Understanding GNL Public License with Opencart

Hello first of all, love Opencart great software. I love it so much, I want to use Opencart as a part of a commercial product I gonna develop. I've a read the cryptic GNU license a couple of times and I have still some questions about its usage. The GNU license says I have to share any modified work that I perform, thats clear to me and understandable. I am gonna break the program in 3 seperate parts.

1. Front-end (Catalog)
2. Back-end (Admin)
3. Database

I will modify the Back-end and use the same Database as Opencart. Ofcourse I will share these under the GNU license. I will replace the Catalog folder (Front-end) with my custom made routing and templating system. This system I don't want to share under the GNU license, but because I use a database thats under the GNU license will it cause problems?

And if I use the same langauge files as Opencart with my custom front-end system, do I need publish the custom front-end system under a GNU license because its uses GNU licensed code(the language files)? Or only the language files?

Hope its a bit clear what I am asking.

George

If you use any part of opencart all of the resulting program will have to be released under the GPL.

Ok, but why do paid modules exist ? If you say is true, all extensions etc. has to be released with the GNU license.

I believed they are released under the GNU license, but that does not mean the need to be Free *gratis*

But that means you don't have to buy any of the paid extensions, you only have to ask for the source code(requirement GNU license). That make no sense at all for me I know software under the GNU license doens't have to be free(you can ask money for installation and customization etc.), but you must provide the "modified" source code when asked for it.

I have read this article (IP expert).
http://www.iusmentis.com/computerprogra ... xedsource/

it basicly says if you have a good seperated software architecture you can mix open- with closed source.

George Mason wrote:But that means you don't have to buy any of the paid extensions, you only have to ask for the source code(requirement GNU license). That make no sense at all for me I know software under the GNU license doens't have to be free(you can ask money for installation and customization etc.), but you must provide the "modified" source code when asked for it.

I have read this article (IP expert).
http://www.iusmentis.com/computerprogra ... xedsource/

it basicly says if you have a good seperated software architecture you can mix open- with closed source.

actually you only have to provide the modified source when asked for it if you have distributed it to the person asking. So you can charge for mods whatever, but if that person asks for the source code you have to provide it to them under the terms of the license, and the big rub they can then distribute it modified or unmodified however they wish for free/pay whatever.

and of course we're only talking about the GPL here. there are many open source licenses some of which do allow you to modify without giving away the source, or in the case of libraries the LGPL allows you to build programs based on the libraries without having to give away the source.

What is the exact license of opencart?
There are no code comments ...

I don't think mods have to be GPL.. You do have to interface with the opencart GPL system, but aside from the general required structure, the code itself is yours. Just like Windows is a commercial system but software of all license types can run on it.

Qphoria wrote:I don't think mods have to be GPL.. You do have to interface with the opencart GPL system, but aside from the general required structure, the code itself is yours. Just like Windows is a commercial system but software of all license types can run on it.

well there are several views on this, but In the case of opencart since most usefull mods actually have to change the core code I don't really see how you could possibly say that they don't have to be GPL and are not derivative works. Even if there were a more robust observer/hook system in place there are still arguments that any mods would fall under GPL just have a look at the wordpress/thesis controversy.

?

I still don't get it. Since opencart is available on googlecode would that mean it is GPL/BSD/MIT ... etc ...
Would like to know which license opencart is under.
At the moment, I'm asking so that I can properly release mods/extensions/code.

* I am not a lawyer .... (take only as personal understanding)
As for mods/extensions, from my understanding, normally you are supposed to release under the same license if you derive your code from the main source code. ie, like the extension I just finished the other day. I copied the information module. Then I'd be required to release it under the same license that opencart uses. However, IF I were to create code on my own that hooks into the main code, I'd be still required to go with the same license however, I think that in this situation I could refuse opencart the ability to request my code. lolo I could be wrong about this non-derivative code.

opencart is GPL I don't see how you are having such a hard time figuring it out. You obviously downloaded opencart and there is a license.txt file with the download.

Ooops, you are right. I moved the file to the installation directory.

Does a file work just like having all files use header declarations?

Sorry if this has been discussed many times, but please correct me if I am wrong:
As long as the module/extension author provides you the source code of the module that you have to paste into existing OpenCart code, you are free to do whatever with the module (including resell, publish freely, modify, use everywhere).

This means that the license that comes with the module is completely useless, as it goes against GPL (except for not stating the original author):
By purchasing extensions / templates you agree to:

Use it for one website ONLY (sub-domains act as separate website), unless stated by the original developer. Written approval (or attached terms of use) must be obtained from the original owner of the work prior to the re-using.

Reselling the downloaded work is NOT ALLOWED, unless stated by the original developer. Written approval (or attached terms of use) must be obtained from the original owner of the work prior the reselling.

Copyrights removal is NOT ALLOWED, unless stated by the original developer. Written approval (or attached terms of use must) must be obtained from the original owner of the work prior to the removal.

Can't claim the downloaded work as your own, please respect the effort and time spent to accomplish this work.

In case of a defaulted downloaded work, you have the right to claim a full refund. Opencart team's verification must be in place prior to any refund action.

Note: vQmod is probably a bit different as I understand, as you don't modify the original source code as is subject to debate.

indre1 wrote:Sorry if this has been discussed many times, but please correct me if I am wrong:
As long as the module/extension author provides you the source code of the module that you have to paste into existing OpenCart code, you are free to do whatever with the module (including resell, publish freely, modify, use everywhere).

