How to set a page title for an ashx file? - c#

I would like to change the "page title" for the openned window when a user views an ashx file in the browser. Users click on a document which will open in a new tab in the browser, and the document is shown (i.e. Word, Excel, PDF, etc.). What happens now, is that the page title shows something like "file.ashx?id=5" when I would rather the title show something like "New Document.pdf" or just "New Document" instead of showing the url of the ashx file.
I have looked into setting the filename through a header, that does work, but the file is downloaded instead of simply openning in the broser window. That is not the desired behavior I was going for.
I understand that this may not be possible, but thought I'd check anyway.
Thanks for the help.

For the title of the page: I can only speak to Internet Explorer, but when you show a new window, Internet Explorer requires that the title bar always be displayed (see the MSDN Article About Window Restrictions for more details). The problem when viewing files inline is that you do not send any HTML back to the page so there is no way through this method to have the title change.
I know that we did experiment with several different approaches, but decided that for our user base, it was ok to not have a user-readable value in the title bar. If this is important to you, then I think your only real option would be a frame-based solution where your ashx page is embedded in a frame (or iframe) and the title page is controlled by content in a different frame (or portion of the page in the event you use an iframe).
To view the file in the browser instead of having it downloaded: you need to set the Response ContentType to the appropriate MimeType for the file (i.e. "application/pdf" for PDF files) and add a Content-Disposition header that specifies the file is to be opened inline and the file name for the user. You should also ensure that other content and headers are cleared from the response.
this.Context.Response.ClearContent();
this.Context.Response.ClearHeaders();
this.Context.Response.ContentType = "application/pdf";
this.Context.Response.AddHeader("Content-Disposition", "inline; filename=mytest.pdf");
this.Context.Response.TransmitFile(sLocalFileName);
this.Context.Response.Flush();

Related

Prevent Chrome from downloading files

I need to display files in a HTML page in an object tag.
I use C# MVC4 to send the file. In my code, I set the "Content-Type" and "Content-Disposition" headers.
When I set the Content-Type to something Chrome dosen't know, it will download the file, regardless of the "Content-Disposition" header.
HTML:
<div>
<object data="http://localhost/UncHelper?path=secrectPath\file.dwg"></object></div>
C#:
public override void ExecuteResult(ControllerContext context)
{
context.RequestContext.HttpContext.Response.AddHeader("Content-Type", _contentType);
context.RequestContext.HttpContext.Response.AddHeader("Content-Disposition", "inline; filename=\"" + _fileName + "\"");
context.HttpContext.Response.WriteFile(_uncPath);
context.HttpContext.Response.End();
}
When I try to display a pdf file (_contentType = application/pdf) everything is fine.
But when I try to display a .dwg (_contentType = application/dwg) Chrome will download the file. How can I prevent this?
(I don't want to set a HTML status of 203 based on the browser or anything like that.)
Thanks!
This is not possible, and is also a slight misunderstanding on your part i think. For a browser to be able to display a file, it first has to be downloaded.. This goes for all file types. For instance, if you were displaying an image of image/jpeg, with the disposition set to inline, the browser still downloads the image, and then displays it inline, instead of asking the user where he/she would like to save it. If the browser has no knowledge of how to display the file, this is not an option, and will default to the only other option, which is to ask the user where to save it.

