purl - A simple Python URL class

A simple, immutable URL class with a clean API for interrogation and manipulation. Supports Python 2.6, 2.7, 3.3, 3.4 and pypy.

Also supports template URLs as per RFC 6570

Contents:

Docs
Install
Use
Changelog
Contribute

https://secure.travis-ci.org/codeinthehole/purl.png

Docs

http://purl.readthedocs.org/en/latest/

Install

From PyPI (stable):

$ pip install purl

From Github (unstable):

$ pip install git+git://github.com/codeinthehole/purl.git#egg=purl

Use

Construct:

>>> from purl import URL

# String constructor
>>> from_str = URL('https://www.google.com/search?q=testing')

# Keyword constructor
>>> from_kwargs = URL(scheme='https', host='www.google.com', path='/search', query='q=testing')

# Combine
>>> from_combo = URL('https://www.google.com').path('search').query_param('q', 'testing')

URL objects are immutable - all mutator methods return a new instance.

Interrogate:

>>> u = URL(u'https://www.google.com/search?q=testing')
>>> u.scheme()
u'https'
>>> u.host()
u'www.google.com'
>>> u.domain()
u'www.google.com'
>>> u.username()
>>> u.password()
>>> u.netloc()
u'www.google.com'
>>> u.port()
>>> u.path()
u'/search'
>>> u.query()
u'q=testing'
>>> u.fragment()
u''
>>> u.path_segment(0)
u'search'
>>> u.path_segments()
(u'search',)
>>> u.query_param('q')
u'testing'
>>> u.query_param('q', as_list=True)
[u'testing']
>>> u.query_param('lang', default=u'GB')
u'GB'
>>> u.query_params()
{u'q': [u'testing']}
>>> u.has_query_param('q')
True
>>> u.has_query_params(('q', 'r'))
False
>>> u.subdomains()
[u'www', u'google', u'com']
>>> u.subdomain(0)
u'www'

Note that each accessor method is overloaded to be a mutator method too, similar to the jQuery API. Eg:

>>> u = URL.from_string('https://github.com/codeinthehole')

# Access
>>> u.path_segment(0)
u'codeinthehole'

# Mutate (creates a new instance)
>>> new_url = u.path_segment(0, 'tangentlabs')
>>> new_url is u
False
>>> new_url.path_segment(0)
u'tangentlabs'

Hence, you can build a URL up in steps:

>>> u = URL().scheme('http').domain('www.example.com').path('/some/path').query_param('q', 'search term')
>>> u.as_string()
u'http://www.example.com/some/path?q=search+term'

Along with the above overloaded methods, there is also a add_path_segment method for adding a segment at the end of the current path:

>>> new_url = u.add_path_segment('here')
>>> new_url.as_string()
u'http://www.example.com/some/path/here?q=search+term'

Couple of other things:

Since the URL class is immutable it can be used as a key in a dictionary
It can be pickled and restored
It supports equality operations

URL templates can be used either via a Template class:

>>> from purl import Template
>>> tpl = Template("http://example.com{/list*}")
>>> url = tpl.expand({'list': ['red', 'green', 'blue']})
>>> url.as_string()
u'http://example.com/red/green/blue'

or the expand function:

>>> from purl import expand
>>> expand(u"{/list*}", {'list': ['red', 'green', 'blue']})
u'/red/green/blue'

A wide variety of expansions are possible - refer to the RFC for more details.

Changelog

v1.0.3

Handle some unicode compatibility edge-cases

v1.0.2

Fix template expansion bug with no matching variables being passed in. This ensures purl.Template works correctly with the URLs returned from the Github API.

v1.0.1

Fix bug with special characters in paths not being escaped.

v1.0

Slight tidy up. Document support for PyPy and Python 3.4.

v0.8

Support for RFC 6570 URI templates

v0.7

All internal strings are unicode.
Support for unicode chars in path, fragment, query, auth added.

v0.6

Added append_query_param method
Added remove_query_param method

v0.5

Added support for Python 3.2/3.3 (thanks @pmcnr and @mitchellrj)

v0.4.1

Added API docs
Added to readthedocs.org

v0.4

Modified constructor to accept full URL string as first arg
Added add_path_segment method

v0.3.2

Fixed bug port number in string when using from_string constructor

v0.3.1

Fixed bug with passing lists to query param setter methods

v0.3

Added support for comparison and equality
Added support for pickling
Added __slots__ so instances can be used as keys within dictionaries

Contribute

Clone, create a virtualenv then install purl and the packages required for testing:

$ git clone git@github.com:codeinthehole/purl.git
$ cd purl
$ mkvirtualenv purl  # requires virtualenvwrapper
(purl) $ make

Ensure tests pass using:

(purl) $ ./runtests.sh

or:

$ tox

Hack away.

csdev / purl