core.validation

src.core.validation

Validation framework for input validation.

This module provides utility functions for common validation patterns. All validation functions return Result types for consistent error handling.

Usage

from src.core.validation import validate_email, validate_not_empty from src.core.result import Success, Failure

result = validate_email("user@example.com") match result: case Success(email): # Email is valid pass case Failure(error): # Handle validation error print(error.message)

Classes

Functions

validate_not_empty

validate_not_empty(
    value: Any, field_name: str
) -> Result[Any, ValidationError]

Validate that a value is not empty.

Parameters:

Name	Type	Description	Default
value	Any	Value to validate.	required
field_name	str	Name of the field being validated.	required

Returns:

Type	Description
Result[Any, ValidationError]	Success with value if not empty, Failure with ValidationError otherwise.

Source code in src/core/validation.py

def validate_not_empty(value: Any, field_name: str) -> Result[Any, ValidationError]:
    """Validate that a value is not empty.

    Args:
        value: Value to validate.
        field_name: Name of the field being validated.

    Returns:
        Success with value if not empty, Failure with ValidationError otherwise.
    """
    if value is None or (isinstance(value, str) and not value.strip()):
        return Failure(
            error=ValidationError(
                code=ErrorCode.VALIDATION_FAILED,
                message=f"{field_name} cannot be empty",
                field=field_name,
            )
        )
    return Success(value=value)

validate_email

validate_email(email: str) -> Result[str, ValidationError]

Validate email format.

Parameters:

Name	Type	Description	Default
email	str	Email address to validate.	required

Returns:

Type	Description
Result[str, ValidationError]	Success with email if valid, Failure with ValidationError otherwise.

Source code in src/core/validation.py

def validate_email(email: str) -> Result[str, ValidationError]:
    """Validate email format.

    Args:
        email: Email address to validate.

    Returns:
        Success with email if valid, Failure with ValidationError otherwise.
    """
    # Basic email regex pattern
    pattern = r"^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$"

    if not re.match(pattern, email):
        return Failure(
            error=ValidationError(
                code=ErrorCode.INVALID_EMAIL,
                message="Invalid email format",
                field="email",
            )
        )
    return Success(value=email)

validate_min_length

validate_min_length(
    value: str, min_length: int, field_name: str
) -> Result[str, ValidationError]

Validate minimum string length.

Parameters:

Name	Type	Description	Default
value	str	String to validate.	required
min_length	int	Minimum required length.	required
field_name	str	Name of the field being validated.	required

Returns:

Type	Description
Result[str, ValidationError]	Success with value if valid, Failure with ValidationError otherwise.

Source code in src/core/validation.py

def validate_min_length(
    value: str, min_length: int, field_name: str
) -> Result[str, ValidationError]:
    """Validate minimum string length.

    Args:
        value: String to validate.
        min_length: Minimum required length.
        field_name: Name of the field being validated.

    Returns:
        Success with value if valid, Failure with ValidationError otherwise.
    """
    if len(value) < min_length:
        return Failure(
            error=ValidationError(
                code=ErrorCode.VALIDATION_FAILED,
                message=f"{field_name} must be at least {min_length} characters",
                field=field_name,
            )
        )
    return Success(value=value)

validate_max_length

validate_max_length(
    value: str, max_length: int, field_name: str
) -> Result[str, ValidationError]

Validate maximum string length.

Parameters:

Name	Type	Description	Default
value	str	String to validate.	required
max_length	int	Maximum allowed length.	required
field_name	str	Name of the field being validated.	required

Returns:

Type	Description
Result[str, ValidationError]	Success with value if valid, Failure with ValidationError otherwise.

Source code in src/core/validation.py

def validate_max_length(
    value: str, max_length: int, field_name: str
) -> Result[str, ValidationError]:
    """Validate maximum string length.

    Args:
        value: String to validate.
        max_length: Maximum allowed length.
        field_name: Name of the field being validated.

    Returns:
        Success with value if valid, Failure with ValidationError otherwise.
    """
    if len(value) > max_length:
        return Failure(
            error=ValidationError(
                code=ErrorCode.VALIDATION_FAILED,
                message=f"{field_name} must be at most {max_length} characters",
                field=field_name,
            )
        )
    return Success(value=value)