itextsharp hyperlink a image and have it open in default viewer when picked

I have a pdf file created with itextsharp with images in the file. I would like to put a hyperlink in the file that if you pick the picture it will open that picture in a picture viewer. I can set a hyperlink to a web address but have no idea how to get it to open a file. Below is the code, yes I know that c:\test.jpg is a bad hardcoded file name but it is just a test. When you click the picture it does nothing but I have no idea how to tell it what to do.
iTextSharp.text.Image pic =TextSharp.text.Image.GetInstance(comment.examplePic);
pic.ScaleToFit(200f, 200f);
Chunk cImage = new Chunk(pic, 0, 0, false);
Anchor anchor = new Anchor(cImage);
anchor.Reference = "c:\\test.jpg";
doc.Add(pic);
doc.Add(anchor);
A PDF is self-contained. This means that all the resources needed to show the PDF are (usually) stored inside the PDF (exceptions are for instance fonts that can be retrieved from the operating system).
When you have an image that is shown on a PDF page, the bytes of that image are stored in what we call an Image XObject. An XObject is an object that is external to the page, but that is stored as a separate object inside the PDF file.
You are asking to serve the image bytes stored inside this separate object to a viewer on the operating system. This is impossible. I don't know of any viewer that can take those bytes and somehow forward them to an image viewer.
I can think of three possible workarounds. I don't know if any of these workarounds is acceptable to you.
1. Serve the image online
You could put the image on a server and use the code you have in your snippet to link to that online image. Of course: this will only work if the person viewing the document is online and clicks OK when his viewer asks him if it's OK to link to a resources on the internet.
2. Serve the image as an annotation
In this case, you create an annotation for which you create an appearance that renders that same image XObject in the annotation layer (all annotations are shown on top of the page content). You can easily change the visibility status of an annotation to make it invisible (in your case, this would be the default status) or visible (in your case, this would be triggered by a JavaScript action when clicking the link).
There's an example of such an annotation here: Advertisement. If you open advertisement.pdf, you see an image with a button that says "Close this advertisement". Once you click that, the status of the annotation will be changed to invisible. You could do something similar, but the other way round: click a link to make it visible instead of invisible.
This solution doesn't depend on an external viewer, the image is shown in the PDF viewer.
3. Add the image as optional content
Starting with PDF 1.5, PDF supports optional content. See for instance the OptionalContentExample. In this example, we have some questions and answers, but the answers are not visible by default. See layer_actions.pdf. There are links "on / off / toggle" to make the answers visible or invisible.
You could do the same with images: you could add them to a layer that is invisible by default, but that can be made visible if somebody clicks a link. However: this requires a viewer that supports OCG (optional content groups) and the actions to change the status of these OCGs. For instance: if you would try the layer_actions.pdf example in the PDF viewer in Chrome, it won't work, but if you download the PDF and open it in Adobe Reader, you'll see the behavior I described.
Summarized:
You are asking something that is impossible, but there are workarounds. Please post another question if you have chosen a workaround and you don't succeed in making that workaround word (but please take into account that not all viewers support every workaround).
no offence but too much knowledge sometimes makes you ignorant of small things.
simple solution to this problem is here
http://kuujinbo.info/iTextSharp/imageAnchor.aspx
sample code that i implemented works like charm
PdfPCell p1 = new PdfPCell();
p1 = new PdfPCell();
p1.Padding = 0;
p1.Border = 0;
PdfPTable nav = new PdfPTable(1);
nav.WidthPercentage = 100;
nav.SpacingAfter = 12;
navbarImg.Annotation= new Annotation(0, 0, 0, 0, ur);
p1.Image = navbarImg;
nav.AddCell(p1);
_doc.Add(nav);

