[#46] Changed the fieldtypes.py content to use Django field types instead of sqlalchemy's ones

EditorialModel/fieldtypes.py

@@ -1,190 +1,493 @@
 #-*- coding: utf-8 -*-
 
-from Lodel.utils.mlstring import MlString
-import datetime
 from django.db import models
+import re
+import datetime
+import json
+import importlib
+import copy
+import EditorialModel
+from Lodel.utils.mlstring import MlString
 
 
-##
+## @brief Characterise fields for LeObject and EmComponent
+# This class handles values rules for LeObject and EmComponents.
 #
-# returns an instance of the corresponding EmFieldType class for a given name
+# It allows to EmFieldValue classes family to have rules to cast, validate and save values.
 #
-# @param name str: name of the field type
-# @param kwargs dict: options of the field type
-# @return EmFieldType
-def get_field_type(name):
-    class_name = 'EmField_'+name
-    constructor = globals()[class_name]
-    instance = constructor()
-    return instance
-
-
-##
+# There is exposed methods that allows LeObject and EmType to run a save sequence. This methods are :
+# - EmFieldType.to_value() That cast a value to an EmFieldType internal storage
+# - EmFieldType.is_valid() That indicates wether or not a value is valid
+# - EmFieldType.pre_save() That returns weighted SQL request that must be run before any value save @ref EditorialModel::types::EmType.save_values()
+# - EmFieldType.to_sql() That returns a value that can be inserted in database.
+# - EmFieldType.post_save() That returns weighted SQL request that must be run after any value save @ref EditorialModel::types::EmType.save_values()
 #
-# Generic Field type
-class EmFieldType():
-
+class EmFieldType(object):
+
+    ## Stores options and default value for EmFieldType
+    # options list :
+    # - type (str|None) : if None will make an 'abstract' fieldtype (with no value assignement possible)
+    # - nullable (bool) : tell whether or not a fieldType accept NULL value
+    # - default (mixed) : The default value for a FieldType
+    # - primarykey (bool) : If true the fieldType represent a PK
+    # - autoincrement (bool) : If true the fieldType will be autoincremented
+    # - index (bool) : If true the columns will be indexed in Db
+    # - name (str) : FieldType name
+    # - doc (str) : FieldType documentation
+    # - onupdate (callable) : A callback to call on_update
+    # - valueobject (EmFieldValue or childs) : An object that represent values for this fieldType
+    # - type_* (mixed) : Use to construct an options dictinnary for a type (exemple : type_length => nnewColumn(lenght= [type_lenght VALUE] )) @ref EmFieldSQLType
+    # - validators (list) : List of validator functions to use
+    _opt = {
+        'name': None,
+        'type': None,
+        'nullable': True,
+        'default': None,
+        'primarykey': False,
+        'autoincrement': False,
+        'uniq': False,
+        'index': False,
+        'doc': None,
+        'onupdate': None,
+        'valueobject': None,
+        'validators': None
+    }
+
+    ## Instanciate an EmFieldType
+    # For arguments see @ref EmFieldType::_opt
+    # @see EmFieldType::_opt
     def __init__(self, **kwargs):
-        self.name = kwargs['name'] #TODO gérer le cas où le name n'est pas passé
-        self.value = None
-        self.options = kwargs
-
-    def from_python(self, value):
-        self.value = value
-
-
-##
-#
-# Integer field type
-class EmField_integer(EmFieldType):
-
-    def __init__(self, **kwargs):
-        super(EmField_integer, self).__init__(**kwargs)
-
-    def to_django(self):
-        return models.IntegerField(**self.options)
-
-
-##
-#
-# Boolean field type
-class EmField_boolean(EmFieldType):
-
-    def __init__(self):
-        super(EmField_boolean, self).__init__(**kwargs)
-
-    def to_django(self):
-        if 'nullable' in self.options and self.options['nullable'] == 'true':
-            return models.NullBooleanField(**self.options)
+        self.__init(kwargs)
+        self.type_options = dict()
+
+        # stores all col_* arguments into the self.type_options dictionary
+        args = kwargs.copy()
+        for optname in args:
+            type_opt = re.sub(r'^type_', '', optname)
+            if type_opt != optname:
+                self.type_options[type_opt] = args[optname]
+                del kwargs[optname]
+
+        # checks if the other arguments are valid
+        if len(set(kwargs.keys()) - set(self.__class__._opt.keys())) > 0:
+            badargs = ""
+            for bad in set(kwargs.keys()) - set(self.__class__._opt.keys()):
+                badargs += " " + bad
+            raise TypeError("Unexpected arguments : %s" % badargs)
+
+        # stores other arguments as instance attribute
+        for opt_name in self.__class__._opt:
+            setattr(self, opt_name, (kwargs[opt_name] if opt_name in kwargs else self.__class__._opt[opt_name]))
+
+        # checks type's options valididty
+        if self.type != None:
+            try:
+                EmFieldSQLType.sqlType(self.type, **self.type_options)
