Develop Reference

Self updating game in java

I'm making a game, in Java, that has these following important features:
1) Connects to a remote Server (which i made), and will check for updates and install them if necessary
2) is NOT A SINGLE .JAR FILE (ie. has multiple .jar's and other things, such as .png, .wav, etc)
3) JAVA WEB START IS NOT AN OPTION, AS I WANT TO MAKE THIS ALL MYSELF
keeping the things above in mind, i have run into a problem. i have no clue how to implement a multiple "patch" update system. currently i have 1 .txt file, that the server reads from, and sends the files listed in the .txt to the client, which then moves them into place. The problem is, that is only useful for maybe 2 updates. I'm looking for a more useful, long term solution, and i need some help. here are some of the things i've thought of:
1) have a zip folder named after each version (problem: how would the client get ALL of the most updated files
2) have a .txt file INSIDE of each jar containing the version (problem: cant do that with png's or wav's, and i dont know how i would read the txt file to begin with)
i really need some help, i've tried googling it, i've thought about it for going on 3 weeks now, and cannot think of anything.
QUESTION: how would i make a game/program update with multiple patches?

Firstly, the best solution by a long, long way is to use Webstart / JNLP.
But if you insist on not using it (for whatever reason then) then it is technically possible. However:
It is messy and complicated.
It will either be very inefficient ('cos you have to load the entire program each time the user), or the user has to trust you enough to install your program with permissions that will allow it to install random stuff on his machine without notice.
The way to do it is to split the game into a launcher part and an application part. The launcher needs permissions to write and delete (non-temporary) files, and fetch stuff from the internet. It "calls home" to find out the latest version(s) of the application files, and then downloads and installs them. It has to cope with all sorts of error conditions, and it needs to make sure that nothing can trick it into installing bad stuff on the user's machine, etcetera, is someone spoofs your update service.
Of course, JNLP takes care of all of this, and lots more besides. People are going to be more willing to install the JNLP infrastructure that yours ... which might be insecure, or actively nasty (for all they know). (I for one wouldn't install a self updating application on my machine unless it was supplied by a company with impeccable credentials.)

I think you need here JNLP framework.
JNLP provides followed things:
allows to user to download jars from server
on launch verifies if application need to update
runs on local JVM
Actually, every java application you can convert to JNLP. Just to sign on all jars that your game contains, create executable jar from your game and create single Web page from where you can download your game

How to sign (dynamic) JNLP files for OSX and Gatekeeper

My company produces Java Applications for Servers and delivers JNLP files to start local Applications. Since OSX 10.8.4 it is required to sign JNLP files with a Developer ID to keep Gatekeeper happy (it's actually in the release notes at the very bottom).
The question is: how to accomplish this? AFAIK you can sign Apps (we have some Java Apps signed with Developer IDs) - but JNLP - Files are just that: files.
Next: how to do this with generated JNLP files. We have to modify them as they come from a server - e.g. properties, base URL and so forth.
AFAIK Java has a certain mechanism to say JNLP files are signed via their respective JAR file (the one that holds the main class) - but: Jar files are signed with a different certificate they will not satisfy Gatekeeper as well.
I did find one reference on how to sign tools and stuff, but it does not apply the scenario of dynamic files.
What I do not want as answers: Right-Click and Open to override the Gatekeeper or change the System- or Java settings. This is not an option.
[UPDATE]
Since OSX 10.9.5 you also have to sign using OSX 10.9+ and have valid version 2 signatures. How will this be done?

