django-model-import 0.1.3

Fast CSV imports using django model forms.

# django-model-import

[](https://badge.fury.io/py/django-model-import)

Django Model Import is a light weight CSV importer built for speed.

It uses a standard Django `ModelForm` to parse each row, giving you a familiar API to work with
for data validation and model instantiation. In most cases, if you already have a `ModelForm`
for the `ContentType` you are importing you do not need to create an import specific form.

To present feedback to the end-user running the import you can easily generate a preview
of the imported data by toggling the `commit` parameter.

It also provides some import optimized fields for ForeignKey's, allowing preloading all
possible values, or caching each lookup as it occurs, or looking up a model where multiple
fields are needed to uniquely identify a resource.


## Installation

Standard pip install:

```bash
pip install django-model-import
```


## Quickstart

```python
import djangomodelimport

class BookImporter(ImporterModelForm):
name = forms.CharField()
author = CachedChoiceField(queryset=Author.objects.all(), to_field='name')

class Meta:
model = Book

with default_storage.open('books.csv', 'rb') as fh:
data = fh.read().decode("utf-8")

importer = djangomodelimport.ModelImporter(BookImporter)
preview = importer.process(data, commit=False)
errors = preview.get_errors()

if errors:
print(errors)

results = importer.process(data, commit=True)
for result in results:
print(result.instance)

```


## Composite key lookups

Often a relationship cannot be referenced via a single unique string. For this we can use
a `CachedChoiceField` with a `CompositeLookupWidget`. The widget looks for the values
under the `type` and `variant` columns in the source CSV, and does a unique lookup
with the field names specified in `to_field`, e.g. `queryset.get(type__name=type, name=variant)`.

The results of each `get` are cached internally for the remainder of the import minimising
any database access.

```python
class AssetImporter(ImporterModelForm):
site = djangomodelimport.CachedChoiceField(queryset=Site.objects.active(), to_field='ref')
type = djangomodelimport.CachedChoiceField(queryset=AssetType.objects.filter(is_active=True), to_field='name')
type_variant = djangomodelimport.CachedChoiceField(
queryset=InspectionItemTypeVariant.objects.filter(is_active=True),
required=False,
widget=djangomodelimport.CompositeLookupWidget(source=('type', 'variant')),
to_field=('type__name', 'name'),
)
contractor = djangomodelimport.CachedChoiceField(queryset=Contractor.objects.active(), to_field='name')
```


## Flat related fields

Often you'll have a OneToOneField or just a ForeignKey to another model, but you want to be able to
create/update that other model via this one. You can flatten all of the related model's fields onto
this importer using `FlatRelatedField`.

```python
class ClientImporter(ImporterModelForm):
primary_contact = FlatRelatedField(
queryset=ContactDetails.objects.all(),
fields={
'contact_name': {'to_field': 'name', 'required': True},
'email': {'to_field': 'email'},
'email_cc': {'to_field': 'email_cc'},
'mobile': {'to_field': 'mobile'},
'phone_bh': {'to_field': 'phone_bh'},
'phone_ah': {'to_field': 'phone_ah'},
'fax': {'to_field': 'fax'},
},
)

class Meta:
model = Client
fields = (
'name',
'ref',
'is_active',
'account',

'primary_contact',
)
```