Disclaimer I am aware of the Content-Disposition header to send back to the client to set the downloaded file name - however my problem is a little more complicated than just that
I have an application (RubyOnRails using rails 3.1.3) that is essentially a document search/view application (search for documents and then render them in the browser). This is accomplished using an iframe.
<iframe src="<%= #frameURL %>" width="100%" height="100%">
#frameURL is a call to the plugin function of our Documents controller. The plugin function makes a RESTful call to our back end API to retrieve the referenced document, and then send the document contents back to the browser for rendering inside the iframe.
This works perfectly for documents like JPEG, PDF, TXT, etc. However, when the browser does not know how to handle the content-type (like a word document - we run Mac OS-X) - then the browser downloads the returned file as plugin.doc <- NOTE this is without setting the Content-Disposition header.
Since we want to name the file appropriately when it needs to be downloaded, we set the Content-Disposition header:
response.headers['Content-Disposition'] = "attachment; filename.extension"
Now the file gets downloaded as filename.doc - however, with this header set, even files like JPEG which the browser can render internally, get downloaded.
Questions:
Does anyone know where rails or the browser is getting the name of plugin.extension when we don't set the Content-Disposition header?
Is there a way to set Content-Disposition but have it only applied IF the browser can't render the document - so the default should be browser handles everything it can, and as a fallback, the browser uses the Content-Disposition content to name the downloaded file.
Thanks!
If you are calling some Rails function like "send_file", then search the source code of your version of Rails to find the source code of that function and see what headers it sets. You have to follow the call stack down a couple of levels but you should be able to find out how it sets the headers; I have done this before. As for the browser, I think if it doesn't find a file name in the Content-Disposition header it will more or less use the last portion of the URL for a filename.
Try using "inline" instead of "attachment" in the header.
Related
In ma Rails app I have a route (download.pdf) that returns a PDF
format.pdf do
render pdf: "#{#sale.firstname}#{#sale.lastname}", dpi: 400
end
The PDF is opened in Chrome as download.pdf but when saving the file it gets saved with the correct file name.
But when opening directly with the PDF reader (instead of Chrome) the file gets downloaded as download.pdf
Any ideas how to solve this without changing the route?
Image: when opening with Chrome it works but when opening with the PDF reader the file name is wrong.
Browser uses Content-Disposition header to looking for the correct filename for the file. As you say the browser saving the file with the correct file name, it setting up correctly. But PDF reader doesn't check headers because it's not a browser.
You may try to check response.headers['Content-Disposition'] but looks like you need to change url.
I have setup a rest API inside a ruby on rails application, I now have a requirement to generate a PDF and return this PDF from a get request. I am looking for some advice on how to implement this feature.
Some of the requirements that I have are as follows: I can't save the file and give the end user a link to the file because the data in the file can be updated at any time. I am using the application as microservice so there isn't a front end that I can use to display the file.
So here is my thinking I would love some advice on how to implement this feature.
I would like to make a get request to a specific endpoint in the application. I expect a PDF file to be returned which I can then display to the end user.
I am currently using WickedPdf gem to generate a temporary PDF file, but I am really struggling with how the response should look.
Any advice would be much appreciated.
One way is to create a PDF file in memory and stream it to the client. I prefer this way, maybe later you will have to send PDF files via email, or just save them to some backup disk etc...
def get_pdf
pdf = WickedPdf.new.pdf_from_string('<h1>Hello There!</h1>')
send_data pdf, filename: 'file_name.pdf'
end
You can put the PDF generation to a different service and just call it in the controller. This provides isolation and you can test it separately.
Also you can debug the endpoint response with HTTPie http get http://localhost:3000/invoices/1/get_pdf
Rails will set all the necessary HTTP response headers:
Content-Disposition: attachment; filename="file_name.pdf"
Content-Length: 5995
Content-Transfer-Encoding: binary
Content-Type: application/pdf
So when the user clicks on a link that points to the endpoint, most probably the download dialog will pop up because of the Content-Disposition: attachment; header
Other solution is to render the get_pdf.html as PDF and send back to the client:
def get_pdf
render pdf: "file_name"
end
But in this case the Content-Disposition header will be inline, which means the browser will open the pdf (if it can read PDF format) instead of offering to download it.
Upload pdf to Amazon s3 and generate link then get pdf link in apis.
