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GitHub User: MaxGabriel
Just a warning to anyone using page caching for more than HTML pages (e.g. JSON responses), the Rails will default to saving the cached file with the HTML extension, so requests hitting the cache will get the wrong format. To get around this, just append the format you're using in your request: curl railsapp.com/method.json. Rails will then save the file with the correct extension.
Thanks this worked for me