Working with iOS Simulator files

Simulator Data Finder greatly improves my workflow in working and debugging apps in Xcode 6. You can download it here. My apps relies on many downloaded json and xml files, as well as keeping all its data as sqlite files. I use Simulator Data Finder to easily access these files, copy them from one simulator to another or bring into the simulator the files from a device.

Accessing the files

The first use is to access the files, either by the finder or terminal. The terminal is actually quite handy to work with sqlite files and sqlite3 directly, use grep or any kind of other shell tools for old school developers… Simulator Data finder has a clipboard button so when terminal’s tool are not enough, it’s easy to paste the directory and access it from emacs for example.


Copying file between iOS Simulator versions

Another typical use is when you have a lot of files and you want to keep the same setup into a new iOS Simulator version. For example you have everything setup on the iPhone 6 simulator, but want to see how it looks on iPhone 5. Simulator Data Finder makes that a breeze. You can easily choose the two simulators from the table, open the two Documents folder with the finder and copy the files over.

This makes it very easy when a new version of iOS or Xcode comes out to move all the files you need. The older version will be easily accessible and clearly labeled.

If you work across two device simulators, the modified date also lets you see at a glance which of the two simulator has the latest modified files.


Copying file from device to the simulator

The other task that Simulator Data Finder makes easy is to move around of files between the device container and the simulators.

When a developer device is connected, download the application container to your download folder using the standard name. Simulator Data Finder will then present all the container it finds in the Download folder that match the app you have currently selected. If you pop up the finder for the container and for the simulator it becomes very easy to copy files. The containers will also be conveniently sorted with the most recent on the top of the table.


Find the iOS Simulator Document Directory

I really enjoy working with Xcode 6, but it has been quite annoying that the iOS Simulator changes the name of the directory it uses as data container each time you start it. There are a few manual method to find and get to the document container I had been using. I will describe them here. Because my apps tends to use a lot of files in data that I need to check while debugging, I also created a little tool that wraps the manual methods into a very useful (at least to me) and easy workflow. you can download the app here.

Manual logging

The easiest way is to add logging of the directory location on startup. I typically make it conditional to being in the simulator as to no clutter the log in a device. Here is what I typically add to the applicationDidFinishLaunching function.

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
	NSLog(@"Simulator : %@", NSSearchPathForDirectoriesInDomains( NSDocumentDirectory, NSUserDomainMask, YES)[0]);

I then copy from the output of the console the directory and paste it into finder, terminal, emacs or your tool of choice

Simple. Efficient. Tedious

Needle in a haystack

A different approach would be to save a small file in the document directory on start up which then allows you to find that simulator without having to start the app and refer to the console. It would look something like this:

    NSString * __rzSimNeedlePath = NSSearchPathForDirectoriesInDomains( NSDocumentDirectory, NSUserDomainMask, YES)[0];
    [[NSData data] writeToFile:[NSString stringWithFormat:@"%@/.needle", __rzSimNeedlePath] atomically:YES];

If as above you save a file with the app identifier in the name as above, you can then later generically find that directory using a find command and then wrap that into your favourite scripting language

find ~/ -name .needle -print


You can also find a file in the Library of the device directory of a simulator that contains the path of the last container. That file is under the path Library/MobileInstallation/LastLaunchServicesMap.plist. You can then print it using plutil -p LastLaunchServicesMap.plist, the key User contains information about each application in the simulator. Somehow it still seems to be missing some apps, but contains most of them.

Simulator Data Finder

To make my life easier, I built this app that leverages the last two methods to make it easy for you to find your simulators and files. The app can present you with a list of simulators and app as below. It then has a easy access button to finder, copy to clipboard or terminal for the path. It will try to find the directory using the LastLaunchServicesMap.plist file and if it still doesn’t find it, you can download this header file and add the following macro call in your applicationDidFinishLaunching,

You can download the app here. You can read here why I was unable to publish this app in the apple App Store which would have been more convenient.

One added bonus to the app is that it organises for easy access container you’d have downloaded from a device for a given app. It matches them by bundle identifier and currently looks for them in the download directory.

