I’ve got a library up on GitHub, with some of the binaries also distributed on NuGet:
https://github.com/relentless/Http.fs
I’d ignored licencing up until now, but somebody’s asking about it so I though I should put something on. I want to keep it permissive, and having done a little research MIT seems like a good one to use. However, my library references/uses three other libraries, all with different licences, so I’m not quite sure what I need to do.
It includes the binaries of:
- FsUnit, which has it’s own licence (similar to the BSD 3-clause): https://github.com/fsharp/FsUnit/blob/master/license.txt
- NancyFx, which uses MIT: https://github.com/NancyFx/Nancy/blob/master/license.txt
And a source file from:
- FSharpX, which uses Apache 2.0: https://github.com/fsprojects/fsharpx/blob/master/LICENSE.md
The MIT of Nancy doesn’t seem to be a problem. The Apache of fsharpx and the FsUnit one both say I need to include the licence text in my project.
So my questions are:
- What do I do with the other licences, just copy the files into the root of my source? I assume I can rename them and add a comment specifying which part of my project this licence refers to.
- Assuming I go for MIT, could I reasonably describe my project as having an MIT licence? Or is the reality that it’s a mixed MIT/Apache 2.0/Random licence?
The good news is all of the licenses are compatible. The most restrictive being the ASL 2.0 which requires that there are no patents in the library licensed by the ASL. The open source projects I’ve seen that have had multiple licenses for the libraries follow a pattern like this:
- Each license is in a file like this: LICENSE.{library_name}.txt
- If there are a number of different licenses, they are in a folder named LICENSES
So with your library it would look something like this:
/LICENSE.txt
/LICENSE.Fsunit.txt
/LICENSE.NancyFx.txt
/LICENSE.FSharpX.txt
LICENSE.txt would be the license for your project. It’s up to you what license you feel most comfortable with. You would be perfectly fine with the MIT license for your source code.
Also, if the FsUnit library isn’t directly linked to in your library’s distributable, but only used to unit test your code, then you don’t have worry about that license. The only time you need to worry about the license is if the library is being redistributed with your code.
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As none of the libraries has a copyleft license, you are free to choose any license you like for your own library. And if you choose to use the MIT license, then your library is MIT licensed. The fact that you use third-party libraries that have a different license does not affect that.
If you don’t distribute those libraries along with your library, then there are no further considerations. The copyright licenses only come into effect when you distribute the library/program that the license applies to.
If you do distribute the libraries along with yours, then the easiest way to meet the requirements of the licenses is to put a complete copy of each library in a directory of its own (like you have done with your packages directory).
Then you have all the required license files for each of those libraries in your distributing in a place where they are easy to find and associate with the right library.
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