+            except TypeError as e:
+                raise e
+
+        # Default value for name
+        if self.name == None:
+            if  self.__class__ == EmFieldType:
+                self.name = 'generic'
+            else:
+                self.name = self.__class__.__name__
+
+        # Default value for doc
+        if self.doc == None:
+            if self.__class__ == EmFieldType:
+                self.doc = 'Abstract generic EmFieldType'
+            else:
+                self.doc = self.__class__.__name__
+
+    ## MUST be called first in each constructor
+    # @todo this solution is not good (look at the __init__ for EmFieldType childs)
+    def __init(self, kwargs):
+        try:
+            self.args_copy
+        except AttributeError:
+            self.args_copy = kwargs.copy()
+
+    @property
+    ## A predicate that indicates whether or not an EmFieldType is "abstract"
+    def is_abstract(self):
+        return (self.type == None)
+
+    ## Returns a copy of the current EmFieldType
+    def copy(self):
+        args = self.args_copy.copy()
+        return self.__class__(**args)
+
+    def dump_opt(self):
+        return json.dumps(self.args_copy)
+
+    @staticmethod
+    ## Return an instance from a classname and options from dump_opt
+    # @param classname str: The EmFieldType class name
+    # @param json_opt str: getted from dump_opt
+    def restore(colname, classname, json_opt):
+        field_type_class = getattr(EditorialModel.fieldtypes, classname)
+        init_opt = json.loads(json_opt)
+        init_opt['name'] = colname
+        return field_type_class(**init_opt)
+
+    ## Return a value object 'driven' by this EmFieldType
+    # @param name str: The column name associated with the value
+    # @param *init_val mixed: If given this will be the initialisation value
+    # @return a EmFieldValue instance
+    # @todo better default value (and bad values) handling
+    def valueObject(self, name, *init_val):
+        if self.valueObject == None:
+            return EmFieldValue(name, self, *init_val)
+        return self.valueObject(name, self, *init_val)
+
+    ## Cast to the correct value
+    # @param v mixed : the value to cast
+    # @return A gently casted value
+    # @throw ValueError if v is innapropriate
+    # @throw NotImplementedError if self is an abstract EmFieldType
+    def to_value(self, v):
+        if self.type == None:
+            raise NotImplemented("This EmFieldType is abstract")
+        if v == None and not self.nullable:
+            raise TypeError("Field not nullable")
+        return v
+
+    ## to_value alias
+    # @param value mixed : the value to cast
+    # @return A casted value
+    def from_string(self, value):
+        return self.to_value(value)
+
+    ## Returns a gently sql forged value
+    # @return A sql forged value
+    # @warning It assumes that the value is correct and comes from an EmFieldValue object
+    def to_sql(self, value):
+        if self.is_abstract:
+            raise NotImplementedError("This EmFieldType is abstract")
+        return True
+
+    ## Returns whether or not a value is valid for this EmFieldType
+    # @note This function always returns True and is here for being overloaded  by child objects
+    # @return A boolean, True if valid else False
+    def is_valid(self, value):
+        if self.is_abstract:
+            raise NotImplementedError("This EmFieldType is abstract")
+        return True
+
+    ## Pre-save actions
+    def pre_save(self):
+        if self.is_abstract:
+            raise NotImplementedError("This EmFieldType is abstract")
+        return []
+
+    ## Post-save actions
+    def post_save(self):
+        if self.is_abstract:
+            raise NotImplementedError("This EmFieldType is abstract")
+        return []
+
+    @classmethod
+    ## Function designed to be called by child class to enforce a type
+    # @param args dict: The kwargs argument of __init__
+    # @param typename str: The typename to enforce
+    # @return The new kwargs to be used
+    # @throw TypeError if type is present is args
+    def _setType(cl, args, typename):
+        return cl._argEnforce(args, 'type', typename, True)
+
+    @classmethod
+    ## Function designed to be called by child's constructo to enforce an argument
+    # @param args dict: The constructor's kwargs
+    # @param argname str: The name of the argument to enforce
+    # @param argval mixed: The value we want to enforce
+    # @param Return a new kwargs
+    # @throw TypeError if type is present is args and exception argument is True
+    def _argEnforce(cl, args, argname, argval, exception=True):
+        if exception and argname in args:
+            raise TypeError("Invalid argument '"+argname+"' for "+cl.__class__.__name__+" __init__")
+        args[argname] = argval
+        return args
+
+    @classmethod
+    ## Function designed to be called by child's constructor to set a default value
+    # @param args dict: The constructor's kwargs