The path to rejection in the apple App Store

I have been developing apps on iOS for quite a while now as a side hobby. The latest Xcode has an ever changing directory for the Xcode simulator, which has been a bit painful to work around, despite a few tricks. So I decided it was a good opportunity for me to get into OS X application development and build a little tool that would let me organise and access files on the simulator for each app work on. I had been always writing my user interfaces fully programmatically so I also decided I would take this opportunity to explore interface builder and storyboard.

The first impression of OS X was that it’s actually not that different, some classes have different names and APIs but it’s remarkably similar. I felt right at home using NSTable. I got the basic of the app working very quickly and it instantaneously proved quite useful to my app development workflow. So much so that decided to share it on the AppStore as a free utility for other developers.

So on I go, paid my $99 to apple to become a Mac registered developer, as until know I only was an ios developer.


First hurdle was that I had to sandbox the application. This meant that access to the terminal via AppleScript stopped working, but most significantly it wasn’t possible to access the simulator directory as it was outside the sandbox. I used the terminal as I wanted the app to let you pop up a finder window or a terminal window on the directory of a selected app.

Not to worry, according to the sandbox guideline you can access any directory as long as the user grant access by showing intent: all I had to do was to bring up a open dialog window on the directory where the simulator reside and once the user pressed ok, the app had access.

For the terminal, once you figure the syntax you could explicitly ask for access to terminal in the entitlement file. Et voila, all the functionality was working again in a sandboxed app.

There was though one major issue. Every time you pop up the open dialog, it would pop up a new duplicate window. It was really annoying and drove me nuts for a while. Without sandboxing it was all working fine, as soon as you turned on sandboxing that duplicate window kept coming up. I searched in the development forums, documentation, etc. I didn’t find any solution or mention of that problem. So I filed a bug report (easy to reproduce the problem with a very simple project) and used one of my support tickets (you get two as a registered developer) to ask an apple engineer for help.

Almost two weeks later I got the answer from apple. It is a bug on apple side, to solve it I should not use storyboard… Great. So I refactored all my code to use an xib file instead of storyboard and now it worked!

First Submission

Feeling all set to go, I purchased an icon on shutterstock, quickly added some help and documentation to the app and submitted it to the Apple Store for review. One week later, I got my first rejection. I so far never received a rejection for my iOS app, so it was quite disappointing. The feedback was that I used entitlement that I shouldnt.

I figured this must have been the access to terminal. Even though it seemed to use the standard method to request entitlement, I had always been a bit worried in the back of my mind that accessing terminal could be a security issue because it would let you execute potentially damaging commands.

It made sense and I removed that functionality and resubmitted the app. One week later another rejection with the same reason. You can’t be serious! Actually it was: silly me I had resubmitted the app without selecting the new binary, so they reviewed the same app I had submitted the first time. Another week wasted.

Final Rejection

I carefully selected the updated binary and resubmitted the app.

Almost two weeks later the app goes into review. There are typically two stages in a review: waiting for review, that in my previous experience takes a few days to a week, then it becomes in review, which takes a few hours to a day or two. Nice, I felt hopefully it will go through soon…

Not so fast. A few days pass. Then a week. Still in review. I almost forgot about it when after over three weeks, I start to wonder. Did something happen? I did some research on the Internet, app review times gives some average days to review of 8 or 9 days. I am way beyond… After a month of being in review I write to apple asking if there is any information they need from me to review the app. The answer comes quickly: no information needed, they are still reviewing the app and just had to be patient.

After more than once month I just received the final rejection. The app is rejected because “I am modifying user file in a way that is not publicly documented”. I am not modifying any file in the app! But it then hits me: apple just does not want me to write this app.

I write a last appeal to the reviewer: I do not modifying any file in my app, only bring up a finder window on a directory after the user has granted access and showed intent by clicking Authorize on an open dialog box. The final answer from the reviewer: we just don’t want app to access simulator files.

Here we go. Hard to not feel a bit of frustration and disappointment, almost three months after starting the app. I still believe this app is really useful and became an important part of my debugging workflow. So I put a bit of wrap around and made it available to download via this website and hope others will find it useful as well.