I don't know if you still need this, but for anyone in the future I found a nice solution:
pdf = WickedPdf.new.pdf_from_string(render_to_string "entradas/entradaspdf.pdf.erb")
send_data pdf, filename: "bergha.pdf", disposition: "inline"
I'm loading my pdf-html-view based template through "render_to_string" ruby method which returns the view contents in string. Then WickedPdf converts it to a pdf binary, and finally save that to "pdf" var.
Finally instead of "render" I use the "send_data" method, where first parameter is the output data (my pdf var), second is the filename of the output data, and third (optional) is to change Content-Disposition header to tell browser whether to load the file (inline) or just download it (attachment).
Hope it works, it does just fine for me
I'm using pdf.js as an embedded PDF viewer in a web application I'm building. I have an iframe that I use as the 'viewer' by setting (via javascript) the SRC attribute to the following:
$('#fileViewer-1').find('iframe').attr('src', 'js/pdfjs-1.4.20/web/viewer.html?file%2FMYFOLDER%2FIMAGES%2FPDFdocs%2F' + filename + '#zoom=page-width');
so I'm basically just calling this URL as the SRC of my iframe:
js/pdfjs-1.4.20/web/viewer.html?file=MYFILENAMEHERE.pdf
and now I see memory increasing with each subsequent PDF load (where I change the SRC url attribute to a new PDF document).
QUESTION: how can I call the pdfViewClose() function / method I see on line #6432 of viewer.js?
As I understand it, without calling this, memory in the browser may not be de-allocated.
Currently I'm seeing memory increase steadily and eventually the browser (Firefox) crashes after a number of PDF changes.
EDIT
Here is a related answer: https://stackoverflow.com/a/16017576/6828657
Is this the pdf viewer you're using?
https://github.com/mozilla/pdf.js/wiki/Frequently-Asked-Questions#user-content-can-i-specify-a-different-pdf-in-the-default-viewer
As it says there, can you try to use PDFViewerApplication.open(file) to open a new pdf?
I have in my browser.xul code,what I am tyring to is to fetch data from an html file and to insert it into my div element.
I am trying to use div.innerHTML but I am getting an exception:
Component returned failure code: 0x804e03f7
[nsIDOMNSHTMLElement.innerHTML]
I tried to parse the HTML using Components.interfaces.nsIScriptableUnescapeHTML and to append the parsed html into my div but my problem is that style(attribute and tag) and script isn`t parsed.
First a warning: if your HTML data comes from the web then you are trying to build a security hole into your extension. HTML code from the web should never be trusted (even when coming from your own web server and via HTTPS) and you should really use nsIScriptableUnescapeHTML. Styles should be part of your extension, using styles from the web isn't safe. For more information: https://developer.mozilla.org/En/Displaying_web_content_in_an_extension_without_security_issues
As to your problem, this error code is NS_ERROR_HTMLPARSER_STOPPARSING which seems to mean a parsing error. I guess that you are trying to feed it regular HTML code rather than XHTML (which would be XML-compliant). Either way, a better way to parse XHTML code would be DOMParser, this gives you a document that you can then insert into the right place.
If the point is really to parse HTML code (not XHTML) then you have two options. One is using an <iframe> element and displaying your data there. You can generate a data: URL from your HTML data:
frame.src = "data:text/html;charset=utf-8," + encodeURIComponent(htmlData);
If you don't want to display the data in a frame you will still need a frame (can be hidden) that has an HTML document loaded (can be about:blank). You then use Range.createContextualFragment() to parse your HTML string:
var range = frame.contentDocument.createRange();
range.selectNode(frame.contentDocument.documentElement);
var fragment = range.createContextualFragment(htmlData);
XML documents don't have innerHTML, and nsIScriptableUnescapeHTML is one way to get the html parsed but it's designed for uses where the HTML might not be safe; as you've found out it throws away the script nodes (and a few other things).
There are a couple of alternatives, however. You can use the responseXML property, although this may be suboptimal unless you're receiving XHTML content.
You could also use an iframe. It may seem old-fashioned, but an iframe's job is to take a url (the src property) and render the content it receives, which necessarily means parsing it and building a DOM. In general, when an extension running as chrome does this, it will have to take care not to give the remote content the same chrome privilages. Luckily that's easily managed; just put type="content" on the iframe. However, since you're looking to import the DOM into your XUL document wholesale, you must have already ensured that this remote content will always be safe. You're evidently using an HTTPS connection, and you've taken extra care to verify the identity of the server by making sure it sends the right certificate. You've also verified that the server hasn't been hacked and isn't delivering malicious content.
