Django management command to load json data of any shape by defining "manifest" that describes mapping instructions.
Python 2.7, 3.4, 3.5 Django >= 1.7
pip install django-loadjson
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.
- model (required) - a string in format "<app_label>.<model_name>"
- 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 stringinteger
- convert to integerboolean
- convert to boolean. Optional, define"invert": true
to invert.datetime
- parse datetime stringrelative_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
ormanifest
requireddata_name
- for regular manifest lookupmanifest
- define manifest right on the spotmany
- 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.
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"
}
}
}
}
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. Extendloadjson.adaptors.BaseAdaptor
to define your custom adaptors. Defaults to None.MODEL_HANDLER
(optional) - a string that references a class that handles model lookups. Defaults toloadjson.adaptors.ModelHandler
FINDER_CLASSES
(optional) - a list of classes that are used to find data. By default loadjson usesloadjson.finders.DefaultDataFinder
that uses definedDATA_DIRS
to find data and manifest.MANIFEST_DEFAULTS
(optional) - a dictionary of default manifest values to use.
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.
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.
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.