Scenario:
Have already deployed a Rails 3.2 app, and it ran the asset pipeline flow…
Now as a result of a user action, we have a new image and we want it to be a part of the asset pipeline for benefits like cache busting (though now I think about it, with user-uploaded images given unique filenames each time, that is a moot point)
Is there any way to be able to / is it a good idea to use the asset pipeline at this point, for that new image?
I have a feeling this is a stupid question.
Compiling assets is just a rake task, you could invoke the task at any point. The task is bundle exec rake assets:precompile. See http://guides.rubyonrails.org/asset_pipeline.html for more information.
However, I would not treat user uploaded images as assets to be compiled. I think doing so would be a bad idea.
Instead, like you touched on, make your user uploaded images have unique names. So when new images get uploaded/replaced new names will be generated. An example of this being done can be found in the paperclip gem. It writes the images to disk and saves a record/reference in the database. Those images have an id in the databases and the URLs involve that id. So you would have /photos/4/nothing.png and /photos/2/yes.png. Where 2 and 4 point back to database records with metadata/relations to the images.
Also, when you use the image_tag rails view helper it will automatically add a cache buster onto the URL of the image. The cache buster is done as a query string, so image_tag('test.png') becomes /images/test.png?1234567890. Sometimes certain proxies will not 'bust' query string caches, but those are a minority.
Related
My iOS Application has been in review, but was rejected regarding the iOS Data Storage Guidelines. In the end, it was rejected because my Core Data database (sqlite) was located in the /Documents folder. I'm was aware, that this folder should only be used, it the data could not be recreated by my application. The reason why I chose to put it there anyway was, that one of the entities in my database contains an attribute telling if the given news has been read. This information cannot be recreated. Is this not enough to put the database in the /Documents folder?
Another thing is, that the current version of my application does not use this value to visualize if the news item has been read or not. So, should I tell the review-team about this attribute and argument why I think it should be placed in the document-folder -- or should I just move it to the /Library/Cache/?
The app review team wants you to split your data apart. Store the re-creatable parts in the Cache folder and the stuff that can't be re-created in the Documents folder. It's okay if there's a little bit of stuff in Documents that could theoretically be re-created—nobody will even notice a title or datestamp—but long text documents, video, audio, or images should be kept in the Cache folder if they can be downloaded again later.
There are a couple different ways you could do this:
Store the downloaded content in the Cache folder and only put the content's filename in your Core Data database (or calculate the filename from something else, like the SHA-1 hash of the URL it was downloaded from). Make sure your code will re-download any content that's not in the cache.
Use two Core Data stores with a single store coordinator. Note that you can't split an entity's attributes across two stores, so you may have to break some of your entities in half. Nor can you create a relationship from an object in one store to an object in another, so you'll have to store the object ID URI instead. See "Cross-Store Relationships" in the "Relationships and Fetched Properties" section of the Core Data Programming Guide for more details.
Whatever you do, keep in mind that iOS may purge your Cache folder at any time. Be prepared for files in your Cache folder to have disappeared; if that happens, you should re-download the files as the user requests them.
So I am in the process of moving all the thumbnails of my major sites to S3 and now I am thinking about how I can consistently put all my CSS/JS/images that power the actual sites to it. It's easy enough to upload everything the first time but I am trying to think of a way to somehow automate the process everytime I push out to production.
Does anyone have any clever ways of doing this?
I used to use s3sync to compare and update the assets just before upload the site files using a bash file to iterate through my files
This works well but when the amount of likes to compare (lets say thousands) gets big this process start being really slow. If you have an small architecture (in term of assets) this would do the trick
to make this better I would recommend capistrano or some other assistant that helps you to deploy...this way you can run at all once..
upload assets
deploy your files
In the other hand you could take a look to cloudfront (amazon's CDN) and set it up using ORIGIN..this way you dont need to worry about upload the files to s3 since they will be automatically pulled on demand. The down side of this approach is the caching if you need to update a file and keep the same name (AKA expire the object)...you can do this in cloudfront but will need an script to do the task.
Depending in the traffic (and other factors, ofcourse) one or other path will fit the best.
