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Storing Images in DB - Yea or Nay?
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in my website, user can upload a profile image.
I wanted to know what is the best way to store those images.
my thought is simply dedicated directory. the image name will be the user_id.
is that a good solution, or there's a smarter one?
You have two options, store the images or use an external source (gravatar).
If you're going to store the images, do you want these images to be publically available or are they private? If they are publically available, then you can store them in your public folder.
You can use something like carrierwave to handle the uploading, versioning and storing of the images.
For public stuff, I'll store the file in the public directory under the uploader/model name/field name/id location. This is more for organizational purposes on my part.
Check out http://railscasts.com/episodes/253-carrierwave-file-uploads for a good tutorial.
For private images, I'll set the store directory to something outside of the public folder and will create a download action within the controller with the file. This way, the user cannot download the file unless it goes through the controller action. With authorization (cancan) I can allow or disallow a user to access the download action for that particular file (hence making it somewhat secure). If you are going to be using a production server like apache or nginx, make sure that you set the appropriate handlers for sending the file (ie x_sendfile).
Its very common to store images in a directory for small applications. However there are a few of things to take into consideration here:
Do you have anticipate a lot of users? If you have a million users, storing everyone's photo in your directory will take up a lot of memory when running your application
Are you deploying on Heroku? Many RoR apps are, and if you deploy on Heroku it will destroy any files you store locally when your app is moved to a different dyno (and you generally have no way of predicting when this will happen). You can read about the Ephemeral filesystem here https://devcenter.heroku.com/articles/dynos#isolation-and-security
In general I would advise against storing all your images locally because rewriting the code as you scale will become painful. I recommend you upload to an Amazon S3 Bucket and download the images as you need (and cache them for when your user is logged in). Its helpful becasue you might have to deal with image processing (for example resizing the images that are uploaded, creating thumbnail versions of the uploaded images) and its easier to do this when you have background processes that have persistent access to these files. I've used the 'aws' gem and S3 libraries for this, and its really easy to use, you can read more about it here: http://amazon.rubyforge.org/
However, if you intend for this to be a small app and are not deploying on Heroku, just saving it to a local directory is a lot easier and pain-free
Related
A mobile iOS team wants an endpoint that they can send a username, a user ranking, and either an image related to that user or an array of images if the user has a gif or animation related to them. Then they will ping that endpoint in order to render these images on another page in their mobile app.
I decided to build this in Rails as a prototype. At first I thought I would need S3 in order to store the images, but now I'm not so sure. Can't I use the built-in database within my Rails app, since my Rails app won't be rendering any of the images? What are the advantages of using S3 in this case? Is S3 necessary?
For prototyping purposes, no, S3 isn't needed. You can store the images locally in the filesystem or even in DB, though, I'd say you should start with Postgres right away, because it has an array type you can use for the images table.
However, if you are making this an actual feature of a product, yes, consider S3 very seriously. Actually, something else you might want to look into is CloudFront, because it'll allow you to build a CDN and fetching images will be faster on the user side. Locality is significant portion of a fast UI, especially if images are a big part of it.
I have a web app which uses nginx. Suppose it's in Rails, but it doesn't really matter.
I'm planning to have around a hundred of pictures/files uploaded every day by users. I don't want to use any custom solution for storying and uploading images and instead I want to manage that myself.
1) Is there an idiomatic place/path where I should store those images? Or will any path within the reach of nginx will work?
2) Should it be a separate folder from the one that I'm use for storying images for CSS?
3) How would I organize folders forest? That is, should it be something like /my_base_image_folder/{year}/{month}/{day}/{image_sequence_number}.jpg?
Or maybe /my_base_image_folder/{article_id}/{image_sequence_number}.jpg? Or should I put them in the same folder `/my_base_image_folder/{img_guid}.jpg?
And why?
4) What's a recommended solution for naming uploading files? GUID? Or a sequence number?
It all depends on your use case for consuming those images again. If you're planning to retrieve images uploaded by the users for those users on later sessions, ie., if your users have to browse through their images in your application, it's better to store it in a_public_folder/user_id_hashed/. If you're planning to retrieve images based on the uploaded time or date, it's better if you go with a_public_folder/year/month/day/... Make sure the public folder is accessible by your ngnix by using not-too-open permission, just to be safe. Also, naming the image files, a combination of timestamp and a small random hex should do I guess, no big deal.
