Swift clearing JSON cache?

Question

I'm working with some API data that gets updated frequently.

I recently discovered that the data does not update properly on the phone, when it's updated on the server.

After hours on hours trying to troubleshoot this, I finally simply tried deleting the app from my phone, and reinstalling in. And it worked.

After some further testing I discovered that it's printing out old JSON.

Once I delete the app and reinstall it, it successfully prints out the correct updated JSON.

From that I gathered that it's probably an issue with the phone caching the old JSON data somehow.

So how can I go about clearing this cache in swift? or forcing it to make a new request.

(I'm using swiftyJson, although I don't think that has anything to do with this specific problem)

I did find one other question like this, but it's old (2014 in Obj-C) and there was no answers.

Here's how I get my data:

        var request = NSURLRequest(URL: formulaAPI!)
        var data = NSURLConnection.sendSynchronousRequest(request, returningResponse: nil, error: nil)
        var formula = JSON(data: data!)

        // Loop through the api data.
        for (index: String, portfolio: JSON) in formula["portfolio"] {



            // Save the data into temporary variables
            tempStockName = portfolio["name"].stringValue
            tempTicker = portfolio["ticker"].stringValue
            tempPurchasePrice = portfolio["purchase_price"].floatValue.roundTo(2)
            tempWeight = portfolio["percentage_weight"].floatValue
            latestAPIPrice = portfolio["latest_price"].floatValue.roundTo(2)
            tempDaysHeld = portfolio["days_owned"].intValue

            // Continues on for quite a while, but the data in the above segment is definitely getting filled with old JSON data, so the issue is arising before this point
}

I tried changing my request to the following:

var request = init(formulaAPI: NSURL, cachePolicy: NSURLRequestCachePolicy, timeoutInterval: NSTimeInterval)

But that causes an error: "Use of local variable 'request' before it's declaration"

Any help figuring this out would be greatly appreciated!

Answer 1

Instead of creating your request with,

NSURLRequest(URL: formulaAPI!) 

you should use the following method so that you can explicitly set the cache policy.

var request = NSURLRequest(URL: formulaAPI!, cachePolicy: .ReloadIgnoringLocalCacheData, timeoutInterval: 30)

NSURLRequest(URL:) uses the default came policy, NSURLRequestUseProtocolCachePolicy, and a time out interval of 60 seconds.