Example

It’s as easy as instantiating the FieldsIterator class with your model, and then iterate:

from django_fields_iterator import FieldsIterator

iterator = FieldsIterator(MyModel)

for field, name, field_type in iterator:
    do_stuff()

The field is the real Field object from django. The name is the attribute name to access this name from an instance the field type is one of FieldTypes object, as defined later in this document.

Excluding fields by name

If you don’t want some fields to be returned, you can do it by passing the ignore_fields to the FieldsIterator constructor:

iterator = FieldsIterator(MyModel, ignore_fields=['afield', 'anotherfield'])

Excluding fields by type

Some times you don’t want some fields, for example, to exclude the ManyToManyField:

from django_fields_iterator import FieldsIterator, FieldTypes

iterator = FieldsIterator(MyModel)

for field, name, field_type in iterator.iter_fields(exclude=[FieldTypes.M2M]):
    do_stuff()

The exclude argument is a list that can be empty, or a combination of the following:

• FieldTypes.SIMPLE: For simple fields
• FieldTypes.FK: For foreign keys (and one to one fields)
• FieldTypes.M2M: For many to many fields
• FieldTypes.REVERSE_FK: For reverse foreign keys, ie foreign keys defined on another model, pointing on the model we use
• FieldTypes.REVERSE_M2M: For reverse many to many fields, ie many to many fields defined on another model, pointing on the model we use
• FieldTypes.REVERSE_O2O: For reverse one to one fields, ie one to one fields defined on another model, pointing on the model we use

Including only some field types

The iter_fields method also accepts a only argument, accepting the same kind of value than the exclude argument. Both arguments cannot be set at the same time.

If for example you only want simple fields:

from django_fields_iterator import FieldsIterator, FieldTypes

iterator = FieldsIterator(MyModel)

for field, name, field_type in iterator.iter_fields(only=[FieldTypes.SIMPLE]):
    do_stuff()

Iterating fields for a specific type

The FieldsIterator class provides methods to iterate on fields of a certain type:

• iter_simple_fields, for fields of type FieldTypes.SIMPLE
• iter_foreign_keys, for fields of type FieldTypes.FK
• iter_manytomany_fields, for fields of type FieldTypes.M2M
• iter_reverse_foreign_keys, for fields of type FieldTypes.REVERSE_FK
• iter_reverse_manytomany_fields, for fields of type FieldTypes.REVERSE_M2M
• iter_reverse_onetoone_fields, for fields of type FieldTypes.REVERSE_O2O

Overriding

The FieldsIterator provides two methods that are great to override to avoid some fields to be returned, based on their class for example:

• can_return_field: for fields directly defined on the model
• can_return_reverse_field: for fields defined on another model that point to the current one

They simple accept the field (as returned by the get_fields django method on the model _meta attribute) and the field type (maybe useful in subclasses), and should return a boolean.

They simply check if the field name (the accessor name for the reverse fields) is in the ignore_fields attribute, but can be overridden to add more logic.