Django Rest Framework: Serialize data from nested json fields to plain object
Solution 1
Finally, solution was found in tests of django-rest-framework.
https://github.com/tomchristie/django-rest-framework/blob/master/tests/test_serializer.py#L149
You may easily define nested serializers which will act as a containers and extract data to your plain object. Like so:
class NestedSerializer1(serializers.Serializer):
a = serializers.IntegerField()
b = serializers.IntegerField()
class NestedSerializer2(serializers.Serializer):
c = serializers.IntegerField()
d = serializers.IntegerField()
class TestSerializer(serializers.Serializer):
nested1 = NestedSerializer1(source='*')
nested2 = NestedSerializer2(source='*')
data = {
'nested1': {'a': 1, 'b': 2},
'nested2': {'c': 3, 'd': 4}
}
serializer = TestSerializer(data=self.data)
assert serializer.is_valid()
assert serializer.validated_data == {
'a': 1,
'b': 2,
'c': 3,
'd': 4
}
Solution 2
I would suggest you create your own custom serializer to receive the data. You can do this like so:
from rest_framework import serializers
class MySerializer(serializers.Serializer):
"""
Custom serializer
"""
id = serializers.IntegerField(read_only=True)
name = serializers.CharField()
def create(self, validated_data):
"""Create a new object"""
validated_data['custom_value'] = 0 # you can manipulate and restructure data here if you wish
return MyModel.objects.create(**validated_data)
You can then manipulate the data as you wish in the create()
function. You could also create nested custom serializers to parse this data.
Eugene Lisitsky
Updated on July 02, 2022Comments
-
Eugene Lisitsky almost 2 years
I want to serialize non-flat structure to a one flat object. Here's an example of an API call I receive (I cannot control it unfortunately):
{ "webhookEvent": "jira:issue_updated", "user": { "id": 2434, "name": "Ben", }, "issue": { "id": "33062", "key": "jira-project-key-111", "fields": { "summary": "The week ahead", }, "changelog": { "id": "219580", "items": [{ "field": "status", "fieldtype": "jira", "from": "10127", "fromString": "Submitted", "to": "10128", "toString": "Staged" }] }, "timestamp": 1423234723378 }
I'd like to serialize it to the models like these:
class Issue(models.Model): jira_id = models.IntegerField() jira_id = models.CharField() summary = models.CharField() class Change(models.Model): issue = models.ForeignKey(Issue) timestamp = models.DataTimeField()
As you can see, model
Issue
's fieldsummary
is located on the same object asid
andkey
unlike in JSON data.My Serializer are next:
class ChangeSerializer(serializers.ModelSerializer): """Receives complex data from jira and converts into objects.""" issue = JiraIssueSerializer() timestamp = TimestampField(source='created_at') class Meta: model = Change fields = ('issue', 'timestamp') def create(self, validated_data): super(serializers.ModelSerializer, self).create(validated_data=validated_data) jira_issue = JiraIssueSerializer(data=validated_data) issue = Issue.objects.get(jira_issue) self.created_at = datetime.utcnow() change = Change(**validated_data) return change class JiraIssueSerializer(serializers.ModelSerializer): """Issue serializer.""" id = serializers.IntegerField(source='jira_id') key = serializers.CharField(source='jira_key') summary = serializers.CharField() ### I want field to work! # fields = serializers.DictField(child=serializers.CharField()) class Meta: model = Issue fields = ('id', 'key', 'summary', ) def to_internal_value(self, data): # ret = super(serializers.ModelSerializer, self).to_internal_value(data) ret = {} # ret = super().to_internal_value(data) ret['jira_id'] = data.get('id', None) ret['jira_key'] = data.get('key', None) jira_issue_fields_data = data.get('fields') if jira_issue_fields_data or 1: summary = jira_issue_fields_data.get('summary', None) ret.update(summary=summary) print('to_internal_value', ret) return ret def to_representation(self, instance): ret = {} ret = super().to_representation(instance) fields = {} fields['summary'] = instance.summary ret.update(fields=fields) print(ret) return ret
I works well for fields in
issue
object in JSON. But how can I add to the JiraIssueSerializer some fields likesummary
? They are not direct fields ofissue
object, but located in substrcucturefields
. I see these ways:Make one more Model
Fields
to keep them, but it's ridiculous. I do not need it and my API strictly depends on the foreign structure.Make some
.to_internal_fields()
convertors. But in this case I have to manually validate and prepare all the fields in myIssue
and repeat myself several times. Also If fieldsummary
is not enlisted in Serializer, latter cannot use it or validation fails.Add
DictField
to Serializer (commented in code) and take data from it. Is it good? How to validate it? Again, I have n clean structure of code.
Next I'd like to parse and save changelog data.
How to deal better with such structures?
Thank you!