I think I found a solution. The only one I can currently think up. We basically need to wrap the JNLP with a custom app launcher, sign the app, make sure we can modify the JNLP on the fly on a server and then have it run.
As you may be aware, there is an app bundler project which can wrap up any JAR files into an OSX executable. This can be signed, delivered and will not fail Gatekeeper. I made a custom fork (which is up for a pull int o the main fork) that can take an JNLP file, wrap it up and you have a custom application doing just all the stuff a JNLP should do.
A Requirement is, however, that you do have a valid "Developer ID Application" certificate
Head over to bitbucket.org and download the current version
Run the ant task and build the appbundler package.
Have a look at the documentation for an example build script that will create the app container.
The example does not include the JNLP into the application right now.
The applications signature is created in a way so that the JNLP file can be modified later.
The application is being put into a zip file. This is important for downloading an application since they are only directories
Create your server code. Load the ZIP file, put the JNLP File into the directory <yourapp>.app/Contents/Java/
Deliver the zip file.
Now, if everything went fine, the zip file should automatically be unpacked in the Download folder and you should see your application icon. If you really made no mistake, you can execute the application as if it was a normal one.
I hope this will help a lot of developers fixing the broken JNLP behavior with OSX.
[UPDATE for modifiable JNLPs]
Since OSX 10.9.5 it is required to have valid version 2 signatures on your app. This means that it the trick that was previously used by the app bundler (set a resource list file) does not work anymore. Everything and anything has to be signed now and it is virtually impossible to change the signed app afterwards.
I did however find a way: Use the app bundler. Set the JNLP to a file inside the Contents/_CodeSignature directory. Do not yet copy your modifiable JNLP in there but do this e.g. using Java later on when patching the zip (you'll need some code here anyway).
Please note: this should really only be needed if you have to put another JNLP file dynamically into the app container (thats is what the questions was about)
UPDATE (08-2017)
Oracle will be releasing Java 9 by the end of September. The appbundler does not handle the java9 vm correctly. They changed a whole lot of the API and the way that javaws works. For I need to say: stick with java8 if you want to use wrapped JNLP apps.

We've been able to determine that you can sign a jnlp file with codesign, using the "Developer ID Application" Certificate, like this:
codesign -f -s "Developer ID Application: " foo.jnlp
The result from this operation seems to pass Gatekeeper on the local machine. However, it seems like the signature gets stored as extended HFS attributes, and as a result, it is not transmitted if a user fetches the file from a HTTP transaction.
It might work if you took the .jnlp file, and packaged it in some kind of container, like a .dmg or maybe a .tar.gz, however, that's both a lot of work, and it provides a fairly challenging user experience.

From an email thread with Apple tech support, it seems the official word is to use the xip tool to work around the reliance on HFS extended attributes with codesign:
Instead of codesign, use xip (pronounced "chip")
to create a signed archive of your JNLP file. Provide your Developer
ID Installer identity as the argument to the --sign option, not your
Developer ID Application identity.
A xip archive is essentially a signed zip archive so it can be served
over the Internet in the same way as a zip archive. It will be
unarchived automatically on the client Mac.
https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man1/xip.1.html
From my experimentation the xip tool always generates an archive with the jnlp contained in a folder when unxip'd.

Just to summarise the discussion; currently there is no existing solution on how to come around this.
This means that end users cannot launch an application via JNLP easily. Basically one needs to tell the user to Right-Click and Open to override the Gatekeeper.
The other solution would be to make an signed Mac application and have users install that via disk image.

Would it work to bundle a simple executable shell script called something like "myapp" in a signed .dmg which looks like this:
javaws http://path/to/my/app.jnlp
that way you can change the .jnlp however you like without changing your .dmg. I don't have an Apple Developer ID, so I can't try it myself right now.

Set write permissions on ProgramData subfolder using JNA

I have a program, written in Java, which originally used its directory in Program Files to write files accessible to all users of this program. This required our users to run as administrator all the time. In an effort to alleviate that, we decided to move files which needed to be written during regular usage to the ProgramData folder using the %ALLUSERSPROFILE% environment variable. Using a subfolder in this directory for our application works great if it is designated as writable during the installation process, which works fine using NSIS.
The problem comes with upgrading existing users. The Java File API provides setWritable but this does not appear to work after testing on development machines. It looks as though the new file API with Java 7 would solve this problem, but with no release date on the horizon I would rather not wait.
It seems the simplest solution would be to use JNA to call the appropriate Windows API call to set this directory writable. Since upgrading the software necessitates admin rights, similar to installing, it should let this change go through fine. However, I'm unsure where to start, having never used JNA before or the Windows API. Suggestions as to which Windows library to load and what functions to call would be appreciated, especially if someone has encountered a similar problem before.

Well, I'm glad you gave some background...You could use JNA, but the easier way would be to execute a call to the command-line utility cacls. It's included by default in Windows XP installations, I believe, so it should do the trick for you. Try Runtime.getRuntime().exec("C:\\Windows\\System32\\cacls.exe"+options)
Check out the documentation here -> http://technet.microsoft.com/en-us/library/bb490872.aspx

I use the follow line:
Runtime.getRuntime().exec( "C:\\Windows\\System32\\icacls.exe \"%ProgramData%\my application" /grant *S-1-5-32-545:(OI)(CI)(W,M)" );
S-1-5-32-545 is the SID for BUILTIN\Users because the name work only on English systems. https://support.microsoft.com/de-de/kb/163846
This give the BUILTIN\Users write access to all files in the given directory independent which user has create it.

