checkr 0.1.3

Data validation made easy

Checkr

Checkr is a powerful validation library that enables developers to easily and accurately validate user input and other data. With Checkr, you can quickly perform a wide range of checks, and ensuring that data conforms to specific formatting requirements. With a simple and intuitive API, Checkr is easy to integrate into any project, and its flexible configuration options make it a powerful tool for building robust and reliable applications.

Installation

pip install checkr

Usage

1. First of all, You need to create a request class that has two methods:

from checkr.BaseRequest import BaseRequest
from typing import Dict


class SampleRequest(BaseRequest):

    @staticmethod
    def authorize() -> bool:
        return True

    @staticmethod
    def rules() -> Dict:
        return {
            'name': 'required|string|min:3',  # You can use the pipe
            'age': ['required', 'numeric', 'gte:18'],  # Or you can just provide a list
        }

2. Use the request class to validate data:

from checkr import validate
from checkr.exceptions import ValidationError


request_data = {
    'name': 'john doe'
}

try:
    validate(SampleRequest, request_data)
except ValidationError as e:
    # Do anything with the validation result here.
    print(e.errors)

Authorizing the request

This method is useful when you want to ensure that validation is performed only by certain parties or by specific users. In your request class, include a static method named authorize that returns a boolean.

Customizing the validation messages

To customize the validation messages returned when the validation of a field fails, you can use the messages method. Here's an example:

from typing import Dict
from checkr.BaseRequest import BaseRequest


class SampleRequest(BaseRequest):
    ...

    @classmethod
    def messages(cls) -> Dict:
        return {
            'name.required': 'Please provide a name!',
            'age.number': 'Oops! not a number!'
        }

    ...

Adding fields before starting the validation

Sometimes, you may find it useful to add a field before the process of validation starts. You can accomplish this by using the prepare_for_validation hook as demonstrated in the following example:

from typing import Dict
from checkr.BaseRequest import BaseRequest


class SampleRequest(BaseRequest):
    ...

    @classmethod
    def prepare_for_validation(cls) -> Dict:
        cls.merge(data_to_add={'foo': 'bar'})

    ...

Adding fields after finishing the validation

It's almost identical to adding fields before starting the validation. You'll use passed_validation hook as demonstrated in the following example:

Notice that this method will not run if the validation finds invalid data.

from typing import Dict
from checkr.BaseRequest import BaseRequest


class SampleRequest(BaseRequest):
    ...

    @classmethod
    def passed_validation(cls) -> Dict:
        cls.merge(data_to_add={'foo': 'bar'})

    ...

Available rules

Rule Name	Description	Usage
between	Checks if a value is between a minimum and maximum value	between:x,y where x and y are required. If provided with more than 2 numbers, the first and last numbers will be taken into account
string	Checks if a value is a string	string
int	Checks if a value is an integer	int
required	Checks if a value is present	required
numeric	Checks if a value is numeric	numeric
array	Checks if a value is a valid Python list	array
array_of	Checks if an array contains only elements of a specific type	array_of:string
in_array	Checks if a value is in an array of valid options	in_array:a,b,c
not_in_array	Checks if a value is not in a list of invalid options	not_in_array:a,b,c
date_after	Checks if a date is after a specific date	date_after:YYYY-mm-dd
date_after_or_equal	Checks if a date is after or equal to a specific date	date_after_or_equal:YYYY-mm-dd
date_before	Checks if a date is before a specific date	date_before:YYYY-mm-dd
date_before_or_equal	Checks if a date is before or equal to a specific date	date_before_or_equal:YYYY-mm-dd
min	Checks if a value is greater than or equal to a minimum value if it's a number. If provided a string, it checks if the string length is greater than or equal to the provided value.	min:x where x is a number amd required
max	Checks if a value is greater than or equal to a maximum value if it's a number. If provided a string, it checks if the string length is less than or equal to the provided value.	max:x where x is a number and required
min_digits	Checks if a numeric value has at least a specified number of digits	min_digits:n
max_digits	Checks if a numeric value has at most a specified number of digits	max_digits:n
json	Checks if a value is a valid JSON object	json
nullable	Allows a value to be null or undefined	nullable
decimal	Checks if a value is a decimal number	decimal:x where x is the number of decimal places and is optional
gt	Checks if a value is greater than a specified value	gt:x where x is a number
gte	Checks if a value is greater than or equal to a specified value	gte:x where x is a number
lt	Checks if a value is less than a specified value	lt:x where x is a number
lte	Checks if a value is less than or equal to a specified value	lte:x where x is a number
ip	Checks if a value is a valid IPv4 or IPv6 address	ip
ipv4	Checks if a value is a valid IPv4 address	ipv4
ipv6	Checks if a value is a valid IPv6 address	ipv6
lowercase	Checks if a string is lowercase	lowercase
uppercase	Checks if a string is uppercase	uppercase
mac_address	Checks if a value is a valid MAC address	mac_address
uuid	Checks if a value is a valid UUID	uuid:v where v is the version and defaults to v4 if no version provided
ulid	Checks if a value is a valid ULID	ulid
url	Checks if a value is a valid URL	url
startswith	Checks if a string starts with a specific value	startswith
endswith	Checks if a string ends with a specific value	endswith
email	Checks if a value is a valid email address	email
bool	Checks if a value is a boolean (true or false)	bool

Adding custom validation rules:

In some cases, it is useful to create a rule that validates an input in custom way like checking if a phone number has a specific format or checking that a city name exists in reality. The following example demonstrates how to accomplish this:

from typing import Any
from checkr.rules.BaseRule import BaseRule

class CustomRule(BaseRule):

    def __str__(self):
        return 'custom_rule'  # required. If not provided, incorrect errors dictionary will be returned

    def validate(self, attribute: str, value: Any) -> bool:
        return True

    def message(self, attribute: str):
        return f'This field failed because something was incorrect'

You can use the validate method to validate against a condition. note that this method takes two arguments:

• attribute which is the name of the field
• value which is the actual value.

There's also another method called message which is used to return a message in case the validation fails. This method receives one parameter, attribute, which is the name of the field under validation.