=======================================
Installing and Using Python Keyring Lib
=======================================

.. contents:: **Table of Contents**

---------------------------
What is Python keyring lib?
---------------------------

The Python keyring lib provides a easy way to access the system keyring service
from python. It can be used in any application that needs safe password storage.

The keyring library is licensed under both the `MIT license
<http://opensource.org/licenses/MIT>`_ and the PSF license.

The keyring services supported by the Python keyring lib:

* **OSXKeychain**: supports the Keychain service in Mac OS X.
* **KDEKWallet**: supports the KDE's Kwallet service.
* **GnomeKeyring**: for Gnome 2 environment.
* **SecretServiceKeyring**: for newer GNOME and KDE environments.
* **WinVaultKeyring**: supports the Windows Credential Vault

Besides these native password storing services provided by operating systems.
Python keyring lib also provides following build-in keyrings.

* **Win32CryptoKeyring**: for Windows 2k+.
* **CryptedFileKeyring**: a command line interface keyring base on PyCrypto.
* **UncryptedFileKeyring**: a keyring which leaves passwords directly in file.

-------------------------
Installation Instructions
-------------------------

easy_install or pip
===================

Run easy_install or pip::

    $ easy_install keyring
    $ pip install keyring

Source installation
===================

Download the source tarball, and uncompress it, then run the install command::

    $ wget http://pypi.python.org/packages/source/k/keyring/keyring-0.3.tar.gz
    $ tar -xzvf keyring-0.3.tar.gz
    $ cd keyring-0.3
    $ python setup.py install


-------------
Using Keyring
-------------

The basic usage of keyring is pretty simple: just call `keyring.set_password`
and `keyring.get_password`:

    >>> import keyring
    >>> keyring.set_password("system", "username", "password")
    >>> keyring.get_password("system", "username")
    'password'

--------------------------
Configure your keyring lib
--------------------------

The python keyring lib contains implementations for several backends, including
**OSX Keychain**, **Gnome Keyring**, **KDE Kwallet** and etc. The lib will
automatically choose the keyring that is most suitable for your current
environment. You can also specify the keyring you like to be used in the config
file or by calling the ``set_keyring()`` function.

Customize your keyring by config file
=====================================

This section is about how to change your option in the config file.

Config file path
----------------

The configuration of the lib is stored in a file named "keyringrc.cfg". This
file must be found in a platform-specific location. To determine
where the config file is stored, run the following::

    python -c "import keyring.util.platform_; print(keyring.util.platform_.config_root())"

Some keyrings also store the keyring data in the file system. To determine
where the data files are stored, run this command::

    python -c "import keyring.util.platform_; print(keyring.util.platform_.data_root())"


Config file content
-------------------

To specify a keyring backend, you need tell the lib the module name of the
backend, such as ``keyring.backends.OS_X.Keyring``. If the backend is not
shipped
with the lib, in another word, is made by you own, you need also tell the lib
the path of your own backend module. The module name should be written after the
**default-keyring** option, while the module path belongs the **keyring-path**
option.

Here's a sample config file(The full demo can be accessed in the ``demo/keyring.py``):
::

    [backend]
    default-keyring=simplekeyring.SimpleKeyring
    keyring-path=/home/kang/pyworkspace/python-keyring-lib/demo/


Write your own keyring backend
==============================

The interface for the backend is defined by ``keyring.backend.KeyringBackend``.
By extending this base class and implementing the three functions
``supported()``, ``get_password()`` and ``set_password()``, you can easily create
your own backend for keyring lib.

The usage of the three functions:

* ``supported(self)`` : Return if this backend is supported in current
  environment. The returned value can be **0**, **1** , or **-1**. **0** means
  suitable; **1** means recommended and **-1** means this backend is not
  available for current environment.
* ``get_password(self, service, username)`` : Return the stored password for the
  ``username`` of the ``service``.
* ``set_password(self, service, username, password)`` : Store the ``password``
  for ``username`` of the ``service`` in the backend.
* ``delete_password(self, service, username)`` : Delete the stored password for
  the ``username`` of the ``service``.

For an instance, there's the source code of the demo mentioned above. It's a
simple keyring which stores the password directly in memory.

::

    """
    simplekeyring.py

    A simple keyring class for the keyring_demo.py

    Created by Kang Zhang on 2009-07-12
    """
    from keyring.backend import KeyringBackend

    class SimpleKeyring(KeyringBackend):
        """Simple Keyring is a keyring which can store only one
        password in memory.
        """
        def __init__(self):
            self.password = ''

        def supported(self):
            return 0

        def get_password(self, service, username):
            return self.password

        def set_password(self, service, username, password):
            self.password = password
            return 0

        def delete_password(self, service, username):
            self.password = None


Set the keyring in runtime
==========================

Besides setting the backend through the config file, you can also set the
backend to use by calling the api ``set_keyring()``. The backend you passed in
will be used to store the password in your application.