That is correct!

indre1 wrote:This means that the license that comes with the module is completely useless, as it goes against GPL (except for not stating the original author):
By purchasing extensions / templates you agree to:

Use it for one website ONLY (sub-domains act as separate website), unless stated by the original developer. Written approval (or attached terms of use) must be obtained from the original owner of the work prior to the re-using.

Reselling the downloaded work is NOT ALLOWED, unless stated by the original developer. Written approval (or attached terms of use) must be obtained from the original owner of the work prior the reselling.

Copyrights removal is NOT ALLOWED, unless stated by the original developer. Written approval (or attached terms of use must) must be obtained from the original owner of the work prior to the removal.

Can't claim the downloaded work as your own, please respect the effort and time spent to accomplish this work.

In case of a defaulted downloaded work, you have the right to claim a full refund. Opencart team's verification must be in place prior to any refund action.

Note: vQmod is probably a bit different as I understand, as you don't modify the original source code as is subject to debate.

Let me take these points one by one.
You cannot legally restrict a user who downloads a product to only install ONE copy of the extension per domain. The code author can ask, but cannot legally hold you to it if it's a GNU GPL licensed product.

Reselling - the GNU GPL gives you the right to resell and redistribute in any way you see fit provided you do so using the same GNU GPL license and adhere to the license yourself. It is generally considered to be NOT in accordance with the GPL if you simply sell the software for a specific price, instead you sell the software to cover bandwidth and other miscellaneous costs.

Removal of in-file copyrights is NOT permitted. The only person allowed to remove in-file copyrights is the code author and he can only remove references to himself. The exception to this is if you bought the full rights to the software and the original author has handed you all rights to the software. What the original author can NOT do is sell you a copy of the software under a different license so you can remove the copyrights.

If you modify the original source code, you are entitled to call the work your own. This is known as 'forking' or 'a derivative work'. You still have to retain the original in-file copyrights and re-distribute your 'fork' under the same license.

There is a very simple test you can apply to see if your product falls under the GNU GPL license. Assuming the main software is GNU GPL licensed, if your products requires the original software to run, then it is GNU GPL. In the case of Open Cart, if third party code requires Open Cart for it to work, the the third party code is consumed under the GNU GPL.

Theme developers have yet to figure this out yet BUT if you are a theme developer and your developing themes for a GNU GPL project like OC, you sell the theme code in one zip package. Since it requires Open Cart to work it is consumed by the GNU GPL. If you put your images in a seperate zip package, your images are NOT consumed by the GNU GPL (since images do not require OC to work) and you can atleast legally enforce copyright ownership on your images (assuming you created them yourself).

I forgot about vQMod. I am not familiar with it but the same test applies. If it requires OC for it to work, then it gets consumed by the GNU GPL.

It does actually state in the GPL what the term "free" means.

When we speak of free software, we are referring to freedom, not price. Our General Public Licenses are designed to make sure that you have the freedom to distribute copies of free software (and charge for them if you wish), that you receive source code or can get it if you want it, that you can change the software or use pieces of it in new free programs, and that you know you can do these things.

Step 1 of the OpenCart installation process requires that you accept the terms of this licence. Perhaps you should actually read it!

GPL implies that a derivative work is one that is linked, statically or dynamically, with the original work.

All modules use OC routines, so they are linked to original work, which further implies that all modules, commercial or free, are also bound with original GPL of OpenCart. This excludes any CSS or images included with the module, because those can be viewed (executed in browser) without having OpenCart.

This further means that you can do whatever you want with all modules (regardless if you paid for it or not), as long as you keep the original license intact.

You can modify it in any way you want, give it away modified/unmodified, you can even charge for it if you want.

Though technically then if you write your mods to link to stand alone class files that are only included and not dependent on opencart, that part of the mod wouldnt be allowed to be reused as it isn't part off the opencart subroutine.

True, but then you would need to rewrite all OC routines from scratch (product handling, user handling or whatever data that custom module works with), as you would not be able to use none of the routines defined in OC core, which would end up being a pretty time consuming module to write

edit
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Thinking a bit more about this brings to the conclusion that even if you write your own handling methods (which would need to be pretty generic to be able to handle specific classes OC uses) and then include that new class, you would not be able to release such a module without breaking the GPL because you would still be working with the data the original program provides.

Sources

http://www.gnu.org/licenses/gpl-faq.html#GPLAndPlugins
http://www.gnu.org/licenses/gpl-faq.htm ... GPLPlugins

As said there (last paragraph of the second link)

Using shared memory to communicate with complex data structures is pretty much equivalent to dynamic linking.

It is all a bit shady, because they also mention it is a "borderline case", but no details are given on how to determine what is "communication with complex data structures", nor what those "data structures" are.

The paid module license breaks the GPL.

IMO, Opencart should be licensed under LPGL.

GPL is like a virus. It doesn't give you real freedom. One line of GPL'd code will "infect" your entire project (you HAVE TO release ALL the code under GPL too). So, it's not really "free".

If you use a custom (modified) version of opencart and your competitor asks for the source code, you HAVE TO give it to him.

LGPL is perfect for opencart. If you modify the core, you have to give away the source. But if you want to develop some paid modules and don't want to allow your customers to give it for free (throwing into the trash all your hard work), you are free to do so.

ps.: sorry my english