license is a Python library providing some metadata about common free software licenses, such as GNU GPL, MIT and others. It is compatible with Python 3.3+ and legacy Python 2.7.
To get a license, you can use SPDX license identifier:
import license
mit = license.find('MIT')
Each license is a static class providing a few properties:
id
- the SPDX identifiername
- a human readable name of the licenserpm
- license identifier used in Fedora, RHEL and CentOS RPMspython
- PyPI classifierurl
- link to a license description or website
mit.python
'License :: OSI Approved :: MIT License'
License classes also offer a static method render()
that will output the entire license text.
Some variables have to be passed to it, usually name
, email
and optional year
(current year is used when omitted).
mit.render(name='Petr Foo', email='[email protected]')
'''The MIT License (MIT)
Copyright (c) 2015 Petr Foo <[email protected]>
Permission is hereby granted... (snip)'''
Some licenses (such as the ones from GPL family) also have a header text, that's supposed to be
added to each source file. header()
is used to render that, but be careful, if the license does
not use special header, AttributeError
is risen.
mit.header(name='Petr Foo', email='[email protected]')
AttributeError: The MIT license uses no header
If you want to search the licenses by some other key, you can:
bsd = license.find_by_key('rpm', 'BSD')
bsd
[license.licenses.BSD3ClauseLicense, license.licenses.BSD2ClauseLicense]
bsd
is now a list, because unlike SPDX identifiers, other keys might not always be unique. If
you only need the first license with such identifier, you can pass multiple=False
to
find_by_key()
:
bsd = license.find_by_key('rpm', 'BSD', multiple=False)
bsd
license.licenses.BSD3ClauseLicense
If such license is not found, you'll get KeyError
instead, the same as with regular find()
.
In case you would like to perform a lot of searches by some key, you can build and index, which should (in theory) make the searches faster (no measurements have been performed).
license.build_index('rpm')
In case you want to get rid of an index, use license.delete_index(key)
. It is safe to call it
even if the index does not exist.
It is also possible to use find_by_function()
to find licenses that match a certain expression.
The function should accept one argument (the license class) and return True if the license is
supposed to be in the results:
osi = license.find_by_function(lambda l: l.python.startswith('License :: OSI Approved :: '))
Again, it returns a list and has multiple
argument to change that.
In case a simple function is not enough, you can iterate over all the license with
license.iter()
:
for cls in license.iter():
# do something
The current license list is in no way much extensive, so maybe your favorite license is not in
there. If you wish to change that, add the license to license/licenses.py
and a template(s) to
license/templates
, and send a pull request on GitHub. See the current licenses to learn how to do it.
A license class looks like this:
class AGPLv3LaterLicense(license.base.License):
'''
GNU Affero General Public License v3.0 or later
'''
id = 'AGPL-3.0+'
rpm = 'AGPLv3+'
python = 'License :: OSI Approved :: GNU Affero General Public License v3 or later (AGPLv3+)'
url = 'http://www.gnu.org/licenses/agpl-3.0.html'
One license can inherit from other and omit the keys that are equal. Note that the docstring is
important and it is used as name
property. License template is named as id
, header template
is named with __header
suffix.
If you wish to add custom licenses in your code, you can do that as well. If you won't use
render()
or header()
, the thing is simple. Just define such class anywhere and call
license.register()
on it.
However, if you would then call render()
or header()
, the template would hove not been
found. In that case, you have to create a Custom Base License with a jinja2
template loader.
CustomBaseLicense = license.base.custom_license_base_class(loader=jinja2.FileSystemLoader('path/to/templates'))
class CustomLicense(CustomBaseLicense):
...
license.register(CustomLicense)
The loader
can be any valid jinja2 loader.
If you wish to register multiple classes at once, you can use license.autoregister()
that will
register all classes present in given module. You will not want to register your
CustomBaseLicense
, so you'll pass it in the ignore
argument.
license.autoregister(sys.modules[__name__], ignore=[CustomBaseLicense])
Note that if you add custom licenses and use license.build_index()
, you want to build the index
after registering them. Calling build_index()
multiple times is safe.
This way, it is easier to inherit data between multiple licenses. The definition of classes is easier maintainable and readable.
Yes, it is, it prints the Python's license. Possibly something you would only use in an interactive
Python console. By importing this library, you are overriding it. We could have named the library
with something cool and unique, such as licenraptor
, but we wanted to make the name as easy as
possible. In case you don't like this, you can always do import license as somethignelse
.
Yes, they are. However all of them are command line utilities and provide no API for Python programmers.