I'm getting started with Objective C and Cocoa on Mac and i would like to develop a app that will have a trial period of 30 days for example like most of the apps have.
How can this be implemented on Mac OSX? Do i store somewhere the installation date and then on each run i check for that? Or what is the general way of achieving this?
That is certainly one way to check the expiry of a trial, but I've found that implementing time based trials can be troublesome when dealing with slightly cleverer users.
If you use a time trial (i.e. 30 days) how do you check the time? You can store the time that the app was installed, and you can read the current time to work out the difference, but how can you guarantee the time(s) you are reading is correct. The user may have edited one or both of these values. (By changing your stored value if it's not encrypted or by changing the system time).
You could use the Internet to verify the time, but what would you do if the user isn't connected to the Internet?
I'm sure there will be more sophisticated ways of checking how long the user has had the program installed, but I'm afraid I can't enlighten you to any.
I'd consider one of the alternatives methods of providing a trial:
Number of times the app has been started - (take into account that your app may crash, or the user may keep the app open). You may wish to count instead, the number of days on which the app has been opened and allow the user to open the app on 15 different days.
Restricted Content - Make a separate target for your app with less content. This is a safer way to ensure that the user can't work around your restrictions, but it's also more work for them to install a separate version. Consider that you may lose some sales.
Related
For my VB.NET applications, I am wanting the user to have a free trial for x amount of days.
Where is the best place to record the amount of days past?
In the registry? Can't someone just delete the registry key, and then have the full x amount of days again?
Is there a better way?
Anything you store on the user machine could be compromised.
If you are serious about this thing then your "best" option is to have a webservice that your apps call at every startup passing some form of identification string.
(And this could be compromised too).
For the purpose to generate an identification string you could look at this question and the following answers
It doesn't matter where you store something on the local machine because it can always be removed.
A user could start up a Virtual PC install your app, and then roll back the virtual PC after 28 days and install again.
One option is to generate a key that is unique to the machine and then verify this with a web service. This is not completely hacker proof but it is better.
You could add some information to any file saved with the trial version of your app which is unique to that specific version of the app (perhaps a timestamp from when it was installed).
When a trial version of your app tries to open a file, it will check this signature and ensure that it was created with that same instance, otherwise refuse to open the file.
This essentially neuters the ability to simply reinstall the app and continue using it.
When creating Metro applications in XAML/C#, how do I detect when the application is first installed or run for the first time since installation (or potentially upgrade)? I need to use this opportunity to ensure that my database schema is correct and potentially synchronise some base data.
I had hoped that I could pick this up from the LaunchActivatedEventArgs within the OnLaunched method, but there does not seem to be a valid value for the Kind or PreviousExecutionState that I can use.
Thanks.
http://msdn.microsoft.com/en-us/library/windows/apps/windows.storage.applicationdata.localsettings.aspx#Y0
When your app starts, write a setting called "AppHasBeenStarted" or something to LocalSettings. If the setting has not already been written, you know your app hasn't been started before. And you could improve on this, by making it "AppVersion", and writing the app's version. This way your app can detect upgrades by comparing the stored version with its own version.
I was wanting to use a file sharing server to keep certain files up-to-date and constant across multiple instances of my application across multiple computers - like (for example) writing a multiplayer game, which stores all the player's positions in a text file, and uses something like Dropbox to keep the text file constant across all the applications, and each application instance can change the file with that application's player's position, and then the rest of the applications can update accordingly. This is only an example, and is not what I intend to do using this technology. What I want to do does not rely on fast sharing of data very quickly - but only periodically downloading and updating the text file.
I was wondering how I might be able to do this using the Dropbox API for Objective-C without prompting the user for any Dropbox username/password - just store a single Dropbox account's login information, log into it automatically and update/download the file stored on it?
From what I have found out from experimenting, Dropbox prompts users for their passwords via a web-broswer, and is designed to accommodate multiple accounts, whereas I only need to accommodate the 'Server' account.
So, is there anyway to do this sort of thing using the Dropbox API, or should I use something else. Or do I need to find out how to write my own server. Using some sort of file sharing API seems a lot easier to me than writing an actual server.
Thanks for any help,
Ben
You might think about using Google App Engine (GAE). I had a similar requirement recently and I'm thinking this is a good option when you want centralized data. Plus you can do the no-browser account login by using your own custom authentication, or I think it's even possible via OAuth? Depends on how sensitive the data is I guess. I just rolled my own.
From my research I found that using Dropbox as a server has some issues with scalability, since you'll be limited to maybe 5,000 calls per day. source It's built on Amazon S3, so you could also look at using that directly.