Here's a code snippet from the ``keyringdemo.py``. It shows the usage of
``set_keyring()``
::

    # define a new keyring class which extends the KeyringBackend
    import keyring.backend
    class TestKeyring(keyring.backend.KeyringBackend):
        """A test keyring which always outputs same password
        """
        def supported(self): return 0
        def set_password(self, servicename, username, password): return 0
        def get_password(self, servicename, username):
            return "password from TestKeyring"
        def delete_password(self, servicename, username, password): return 0

    # set the keyring for keyring lib
    import keyring
    keyring.set_keyring(TestKeyring())

    # invoke the keyring lib
    try:
        keyring.set_password("demo-service", "tarek", "passexample")
        print "password stored sucessfully"
    except keyring.backend.PasswordSetError:
        print "failed to store password"
    print "password", keyring.get_password("demo-service", "tarek")


-----------------------------------------------
Integrate the keyring lib with your application
-----------------------------------------------

API interface
=============

The keyring lib has a few functions:

* ``get_keyring()`` : Return the currently-loaded keyring implementation.
* ``get_password(service, username)`` : Returns the password stored in keyring.
  If the password does not exist, it will return None.
* ``set_password(service, username, password)`` : Store the password in the
  keyring.
* ``delete_password(service, username)`` : Delete the password stored in
  keyring. If the password does not exist, it will raise an exception.

Example
=======

Here's an example of using keyring for application authorization. It can be
found in the demo folder of the repository. Note that the faked auth function
only returns true when the password equals to the username.
::

    """
    auth_demo.py

    Created by Kang Zhang 2009-08-14
    """

    import keyring
    import getpass
    import ConfigParser

    def auth(username, password):
        """A faked authorization function.
        """
        return username == password

    def main():
        """This scrip demos how to use keyring facilite the authorization. The
        username is stored in a config named 'auth_demo.cfg'
        """
        # config file init
        config_file = 'auth_demo.cfg'
        config = ConfigParser.SafeConfigParser({
                    'username':'',
                    })
        config.read(config_file)
        if not config.has_section('auth_demo_login'):
            config.add_section('auth_demo_login')

        username = config.get('auth_demo_login','username')
        password = None
        if username != '':
            password = keyring.get_password('auth_demo_login', username)

        if password == None or not auth(username, password):

            while 1:
                username = raw_input("Username:\n")
                password = getpass.getpass("Password:\n")

                if auth(username, password):
                    break
                else:
                    print "Authorization failed."

            # store the username
            config.set('auth_demo_login', 'username', username)
            config.write(open(config_file, 'w'))

            # store the password
            keyring.set_password('auth_demo_login', username, password)

        # the stuff that needs authorization here
        print "Authorization successful."

    if __name__ == "__main__":
        main()

------------
Get involved
------------

Python keyring lib is an open community project and highly welcomes new
contributors.

* Repository: http://bitbucket.org/kang/python-keyring-lib/
* Bug Tracker: http://bitbucket.org/kang/python-keyring-lib/issues/
* Mailing list: http://groups.google.com/group/python-keyring

Running Tests
=============

Tests are `continuously run <https://travis-ci.org/#!/jaraco/keyring>`_ using
Travis-CI.

|BuildStatus|_

.. |BuildStatus| image:: https://secure.travis-ci.org/jaraco/keyring.png
.. _BuildStatus: http://travis-ci.org/jaraco/keyring

To run the tests yourself, you'll want keyring installed to some environment
in which it can be tested. Three recommended techniques are described below.

Using pytest runner
-------------------

Keyring is instrumented with `pytest runner
<https://bitbucket.org/jaraco/pytest-runner>`_. Thus, you may invoke the tests
from any supported Python (with distribute installed) using this command::

    python setup.py ptr

pytest runner will download any unmet dependencies and run the tests using
`pytest <https://bitbucket.org/hpk42/pytest>`_.

This technique is the one used by the Travis-CI script.

Using virtualenv and pytest/nose/unittest2
------------------------------------------

Pytest and Nose are two popular test runners that will discover tests and run
them. Unittest (unittest2 under Python 2.6) also has a mode
to discover tests.

First, however, these test runners typically need a test environment in which
to run. It is recommended that you install keyring to a virtual environment
to avoid interfering with your system environment. For more information, see
the `virtualenv homepage <http://www.virtualenv.org>`_.

After you've created (or designated) your environment, install keyring into
the environment by running::

    python setup.py develop

Then, invoke your favorite test runner, e.g.::

    py.test

or::

    nosetests

Using buildout
--------------

Keyring supplies a buildout.cfg for use with buildout. If you have buildout
installed, tests can be invoked as so::

    1. bin/buildout  # prepare the buildout.
    2. bin/test  # execute the test runner.

For more information about the options that the script provides do execute::

    python bin/test --help

-------
Credits
-------

The project was based on Tarek Ziade's idea in `this post`_. Kang Zhang
initially carried it out as a `Google Summer of Code`_ project, and Tarek
mentored Kang on this project.

.. _this post: http://tarekziade.wordpress.com/2009/03/27/pycon-hallway-session-1-a-keyring-library-for-python/
.. _Google Summer of Code: http://socghop.appspot.com/

See CONTRIBUTORS.txt for a complete list of contributors.