+    # @param argname str: The name of the argument with default value
+    # @param argval mixed : The default value
+    # @return a new kwargs dict
+    def _argDefault(cl, args, argname, argval):
+        if argname not in args:
+            args[argname] = argval
+        return args
+
+class EmFieldValue(object):
+
+    ## Instanciates a EmFieldValue
+    # @param name str : The column name associated with this value
+    # @param fieldtype EmFieldType: The EmFieldType defining the value
+    # @param *value *list: This argument allow to pass a value to set (even None) and to detect if no value given to set to EmFieldType's default value
+    # @throw TypeError if more than 2 arguments given
+    # @throw TypeError if fieldtype is not an EmFieldType
+    # @throw TypeError if fieldtype is an abstract EmFieldType
+    def __init__(self, name, fieldtype, *value):
+        if not isinstance(fieldtype, EmFieldType):
+            raise TypeError("Expected <class EmFieldType> for 'fieldtype' argument, but got : %s instead" % str(type(fieldtype)))
+        if fieldtype.is_abstract:
+            raise TypeError("The given fieldtype in argument is abstract.")
+
+        # This copy ensures that the fieldtype will not change during the value lifecycle
+        super(EmFieldValue, self).__setattr__('fieldtype', fieldtype.copy())
+
+        if len(value) > 1:
+            raise TypeError("Accept only 2 positionnal parameters. %s given." % str(len(value)+1))
+        elif len(value) == 1:
+            self.value = value[0]
         else:
-            return models.BooleanField(**self.options)
-
-##
-#
-# Varchar field type
-class EmField_char(EmFieldType):
+            self.value = fieldtype.default
+
+        # Use this to set value in the constructor
+        setv = super(EmFieldValue, self).__setattr__
+        # This copy makes column attributes accessible easily
+        for attrname in self.fieldtype.__dict__:
+            setv(attrname, getattr(self.fieldtype, attrname))
+
+        # Assign some EmFieldType methods to the value
+        setv('from_python', self.fieldtype.to_value)
+        setv('from_string', self.fieldtype.to_value)
+        #setv('sqlCol', self.fieldtype.sqlCol)
+
+    ## The only writable attribute of EmFieldValue is the value
+    # @param name str: Have to be value
+    # @param value mixed: The value to set
+    # @throw AtrributeError if another attribute than value is to be set
+    # @throw ValueError if self.to_value raises it
+    # @see EmFieldType::to_value()
+    def __setattr__(self, name, value):
+        if name != "value":
+            raise AttributeError("EmFieldValue has only the value property settable")
+        super(EmFieldValue,self).__setattr__('value', self.fieldtype.to_value(value))
+
+        ##
+    # @warning When getting the fieldtype you actually get a copy of it to prevent any modifications !
+    def __getattr__(self, name):
+        if name == 'fieldtype':
+            return self.fieldtype.copy()
+        return super(EmFieldValue, self).__getattribute__(name)
+
+    ## @brief Return a valid SQL value
+    #
+    # Can be used to convert any value (giving one positionnal argument) or to return the current value
+    # @param *value list: If a positionnal argument is given return it and not the instance value
+    # @return A value suitable for sql
+    def to_sql(self, *value):
+        if len(value) > 1:
+            raise TypeError("Excepted 0 or 1 positional argument but got "+str(len(value)))
+        elif len(value) == 1:
+            return self.fieldtype.to_sql(value[0])
+        return self.fieldtype.to_sql(self.value)
+
+class EmFieldSQLType(object):
+    _integer = {'sql': models.IntegerField}
+    _bigint = {'sql': models.BigIntegerField}
+    _smallint = {'sql': models.SmallIntegerField}
+    _boolean = {'sql': models.BooleanField}
+    _nullableboolean = {'sql': models.NullBooleanField}
+    _float = {'sql': models.FloatField}
+    _varchar = {'sql': models.CharField}
+    _text = {'sql': models.TextField}
+    _time = {'sql': models.TimeField}
+    _date = {'sql': models.DateField}
+    _datetime = {'sql': models.DateTimeField}
+
+    _names = {
+        'int': _integer,
+        'integer': _integer,
+        'bigint': _bigint,
+        'smallint': _smallint,
+        'boolean': _boolean,
+        'bool': _boolean,
+        'float': _float,
+        'char': _varchar,
+        'varchar': _varchar,
+        'text': _text,
+        'time': _time,
+        'date': _date,
+        'datetime': _datetime,
+    }
+
+    @classmethod
+    def sqlType(cls, name, **kwargs):
+        if not isinstance(name, str):
+            raise TypeError("Expect <class str>, <class int>|None but got : %s %s" % (str(type(name)), str(type(size))))
+        name = name.lower()
+        if name not in cls._names:
+            raise ValueError("Unknown type '%s'" % name)
+
+        if name in ['boolean','bool'] and kwargs['nullable'] in [1,'true']:
+            sqlclass = _nullableboolean
+        else:
+            sqlclass = cls._names[name]
 
