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Description:

djangoloadjson 0.1.2

Django management command to load json data of any shape by defining
“manifest” that describes mapping instructions.

Requirements
Python 2.7, 3.4, 3.5 Django >= 1.7

Installation
pip install django-loadjson

Quick setup
Include loadjson in settings.py
INSTALLED_APPS = [
... ,
'loadjson',
...
]
Define loadjson data directories - a place loadjson will look for data
(.json) files.
LOAD_JSON = {
'DATA_DIRS': [os.path.join(BASE_DIR, 'dumpdata')],
}
Dump all your .json files inside the specified directory(ies).
Each *.json file must also have corresponding *.manifest.json
that describes how the data should be handled. For “manifest” reference,
see Manifest section.
Once the data and manifest is in place, run
python manage.py loadjson <data_name>, where <data_name>
corresponds to the filename of the data (with or without the .json
part).
Note, loadjson will look in all specified directories for the requested
<data_name> and will use the first file it will find. Same goes for the
manifest file. Data file and manifest do not have to live in the same
directory, but both must be in a path of defined “DATA_DIRS”.
It is also possible to handle data and manifest in other ways by
providing custom “finder_classes”. See Advanced Usage for
instructions.

Manifest

model (required) - a string in format “.”
mapping (required) - an object representing the model - data mapping.
parsers (optional) - an object the describes how to parse the data.
Supported types:

string - convert to string
integer - convert to integer
boolean - convert to boolean. Optional, define
"invert": true to invert.
datetime - parse datetime string
relative_key - lookup the relative key by the field value in
another dataset. Required:

data_name - is a data name where related object should be
looked up.
rk_lookup - the field for the lookup in the related dataset
using one key. Ex., “email”.
lookup - overwrite the related data lookup field(s). By
default will use the lookup fields that are defined in data
manifest.
many (optional) - for many-to-many relationship.

relative_object - get/create/update a related object.
data_name or manifest required

data_name - for regular manifest lookup
manifest - define manifest right on the spot
many - one related object or many-to-many relationship.

lookup (required for updates are relative lookups) - a string or a
list of fields to use when looking up an object. Ex., id,
email, ["username", "email"]. Note, lookup fields are used to
lookup an object. The result of a lookup must be one object, so
choose accordingly.
nullable (optional) - a list of fields that are nullable.
m2m_fields (optional) - a list of many-to-many fields. Note, if data
contains many-to-many field, this field should include it, or
alternatively use custom adaptors to handle it, otherwise Django will
throw an error when saving.

Example:
users.json
[
{
"username": "PinkRabbit",
"email": "pink.rabbit@example.com"
"member_since": "",
"active": true,
"not_superuser": true,
"preferences": {
"email_notifications: true,
"number_of_friends": "2"
},
"friends": ["blue.hippo@example.com", "funny.tiger@example.com"],
"badges": [
{
"name": "For being pink",
"date_awarded": ""
},
{
"name": "For being there for friends",
"date_awarded": ""
}
]
},
...
]
users.manifest.json
{
"model": "account.User",
"lookup": "pk",
"mapping": {
"username": "username",
"email": "email",
"date_joined": "member_since",
"active": "active",
"is_superuser": "not_superuser",
"email_notifications": "preferences.email_notifications",
"friends_number": "preferences.number_of_friends",
"friends": "friends",
"badges": "badges"
},
"parsers": {
"is_superuser: {
"type": "boolean",
"invert": true
},
"date_joined": {
"type": "datetime"
},
"friends": {
"type": "relative_key",
"data_name": "users",
"rk_lookup": "email",
"lookup": "username",
"many": true
},
"badges": {
"type": "relative_object",
"many": true,
"manifest" {
"model": "account.Badge"
"mapping": {
"name": "name",
"awarded": "date_awarded"
},
"parsers": {
"awarded": {
"type": "datetime"
}
},
"lookup": "name"
}
}
}
}

LOAD_JSON settings
All loadjson-related settings should go into LOAD_JSON var inside
project’s settings.py.
Possible LOAD_JSON settings:

DATA_DIRS (required) - a list of absolute paths to use by the
default finder to find data and manifest.
ADAPTOR_CLASSES (optional) - a list of classes that are used to
customize the import. Extend loadjson.adaptors.BaseAdaptor to
define your custom adaptors. Defaults to None.
MODEL_HANDLER (optional) - a string that references a class that
handles model lookups. Defaults to loadjson.adaptors.ModelHandler
FINDER_CLASSES (optional) - a list of classes that are used to
find data. By default loadjson uses
loadjson.finders.DefaultDataFinder that uses defined
DATA_DIRS to find data and manifest.
MANIFEST_DEFAULTS (optional) - a dictionary of default manifest
values to use.

Defining ADAPTOR_CLASSES
ADAPTOR_CLASSES are used to further massage the data before saving.
To define Adaptor Class, extend loadjson.adaptors.BaseAdaptor and
overwrite adapt and/or adapt_post_save methods like so:
from loadjson.adaptors import BaseAdaptor

class MyCusomAdaptor(BaseAdaptor):
"""
Available attributes:
- model - model class
- app_model - a string in format <app_label>.<model_name>
- manifest - a dictionary with defined manifest values
"""

def adapt(self, data):
"""
Method provides a base hook to provide additional data, set defaults,
or modify the data before saving.

Usage: what returned gets saved
"""
return data

def adapt_post_save(self, obj, data, m2m_data):
"""
In some cases (like saving many-to-many relations) data might require
some additional tweaks. That is done here.
Note: Many-to-Many objects are attached by default, however in case if many-to-many relationship
is done through a custom model, this method provides a hook to process such customization.
"""
pass
Don’t forget to include your custom adaptors in
LOAD_JSON.ADAPTOR_CLASSES.

Advanced usage

MODEL_HANDLER
Define custom ModelHandle if you want to use custom model manager, or
your same method has any customization. get, create,
get_or_create, update_or_create methods are available for
overwrite.

FINDER_CLASSES
It is also possible to overwrite or extend the default finder classes.
The purpose of the finder class is to lookup the data by data_name.
DefaultDataFinder is a default finder, but can be extended by
defining FINDER_CLASSES in LOAD_JSON settings. Note, if you define
this setting and not include DefaultDataFinder, then it will not be
used, unless you add it explicitly as well.
It is possible to define as many finders as you will, but be aware that
only the first occurrence found will be used.