Module shortner.models

Models module deals with models representing entities in the application

"""Models module deals with models representing entities in the application"""

import json
from random import seed, choice
from uuid import uuid4

from django.db import models

from shortner.constants import CHARS, STUB_LENGTH


class Link(models.Model):
    """Link model refers to a conversion of a long URL to a shortened one"""

    # 2083 is the max length of URL supported by Microsoft Edge
    long_url = models.CharField(max_length=2083)
    special_code = models.UUIDField(
        primary_key=True, default=uuid4, editable=False)
    stub = models.CharField(max_length=STUB_LENGTH, unique=True)

    def save(self, *args, **kwargs):
        seed(str(self.special_code))
        self.stub = "".join(choice(CHARS) for _ in range(STUB_LENGTH))
        super().save(*args, **kwargs)

    def to_json(self):
        """to_json converts link to JSON string"""
        return json.dumps(
            {
                "long_url": self.long_url,
                "special_code": str(self.special_code),
                "stub": self.stub,
            }
        )

Classes

class Link (*args, **kwargs)

Link model refers to a conversion of a long URL to a shortened one

Expand source code

class Link(models.Model):
    """Link model refers to a conversion of a long URL to a shortened one"""

    # 2083 is the max length of URL supported by Microsoft Edge
    long_url = models.CharField(max_length=2083)
    special_code = models.UUIDField(
        primary_key=True, default=uuid4, editable=False)
    stub = models.CharField(max_length=STUB_LENGTH, unique=True)

    def save(self, *args, **kwargs):
        seed(str(self.special_code))
        self.stub = "".join(choice(CHARS) for _ in range(STUB_LENGTH))
        super().save(*args, **kwargs)

    def to_json(self):
        """to_json converts link to JSON string"""
        return json.dumps(
            {
                "long_url": self.long_url,
                "special_code": str(self.special_code),
                "stub": self.stub,
            }
        )

Ancestors

• django.db.models.base.Model

Class variables

var DoesNotExist

The requested object does not exist

var MultipleObjectsReturned

The query returned multiple objects when only one was expected.

var objects

Instance variables

var long_url

A wrapper for a deferred-loading field. When the value is read from this object the first time, the query is executed.

Expand source code

def __get__(self, instance, cls=None):
    """
    Retrieve and caches the value from the datastore on the first lookup.
    Return the cached value.
    """
    if instance is None:
        return self
    data = instance.__dict__
    field_name = self.field.attname
    if field_name not in data:
        # Let's see if the field is part of the parent chain. If so we
        # might be able to reuse the already loaded value. Refs #18343.
        val = self._check_parent_chain(instance)
        if val is None:
            instance.refresh_from_db(fields=[field_name])
        else:
            data[field_name] = val
    return data[field_name]

var special_code

A wrapper for a deferred-loading field. When the value is read from this object the first time, the query is executed.

Expand source code

def __get__(self, instance, cls=None):
    """
    Retrieve and caches the value from the datastore on the first lookup.
    Return the cached value.
    """
    if instance is None:
        return self
    data = instance.__dict__
    field_name = self.field.attname
    if field_name not in data:
        # Let's see if the field is part of the parent chain. If so we
        # might be able to reuse the already loaded value. Refs #18343.
        val = self._check_parent_chain(instance)
        if val is None:
            instance.refresh_from_db(fields=[field_name])
        else:
            data[field_name] = val
    return data[field_name]

var stub

A wrapper for a deferred-loading field. When the value is read from this object the first time, the query is executed.

Expand source code

def __get__(self, instance, cls=None):
    """
    Retrieve and caches the value from the datastore on the first lookup.
    Return the cached value.
    """
    if instance is None:
        return self
    data = instance.__dict__
    field_name = self.field.attname
    if field_name not in data:
        # Let's see if the field is part of the parent chain. If so we
        # might be able to reuse the already loaded value. Refs #18343.
        val = self._check_parent_chain(instance)
        if val is None:
            instance.refresh_from_db(fields=[field_name])
        else:
            data[field_name] = val
    return data[field_name]

Methods

def save(self, *args, **kwargs)

Save the current instance. Override this in a subclass if you want to control the saving process.

The 'force_insert' and 'force_update' parameters can be used to insist that the "save" must be an SQL insert or update (or equivalent for non-SQL backends), respectively. Normally, they should not be set.

Expand source code

def save(self, *args, **kwargs):
    seed(str(self.special_code))
    self.stub = "".join(choice(CHARS) for _ in range(STUB_LENGTH))
    super().save(*args, **kwargs)

def to_json(self)

to_json converts link to JSON string

Expand source code

def to_json(self):
    """to_json converts link to JSON string"""
    return json.dumps(
        {
            "long_url": self.long_url,
            "special_code": str(self.special_code),
            "stub": self.stub,
        }
    )