GAE lifts that limit up to 675,000, but can be increased up to 91 million for free.
https://developers.google.com/appengine/docs/quotas
I did find an open-source project for doing this with Java, alternative you could look at Python example
I've written a daemon that continuously checks for updated files and syncs them. I wrote it for my own file manager iOS app. You can find the implementation here:
https://github.com/H2CO3/MyFile/tree/master/DropboxDaemon
I'm personally not an iOS developer but I came across this question while looking for something else and thought I would offer up another potential solution to the OP's question.
Microsoft just released something called Azure Mobile Services which supports iOS development (among other platforms). It's basically a convenient way to set up a back end system complete with push notifications, authentication, etc. without rolling your own. You don't need to know anything about Azure or servers as the setup process walks you through most of it. It is new so keep that in mind, but it looks promising for situations like this.
Here's a 10 minute video explaining how to use it with an iOS developed app along with links to more documentation:
http://channel9.msdn.com/posts/iOS-Support-in-Windows-Azure-Mobile-Services/
Hope this helps.
I am writing a program in Objective-C (Xcode 3.2, on Snow Leopard) that is capable of either selectively blocking certain sites for a duration or only allow certain sites (and thus block all others) for a duration. The reasoning behind this program is rather simple. I tend to get distracted when I have full internet access, but I do need internet access during my working hours to get to a number of work-related websites. Clearly, this is not a permanent block, but only helps me to focus whenever I find myself wandering a bit too much.
At the moment, I am using a Unix script that is called via AppleScript to obtain Administrator permissions. It then activates a number of ipfw rules and clears those after a specific duration to restore full internet access. Simple and effective, but since I am running as a standard user, it gets cumbersome to enter my administrator password each and every time I want to go "offline". Furthermore, this is a great opportunity to learn to work with XCode and Objective-C. At the moment, everything works as expected, minus the actual blocking. I can add a number of sites in a list, specify whether or not I want to block or allow these websites and I can "start" the blocking by specifying a time until which I want to stay "offline".
However, I find it hard to obtain clear information on how I can run a privileged Unix command from Objective-C. Ideally, I would like to be able to store information with respect to the Administrator account into the Keychain to use these later on, so that I can simply move into "offline" mode with the convenience of clicking a button. Even more ideally, there might be some class in Objective-C with which I can block access to some/all websites for this particular user without needing to rely on privileged Unix commands. A third possibility is in starting this program with root permissions and the reducing the permissions until I need them, but since this is a GUI application that is nested in the menu bar of OS X, the results are rather awkward and getting it to run each and every time with root permission is no easy task.
Anyone who can offer me some pointers or advice? Please, no security-warnings, I am fully aware that what I want to do is a potential security threat.
If you want to do something with admin privileges, and you don't want to have to authenticate each time, it sounds like you need to look at setuid.
Make little command-line executable to do the rule changing, and then set that tool's owner to root. Then, set the setuid bit. Now, you can run it as a user and it will run as root.
Look here for more info:
http://en.wikipedia.org/wiki/Setuid
You have to create a separate process that runs with higher privileges. Have a look at the BetterAuthorizationSample on how to run such helper applications using launchd.
We have our production server running our website. Then we have a test server which has exact same data but with changes to code to do some new functionality. This web app has over 500 pages.
Is there any program that can
Login to the test site
Crawl through each page and then save the page as html
Compare with the same page saved with live site?
This way we can make sure that new features that we add to our test site will not break the live site when code updates are applied to production.
I am currently trying to use WinHTTrack website copier and then comparing the test and live folders with some code comparison tool like beyond compare. This works ok but there are lot of files changed because of the domain name changes.
Looking forward to ideas / solutions for this problem.
Regards
Have you looked at using Watir for this? It's not exactly the thing you are looking for but it might allow you some more granularity in your tests and ensure the site is functionally identical rather than getting caught up on changing guids, timestamps and all the other things that tend to change across any significant size website from day to day as part of it's standard functionality.
Apparently you can't make consistent, reproduceable builds in your project, can you? I would recommend moving towards that in the long run, it will save you a lot of headaches. That way you would know exactly what was deployed to which server when, so there would be no more need to bend around backwards to get the deployed sources back like this...
I know this is not a direct solution to your problem... but maybe it is worth comparing, whether you would save more in the long run by investing the efforts into your build process now, instead of implementing this workaround (and then improving your build process anyway - because one day you will almost surely need to do that).
wget has a --convert-links option, there are also some options to preserve cookies that might let you do it logged in http://drupal.org/node/118759#comment-664498
use an Offline Downloader, download all files to your computer from both sources, then compare the folder contents using a free tool like Total Commander.
EDIT
Load both of your sources into a CVS, and compare it there.