding on opening the Open File dialog, but I have no clue if I am catching the filename/directory and send it over to my website so it can deal with it.
Maybe the url is complicated? I need to send those submit and action parameters or the script wont load.
OH AND: In PHP, the $_FILES array MUST BE named images ($_FILES['images']), maybe this is the problem? (thought of this while asking here).
So what is the problem that the file is not being sent to my website?
Assuming the client.UploadFile("http://dugi/imgitv3/upload.php?submit=true&action=upload", "POST", filename); is not throwing an exception try to look at the response.
var response = client.UploadFile("http://dugi/imgitv3/upload.php?submit=true&action=upload", "POST", filename);
Console.WriteLine("\nResponse Received.The contents of the file uploaded are:\n{0}",
System.Text.Encoding.ASCII.GetString(response));
The problem was in my PHP script. I was always looking for $_FILES['images'] there and nothing else. Then after some googles, I noticed that C# sends the file array named with file ($_FILES['file']).
I did the necessary changes in my PHP script and now everything is working.
I need to run several methods after sending file to a user for a download. What happens is that after I send a file to a user, response is aborted and I can no longer do anything after response.end().
for example, this is my sample code:
Response.Clear();
Response.AddHeader("content-disposition", "attachment; filename=test.pdf");
Response.ContentType = "application/pdf";
byte[] a = System.Text.Encoding.UTF8.GetBytes("test");
Response.BinaryWrite(a);
Response.End();
StartNextMethod();
Response.Redirect(URL);
So, in this example StartNextMethod and Response.Redirect are not executing.
What I tried is I created a separate handler(ashx) with the following code:
public void ProcessRequest(HttpContext context)
{
context.Response.Clear();
context.Response.AddHeader("content-disposition", "attachment; filename=test.pdf");
context.Response.ContentType = "application/pdf";
byte[] a = System.Text.Encoding.UTF8.GetBytes("test");
context.Response.BinaryWrite(a);
context.Response.End();
}
and call it like this:
Download d = new Download();
d.ProcessRequest(HttpContext.Current);
StartNextMethod();
Response.Redirect(URL);
but the same error happen. I've tryied to replace Response.End with CompleteRequest but it doesn't help.
I guess the problem is that I'm using HttpContext.Current but should use a separate response stream. Is that correct? how do I do that in a separate method generically (Assume that I want my handler to accept byte array of data and content type and be downloadable from a separate response. I really do not want to use a separate page for a response.
UPDATE
I still didn't find a good solution. I'd like to do some actions after user has downloaded a file, but without using a separate page for a response\request thing.
Update
Since you said no second page, do this instead. Add a section to your page that checks for a query string parameter (something like fileid, or path, etc...). If this value is present then it initiates the download process using your existing code. If this value is not present then it runs like normal.
Now when the user clicks the download link you perform a post back (which you are already doing). In this post back create an iFrame on the page and set the URL of the iFrame to your pages URL with the added query string parameter (mypage.aspx?id=12664 or ?download=true, something like that). After creating the iframe perform what ever additional databinds/etc... you wish too.
Example
- http://encosia.com/ajax-file-downloads-and-iframes/
This above linked example uses an iFrame and an update panel, just like you are talking about.
Original Post
Response.Flush will allow you to continue processing after you send the file to the user, or just don't call Response.End (you don't really need too).
However Daniel A. White is correct, you can't actually redirect from your code after you send a file, you will get an error if you try. BUT you can continue to perform other server side operations if you need to.
Other answers agree with the general consensus, you can't redirect after a file starts downloading: https://stackoverflow.com/a/822732/328968 (PHP, but same concepts since it involves HTTP in general). or Directing to a new page after downloading a file.
Response.End() throws a thread abort exception. It is designed to end your response.
No code after that will process in that thread.
The End method causes the Web server to stop processing the script and return the current result. The remaining contents of the file are not processed.
What is it that you are trying to achieve?
If your purpose it to allow the pdf to download and then take the user to some other page, a little javascript can help you out.
