如何使用 DRF 串行器处理数据

Question

How can I convert time data (in seconds) to HH:MM:SS form in the DRF serializer? There is a model and a serializer like this.

Model

class Entry(models.Model):
    project = models.ForeignKey(Project,
                                related_name='entries',
                                on_delete=models.CASCADE)
    time = models.IntegerField(default=0)
    user = models.ForeignKey(User,
                             related_name='entries',
                             on_delete=models.CASCADE)
    created_at = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return '%s - %s' % (self.project.name, self.created_at)

Serializer

class EntrySerializer(serializers.ModelSerializer):
    project = ProjectSerializer(read_only=True)
    project_post = serializers.PrimaryKeyRelatedField(
        queryset=Project.objects.all(), write_only=True)
    hms = serializers.SerializerMethodField()

    class Meta:
        model = Entry
        fields = '__all__'

    def create(self, validated_date):
        validated_date['project'] = validated_date.get('project_post', None)
        if validated_date['project'] is None:
            raise serializer.ValidationError("project")
        del validated_date['project_post']
        return Entry.objects.create(**validated_date)

In the case of JavaScript, I was able to convert it with the following code, but how do I do it with the DRF Serializer?

const time = this.state.time + 1;
const hours = parseInt(time / 60 / 60, 10);
const minutes = parseInt(time / 60 % 60, 10);
const seconds = parseInt(time % 60, 10);
this.setState({
    hours: this.toText(hours),
    minutes: this.toText(minutes),
    seconds: this.toText(seconds),
    time: time
});

Answer 1

If request data is in seconds(ex: 1675716401) as below, then it should be doable with python datetime library, if not please specify the format in which datetime is provided and re-format it using strftime [https://strftime.org][1]

 from datetime import datetime
    datetime.fromtimestamp(1675716401).strftime("%H:%M:%S")

In EntrySerializer you can add method as below with needed format

def get_hms(hms):
    return datetime.fromtimestamp(hms).strftime("%H:%M:%S")

Time I have used is Epoch time, so converting exact 84 seconds deosnt make much sense, If you are aware of the date then use relativedelta to adjust time and it mainly depend on how the input you get.

Below is sample to add seconds to current time

from dateutil.relativedelta import relativedelta
from datetime import datetime
datetime.now() + relativedelta(seconds=90)
datetime.datetime(2021, 2, 22, 14, 29, 56, 758793)