-    def __init__(self, **kwargs):
-        super(EmField_char, self).__init__(**kwargs)
+        if len(kwargs) == 0:
+            return sqlclass['sql']
 
-    def to_django(self):
-        return models.CharField(**self.options)
+        return sqlclass['sql'](**kwargs)
 
 
-##
-#
-# Date field type
-class EmField_date(EmFieldType):
+## @brief Represents values with common arithmetic operations
+class EmFieldValue_int(EmFieldValue):
+    def __int__(self):
+        return self.value
 
-    def __init__(self, **kwargs):
-        super(EmField_date, self).__init__(**kwargs)
+    def __add__(self, other):
+        return self.value + other
 
-    def to_django(self):
-        return models.DateField(**self.options)
+    def __sub__(self, other):
+        return self.value - other
 
+    def __mul__(self, other):
+        return self.value * other
 
-##
-#
-# Text field type
-class EmField_text(EmFieldType):
-    def __init__(self, **kwargs):
-        super(EmField_text, self).__init__(**kwargs)
+    def __div__(self, other):
+        return self.value / other
 
-    def to_django(self):
-        return models.TextField(**self.options)
+    def __mod__(self, other):
+        return self.value % other
 
+    def __iadd__(self, other):
+        self.value = int(self.value + other)
+        return self
 
-##
-#
-# Image field type
-class EmField_image(EmFieldType):
+    def __isub__(self, other):
+        self.value = int(self.value - other)
+        return self
 
-    def __init__(self, **kwargs):
-        super(EmField_image, self).__init__(**kwargs)
+    def __imul__(self, other):
+        self.value = int(self.value * other)
+        return self
 
-    def to_django(self):
-        return models.ImageField(**self.options)
+    def __idiv__(self, other):
+        self.value = int(self.value / other)
+        return self
 
 
-##
-#
-# File field type
-class EmField_file(EmFieldType):
+## @brief Handles integer fields
+# @note Enforcing type to be int
+# @note Default name is 'integer' and default 'valueobject' is EmFieldValue_int
+class EmField_integer(EmFieldType):
 
     def __init__(self, **kwargs):
-        super(EmField_file, self).__init__(**kwargs)
+        self._init(kwargs)
+        # Default name
+        kwargs = self.__class__._argDefault(kwargs, 'name', 'integer')
+        # Default value object
+        kwargs = self.__class__._argDefault(kwargs, 'valueobject', EmFieldValue_int)
+        # Type enforcing
+        kwargs = self.__class__._setType(kwargs, 'int')
+        super(EmField_integer, self).__init__(**kwargs)
 
-    def to_django(self):
-        return models.FileField(**self.options)
+    ##
+    # @todo catch cast error ?
+    def to_sql(self, value):
+        return value
 
+    def to_value(self, value):
+        if value == None:
+            return super(EmField_integer, self).to_value(value)
+        return int(value)
 
-##
-#
-# URL field type
-class EmField_url(EmFieldType):
 