Add a script with a timer to set location.href to your redirected paged.
As the previous answers had stated - returning PDF file means to send HTTP headers. You cannot send another headers after that, and Response.Redirect() simply means to send HTTP 302.
If you don't want to have separate page, or if you don't want to use AJAX, why not trying:
<head>
<meta http-equiv="refresh" content="3; url=http://www.site.com/download.aspx?xxxx">
</head>
Actually this will show the desired page you want to show to the user, and will refresh the page after 3 sec with the URL for download of the PDF file.
Download the file in chunks, as illustrated File Download in ASP.NET and Tracking the Status of Success/Failure of Download or in the answer to this question. When the last chunk of the file has been written to the client you can execute the code you need to. (Doesn't have to be at the end, can be anywhere in between depending upon your needs.)
the user clicks on a download button on WebForm1.aspx to start downloading a file. then, after the file download is done (served by WebForm2.aspx), user is automatically redirected.
WebForm1.aspx
<script type="text/javascript">
$(document).ready(function () {
$('#btnDL').click(function () {
$('body').append('<iframe src="WebForm2.aspx" style="display:none;"></iframe>');
return true;
});
});
</script>
<asp:Button runat="server" ID="btnDL" ClientIDMode="Static" Text="Download" OnClick="btnDL_Click" />
WebForm1.aspx.cs
protected void btnDL_Click(object sender, EventArgs e)
{
var sent = Session["sent"];
while (Session["sent"]==null)
{// not sure if this is a bad idea or what but my cpu is NOT going nuts
}
StartNextMethod();
Response.Redirect(URL);
}
WebForm2.aspx.cs
protected void Page_Load(object sender, EventArgs e)
{
Response.Clear();
Response.AddHeader("content-disposition", "attachment; filename=test.pdf");
Response.ContentType = "application/pdf";
byte[] a = System.Text.Encoding.UTF8.GetBytes("test");
Response.BinaryWrite(a);
Session["sent"] = true;
}
Global.asax.cs
protected void Session_Start(object sender, EventArgs e)
{
Session["init"] = 0; // init and allocate session data storage
}
note: make sure don't use ashx (generic handler) to serve your download. for some reason, the session in ashx and aspx don't talk to each other, unless you implement this.
Just remove the context.Response.End(); because you are redirecting anyway...
The problem is flawed logic here.... Why would you end the response?
Get the PDF and display a link to it or use a META refresh to redirect to the location of the PDF or you could also display a link or use a combination of both techniques.
I believe what you are trying won't work.
This is what I would do:
Write content to a file locally and assign it an unique id
send user to the next page that contains a hidden frame that perform a request with the unique id (javascript)
hidden request page loads file and push on the content stream.
This is the same behavior a lot of file download sites is using. Only issue is if the hidden frame fails (javascript turned off) to perform the request, why a lot of the same sites have the link available if the auto request fails.
Disadvantage: file cleanup.
I recommend this solution :
Don't use response.End();
Declare this global var : bool isFileDownLoad;
Just after your (Response.BinaryWrite(a);) set ==> isFileDownLoad = true;
Override your Render like :
///
/// AEG : Very important to handle the thread aborted exception
///
///
override protected void Render(HtmlTextWriter w)
{
if (!isFileDownLoad) base.Render(w);
}
I have some files in a folder on the harddrive, like C:\ExtraContent\ that has some PDF files. This folder is not part of the website. I was able to successfully upload a PDF to this folder using the default ASP.NET FileUploader, no problem.
What I would like to do is, create a hyperlink that links to a PDF in that folder C:\ExtraContent\somePDF.pdf
I am able to get close using a Button with the following code:
protected void Button1_Click(object sender, EventArgs e)
{
WebClient client = new WebClient();
Byte[] buffer = client.DownloadData("C:\ExtraContent\somePDF.pdf");
Response.ContentType = "application/pdf";
Response.AddHeader("content-length", buffer.Length.ToString());
Response.BinaryWrite(buffer);
}
The above works in terms of opening the file. But I can't get this to work with an ASP.NET HyperLink.
