Carrierwave + Fog(s3). Letting the users to download the file - ruby-on-rails

I am working on a project where I have to provide download links to user for the files which are stored in the s3. Initially I tried,
link_to "Download", #medium.file.url
But this opens the file directly on the browser. When i tried to download an mp4 file, chrome started playing it automatically. I don't want that to happen. So I am using send_file for this task,
def download
#medium = Medium.find(params[:id])
send_file #medium.file.url
end
In my local, I have set the storage to file and I have tested this, which works perfectly fine. But on staging, the files are served from s3, I am always getting ActionController::MissingFile. My app is hosted on heroku. I also want to know if using send_file is good choice or if there is a better way of doing this.
config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect'
When i was googling, i found that nginx header setting for sending files should be enabled for production. I added the following line in config/environments/production.rb. Still no luck. I need some help on this. Thanks.

I think this is because S3 wants the file to be played.
I don't have access to my S3 here, but I solved the problem by changing the action for PDF files (which was shown my case) in the S3 control panel.
If you can fix this, I think you can avoid using send_file completely.
Edit: I managed to access S3 now. Go to properties -> Metadata, and add the key
Content-Disposition: Attachment
Then your file will always be downloaded instead of shown.

Related

Upload file directly to S3 without need to use forms in Rails

For my Rails application, I download a bunch of files from a remote URL to my application. I would like to directly upload them to Amazon S3, without needing a form to do the upload, since I will temporarily cache the file I downloaded on the EC2 instance.
I would also like to retain the links to the files I uploaded so I can download them later.
I am essentially reposting the files I downloaded.
I looked around, but most of the solution seem to involve form uploading to S3 with a user.
Is there s direct upload solution?
You can upload directly to S3 using the AWS SDK for Ruby. The easiest way is:
require 'aws-sdk'
s3 = Aws::S3::Resource.new(region:'us-west-2')
obj = s3.bucket('bucket-name').object('key')
obj.upload_file('/path/to/source/file')
Or you can find a couple other options here.
You can simply use EvaporateJS to achieve this. You can also take advantage of sending ajax request to update file name to the database after each file upload. Though javascript exposes few details your bucket is not vulnerable to hack as S3 service provide a bucket policy.
Just set the <AllowedOrigin>*</AllowedOrigin> to <AllowedOrigin>specificwebsite.com</AllowedOrigin> in production mode.

Rails s3_direct_upload without file field

My website generates a file in javascript (audio recording) and I then want it to be uploaded to Amazon S3.
I first managed to get the uploading part working by sending the generated file to my server, where it is uploaded. However I would like now to upload the file directly to S3, without going through my server.
So I started to use the s3_direct_upload gem, which works great when using a file_field. However my file is generated by the javascript and :
- The value of a file field has to be set by the user for security reasons
- I do not want the user to have to interact with the upload
I tried to play with the S3Uploader class and to directly add data, without any success for now, it seems that I do not use the correct method.
Does anyone has any idea on how to achieve S3 direct upload without a file field ?
Thanks
Never mind, I found out that the S3Uploader class used by the s3_direct_upload gem has the same methods as the jQuery-File-Upload from which it is derived.
So one can call $("#s3_uploader").fileupload('send', {files: [f]});
And the f File will be uploaded to S3 directly

rails as proxy for remote file download

I am having a rails application on e.g. example.com . I am using a cloud storage provider for any kind of files (videos, images, ...).
No I would like to make them available for download without exposing the url of the actual storage location.
So I was thinking of a kind of proxy. A simple controller which could look like this :
data = open(params[:file])
filename = "#{RAILS_ROOT}/tmp/my_temp_file"
File.open(filename, 'r+') do |f|
f.write data.read
end
send_file filename, ...options...
( code taken from a link ).
Point being is that I would have to download the file first.
So I was wondering if it would be possible to stream the file right away without downloading from the cloud storage first.
best
philip
I was working on this exact issue a while ago and came to the conclusion that this would not be possible without having to download the file to your server and then pass it on to the client as you say.
I'd recommend generating a signed, expiring download link that you insert into a hidden iframe whenever a user clicks a download link on your page. In this way they will get the experience of downloading from your page, without the file making an unnecessary roundtrip to your server.