+## @brief Handles boolean fields
+# @note Enforce type to be 'boolean'
+# @note Default name is 'boolean'
+class EmField_boolean(EmFieldType):
     def __init__(self, **kwargs):
-        super(EmField_url, self).__init__(**kwargs)
+        self._init(kwargs)
+        #Default name
+        kwargs = self.__class__._argDefault(kwargs, 'name', 'boolean')
+        #Type enforcing
+        kwargs = self.__class__._setType(kwargs, 'boolean')
+        super(EmField_boolean, self).__init__(**kwargs)
+        pass
 
-    def to_django(self):
-        return models.URLField(**self.options)
+    def to_sql(self, value):
+        return 1 if super(EmField_boolean, self).to_sql(value) else 0
 
+    def to_value(self, value):
+        if value == None:
+            return super(EmField_boolean, self).to_value(value)
+        self.value = bool(value)
+        return self.value
 
-##
-#
-# Email field type
-class EmField_email(EmFieldType):
 
+## @brief Handles string fields
+# @note Enforce type to be (varchar)
+# @note Default 'name' is 'char'
+# @note Default 'type_length' is 76
+class EmField_char(EmFieldType):
+    default_length = 76
     def __init__(self, **kwargs):
-        super(EmField_email, self).__init__(**kwargs)
-
-    def to_django(self):
-        return models.EmailField(**self.options)
+        self._init(kwargs)
+        kwargs = self.__class__._argDefault(kwargs, 'type_length', self.__class__.default_length)
+        kwargs = self.__class__._argDefault(kwargs, 'name', 'char')
+        #Type enforcing
+        kwargs = self.__class__._setType(kwargs, 'varchar')
+        super(EmField_char, self).__init__(**kwargs)
+    def to_sql(self, value):
+        return str(value)
 
 
-##
-#
-# Datetime field type
-class EmField_datetime(EmFieldType):
-
+## @brief Handles date fields
+# @note Enforce type to be 'datetime'
+# @todo rename to EmField_datetime
+# @todo timezones support
+class EmField_date(EmFieldType):
     def __init__(self, **kwargs):
-        super(EmField_datetime, self).__init__(**kwargs)
-
-    def to_django(self):
-        return models.DateTimeField(**self.options)
-
+        self._init(kwargs)
+        kwargs = self.__class__._argDefault(kwargs, 'name', 'date')
+        #Type enforcing
+        kwargs = self.__class__._setType(kwargs, 'datetime')
+        super(EmField_date, self).__init__(**kwargs)
 
-##
-#
-# Time field type
-class EmField_time(EmFieldType):
+    def to_sql(self, value):
+        return value #thanks to sqlalchemy
 
-    def __init__(self, **kwargs):
-        super(EmField_datetime, self).__init__(**kwargs)
+    def to_value(self, value):
+        if value == None:
+            return super(EmField_date, self).to_value(value)
+        if isinstance(value, int):
+            #assume its a timestamp
+            return datetime.fromtimestamp(value)
+        if isinstance(value, datetime.datetime):
+            return value
 
-    def to_django(self):
-        return models.TimeField(**self.options)
 
-
-##
-#
-# mlstring field type
+## @brief Handles strings with translations
 class EmField_mlstring(EmField_char):
 
     def __init__(self, **kwargs):
+        self._init(kwargs)
+        kwargs = self.__class__._argDefault(kwargs, 'name', 'mlstr')
         super(EmField_mlstring, self).__init__(**kwargs)
 
-    def to_django(self):
-        return models.CharField(**self.options)
+    def to_sql(self, value):
+        return value.__str__()
 
+    def to_value(self, value):
+        if value == None:
+            return super(EmField_mlstring, self).to_value(value)
+        if isinstance(value, str):
+            return MlString.load(value)
+        elif isinstance(value, MlString):
+            return value
+        raise TypeError("<class str> or <class MlString> excepted. But got "+str(type(value)))
 
-##
-#
-# Icon field type
-class EmField_icon(EmField_char):
 
+## @brief Handles lodel uid fields
+class EmField_uid(EmField_integer):
     def __init__(self, **kwargs):
-        super(EmField_icon, self).__init__(**kwargs)
+        self._init(kwargs)
+        kwargs = self.__class__._argEnforce(kwargs, 'primarykey', True)
+        super(EmField_uid, self).__init__(**kwargs)
+        pass
 
-    def to_django(self):
-        return models.CharField(**self.options)