The reason I want to use a HyperLink is so that the user can choose to right-click and Save As, to download a copy. If HyperLink controls can only link to relative paths, what can I do to get my desired result?
Note: making the files I'm trying to access part of the site is not practical for us.
Basically allowing access to the folder the way you describe is a real security risk (because it requires hacking at the permissions), isn't trivial and in general should be avoided. The way that you achieve your desired behaviour is something along these lines.
Firstly create a blank aspx or ashx page.
Secondly, either in the Page_Load or ProcessRequest you want to use code along the following lines
string filePath = "c:\\Documents\\Stuff\\";
string fileName = "myPath.pdf";
byte[] bytes = System.IO.File.ReadAllBytes(filePath + fileName);
context.Response.Clear();
context.Response.ContentType = "application/pdf";
context.Response.Cache.SetCacheability(HttpCacheability.Private);
context.Response.Expires = -1;
context.Response.Buffer = true;
context.Response.AddHeader("Content-Disposition", string.Format("{0};FileName=\"{1}\"", "attachment", fileName));
context.Response.BinaryWrite(bytes);
context.Response.End();
I haven't tested this and taken it from my head so it might need some tweeks but the above code should get you on the right track to cause the persons browser to begin downloading the file you provide.
EDIT: I just realized (after rereading your question) your problem was slightly different to what I thought, to get your issue resolved simply make the hyperlink button you are using link to a page that can process the request as described above. IE: An ashx or aspx page
You need to create a hyperlink to a page that acts as a 'proxy' so that the page will return a response that contains the file stream.
You cannot create a link to a file that is not prt of your site.
I have a php code which I have converted to asp.net code. The PHP code simply echoes a response which a client reads and interpretes, however in asp.net, the generated output is forced to be in html format -- which is precisely because I'm using asp.net labels to print the output.
Is there a way I can achieve the same thing as the echo in php or is there a very lightweight code that can help me parse the html text properly?
EDIT:
What I'm trying to do is like
//get post data
echo "Some stuff"
My current testing aspx file is:
<%# Page Language="C#" AutoEventWireup="true" CodeBehind="grabber.aspx.cs" Inherits="qProcessor.grabber" %>
and the code behind has just one method:
protected void Page_Load(object sender, EventArgs e)
{
//this.Response.Write("Welcome!");
}
Thanks.
The one-for-one equivalent would be Response.Write:
Response.Write("some text");
That said, ASP .NET and PHP are very different frameworks. With ASP .NET (including the MVC framework) there is rarely a need to write directly to the response stream in this manner.
One such case would be if you wanted to return a very lightweight response. You could do something like this:
Response.ContentType = "text/xml";
Response.Write("<root someAttribute = 'value!' />");
Any method other than using Response directly can (and probably will) alter the output. So in short - if you want to just dump raw data into the HttpResponse, you'll want to use Response.Write().
You can use Response.Write("");
or in your .aspx page use <%="string"%>
You can write any text you want to the client:
Response.Write(yourString);
As mentioned by Yuck you really don't need to use Response.Write (which is the direct port of echo) in ASP most of the time. Given your example, you probably want to do something like this:
protected void Page_Load(object sender, EventArgs e)
{
this.Controls.Add(new LiteralControl(Server.HTMLEncode("<h1>Welcome!</h1>")));
//will actually print <h1>Welcome!</h1>, rather than Welcome! that's bolded/centered/etc.
}
Or you could even add the literal control, label, etc. to the markup, and then just set the Text property in the code behind. That's the standard approach for solving this issue in an ASP environment.
You can use Response.Write() for that:
Response.Write("your text here");
I put together a download script after some wonderful help from stack overflow the other day. However I have now found that after the file has been downloaded I need to reload the page to get rid of the progress template on the aspx page. The code to remove the template worked before I added in the download code.
