source: main/waeup.sirp/trunk/src/waeup/sirp/accesscodes/accesscodes.txt @ 5127

:mod:`waeup.sirp.accesscodes.accesscodes` -- access codes (aka PINs)
********************************************************************

.. module:: waeup.sirp.accesscodes.accesscodes

Components that represent access codes and related.

.. :doctest:

About access-codes
==================

Access codes are ids used to grant first-time access to the system for
students.

They are normally not generated by third-party components but always
part of batches.

An access-code consists of three parts::

    APP-12-0123456789
    ^^^ ^^ ^^^^^^^^^^
     A  B  C

where ``A`` tells about the purpose of the code, ``B`` gives the
number of batch the code belongs to (1 to 3 digits), and ``C`` is a
unique random number of 10 digits.

For the generation of the random number :mod:`waeup.sirp` requires a
'urandom' entropy provider which is available with most standard
Unix/Linux systems. This makes the generated numbers relatively
secure, especially when compared with recent PHP-based applications.


AccessCode
==========

.. class:: AccessCode(batch_serial, random_num[,invalidation_date=None[, student_id=None]])

   You normally shouldn't create standalone access-codes. Use
   instances of :class:`AccessCodeBatch` instead as they generate them
   (in masses) and care for them.

   Note, that :class:`AccessCode` instances are not persistent on
   themselves. They have to be stored inside a persistent object (like
   :class:`AccessCodeBatch`) to be kept.

   The class implements
   :mod:`waeup.sirp.accesscodes.interfaces.IAccessCode`:

    >>> from waeup.sirp.accesscodes.interfaces import IAccessCode
    >>> from waeup.sirp.accesscodes.accesscodes import AccessCode
    >>> from zope.interface.verify import verifyClass
    >>> verifyClass(IAccessCode, AccessCode)
    True

   .. attribute:: representation

      The 'full' id of an access-code as described above. Something
      like ``'APP-12-0123456789'``.

      Read-only attribute.

   .. attribute:: batch_serial

      Serial number of this access-code inside the batch.

      .. note:: XXX: Do we really need this?

         Subject to be dropped.

   .. attribute:: student_id

      A string or ``None``. Set when an access-code is
      invalidated. ``None`` by default.

   .. attribute:: batch_prefix

      The prefix of the batch the access-code belongs to.

      Read-only attribute.

   .. attribute:: batch_num

      The number of the batch the access-code belongs to.

      Read-only attribute.

   .. attribute:: cost

      What the access-code costs. A float.

      Read-only attribute.

   .. attribute:: invalidation_date

      Python datetime when the access code was invalidated, or
      ``None``. ``None`` by default.

      Read-only attribute. Only batches are supposed to set this value.

   Access codes that are not part of a batch, will give strange
   representations:

    >>> ac = AccessCode(None, '9999999999', 12.12)
    >>> ac.representation
    '--<10-DIGITS>'


AccessCodeBatch
===============

.. class:: AccessCodeBatch(creation_date, creator, batch_prefix, cost, entry_num, num)

   Create a batch of access-codes.

   :param creation_date: python datetime
   :param creator: creators user id
   :type creator: string
   :param batch_prefix: prefix of this batch
   :param cost: cost per access code
   :type cost: float
   :param entry_num: number of access codes to create
   :param num: number of this batch

   A persistent :class:`grok.Model`. It implements
   :class:`waeup.sirp.accesscodes.interfaces.IAccessCodeBatch`.

   When creating a batch, all entries (access-codes) are generated as
   well.

   .. attribute:: creation_date

      The datetime when the batch was created.

   .. attribute:: creator

      String with user id of the user that generated the batch.

   .. attribute:: cost

      Float representing the costs for a single access-code. All
      entries inside the batch share the same cost.

   .. attribute:: entry_num

      Number of entries (access-codes) inside the batch.

   .. attribute:: invalidated_num

      Number of entries that were already invalidated.

   .. attribute:: prefix

      Prefix of the batch. This tells about the purpose of this batch.

   .. attribute:: num

      Number of this batch. For a certain prefix there can exist
      several batches, which are numbered in increasing order. The
      number is normally computed by the
      :class:`AccessCodeBatchContainer` in which batches are
      stored.

      .. seealso:: :class:`AccessCodeBatchContainer`

   .. method:: entries()

      Get all accesscodes stored in the batch.

      Returns a generator over all stored entries.

   .. method:: getAccessCode(acesscode_id)

      Get the :class:`AccessCode` object for the given
      ``accesscode_id``.

      Certain single access codes can be accessed inside a batch by
      their representation (i.e. something like ``'APP-12-0123456789'``.

      When a code cannot be found :exc:`KeyError` is raised.

   .. method:: addAccessCode(serial_num, random_num)

      Add an access code to the batch.

      ``serial_num`` denotes the serial number of the new access-code
      inside the batch. ``random_num`` is a string of 10 digits unique
      in this batch.

   .. method:: invalidate(ac_id[, student_id=None])

      Invalidate the access-code with ID ``ac_id``.

      Sets also the ``student_id`` attribute of the respective
      :class:`AccessCode` entry.

   .. method:: createCSVLogFile()

      Create a CSV file with data in batch.

      Data will not contain invalidation date nor student ids.  File
      will be created in ``accesscodes`` subdir of data center storage
      path.

      Returns name of created file.

   .. method:: archive()

      Create a CSV file for archive. Archive files contain also
      ``student_id`` and ``invalidation_date``.

