IPhone Nightly Data Usage -- Culprit found?

http://rephorm.com/thoughts/iphone-nightly-data-usage-culprit-found/

by morpher • 14 years ago

6 4 14 years ago

acqq2• 14 years ago

Short version: It seems that if you: a) don't perform updates of the current apps b) In "Settings" "Store" you enable "Automatic download" of "Apps" and disable "Use Mobile Data" then iPhone still downloads an xml with the list of your apps every minute even if not connected to a WiFi.

This looks like a real, inconvenient bug. The article author's list was 30 KB which still adds up to cca 40 MB daily or 1 GB per month, really too much over the mobile network.

Still, curiosity only, I'd like to see how that xml looks like, or how many appy you have to have to make it 30 KB big.

morpher2• 14 years ago

I have ~60 apps installed. So, hardly a large number. The 30K is actually 83K that has been gzip compressed. The uncompressed file is a plist containing some encoded data. You can see the form at: https://gist.github.com/1855135 But, since I haven't taken the time to dig into decoding the data, and don't know exactly what it contains, I removed it from the posted file.

acqq2• 14 years ago

Thanks! Wow, it looks really inefficient: some binary data are stored in xml (I guess as base64), then xml gzipped which again produces a binary file. Interestingly enough, if the binary data were encrypted, the gzipped size would be bigger like 60 KB and not 30 KB so even when I don't see the data I know that these 80 KB binary values aren't compressed or encrypted.

If you copy only these 80 KB encoded you can easily convert it from base64 to binary with this:

http://ostermiller.org/calc/encode.html

You can copy the encode.html to your computer, then open it there, it's client side javascript so the decoded data stays in your computer.

IPhone Nightly Data Usage -- Culprit found?

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