I have the following scenario:
I'm starting development of a long project (around 6 months) and I need to have some information on the database in order to test my features. The problem is that right now, I don't have the forms to insert this information (I will in the future) but I need the information loaded on the DB, what's the best way to handle this? Specially considering that once the app is complete, I won't need this process anymore.
As an example, lets say I have tasks that need to be categorized. I've begun working on the tasks, but I need to have some categories loaded on my db already.
I'm working with Rails 3.1 btw.
Thanks in advance!
Edit
About seeds:I've been told that seeds are not the way to go if your data may vary a bit, since you'd have to delete all information and reinsert it again. Say.. I want to change or add categories, then I'd have to edit the seeds.rb file, do my modifications and then delete and reload all data...., is there another way? Or are seeds the defenitely best way to solve this problem?
So it sounds like you'll possibly be adding, changing, or deleting data along the way that will be intermingled amongst other data. So seeds.rb is out. What you need to use are migrations. That way you can search for and identify the data you want to change through a sequential process, which migrations are exactly designed for. Otherwise I think your best bet is to change the data manually through the rails console.
EDIT: A good example would be as follows.
You're using Capistrano to handle your deployment. You want to add a new Category, Toys, to your system. In a migration file then you would add Category.create(:name => "Toys") or something similar in your migration function (I forget what they call it now in Rails 3.1, I know there's only a single method though), run rake db:migrate locally, test your changes, commit them, then if it's acceptable deploy it using cap:deploy and that will run the new migration against your production database, insert the new category, and make it available for use in the deployed application.
That example aside, it really depends on your workflow. If you think that adding new data via migrations won't hose your application, then go for it. I will say that DHH (David Heinemeier Hansson) is not a fan of it, as he uses it strictly for changing the structure of the database over time. If you didn't know DHH is the creator of Rails.
EDIT 2:
A thought I just had, which would let you skip the notion of using migrations if you weren't comfortable with it. You could 100% rely on your db/seeds.rb file. When you think of "seeds.rb" you think of creating information, but this doesn't necessarily have to be the case. Rather than just blindly creating data, you can check to see if the pertinent data already exists, and if it does then modify and save it, but if it doesn't exist then just create a new record plain and simple.
db/seeds.rb
toys = Category.find_by_name("Toys")
if toys then
toys.name = "More Toys"
toys.save
else
Category.create(:name => "More Toys")
end
Run rake db:seeds and that code will run. You just need to consistently update the seeds.rb file every time you change your data, so that 1) it's searching for the right data value and 2) it's updating the correct attributes.
In the end there's no right or wrong way to do this, it's just whatever works for you and your workflow.
The place to load development data is db/seeds.rb. Since you can write arbitrary Ruby code there, you can even load your dev data from external files, for instance.
there is a file called db/seeds.rb
you can instantiate records using it
user1=User.create(:email=>"user#test.com",
:first_name=>"user",
:last_name=>"name",
:bio=>"User bio...",
:website=>"http://www.website.com",
:occupation=>"WebDeveloper",
:password=>"changeme",
:password_confirmation=>"changeme",
:avatar => File.open(File.join(Rails.root, '/app/assets/images/profiles/image.png'))
)
user2=User.create(:email=>"user2#test.com",
:first_name=>"user2",
:last_name=>"name2",
:bio=>"User2 bio...",
:website=>"http://www.website.com",
:occupation=>"WebDeveloper",
:password=>"changeme",
:password_confirmation=>"changeme",
:avatar => File.open(File.join(Rails.root, '/app/assets/images/profiles/image.png'))
)
Just run rake db:seed from command line to get it into the db
I'm using Paperclip (2.3) to handle image uploads on a Rails 3.0.3 app running on Ubuntu. Paperclip is handling the uploads as advertised BUT the RackMultipart* files that are created in the application's /tmp folder persist -- that is, they simply accumulate rather than deleting themselves. I realize that I could use tmpreaper to delete old tmpfiles but I'd really like to find a more elegant (and scalable) solution.