      Returns name of created file.


Examples
--------

:class:`AccessCodeBatch` implements :class:`IAccessCodeBatch`:

    >>> from waeup.sirp.accesscodes.interfaces import IAccessCodeBatch
    >>> from waeup.sirp.accesscodes.accesscodes import AccessCodeBatch
    >>> from zope.interface.verify import verifyClass
    >>> verifyClass(IAccessCodeBatch, AccessCodeBatch)
    True

Creating a batch of three access-codes, with a cost of ``12.12`` per
code, the batch prefix ``APP``, batch number ``10``, creator ID
``Fred`` and some arbitrary creation date:

    >>> import datetime
    >>> from waeup.sirp.accesscodes.accesscodes import AccessCodeBatch
    >>> batch = AccessCodeBatch(
    ...   datetime.datetime(2009, 12, 23), 'Fred','APP', 12.12, 3, num=10)

Getting all access-codes from a batch:

    >>> ac_codes = batch.entries()
    >>> ac_codes
    <generator object at 0x...>

    >>> [x.representation for x in ac_codes]
    ['APP-10-<10-DIGITS>', 'APP-10-<10-DIGITS>', 'APP-10-<10-DIGITS>']

    >>> [x for x in batch.entries()]
    [<waeup.sirp...AccessCode object at 0x...>, ...]

Getting a single entry from the batch:

    >>> ac_id = list(batch.entries())[0].representation
    >>> ac = batch.getAccessCode(ac_id)
    >>> ac
    <waeup.sirp...AccessCode object at 0x...>

    >>> ac is list(batch.entries())[0]
    True

Trying to get a single not-existent entry from a batch:

    >>> batch.getAccessCode('blah')
    Traceback (most recent call last):
    ...
    KeyError: 'blah'

Invalidating an entry:

    >>> batch.invalidated_num
    0

    >>> str(ac.invalidation_date), str(ac.student_id)
    ('None', 'None')

    >>> batch.invalidate(ac_id)
    >>> batch.invalidated_num
    1

    >>> ac.invalidation_date , str(ac.student_id)
    (datetime.datetime(...), 'None')

    >>> batch.invalidate(ac_id, 'some_user_id')
    >>> ac.student_id
    'some_user_id'

Access codes get their ``cost`` from the batch they belong to. Note,
that it is advisable to print costs always using a format, as Python
floats are often represented by irritating values:

    >>> ac.cost
    12.119999999999999

    >>> print "%0.2f" % ac.cost
    12.12


AccessCodeBatchContainer
========================

.. class:: AccessCodeBatchContainer()

   A container for access code batches.

   .. method:: addBatch(batch)

      Add a batch in this container.

   .. method:: getNum(prefix)

      Get next unused num for a new batch and a given prefix.

      Batches for a given prefix are numerated. Whenever a new batch
      is created and other batches inside the container already have
      the same prefix, the new one will get the lowest unused number.


Access code plugin
==================

.. class:: AccessCodePlugin

  .. attribute:: grok.implements(IWAeUPSIRPPluggable)
  .. attribute:: grok.name('accesscodes')

  .. method:: setup(site, name, logger)

     Create an accesscodebatch container in ``site``. Any events are
     logged to ``logger``.

  .. method:: update(site, name, logger)

     Check if ``site`` contains an accesscodebatch container and add
     it if missing. Any events are logged to ``logger``.

  The AccessCodePlugin is available as a global named utility for the
  IWAeUPSIRPPluggable interface named ``accesscodes``.

  It is looked up by a university instance when created.

    >>> from zope.component import getUtility
    >>> from waeup.sirp.interfaces import IWAeUPSIRPPluggable
    >>> plugin = getUtility(IWAeUPSIRPPluggable, name='accesscodes')
    >>> plugin
    <waeup.sirp.accesscodes.accesscodes.AccessCodePlugin object at 0x...>

  It provides a `setup()` and an `update()` method. Both have to be
  fed with a site object (the `IUniversity` instance to modify), a
  logger and a name.

  We create a faked site and a logger:

    >>> import logging
    >>> faked_site = dict()
    >>> logger = logging.getLogger('ac_test')
    >>> logger.setLevel(logging.DEBUG)
    >>> ch = logging.FileHandler('ac_tests.log', 'w')
    >>> ch.setLevel(logging.DEBUG)
    >>> logger.addHandler(ch)

  Now we can install our stuff in the faked site:

    >>> plugin.setup(faked_site, 'blah', logger)

  The faked site now has an access code container:

    >>> faked_site.keys()
    ['accesscodes']

  The action is described in the log:

    >>> print open('ac_tests.log', 'r').read()
    Installed container for access code batches.

  We can also update an existing site, by calling `update()`:

    >>> plugin.update(faked_site, 'blah', logger)

  There was nothing to do for the updater:

    >>> print open('ac_tests.log', 'r').read()
    Installed container for access code batches.
    AccessCodePlugin: Updating site at {'accesscodes'...: Nothing to do.

  But if we remove the created batch container and call the updater, it
  will create a new one:

    >>> del faked_site['accesscodes']
    >>> plugin.update(faked_site, 'blah', logger)
    >>> print open('ac_tests.log', 'r').read()
    Installed container for access code batches.
    AccessCodePlugin: Updating site at {'accesscodes'...: Nothing to do.
    Updating site at {}. Installing access codes.
    Installed container for access code batches.

  Clean up:

    >>> import os
    >>> os.unlink('ac_tests.log')