Impressive stuff to be sure though.

You have done a great job with this demo. I apologize that your comments were hijacked to discuss the merits of open source licensing.

The demo code that reflects the integration between Mapfish/Ext and GE is licensed under a FLOSS license. This allows other developers the freedom to obtain the code, modify it for their usage, and redistribute it. That is what is most important to us. As such, Ext is proud to be associated with the Mapfish project and its community members. Keep up the good work.

How is that relevant? Should I disclose that I am a MapFish user, or a participant in the GeoExt mailing lists? Or that I work on OpenLayers? Is that important to the discussion of whether the use of GeoExt within commercial applications or alongside proprietary applications may be problematic?

Also, considering GeoDjango and MapFish as ‘competitors’ seems odd to me; they do different things well, they don’t compete at the same tasks. This is especially true with regard to the client side developments that this discussion applies to.

Not at all. It would just be impossible to use Javascipt libraries under the terms of anything other than the GPL — which means you need to distribute your software as well. This is exactly the kind of situation the AGPLv3 was designed to create on the server side: The GPL wasn’t considered ‘strong enough’ with many things moving into the ‘cloud’, so the AGPLv3 is designed to require that you share your source code even when you *don’t* ‘distribute’ your application, just make it accessible to people.

The key things that determine aggregation vs. linking, as described by the FSF, are the use of APIs. A comparison from a more sane/well known language setup is whether importing modules in Python is considered mere aggregation. A Python ‘import’ statement is like a <script> tag in Javascript: including a library for use. Then functions provided by this module are callable. Though there is some debate on this topic as well (as with all things legal-related in absence of case law), the general agreement is that this is *not* aggregation, but is linking instead. (Very few modules are licensed GPL — generally speaking, Python is licensed in a permissive manner, following the nature of Python itself.)

Essentially, the way the GPL intends to make this work from a legal perspective is by saying “We copyright our library. By copyrighting our library, we are making a creative work — function names, parameters, etc. are copyrighted. If you use these function names in your code, you are creating a derivative work.” Derivative works are exactly what the GPL intends to cover.

That said, if Ext is encouraging use in this manner — regardless of the GPL — then it doesn’t matter if Ext is GPL licensed or not, because the only people who can legally sue you for violation of their copyright are the copyright owners. As far as I know, Ext is not an open development project, so the copyright owners are Ext, which means that they can make statements about their interpretation of the license, and if you do not expect that interpretation to change, you’re okay… but if you’re commercially dependent on it, it might make sense to ask to get it in writing. (Or just buy a license, which removes any doubt.)

I will point out that if this ever went to a court case, I’m not sure I agree that “importing is linking” would actually be legally accepted in court — but it *is* the position of the GPL proponents I talk to, so my feeling is simply that the GPL interpretations that are in vogue at the moment — based on my understanding of them — would state that this use of Ext is a violation of the GPL, and that even if it’s not, legally speaking, the idea that it could be *is* something that the FSF could want as an option, since they wrote the AGPLv3 specifically to handle making cases like this more clear that you’re limited by the GPL.

Trying to make the argument that Javascript libraries which call each other are “mere aggregation” is simply misleading. The libraries communicate through APIs, are at the very least included in the page together, and sometimes even put together into the same ‘compiled’ file. Aggregation is simply not relevant in this case.

What Aggregation is about is sticking MapFish and proprietary code on the same CD — not about using them together. This is *not* aggregation.

Cedric,

I can’t use the Google Earth plugin on my machine — I don’t think there’s a Linux version yet, anyway. So I can’t comment no that.