Skip to main content

JSON caching with Rails

So the other day, I needed to cache an action which was basically a proxy action to return JSON.

Basically, 3rd party company X has an XML API for it's deals. Ideally we would use JavaScript to pull the feed, but unfortunately, the feed is using XML which means we need to use the server to pull this "deal" and then reformat it in JSON for our site to use.

To render the JSON we were using a render call


render offer.to_json


It can get expensive to pull this deal over the wire every time, so we looked into using caches action and set it to expire in 5 minutes (because that is how often the deal feed updates).


caches_action :index, :expires_in => 5.minutes


(Oh, also we need to turn caching on in dev to see this happening)


config.action_controller.perform_caching = true


While this worked fine for the first call, I noticed that in the subsequent calls, the application type was being set to 'text/html' instead of 'application/json'. This was causing the AJAX call to fail. I then noticed that the AJAX call was calling the action directly instead of using the .json suffix.

i.e.
/offers/1234

instead of

/offers.json/1234

So it appeared that because I was not using the suffix, the cache was forcing the application/type header to text/html.

In any case, after a quick update to the JavaScript call, the caching worked fine.

Comments

unsymbol said…
How did you change the js to fix this? I'm having a similar issue but with serving js for ajax requests.
Anonymous said…
Where the url used to point to "/offers" I updated it to point to "/offers.json" instead.
Anonymous said…
Hey thanks for the great info... i was looking for same...
Anonymous said…
Hey thanks for great info..

Popular posts from this blog

Master of my domain

Hi All, I just got myself a new domain ( http://www.skuunk.com ). The reason is that Blogspot.com is offering cheap domain via GoDaddy.com and I thought after having this nickname for nigh on 10 years it was time to buy the domain before someone else did (also I read somewhere that using blogspot.com in your domain is the equivalent of an aol.com or hotmail.com email address...shudder...). Of course I forgot that I would have to re-register my blog everywhere (which is taking ages) not to mention set up all my stats stuff again. *sigh*. It's a blogger's life... In any case, don't forget to bookmark the new address and to vote me up on Technorati !

Elixir - destructuring, function overloading and pattern matching

Why am I covering 3 Elixir topics at once? Well, perhaps it is to show you how the three are used together. Individually, any of these 3 are interesting, but combined, they provide you with a means of essentially getting rid of conditionals and spaghetti logic. Consider the following function. def greet_beatle(person) do case person.first_name do "John" -> "Hello John." "Paul" -> "Good day Paul." "George" -> "Georgie boy, how you doing?" "Ringo" -> "What a drummer!" _-> "You are not a Beatle, #{person.first_name}" end end Yeah, it basically works, but there is a big old case statement in there. If you wanted to do something more as well depending on the person, you could easily end up with some spaghetti logic. Let's see how we can simplify this a little. def greet_beatle(%{first_name: first_name}) do case first_name d

Speeding up RSpec

So today I have been looking into getting our enormous battery of tests to run faster. I have yet to find anything that works for Cucumber, but I did find an interesting way to speed up RSpec which is detailed here. https://makandracards.com/makandra/950-speed-up-rspec-by-deferring-garbage-collection Basically, it seems that by not collecting garbage too frequently, you can make your tests run much faster (at the expense of memory management of course). We observed a 30% reduction in the time it takes to run an RSpec test suite. I did try to implement this on Cucumber, however because we need to store much more in memory to set up and tear down our objects, it meant that I kept running out of memory when I wasn't using the default Garbage Collection and the tests took even longer (so, buyer beware). I suppose if you had a small set of features though you might see some benefit.