Enable button after writing file to response

There is many similar questions but there is still no clear answer that is solving the problem taking some action after writing some stream to response.
I have a following situation:
On button click I am generating some excel file that I am going to write to response allowing user to download generated file. Imidietly after clicking the button, I am disabling it, to prevent double clicking this button. In Page-Load event handler I have following code:
GenerateBTN.Attributes.Add("onclick", "this.disabled=true;" + ClientScript.GetPostBackEventReference(GenerateBTN, "").ToString());
After Page_Load eventhandler, GenerateBTN_Click handler executes the code needed for generating the file and at the end of this method (handler) I am response writing generated file with following code:
Response.Clear();
Response.ContentType = "application/octet-stream";
Response.AddHeader("Content-Disposition", "attachment; filename=\"" + filename + "\"");
Response.WriteFile(#"C:\Reports\" + filename);
Response.End();
The Save As dialog appears and user can download the generated file, but the problem is that the disabled GenerateBTN remains disabled. How to enable it afer Writing generated file to response? I understand that afer clearing current response I can not continue with the initial Response, but is there any way to solve this problem?
You can put an IFrame on the page and set it's visiblity to hidden. Have your button load the file in the IFrame and use Javascript to detect if the IFrame is still loading or not. When the loading is done, enable your button.
Can't supply a code example at the moment, but if you decide to go this route and need a sample, let me know I will update this answer.
Edit for 2nd answer
What you want to do is create a file like "Download.aspx" that you pass in the file name as a querystring parameter. This way, you can have your server get the file from a location outside of the Web Application's path and adjust the header to force a file download.
Download.aspx
using System.IO;
protected void Page_Load(object sender, EventArgs e)
{
string FileName = Server.UrlDecode(Request.Params["FileName"]); //Example: "MyFile.txt"
Response.AppendHeader("Content-Type", "application/force-download");
Response.AppendHeader("Content-Disposition", "attachment; filename=" + FileName);
Response.WriteFile(#"C:\MyFolder\" + FileName);
}
You would load the page by calling something like "Download.aspx?FileName=MyFile.txt"
You will need to add checks to make sure the file exists and the querystring parameter exists, but that should force the download and allow you to get the file from another location. When you use an ASPX page to serve the file, you can also do credential checks to see if the user is logged into your site (if you have login logic already) or log the download to a log file/database if you want to keep track of it. It gives you a lot more control over the download process.
As for the IFrame loading code, I'm not 100% sure how this works with a file download, but what I was originally thinking was something like this -- view source on: http://sykari.net/stuff/iframe.
Wrap the button in an UpdatePanel, then simply toggle its enabled property before and after the file work.
You can put an IFrame on the page and
set it's visiblity to hidden. Have
your button load the file in the
IFrame and use Javascript to detect if
the IFrame is still loading or not.
When the loading is done, enable your
button.
Can't supply a code example at the
moment, but if you decide to go this
route and need a sample, let me know I
will update this answer.
I've decided to use your suggestion.. but i still have some questions regarding this problem...
Is it possible to load .txt files in iframe?
Is it possible to load some files that are not included in web application's folder?
The problem with loading txt files in iframe is it does not trigger save as dialog to appear, instead of that file content is displayed inside that iframe.
For loading files into an iframe I've used following code:
HiddenFrame.Attributes["src"] = /GeneratedFiles/ + "test.zip";
You can see that I've had to use relative path and my file has to be included in web app's virtual folder.
What is the best javascript (jquery) eventhandler (function) to detect when Iframe has finished loading? I've used jquery function:
$("#ctl00_ContentPlaceHolder1_HiddenFrame").ready(function () {
if ($("#ctl00_ContentPlaceHolder1_HiddenFrame").attr('src') != '') {
$('#ctl00_ContentPlaceHolder1_GenerateSapFilesBTN').removeAttr("disabled");
}
});
But it appears that button is being enabled before Save As dialog actually appears.. Is it possible to solve this problem with this type of eventHandler or do I have to use some other function...

Dynamically append number to PDF or make submit button change its URL based on that number

