Metadata-Version: 1.1
Name: django_model_helpers
Version: 1.0.2
Summary: Helpful functions and classes for your django app's models
Home-page: https://github.com/rewardz/django_model_helpers
Author: Ramast Magdy
Author-email: ramast.com@gmail.com
License: MIT
Description: Model Helpers
        -------------
        
        Model helpers are small collection of django functions and classes that make working
        with models easier. All functions here are compliant with pylint and has
        test cases with over 95% code coverage. This doc describe each of these
        helpers.
        
        **model\_helpers.upload\_to**
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        
        Pass ``model_helpers.upload_to`` as ``upload_to`` parameter for any
        FileField or ImageField. This will generates random file name and return
        it while keeping the original file extension. each model get its own
        storage folder named after model’s name.
        
        ``upload_to`` function also block files with certain harmful extentions
        like “php” or “py” from being uploaded.
        
        **Sample usage:**
        
        ::
        
            import model_helpers
        
            class Profile(models.model):
                name = CharField(max_length=100)
                picture = ImageField(upload_to=model_helpers.upload_to)
        
        uploaded images for this model will be stored in:
        ``media/Profile/<current_year>/<slugified_original_filename>``.
        
        **Note:** If filename exceeds 40 character, it will be trimmedl.
        
        cached\_model\_property decorator
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        
        ``cached_model_property`` is a decorator for model functions that takes
        no arguments. The decorator convert the function into a property that
        support caching out of the box
        
        **Note**: ``cached_model_property`` is totally different from django’s
        ``cached_property`` the later is not true caching but rather memorizing
        function’s return value.
        
        **Sample usage:**
        
        ::
        
            class Team(models.Model):
                @cached_model_property
                def points(self):
                    # Do complex DB queries
                    return result
                
                @cached_model_property(readonly=False)
                def editable_points(self):
                    # get result
                    return result
        
                @cached_model_property(cache_timeout=1)
                def one_second_cache(self):
                    # get result
                    return result
        
        Now try
        
        ::
        
            team = Team.objects.first()
        
        -  ``team.points`` <– complex DB queries will happen, result will be
           returned
        -  ``team.points`` <– this time result is returned from cache (points
           function is not called
        -  ``del team.points`` <– points value has been removed from cache
        -  ``team.points`` <– complex DB queries will happen, result will be
           returned
        
        **How does it work?**: first time the decorator store the function
        output in the cache with
        ``key = "<model_class>_<instance.pk>_<function_name>"`` so if you have
        two models with same name, or have model that provide no primary key you
        can’t use this decorator.
        
        set ``readonly`` parameter to ``False`` to make the property writeable
        
        ``team.editable_points = 88``
        
        In this case the assigned value will replace the value stored in the
        cache
        
        ``team.editable_points`` returns 88
        
        I personally don’t use the writable cached property option but might be
        useful to someone else
        
           from
        
        to
        
        Choices class *inspired by `Django Choices`_.*
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        
        Dealing with Django’s ``choices`` attribute is a pain. Here is a proper
        way of implementing choice field in Django
        
        ::
        
            class Student(models.Model):
                FRESHMAN = 'FR'
                SOPHOMORE = 'SO'
                JUNIOR = 'JR'
                SENIOR = 'SR'
                YEAR_IN_SCHOOL_CHOICES = (
                    (FRESHMAN, 'Freshman'),
                    (SOPHOMORE, 'Sophomore'),
                    (JUNIOR, 'Junior'),
                    (SENIOR, 'Senior'),
                )
                year_in_school = models.CharField(
                                    max_length=2,
                                    choices=YEAR_IN_SCHOOL_CHOICES,
                                    default=FRESHMAN)
        
        Then you can do
        
        ::
        
            student = Student.objects.first()
            if student.year_in_school == Student.SENIOR:
                  # do some senior stuff
        
        With Choices class this becomes
        
        ::
        
            YEAR_IN_SCHOOL_CHOICES = Choices({
                "freshman": "FR",
                "sophomore": "SO",
                "junior": "JR",
                "Senior": "SR"
            })
        
        
            class Student(models.Model):
                year_in_school = models.CharField(
                                    max_length=2,
                                    choices=YEAR_IN_SCHOOL_CHOICES(),
                                    default=YEAR_IN_SCHOOL_CHOICES.freshman)
        
        Then you can do
        
        ::
        
            student = Student.objects.first()
            if student.year_in_school == YEAR_IN_SCHOOL_CHOICES.senior:
                  # do some senior stuff
        
        ``YEAR_IN_SCHOOL_CHOICES`` is a readonly OrderedDict and you can treat
        it as such. for example: ``YEAR_IN_SCHOOL_CHOICES.keys()`` or
        ``YEAR_IN_SCHOOL_CHOICES.iteritems()``
        
        ``Choices`` class is more flexible because it allow you to specify 3
        values. choice name, choice db value, choice display name. The example
        above can be better written like that
        
        ::
        