I had a previous issue with temp files (i.e. RackMultipart* files) accumulating in the Rails app's root directory (instead of in /tmp). I resolved this by explicitly setting the temp path in my environment.rb file like so:
ENV['TMPDIR'] = Rails.root.join('tmp')
Is there another environment variable that needs to be set to make sure that the tempfiles are handled properly -- i.e. deleted once they've been saved in the model? I'm not sure if this is a problem with Paperclip or my Rails setup.
I've searched high and low but have made little progress on this. I'd be grateful for any leads.
Sincere thanks.
PS - I'm using currently using S3 for storage. This doesn't seem to be tied to the problem though -- I had the same problem when I was storing the files locally.
The TempFileReaper is the Rack middleware thought to handle this issue.
http://www.rubydoc.info/github/rack/rack/Rack/TempfileReaper
Including this line in the application.rb solves the problem:
config.middleware.use Rack::TempfileReaper
I don't know if this is anymore elegant but this is what I am doing after the file is saved"
tempfile = params[:file].tempfile.path
if File::exists?(tempfile)
File::delete(tempfile)
end
UPDATE: Problem should be resolved in rack-1.6.0.beta2. I see it's already being used in Rails 4.2.0.rc2.
Below workaround served me well for almost a year:
I've added this at the end of controller action that accepts file uploads:
Thread.new { GC.start }
This triggers Garbage Collection of unused Rack::Request objects which also deletes associated temp files. Note it doesn't sweep temp file of current request, but it does remove previous files, and prevents them from accumulating.
I'm building an application that needs to download web content for offline viewing on an iPad. At present I'm loading some web content from the web for test purposes and displaying this with a UIWebView. Implementing that was simple enough. Now I need to make some modifications to support offline content. Eventually that offline content would be downloaded in user selectable bundles.
As I see it I have a number of options but I may have missed some:
Pack content in a ZIP (or other archive) file and unpack the content when it is downloaded to the iPad.
Put the content in a SQLite database. This seems to require some 3rd party libs like FMDB.
Use Core Data. From what I understand this supports a number of storage formats including SQLite.
Use the filesystem and download each required file individually. OK, not really a bundle but maybe this is the best option?
Considerations/Questions:
What are the storage limitations and performance limitations for each of these methods? And is there an overall storage limit per iPad app?
If I'm going to have the user navigate through the downloaded content, what option is easier to code up?
It would seem like spinning up a local web server would be one of the most efficient ways to handle the runtime aspects of displaying the content. Are there any open source examples of this which load from a bundle like options 1-3?
The other side of this is the content creation and it seems like zipping up the content (option 1) is the simplest from this angle. The other options would appear to require creation of tools to support the content creator.
If you have the control over the content, I'd recommend a mix of both the first and the third option. If the content is created by you (like levels, etc) then simply store it on the server, download a zip and store it locally. Use CoreData to store an Index about the things you've downloaded, like the path of the folder it's stored in and it's name/origin/etc, but not the raw data. Databases are not thought to hold massive amounts of raw content, rather to hold structured data. And even if they can -- I'd not do so.
For your considerations:
Disk space is the only limit I know on the iPad. However, databases tend to get slower if they grow too large. If you barely scan though the data, use the file system directly -- may prove faster and cheaper.
The index in CoreData could store all relevant data. You will have very easy and very quick access. Opening a content will load it from the file system, which is quick, cheap and doesn't strain the index.
Why would you do so? Redirect your WebView to a file:// URL will have the same effect, won't it?
Should be answered by now.
If you don't have control then use the same as above but download each file separately, as suggested in option four. after unzipping both cases are basically the same.
Please get back if you have questions.
You could create a xml file for each bundle, containing the path to each file in the bundle, place it in a folder common to each bundle. When downloading, download and parse the xml first and download each ressource one by one. This will spare you the overhead of zipping and unzipping the content. Create a folder for each bundle locally and recreate the folder structure of the bundle there. This way the content will work online and offline without changes.
With a little effort, you could even keep track of file versions by including version numbers in the xml file for each ressource, so if your content has been partially updated only the files with changed version numbers have to be downloaded again.