I'm serving up PDFs from a SQL db and presenting them in the browser. I'm trying to figure out a way to embed a number in the PDF dynamically so that the recordID for that PDFs SQL record is available to me when the user submits the XML form data. The user hits the submit button on the form and the form submits its XML data to my submission page. If there is some way of changing the submission URL on the fly then I could do a query string to pass my self the recordID. I'm not generating the PDF in code, its being created by hand and then uploaded to my site.
Edit
User is given a link someServer.com/pdfLink.aspx?formID=5 they go there and that pages pulls a PDF from the DB and displays it. This pulls up acrobat in browser full size so my aspx page isn't in control of submitting the completed form, Acrobat is. The user fills out the form and hits the submit button in the form. This submit button was set up at form design time to point to another page someSite.com/pdfSubmit.aspx The submit button posts the XML data to that page and I can process it. I need the recordID in the query string for the someSite.com/pdfSubmit.aspx page. To do this I would need to modify the PDF to either add the recordID and query string to the submit button's submit URL, or embed it in the PDF else ware. The big question is how do I modify the PDF just before I display it via someServer.com/pdfLink.aspx?formID=5 to do either of these two options.
Embedding a number in PDF is not exactly kosher, but there are some things that you can do that will honor the spec.
The current PDF spec says that "The last line of the file shall contain only the end-of-file marker
%%EOF
but there is some wiggle room - the implementation details say that it doesn't technically have to be the last line of the file, but only has to appear in the last 1K and, generally speaking, if you don't muck with things too much, most compliant readers won't even blink. If I had to do this, I would be inclined to add a newline (if there isn't one), then a % (which is a PDF comment), a marker to let me know it's mine, and finally the number. So something like:
// assume we already know it ends with %%EOF
void AppendNumberToPdf(Stream stm, int number, bool addNewline)
{
stm.Seek(0, SeekOrigin.End); // go to EOF
StreamWriter writer = new StreamWriter(stm, new ASCIIEncoding(), 1024);
writer.WriteLine(string.Format("{0}% {1} {2}", (addNewLine ? "\n" : ""), kMyMarkerString, number));
writer.Flush();
}
kMyMarkerString should be something like "MyApplicationDocumentIdentifier:" or some such thing that will make it easy to identify your tracks.
The querystring is read-only so you cannot dynamically change it at runtime. However can you:
Add the recordID to the form at the time the submit page is initially rendered
Can you process the submit form and then do a Response.Redirect or Server.Transfer to the correct page with the recordid parameter added to the querystring
While trying #plinth's suggestion I realized I had to change from XML submission (since his data was on the PDF directly. So I changed the form to submit as XDP which has XML data + embedded PDF. When I did this and viewed the raw XDP that the form submitted I ran across this.
<?xml version="1.0" encoding="UTF-8" ?>
<?xfa generator="XFA2_4" APIVersion="3.0.8262.0"?>
<xdp:xdp xmlns:xdp="http://ns.adobe.com/xdp/" timeStamp="2010-05-04T15:15:00Z" uuid="6d0944c8-1573-442c-9c85-11e372bd38c3">
<xfa:datasets xmlns:xfa="http://www.xfa.org/schema/xfa-data/1.0/">
<xfa:data>
<form1>
<TextField1>TestMe</TextField1>
</form1>
</xfa:data>
</xfa:datasets>
<pdf href="ViewPDF.aspx?formID=10" xmlns="http://ns.adobe.com/xdp/pdf/" />
</xdp:xdp>
Notice the 2nd to last line. It automatically includes the PDF's url which had the formID value that I needed. So all I had to do was get the XDP instead of pure XML post from the form and it gives me everything I needed.

Redirecting to a "Thank you" page and offering the save dialog of downloaded file immediately

I am using ASP.NET2.0. I have created a download form with some input fields and a download button. When the download button is clicked, I want to redirect the user to a "Thank you for downloading..." page and immediately offer him/her the file to save.
I have this following code to show the savefile dialog:
public partial class ThankYouPage : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
Response.Clear();
Response.AddHeader("Content-Disposition",
"attachment; filename=\"downloadedFile.zip\"");
Response.ContentType = "application/x-zip-compressed";
Response.BinaryWrite(this.downloadedFileByteArray);
Response.Flush();
Response.End();
}
}
Obviously, this code does not allow to display any "Thank you" message. Is there an "AfterRender" event or something similar of the Page where, I could move this download code and give a chance for the page to render the "thank you" message to the user? After all, I am truely thankful to them, so I do want to express that.
You could reference a download page from your thank you page using an IFrame
<iframe src="DownloadFile.aspx" style="display:none;" />
In this case, DownloadFile.aspx would have the code behind from your example.
Use a META REFRESH tag in the head of your thank-you page:
<META http-equiv="refresh" content="1;URL=http://site.com/path/to/downloadedFile.zip">
Alternatively, you might use a body onLoad function to replace the current location with the download URL.
<body onLoad="document.location='http://site.com/path/to/downloadedFile.zip'">
In this case the redirection will start after the current page has finished loading and only if the client has JavaScript enabled, so remember to include a link with a download link ("If your download doesn't start in a few seconds..." and so on).
You may also use an IFRAME as suggested by Phil, or even a FRAME or a full-blown pop-up (blockable, mind you). Your mileage may vary.
The code you've written, should actually be redirected to from the 'thank you' page (making it the 2nd redirect). Because you've set the content disposition to attachment, this page will not actually replace the existing 'thank you' page.
if you want to serve a "Thank You" page and the file the client must call twice the server.
So you can just create the thankyou.aspx page for displaying the message (and maybe put a direct download link to the file).
You can start download with a meta tag or just using js (even ms do the same for their download page).
Then to serve the file you sould create a direct link to avoid another page run on the server; otherwise you should create an HttpHandler just to hide the filesys.
The file should be sent to the client with Response.TrasmitFile
Please check the following link, this may help you to sort out your issue.
In Asp.net, on button click, how to open a download dialog, and then redirect the user to another page?

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