             YEAR_IN_SCHOOL_CHOICES = Choices({
                 "freshman": {"id": 0, "display": "New comer"},
                 "sophomore": 1,
                 "junior": 2,
                 "Senior": 3
              }, order_by="id")
        
        
            class Student(models.Model):
                year_in_school = models.SmalllIntegerField(
                                    choices=YEAR_IN_SCHOOL_CHOICES(),
                                    default=YEAR_IN_SCHOOL_CHOICES.freshman)
        
        Then you can do something like this
        
        ::
        
            Student.objects.filter(
                year_in_school__gt=YEAR_IN_SCHOOL_CHOICES.sophomore)
        
        To return all students in grades higher than Sophomore
        
        -  A choice can be defined as key/value ``"sophomore": 1`` in which case
           display name will be code name capitalized ``"Sophomore"`` and will
           be saved in DB as number ``1``
        -  A choice can be fully defined as key/dict
           ``"freshman": {"id": 0, "display": "New comer"}`` in which case
           display name will be ``"New comer"`` and id will be ``0``
        
        Defining extra keys to use in your code.
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        
        As mentioned before ``Choices`` can be treated as an OrderedDictionary
        and so you should feel free to use the free functionality, for example
        adding extra keys
        
        ::
        
                AVAILABLE_SETTINGS = Choices({
                    "max_page_width": {"id": 0, "display": "Maximum page width in pixels", "default": 100})
        
        then in your code you can do
        
        ::
        
            settings = Settings.objects.filter(name=AVAILABLE_SETTINGS.max_page_width).first()
            if settings:
                return settings.value
            return AVAILABLE_SETTINGS["max_page_width"]["default"]
        
        Ordering your ``Choices``
        ^^^^^^^^^^^^^^^^^^^^^^^^^
        
        Assuming you have a big list of choices you might prefer to ask Choices
        class to order them for you.
        
        **Example:**
        
        ::
        
            Choices({
                 "usa": {"display": "United States", "id": 0},
                 "egypt": 1,
                 "uk": {"display": "United Kingdom", "id": 2},
                 "ua": {"display": "Ukraine", "id": 3}
                }, order_by="display")
        
        The fields will be in the order “Egypt”, “Ukraine”, “United Kingdom”,
        “United States”.
        
        ``order_by="id"`` will order the list by id
        
        If you don’t want any sort of ordering then set ``order_by=None`` and in
        this case its better that you pass your choices as tuple of dictionaries
        to maintain order
        
        ::
        
            Choices((
                 ("uk", {"display": "United Kingdom", "id": 2),
                 ("usa", {"display": "United States", "id": 0),
                 ("egypt", 1),
                 ("ua": {"display": "Ukraine", "id": 3})
                ), order_by=None)
        
        **Note:** By default choices are ordered by display name
        
        Useful functions of ``Choices`` class
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        
        -  ``get_display_name``: given choice id, return the display name of
           that id. same as model’s ``get_<field_name>_display()``
        -  ``get_code_name``: Given choice id same as ``get_display_name`` but
           return code name
        -  ``get_value``: Given choice id, return value of any key defined
           inside choice entry
        
        **Example:**
        
        ::
        
            CHOICES_EXAMPLE = Choices({"my_key": {"id": 0, "display": "Display Of My Key", "additional_key": 1234})
            >>> CHOICES_EXAMPLE.get_display_name(0)
            "Display Of My Key"
            >>> CHOICES_EXAMPLE.get_code_name(0)
            "my_key"
            >>> CHOICES_EXAMPLE.get_value(0, "additional_key")
            1234
        
        **model\_helpers.KeyValueField**
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        
        Sometimes you need to have a simple key/value field. most developers
        would rely on ``JsonField`` which is good for some use cases but people
        using django admin may not like to modify json object that look like
        this
        
        ::
        
            {"key1": "value of some sort", "key2": "value containing \" character"}
              
        
        ``KeyValueField`` serialize objects in a more readable way. the
        dictionary above would be stored and displayed like this.
        
        ::
        
            key1 = value of some sort
            key2 = value containing " character
        
        That’s it. For you as a developer you will access your ``KeyValueField``
        as a dictionary.
        
        **Example**:
        
        ::
        
            class MyModel(models.Model):
                 options = KeyValueField(separator=":")
        
            >> my_model.options = "key1 : val1 \n key2 : val2"
            >> my_model.options
            {"key1": "val1", "key2": "val2"}
            >>> str(my_model.options)
            "key1 : val1 \n key2 : val2"
        
        You can find more examples in the test file
        ``tests/test_key_value_field.py``
        
        **``KeyValueField`` is NOT good for:**
        
        -  Maintain original value’s datatype. all values are converted to
           unicode strings
        -  Store a multiline value
        
        
        .. _Django Choices: https://pypi.python.org/pypi/django-choices/
        
        
Keywords: django models keyvaluefield cached_model_property
Platform: UNKNOWN
Classifier: Development Status :: 4 - Beta
Classifier: Intended Audience :: Developers
Classifier: Topic :: Software Development :: Libraries :: Python Modules
Classifier: License :: OSI Approved :: MIT License
Classifier: Programming Language :: Python :: 2
Classifier: Programming Language :: Python :: 2.7