I'm working on a Rails project that currently receives uploaded files using attachment_fu and stores files in the database. I'd like to move them to use the filesystem. The problem is that there are currently several thousand uploaded files in the database, and we need to migrate them out. I can't seem to find anything to help with this; it seems the only migration anyone is posting tips for is filesystem -> S3. How would I go about migrating my files out of the database?
If you are ultimately attempting to serve these static files via S3/CloudFront to reduce load on your web/app servers one thing I may suggest is utilizing the new Custom Origin functionality of CloudFront which would allow you to keep your source files where they are. After being set up the process would basically be:
Your app tells the browser to retrieve the file from http://your-coudfront-host/path/to/file
The browser requests the file
If CloudFront has that file it returns it
If CloudFront does not have the file it retrieves it from your application and caches it for future requests (I believe up to 24 hours.)
This is what I am doing for product images that are dynamically generated on the fly in an application I am currently writing.
The upside of this is that you do not have to get into the overhead of constantly synchronizing data to S3 and if you decide to remove the whole setup you can still service your asset directly like nothing happened.
Im desiging an app which allows users to upload images (max 500k per image, roughly 20 images) from their hard drive to the site so as to be able to make some custom boardgames (e.g. snakes and ladders) in pdf formate. These will be created with prawn instantly and then made available for instant download.
Neither the images uploaded nor the pdfs created need to be saved on my apps side permanently. The moment the user downloads the pdf they are no longer needed.
Heroku doesn't support saving files to the system (it does allow to the tmp directory but says you shouldnt rely on it striking it out for me). I'm wondering what tools / services I should be looking into to get round this. Ive looked into paperclip, I'm wondering if this is right for this type of job.
Paperclip is on the right track, but the key insight is you need to use the S3 storage backend (Paperclip uses the FS by default which as you've noticed is no good on Heroku). It's pretty handy; instead of flushing writes out to the file system, it uses the AWS::S3 gem to upload them to S3. You can read more about it in the rdoc here: http://github.com/thoughtbot/paperclip/blob/master/lib/paperclip/storage/s3.rb
Here's how the flow would work:
I'd let your users upload their multiple source images. Here's an article on allowing multiple attachments to one model with paperclip: http://www.cordinc.com/blog/2009/04/multiple-attachments-with-vali.html.
Then when you're ready to generate the PDF (probably in a background job, right?), what you do is download all the source images to somewhere in tmp/ (make sure the directory is based on your model id or something so if two people do this at once, the files don't get stepped on). Once you've got all the images downloaded, you can generate your PDF. I know this is using the file system, but as long as you do all your filesystem interactions in one request or job cycle, it will work, your files will still be there. I use this method in a couple production web apps. You can't count on tmp/ being there between requests, but within one it's reliably there.
Storing your generated PDF on S3 with paperclip makes sense too, since then you can just hand your users the S3 URL. If you want you can make something to clear the files off every so often if you don't want to pay the S3 costs, but they should be trivial.
Paperclip sounds like an ideal candidate. It will save images in RAILS_ROOT/public/system/, which is both persistent and private (shouldn't be able to be enumerated on shared hosting).
You can configure it to produce thumbnails of your images if you wish.
And it can remove the images it manages when the associated model is destroyed - after your user downloads their PDF, and you delete the record from the database.
Prawn might not be appropriate, depending on the complexity of the PDFs you need to generate. If you have $$$, go for PrinceXML and the princely gem. I've had some success with wkhtmltopdf, which generates PDFs from a Webkit render of HTML/CSS - but it doesn't support any of the advanced page manipulation stuff that Prince does.
In my web application, each user will have a logo. I am pretty sure each user will also have a photo gallery in the future. What is the best way to set up a directory structure for managing user logos and possibly other assets such as photos? Also would be good to get people's opinions on what to store in the database. My application is a Rails app.
Just to be clear, this web application will need to scale to possibly hundreds of thousands of users.
There are plugins that offer drop in functionality for the things you're looking to do.
Essentially they work similarly to what Pindatjuh suggests. But you should check out attachment-fu and paperclip to see how the others have done it.
If it's a small web application and you have a database:
One folder containing all avatars (logos). In the database you set the filename of the avatar. Also another folder containing all photo's in a gallery. In the database you have one entry for each asset, pointing to the resource and user.
If it's a bigger, or growing, application, you can automatically create more folders (scripted: each 100 files create a new folder), or even load-balancing by having more than one server solely providing assets.
If you don't have a database:
Create a folder per user, which contains their avatar and assets. This one does not grow, since you don't have a database which points to the user-assets: if you have more than one server, you can't say "which" server the resources are on.