Lightweight solution to build / handle Package URLs

Current type Support:

• GitHub
• Gitlab
• BitBucket
• PyPi
• npm
• Ruby Gem

Main concepts:

The definition for each component is:

scheme

this is the URL scheme with the constant value of "pkg". One of the 
primary reason for this single scheme is to facilitate the future official 
registration of the "pkg" scheme for package URLs. Required.

type (required)

the package "type" or package "protocol" such as github, bitbucket, 
maven, npm, nuget, gem, pypi, etc.

namespace

some name prefix such as a Maven groupid, a Docker image owner, a GitHub user 
or organization. Optional and type-specific.

name (required)

the name of the package.

version (optional)

the version of the package.

qualifiers (optional)

extra qualifying data for a package such as an OS, architecture, a distro, etc. 
Type-specific.

subpath (optional)

extra subpath within a package, relative to the package root.

How to Use:

# install the package
$ cd pypurl/
$ pip install -e .


# enter interpreter mode
$ python


# import main module
>>> from pypurl.purl import Purl
>>> p = Purl()


# parse the Download URL to dictionary
>>> p.durl_to_dict('https://github.com/vBarbaros/pypurl/archive/refs/heads/main.zip')
{'scheme': 'pkg', 'type': 'github', 'namespace': 'vBarbaros', 'name': 'pypurl'}


# obtain the PURL from the Download URL only
>>> durl = 'https://github.com/vBarbaros/pypurl/archive/refs/heads/main.zip'
>>> p.durl_to_purl(durl)
'pkg:github/vBarbaros/pypurl'


# obtain the PURL from the Download URL + version number/hash-commit
>>> durl = 'https://github.com/vBarbaros/pypurl/archive/refs/heads/main.zip'
>>> p.durl_to_purl(durl, '244fd47e07d1004f0aed9c')
'pkg:github/vBarbaros/pypurl@244fd47e07d1004f0aed9c'


# obtain the PURL from the Download URL + version number/hash-commit + qualifiers
>>> p.durl_to_purl(durl, '244fd47e07d1004f0aed9c', 'param1=one&param2=two&param3=three')
'pkg:github/vBarbaros/pypurl@244fd47e07d1004f0aed9c?param1=one&param2=two&param3=three'


# obtain the PURL from the Download URL + version number/hash-commit + qualifiers + subpath
>>> p.durl_to_purl(durl, '244fd47e07d1004f0aed9c', 'param1=one&param2=two&param3=three', 'some/dummy/path')
'pkg:github/vBarbaros/pypurl@244fd47e07d1004f0aed9c?param1=one&param2=two&param3=three#some/dummy/path'


# parse the PURL containing main fields (+ version) to dictionary
>>> purl = 'pkg:github/vBarbaros/pypurl@244fd47e07d1004f0aed9c'
>>> p.purl_to_dict(purl)
{'scheme': 'pkg', 'type': 'github', 'namespace': 'vBarbaros', 'name': 'pypurl', 'version': '244fd47e07d1004f0aed9c'}


# parse the PURL containing all possible fields, to dictionary
>>> purl = 'pkg:github/vBarbaros/pypurl@244fd47e07d1004f0aed9c?param1=one&param2=two&param3=three#some/dummy/path'
>>> p.purl_to_dict(purl)
{'scheme': 'pkg', 'type': 'github', 'namespace': 'vBarbaros', 'name': 'pypurl', 'version': '244fd47e07d1004f0aed9c', 'qualifiers': 'param1=one&param2=two&param3=three', 'subpath': 'some/dummy/path'}

Install:

$ cd pypurl 
$ pip install -e .

Run Tests:

$ python -m unittest tests/*.py

# Expected output
...
Ran 163 tests in 0.006s

OK

Credits

While this module represents a simple exercise of mine based on some struggles I heard of people having when working with PURLs, the purl-specs page helped me define the roadmap of this module

TODO

• add support for other repositories, besides the currently implemented (GitHub, Gitlab, BitBucket, PyPi, npm, RubyGem)

License

MIT © Victor Barbaros, 2021