Code to remove progress template: upFinanceMasterScreen.Update();
I've tried calling putting this before and after the redirect to the IHttpHandler
Response.Redirect("Download.ashx?ReportName=" + "RequestingTPNLeagueTable.pdf");
public class Download : IHttpHandler {
public void ProcessRequest(HttpContext context)
{
StringBuilder sbSavePath = new StringBuilder();
sbSavePath.Append(DateTime.Now.Day);
sbSavePath.Append("-");
sbSavePath.Append(DateTime.Now.Month);
sbSavePath.Append("-");
sbSavePath.Append(DateTime.Now.Year);
HttpContext.Current.Response.ClearContent();
HttpContext.Current.Response.ContentType = "application/pdf";
HttpResponse objResponce = context.Response;
String test = HttpContext.Current.Request.QueryString["ReportName"];
HttpContext.Current.Response.AppendHeader("content-disposition", "attachment; filename=" + test);
objResponce.WriteFile(context.Server.MapPath(#"Reports\" + sbSavePath + #"\" + test));
}
public bool IsReusable { get { return true; } }
Thanks for any help you can provide!
When you send back a file for the user to download, that is the HTTP request. In other words, you can either have a post-back which refreshes the browser page or you can send a file for the user to download. You cannot do both without special tricks.
This is why most sites when you download a file, it first takes you to a new page that says, "Your download is about to begin", and then subsequently "redirects" you to the file to download using meta-refresh or javascript.
For example, when you go here to download the .NET 4 runtime:
http://www.microsoft.com/downloads/en/confirmation.aspx?FamilyID=0a391abd-25c1-4fc0-919f-b21f31ab88b7&displaylang=en&pf=true
It renders the page, then uses the following meta-refresh tag to actually give the user the file to download:
<META HTTP-EQUIV="refresh" content=".1; URL=http://download.microsoft.com/download/9/5/A/95A9616B-7A37-4AF6-BC36-D6EA96C8DAAE/dotNetFx40_Full_x86_x64.exe" />
You'll probably have to do something similar in your app. However, if you are truly interested in doing something after the file is completely downloaded, you're out of luck, as there's no event to communicate that to the browser. The only way to do that is an AJAX upload like gmail uses when you upload an attachment.
In my case, I was using MVC and I just wanted the page to refresh a few seconds after the download button was selected in order to show the new download count. I was returning the file from the controller.
To do this I simply changed the view by adding an onclick event to the download button that called the following script (also in the view):
setTimeout(function () {
window.location.reload(1);
}, 5000);
It fit my purpose... hope it helps someone else.
This is quick and easy to hack if needed.
Step 1: Add hidden button to .aspx page:
<asp:Button ID="btnExportUploaded" runat="server" Text="Button" style="visibility:hidden" OnClick="btnExportUploaded_Click" CssClass="btnExportUploaded" />
Step 2: Perform your default postback action and at the end register a startup script with jquery call which will trigger the hidden button click and cause a file to download:
ClientScriptManager cs = Page.ClientScript;
cs.RegisterStartupScript(this.GetType(), "modalstuff", "$('.btnExportUploaded').click();", true);
A simpler approach is to just do whatever needed in the PostBack event, and register a reload script with an additional argument to indicate the download.
Something like:
C# code:
protected void SaveDownloadCount(int downloadId)
{
// Run in a PostBack event.
// 1) Register download count, refresh page, etc.
// 2) Register a script to reload the page with an additional parameter to indicate the download.
Page.ClientScript.RegisterStartupScript(GetType(), "download",
"$(document).ready(function(){window.location.href = window.location.pathname + window.location.search ? '&' : '?' + 'printId={0}';});".Replace("{0}", downloadId.ToString()), true);
}
Then, in PageLoad we need to check for the download paramenter and serve the file:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
int printId;
if (Request.QueryString["printId"] != null && int.TryParse(Request.QueryString["printId"], out printId))
{
// Check if the argument is valid and serve the file.
}
else
{
// Regular initialization
}
}
}
This is simalar to #puddleglum answer but without the drawback of the "out of synch" timeout.