Download file on click - Ruby on Rails

My application is using Rails 2 backend, Heroku for hosting, Paperclip for file uploads, and Amazon S3 for file storage.
Right now users can upload files with paperclip + s3 - this works flawlessly. After upload, an icon appears on their dashboard, linked to the file location (in s3 bucket). When the icon is clicked, the browser opens the file in a new window (for most file types - PDF, MP3, img, etc). Instead of opening, I want the file to be automatically downloaded when the user clicks the file's icon (like Gmail attachments). The solution should be able to work for any file type and cross-browser.
Is there a helper to do this in rails, or is javascript needed? I'm really stuck on this one so anything to point me in the right direction would be greatly appreciated. Thanks!
Please try the following:
class Test < ActiveRecord::Base
has_attached_file :testfile,
:storage => :s3,
# All your S3 config
:s3_headers => {"Content-Disposition" => "attachment"}
end
This should tell the Paperclip Gem to set the "Content-Disposition" header to the value "attachment" for newly uploaded files.
Note that you have to manually edit the already uploaded file, e.g. with Cyberduck or another FTP Client.
When you transfer the file, you need to set a Content-Disposition header with a value of attachment; filename=yourfilename.pdf. If it's transfered directly from S3, you'll need to tell S3 to set the Content-Disposition headers as well. Possibly also Content-Type.
Note that if you tell S3 to associate a Content-Disposition header, it will always transmit this header.
FWIW, here's Amazon's documentation on doing a PUT for an Object: http://docs.amazonwebservices.com/AmazonS3/latest/API/RESTObjectPUT.html

Alternative to X-sendfile in Apache for sending file given a URL?

I'm writing a Rails application that serves files stored on a remote server to the end user.
In my case the files are stored on S3 but the user requests the file via the Rails-application (hiding the actual URL). If the file was on my servers local file-system, I could use the Apache header X-Sendfile to free up the Ruby process for other requests while Apache took over the task of sending the file to the client. But in my case - where the file is not on the local file-system, but on S3 - it seems that I'm forced to download it temporarily inside Rails before sending it to the client.
Isn't there a way for Apache to serve a "remote" file to the client that is not actually on the server it self. I don't mind if Apache has to download the file for this to work, as long as I don't have to tie up the Ruby process while it's going on.
Any suggestions?
Thomas, I have similar requirements/issues and I think I can answer your problem. First (and I'm not 100% sure you care for this part), hiding the S3 url is quite easy as Amazon allows you to point CNAMES to your bucket and use a custom URL instead of the amazon URL. To do that, you need to point your DNS to the correct amazon URL. When I set mine up it was similar to this: files.domain.com points to files.domain.com.s3.amazonaws.com. Then you need to create the bucket with the name of your custom URL (files.domain.com in this example). How to call that URL will be different depending on which gem you use, but a word of warning was that the attachment_fu plugin I was using was incorrectly sending me to files.domain.com/files.domain.com/name_of_file.... I couldn't find the setting to fix it, so a simple .sub method for the S3 portion of the plugin fixed it.
On to your other questions, to execute some rails code (like recording the hit in the db) before downloading you can simply do this:
def download
file = File.find(...
# code to record 'hit' to database
redirect_to 3Object.url_for(file.filename,
bucket,
:expires_in => 3.hours)
end
That code will still cause the file to be served by S3, but and still give you the ability to run some ruby. (Of course the above code won't work as is, you will need to point it to the correct file and bucket and my amazon keys are saved in a config file. The above is also using the syntax for the AWS::S3 gem - http://amazon.rubyforge.org/).
Second, the Content-Disposition: attachment issue is a bit more tricky. Hopefully, your situation is a bit more simple than mine and the following solution can work. Assuming the object 'file' (in this example) is the correct S3 object, you can set the disposition to attachment by
file.content_disposition = "attachment"
file.save
The above code can be executed after the file exists on the S3 server (unlike some other headers and permissions), which is nice and it can also be added when you upload the file (syntax depends on your plugin). I'm still trying to find a way to tell S3 to send it as an attachment and only when requested (not every time), and if you find that, please let me know your solution. I need to be able to sometimes download it and other times save embed images (for example) into HTML. I'm not using the above mentioned redirect but fortunately it seems that if you embed (such as a HTML image tag) a file with the content-disposition/attachment header, and the browser still displays the image normally (but I haven't throughly tested that across enough browsers to send it in the wild).
Hope that helps! Good luck.

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