Help with IzPack - Creating Java and JNLP One Click Installations

I took the advice I've been given here to look at IzPack to create a JNLP based one click installation for computer illiterate clients who are using a Java desktop application I've created.
Java Web Start Driven Installation
However, I can't seem to find my way around it.
I don't know where to begin and seems the online tutorials are basic "look at the examples" which are themselves pre compiled and not sourced.
I want to create a simple form - be it in JSP or the JNLP install app (preferably JSP and the JNLP should get arguments from the JSP that launches it).
Then when the users click Install, the program installs to the default directory of userappdata with no questions (except for the UAC).
But IzPack seems to be forcing me to use panels and stuff... Not sure I want all of that.
Or maybe....
Hmmm, writing this just gave me an idea, but I'd still like some feedback.
Thanks.

Another approach perhaps?
If all what you need is to allow the user invoke a JAR, then consider using JSmooth to wrap it in an exe file. The exe file knows how to invoke java correctly and prompt the user to download if not present.
We also have used one-jar to wrap multiple jars in a single jar for exactly this purpose.

Cross-platform executable/runtime delivery method

I need assistance finding a delivery method that best fulfills the following requirements:
We wish to deliver a single file to my clients.
Clients should be able to launch this file from the operating system shell - much like running an '.exe' on Windows.
After being launched, the program/script should be able to display a window with HTML content. this may be done using a stand alone program, a runtime or by running within a browser.
We need the ability to embed a resource within the delivered file, such as an mp3 file, which i can later extract programmatically.
Optimally, the solution should run on Windows, Mac and Linux machines. Less than perfect cross-platform interoperability is acceptable, but we want as broad a penetration as possible.
Clients should not need to pre-install anything (unless it is done transparently), pre-configure anything, or approve any thing for this to happen.
For example:
We could use a regular executable file, written in C++ to do this, but it will not be cross-platform.
We could use a sliverlight XAP file, an adobe Flex file or a Java JAR, but internet explorer warns users when local content is launched. In addition these approaches mean that we have less than perfect penetration, even though it is acceptable in these cases.
We could use a python (or equivalent) script, but the installed-base (penetration) of the python interpreter is not good enough.
Using a standard HTML is not enough because of the difficulty of embedding resources in it. Embedding Silverlight XAML or uuencoded content in HTML causes IE to display a warning.
Using something along the lines of a jpeg as a delivery method is not rich enough since we need to display HTML.

..but internet explorer warns users when local content is launched..
I don't get it, what's the problem with IE saying "Hey this app is trying to run your files!"
I don't mean you don't have a good reason for this, it is just, I don't get it.
IE will only warn the user if the app has not been downloaded and try to access local resources, for instance if running from an applet or a JNLP like this one:(click on the first orange button you see )
But if the users download the jar and run it from the computer ( double click on it ) the app is local and can run without problems.
The jar file is a zip file after all, so you can attach your mp3 file with it. Double click is supported in the desired platform, and the HTML content could be either a local file ( un-packed along with the mp3 file ) or an internet web page.
Java is preinstalled on those OS already.

"internet explorer warns users when local content is launched"
There's a reason for this. How can they distinguish your excellent, well-behaved, polite application from a virus?
Since the line between your app and a virus is very, very blurry, go with any of Silverlight XAP file, an adobe Flex file or a Java JAR.
The IE business is a good thing, not a bad thing.

You could try using the 'Jetty' application server.
This supposes there is a working java environment on the target machine.
Jetty is java servlet container but it is possible to configure
everything (web server, html templates, applications, etc.) in a
single executable jar, which launches the web server and opens a default page.
Exactly how the jar file is launched will vary from platform to platform
but otherwise the user interface will be identicle, and, as its a java application
you can do pretty much anything one it has started.

Sounds like MIME HTML does exactly what you want - unfortunately, it is not supported by many browsers other than IE.

I'd investigate Adobe AIR. It can display both HTML and Flex content in a desktop application without using a web browser. However this will require installation of the AIR runtime, also I'm not sure if the Linux version is out of the beta stage.
http://www.adobe.com/products/air/

You can also use a binary for each platform.
As per your description the app is very simple, and porting from one platf to another sounds like just matter of re-compile and offer binary based on the dist.
Is this an option?