In my web page (rendered by Rails), I'd like to let the user right-click on a photo to bring up the browser's Save As dialog, to let the user save the photo to their hard drive.
However, the photos on my server have unusual filenames (long hex names) with no file extension. The filename prompt in the Save As dialog has this ugly filename. If the user hits save, they'll end up with a poorly-named file, with no file extension.
The web page is aware of the photo's real file name (the name that came off the camera, for example). Is there a way for me to programmatically override the Save As dialog's filename prompt with a filename of my choosing?
I'm aware of the Content-Dispostion header, and that via this header a filename can be specified. However, I think that in order to be able to make use of this header, I need to load/render the entire file to the browser. If the asset to be made available for download is a movie, that loading of the file could timeout the browser...like, if it's a 100meg video.
Thoughts?
-A
I think I understand the problem here because I encountered (and resolved) at least part of it myself not too long ago.
I have some large mp3's and I link to them on my website
A few problems
I needed to set my content-disposition header to attachment in order to prevent files from automatically streaming whenever a user clicked the download button
my files are on a remote server
my files are large (100MB)
large files can tie up rails controllers if not handled properly
Now, Michael Koziarsky advises in this article that the best way to keep your rails processes free when serving large files, is to create a download action in your controller, and the do something like this (note the use of x_sendfile=>true):
def download
send_file '/path/to/podcast.mp3', :type => 'application/octet-stream', :disposition => 'attachment', :filename=>'something.mp3', :x_sendfile=>true
end
:x_sendfile tells apache to let the file through without tying up a rails controller process. The rest of the code sets the filename and the content-disposition header.
Great, but I'm on heroku, like everyone else nowadays. So I can't use x_sendfile.
I found that I couldn't modify the nginx configuration file either as it's locked down by heroku so it was not possible to get x-accel-redirect (nginx equivalent of x-sendfile) working
So, I decided to add a perl script (see below) to the cgi-bin on our asset-host and this script sets the content-disposition to attachment and gives our file a name too.
Instead of doing a restful download like this:
link_to "download", download_podcast_path(#podcast.mp3)
we just link to the mp3 making sure that we go in through the cgi-bin so that the perl script gets called on every mp3 that leaves the server
# I'm using haml
%a{:href=>"http://afmpodcast.com/cgi-bin/download.cgi?ID=#{#podcast.mp3}"}
download
The result is that my rails controller is no longer called into action when someone downloads a file
I found the perl script here and chopped it up a bit to work for me:
#!/usr/local/bin/perl -wT
use CGI ':standard';
use CGI::Carp qw(fatalsToBrowser);
my $files_location;
my $ID;
my #fileholder;
$files_location = "../";
$ID = param('ID');
open(DLFILE, "<$files_location/$ID") || Error('open', 'file');
#fileholder = <DLFILE>;
close (DLFILE) || Error ('close', 'file');
print "Content-Type:application/x-download\n";
print "Content-Disposition:attachment;filename=$ID\n\n";
print #fileholder
My code, is on github but you'll likely have all sorts of problems using it on your machine as i make heavy use of ENV variables that I store in bashrc and I have no documentation or tests ^hides^
You could do some smart server side url rewrite, like for example rewriting foo.mpeg to youveryuglyfilenamewithoutextension.
Set the Content-Disposition to "attachment; filename="...that's fine. "attachment" explicitly means it's not to be rendered in the browser, file renaming works nonetheless (or possibly particularly for that case).
Based on your comments, you have a few problems.
You want to set the filename using your Rails app.
The file is on a remote host and your Rails app is acting as a middleman.
The file might be big, so you want the file to be sent out to the browser as you receive it instead of queuing the whole thing.
Streaming only with Rails is tricky for a few reasons.
You would need an HTTP client that lets you access the message body as you receive data instead of blocking until you have everything. Net::HTTP is not that client. I'm not sure what library would be better suited.
Once you have a more event-driven way to get your file in pieces, you can pass a proc to the render:
render :text => proc { |response, output| ... }
output can be used like an IO object. Some servers may buffer before sending anyway, though, so that's something to look out for.
It would be easier not handle the byte-shuffling in Rails.
If your webserver or the proxy in front of your webserver supports the X-REPROXY-URL HTTP header, your application can set that header and your webserver or proxy will stream the file.
Perlbal is the only proxy server I know of that supports that header out of the box.
An Apache2 module is also available.