I gonna upload files to rackspace(video, audio and images) in rails with paperclip or carrierwave, I need to Know the kind of file, to show in the view with image_tag, or video_tag or audio_tag, rackspace tell me the kind of file? or I have to store in my database? thanks
You can query/set the file type by using the 'content_type' function located in the 'ruby-cloudfiles' library.
See here: https://github.com/rackerlabs/ruby-cloudfiles/blob/master/lib/cloudfiles/storage_object.rb#L80-L82
Something like this should work for creating the object:
container = conn.create_container('new_container')
obj = container.create_object('new_obj.txt')
obj.load_from_filename('./obj.txt')
obj.content_type = 'text/plain'
And to retrieve the object:
obj = container.object('new_obj.txt')
puts obj.content_type # text/plain
Even if rackspace would tell you the file type, you don't want it to, since it would take so long to run roundtrips from your server to theirs.
My code examples below assume carrierwave, but I'm sure paperclip has similar options. Two options:
Interpret the file extension
Something like: File.extname(user.avatar), which you then have to interpret however you like.
Record & interpret the mime type.
The carrierwave readme explains how to get carrierwave to calculate it in the first place, and then you should probably store it to your database manually or using carrierwave-meta. Then user.avatar.content_type would be something like image/jpeg which you could easily interpret as a particular file type.
Related
So, I'm creating an app that works like a bot, it makes a call to an API from time to time, then it receives a response in a json-like format and saves it like this:
finalResult = RestClient.get( apiUrl, headers = apiHeaders )
jsonData = JSON.parse(ActiveSupport::Gzip.decompress(finalResult))
time = Time.now
File.write("public/#{time}.json", jsonData)
I'm using ActiveSupport to be able to parse this Gzip compressed data, since it's a lot of data, otherwise it takes forever to get it. Then I get the time the data was received, basically, and I use it to name the file so that I can keep good track of it.
What I need to do now is compress this .json file, if possible, into a .zip file(it can be .rar, or .7z, or .tz, whatever) before I upload it to my storage so it takes less space. Is there anyway that I can do something similar to File.write but to save it as a zipped json file? I already checked stuff like zlib and ruby-zip, but they only let me zip files that already "exist", so I can't save it as a zipped .json directly, I'd need to take the .json file and then zip it, but how could I do that if the name of the file is a Time.now and it always change?
I'd appreciate any help, thanks in advance :)
EDIT¹
Giving some more details that may help you to help me:
I created a controller and model to handle this, since I'll be using ActiveStorage. It's ResponsesController and Response model, and the only parameter that the Response model has is has_one_attached :json_file. I intend to use Heroku to handle the CRON job of calling the API and I'll upload the .json files(or .zip files) to an AWS storage.
I know that with modern paperclip I can do
model.source = URI.parse source_url
and that will download the file and handle everything for me.
However, what if I want to provide styles that have already been processed internally.
Something like
model.upload_source 'video/mp4', (URI.parse source_url_mp4)
model.upload_source 'video/webm', (URI.parse source_url_webm)
I'm not finding this documented anywhere.
Have you considered finding the mimetype in your application code after loading a source_url?
The flow is:
The user selects an image on the client.
Only filename, content-type and size are sent to the server. (E.g. "file.png", "image/png", "123123")
The response are fields and policies for upload directly to S3. (E.g. "key: xxx, "alc": ...)
The case is that if I change the extension of "file.pdf" to "file.png" and then uploads it, the data sent to the server before uploads to S3 are:
"file.png"
"image/png"
The servers says "ok" and return the S3 fields for upload .
But the content type sent is not a real content type. But how I can validate this on the server?
Thanks!
Example:
Testing Redactorjs server side code (https://github.com/dybskiy/redactor-js/blob/master/demo/scripts/image_upload.php) it checks the file content type. But trying upload fake image (test here: http://imperavi.com/redactor/), it not allows the fake image. Like I want!
But how it's possible? Look at the request params: (It sends as image/jpeg, that should be valid)
When I was dealing with this question at work I found a solution using Mechanize.
Say you have an image url, url = "http://my.image.com"
Then you can use img = Mechanize.new.get(url)[:body]
The way to test whether img is really an image is by issuing the following test:
img.is_a?(Mechanize::Image)
If the image is not legitimate, this will return false.
There may be a way to load the image from file instead of URL, I am not sure, but I recommend looking at the mechanize docs to check.
With older browsers there's nothing you can do, since there is no way for you to access the file contents or any metadata beyond its name.
With the HTML5 file api you can do better. For example,
document.getElementById("uploadInput").files[0].type
Returns the mime type of the first file. I don't believe that the method used to perform this identification is mandated by the standard.
If this is insufficient then you could read the file locally with the FileReader apis and do whatever tests you require. This could be as simple as checking for the magic bytes present at the start of various file formats to fully validating that the file conforms to the relevant specification. MDN has a great article that shows how to use various bits of these apis.
Ultimately none of this would stop a malicious attempt.
I am using paperclip to attach an excel file to a mode.
The purpose is to import the data from the excel file to the database.
Model: Import
has_attached_file: spreadsheet
For the import process, I want to access the file in my model as following.
path = "#{Rails.root}/public/#{spreadsheet.url}"
This doesn't work. I guess because the url has the timestamp at the end.
In general what is the best way to access the attachments on server side ?
I think you're looking for the to_file method. You should be able to do something like this:
excel_file = self.spreadsheet.to_file
which will either return the uploaded file from the server (if you're using s3 or remote storage), or if it has been assigned to the model but not actually stored yet (if you haven't called model.save since it was uploaded), it returns the temp file stored on disk.
From there you should be able to use an excel gem or library to parse the contents.
Alternatively, you can use spreadsheet.url(nil, false) - the second parameter denotes whether or not to append a timestamp.
#spreadsheet.path
http://rdoc.info/gems/paperclip/2.3.8/Paperclip/Attachment#path-instance_method
i started using nginx upload module (which creates upload files like /tmp/000121545) but i need paperclip to use original filename while saving files (like /public/avatars/LuckyLuke.jpg)
previously in the parameters Rails were passing just
"avatar"=>#<File:/tmp/RackMultipart20100413-6151-t3ecq0-0>
no original filename as well, so i am wondering where from does it come in paperclip? i tried looking through plugin code but it's currently a bit too complex for me.
The browser sends a http header with the file name. ("Content-Disposition: filename=original_file.jpg")
Rails makes this available as a instance method of the temp file object: params[:avatar].original_filename, and paperclip uses that.
In detail, Rack parses the multipart form in Rack::Utils::Multipart::UploadedFile and puts a hash in the parameters that includes :tempfile and :filename. Then ActionDispatch::Http::Upload comes along and replaces that hash by the File object (value of :tempfile), extending it with the module ActionDispatch::Http::UploadedFile, which adds a instance variable for original_path and the method original_filename.