our team has a Java REST service that basically creates a PDF when we make a post call to it, and returns the PDF in the response body. Here's a quick look at that service.
#POST
#Path("/")
#Consumes(MediaType.APPLICATION_JSON)
#Produces(MediaType.APPLICATION_OCTET_STREAM)
public Response generatePDF(String data) {
File file = new File(FILE_PATH);
ResponseBuilder response = Response.ok((Object) file);
response.header("Content-Disposition", "attachment; filename=my_file.pdf");
return response.build();
}
All we want to do is call this service from our Ruby on Rails controller and download the PDF (I'm assuming it will prompt us for a download/open dialog box). I've researched many ways to do this but nothing is working. We've tried different gems, such as Prawn, PDFKit, and WickedPDF, with no luck. We don't need to generate or edit the PDF on the Rails side. We just want a way for the user to either view or download it so they can print it. Any help would be appreciated. Thanks!
Related
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 am trying to download an image and displaying it in a view in rails.
The reason why I want to download it is because the url contains some api-keys which I am not very fond of giving away.
The solution I have tried thus far is the following:
#Model.rb file
def getUrlMethod
someUrlToAPNGfile = "whatever.png"
file = Tempfile.new(['imageprependname', '.png'], :encoding => "ascii-8bit")
file.write(open(data).read)
return "#{Rails.application.config.action_mailer.default_url_options[:host]}#{file.path}"
end
#This seems to be downloading the image just fine. However the url that is returned does not point to a legal place
Under development I get this URL for the picture: localhost:3000/var/folders/18/94qgts592sq_yq45fnthpzxh0000gn/T/imageprependname20130827-97433-10esqxh.png
That image link does not point anywhere useful.
My theories to what might be wrong is:
The tempfile is deleted before the user can request it
The url points to the wrong place
The url is not a legal route in the routes file
A am currently not aware of any way to fix either of these. Any help?
By the way: I do not need to store the picture after I have displayed it, as it will be changing constantly from the source.
I can think of two options:
First, embed the image directly in the HTML documents, see
http://www.techerator.com/2011/12/how-to-embed-images-directly-into-your-html/
http://webcodertools.com/imagetobase64converter
Second, in the HTML documents, write the image tag as usual:
<img src="/remote_images/show/whatever.png" alt="whatever" />
Then you create a RemoteImages controller to process the requests for images. In the action show, the images will be downloaded and returned with send_data.
You don't have to manage temporary files with both of these options.
You can save the file anywhere in the public folder of the rails application. The right path would be something like this #{Rails.root}/public/myimages/<image_name>.png and then you can refer to it with a URL like this http://localhost:3000/myimages/<image_name>.png. Hope this will help.
I have string data in the form
http://site.com/location
file://server/folder/
I am showing the data as links so clicking on the link takes you to the appropriate web site or file location. Clicking on a link built from 'http://...' data works fine but I get an 'unable to display web page' message when I click on a link built from 'file://' data.
I'm building the link using Html.ActionLink, passing the data as a parameter to a HandleLink method on the controller. The HandleLink method just does Redirect(data). I know the data is coming in correctly because I can copy the incoming value in the debugger and paste in in the address bar of my browser and that works as expected.
How can I make the 'file://' links work correctly?
EDIT: I botched the first question I asked here -- I hope they have a badge for that. The 'file://...' data items are to a folder, not a specific file. Does that make any difference?
As mentioned above, you can't use file:\ to get files on a remote server however you can serve the files using something like the following:
public FileContentResult GetFile(int fileID)
{
string fileName = GetFileNameFromID(fileID); //Retruns path and filename on server
string contentType = "text/csv"; //or other appropriate type
return new FilePathResult(fileName, contentType);
}
Much more info here
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.
I'm using restclient for a multipart form to send data to a restful web service (it's Panda video encoding service).
The trick though, is that the file I am passing into restclient (Technoweenie branch) is coming from my own form that a user submits.
So, lets walk through this. A user posts a file to my rails app. In my controller, it receives the file from params[:file]. I then want to pass params[:file] down to Panda using RestClient.
The error I'm getting is on the Panda server follows. I noticed that the file param in the stack trace is in a string as well (which I assume is Panda turning into a string for a nicer stacktrace).
~ Started request handling: Wed Aug 12 18:05:15 +0000 2009
~ Params: {"format"=>"html", "multipart"=>"true", "account_key"=>"SECURE_KEY", "action"=>"upload", "id"=>"SECURE_ID", "controller"=>"videos", "file"=>"#<File:0xcf02ca4>"}
~ 9bfb1750-6998-012c-4509-12313900b0f6: (500 returned to client) InternalServerErrorcan't convert nil into String
/var/local/www/panda/app/models/video.rb:246:in `extname'
/var/local/www/panda/app/models/video.rb:246:in `initial_processing'
/var/local/www/panda/app/controllers/videos.rb:79:in `upload'
I doubt you can really pass a CGI-style upload param from Rails into restclient and expect it to work.
A regular upload in Rails would have quite some extra attributes which do not belong in a posted resource (like the original filename and so on), and a Rails upload contains an IO with the actual file data. Also a file upload object in Rails might be a Tempfile handle and might be a StringIO - depending on the size of the upload.
What you effectively need to do is "repackage" your upload for rest-client to handle it properly, and pass the repackaged and rewound Tempfile object to restclient. Maybe you can get away with just picking the upload object itself instead of the whole params[:file]
Confirm that your restclient action can save locally first. If the action cannot save locally, then you will have a better idea where to look while trouble shooting.
Looks like the problem is with rest-client's posting of the file, check out an alternative method for posting like curb.
Lots of examples for posting multipart form data on this question: Ruby: How to post a file via HTTP as multipart/form-data?