Monk
~~~~

An unobtrusive data modeling, manipulation and validation library.

Supports MongoDB out of the box. Can be used for any other DB (or even without one).

Installation
------------

    $  pip install monk

Dependencies
------------

`Monk` is tested against the following versions of Python:

* CPython 2.6, 2.7, 3.2, 3.3
* PyPy 2.0

The MongoDB extension requires `pymongo`.

Documentation
-------------

See the `complete documentation`_ for details. 

.. _complete documentation: http://packages.python.org/monk

Examples
--------

Modeling
........

The schema is defined as a template using native Python data types::

    # we will reuse this structure in examples below

    spec = {
        'title': 'Untitled',
        'comments': [
            { 'author': str,
              'date': datetime.datetime.utcnow,
              'text': str
            }
        ],
    }

You are free to design as complex a document as you need.
The `manipulation` and `validation` functions (described below) support
arbitrary nested structures.

When this "natural" pythonic approach is not sufficient, you can mix it with
a more verbose notation, e.g.::

    title_spec = Rule(datatype=str, default='Untitled', validators=[...])

There are also neat shortcuts::

    spec = {
        'url': optional(str),
        'status': one_of(['new', 'in progress', 'closed']),
        'blob': any_or_none,
        'price': optional(in_range(5, 200)),
    }

By the way, the last one is translated into this one under the hood::

    spec = {
        'price': Rule(datatype=int, optional=True,
                      validators=[monk.validators.validate_range(5, 200)]),
    }

And, yes, you can mix notations.  See FAQ.

This very short intro shows that Monk requires almost **zero learning to
start** and then provides very **powerful tools when you need them**;
you won't have to rewrite the "intuitive" code, only augment complexity
exactly in places where it's inevitable.

Manipulation
............

The schema can be used to create full documents from incomplete data:

.. code-block:: python

    from monk.manipulation import merged

    # default values are set for missing keys

    >>> merge_defaults(spec, {})
    { 'title': 'Untitled',
      'comments': []
    }

    # it's easy to override the defaults

    >>> merge_defaults(spec, {'title': 'Hello'})
    { 'title': 'Hello',
      'comments': []
    }

    # nested lists of dictionaries can be auto-filled, too.
    # by the way, note the date.

    >>> merge_defaults(spec, {'comments': ['author': 'john']})
    { 'title': 'Untitled',
      'comments': [
            { 'author': 'john',
              'date': datetime.datetime(2013, 3, 3, 1, 8, 4, 152113),
              'text': None
            }
        ]
    }

Validation
..........

The same schema can be used to ensure that the document has correct structure
and the values are of correct types:

.. code-block:: python

    from monk.validation import validate

    # correct data: staying silent

    >>> validate(spec, data)

    # a key is missing

    >>> validate(spec, {'title': 'Hello'})
    Traceback (most recent call last):
       ...
    monk.errors.MissingKey: comments

    # a key is missing in a dictionary in a nested list

    >>> validate(spec, {'comments': [{'author': 'john'}]}
    Traceback (most recent call last):
       ...
    monk.errors.MissingKey: comments: #0: date

    # type check; also works with functions and methods (by return value)

    >>> validation.validate(spec, {'title': 123, 'comments': []})
    Traceback (most recent call last):
        ...
    TypeError: title: expected str, got int 123

Custom validators can be used.  Behaviour can be fine-tuned.

The library can be also viewed as a framework for building ODMs
(object-document mappers).  See the MongoDB extension and note how it reuses
mixins provided by DB-agnostic modules.

Here's an example of the MongoDB ODM bundled with Monk::

    from monk.mongo import Document

    class Item(Document):
        structure = dict(text=unicode, slug=unicode)
        indexes = dict(text=None, slug=dict(unique=True))

    # this involves manipulation (inserting missing fields)
    item = Item(text=u'foo', slug=u'bar')

    # this involves validation
    item.save(db)

Links
-----

* `Project home page`_ (Bitbucket)
* `Documentation`_ (Read the Docs)
* `Package distribution`_ (PyPI)
* Questions, requests, bug reports, etc.:

  * `Issue tracker`_
  * Direct e-mail (neithere at gmail com)

.. _project home page: http://bitbucket.org/neithere/monk/
.. _documentation: http://monk.readthedocs.org
.. _package distribution: http://pypi.python.org/pypi/monk
.. _issue tracker: http://bitbucket.org/neithere/monk/issues/

Author
------

Originally written by Andrey Mikhaylenko since 2011.

Please feel free to submit patches, report bugs or request features:

    http://bitbucket.org/neithere/monk/issues/

Licensing
---------

Monk is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published
by the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

Monk is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License
along with Monk.  If not, see <http://gnu.org/licenses/>.
