Question

According to the Ruby on Rails Guide: Caching, caching is disabled by default in the development and testing environments. If I make a small CSS change, run rails server and access my site at localhost:3000, I can see my change. However, if I access my rails server on my iPhone at 10.0.1.2:3000, the CSS doesn’t update, even Chrome in Incognito Mode. When I try different iPhone that has an empty cache, the change is there.

I found a stack overflow post that described the same problem. Here were the suggested solutions:

• Remove the public/assets directory. I don’t have one.
• Add config.serve_static_assets = false to environments/development.rb. It’s already there.
• Delete /tmp/cache/assets, add config.serve_static_assets = false to environments/development.rb and restart the server. I tried this and it didn’t work.

Here’s my relevant environments/development.rb config:

# In the development environment your application's code is reloaded on
# every request. This slows down response time but is perfect for development
# since you don't have to restart the web server when you make code changes.
config.cache_classes = false

# Show full error reports and disable caching
config.consider_all_requests_local       = true
config.action_controller.perform_caching = false

Answer 1

I’m pretty sure this is happening because Rails only does fingerprinting in production: http://guides.rubyonrails.org/asset_pipeline.html#in-production

This means that in development browsers that are more cache-aggressive can run into this issue.

Try adding this to your development.rb:

config.assets.digest = true

Or more preferable something conditional for when you’re doing mobile development

# One of the few exceptions I'd make to a no ENV variables rule 
# for my rails environment config files
config.assets.digest = true if ENV["MOBILE_DEBUG"]