ValidationMixin class enables plugins to perform custom validation of various fields.
Any of the methods described below can be implemented in a custom plugin to provide functionality as required.
For more information on any of the methods described below, refer to the InvenTree source code. A working example is available as a starting point.
Multi Plugin Support
It is possible to have multiple plugins loaded simultaneously which support validation methods. For example when validating a field, if one plugin returns a null value (
None) then the next plugin (if available) will be queried.
By default, part names are not subject to any particular naming conventions or requirements. However if custom validation is required, the
validate_part_name method can be implemented to ensure that a part name conforms to a required convention.
If the custom method determines that the part name is objectionable, it should throw a
ValidationError which will be handled upstream by parent calling methods.
Validation of the Part IPN (Internal Part Number) field is exposed to custom plugins via the
validate_part_IPN method. Any plugins which extend the
ValidationMixin class can implement this method, and raise a
ValidationError if the IPN value does not match a required convention.
Part Parameter Values¶
Part parameters can also have custom validation rules applied, by implementing the
validate_part_parameter method. A plugin which implements this method should raise a
ValidationError with an appropriate message if the part parameter value does not match a required convention.
Batch codes can be generated and/or validated by custom plugins.
validate_batch_code method allows plugins to raise an error if a batch code input by the user does not meet a particular pattern.
generate_batch_code method can be implemented to generate a new batch code.
Requirements for serial numbers can vary greatly depending on the application. Rather than attempting to provide a "one size fits all" serial number implementation, InvenTree allows custom serial number schemes to be implemented via plugins.
The default InvenTree serial numbering system uses a simple algorithm to validate and increment serial numbers. More complex behaviors can be implemented using the
ValidationMixin plugin class and the following custom methods:
Serial Number Validation¶
Custom serial number validation can be implemented using the
validate_serial_number method. A proposed serial number is passed to this method, which then has the opportunity to raise a
ValidationError to indicate that the serial number is not valid.
A plugin which requires all serial numbers to be valid hexadecimal values may implement this method as follows:
def validate_serial_number(self, serial: str, part: Part): """Validate the supplied serial number Arguments: serial: The proposed serial number (string) part: The Part instance for which this serial number is being validated """ try: # Attempt integer conversion int(serial, 16) except ValueError: raise ValidationError("Serial number must be a valid hex value")
Serial Number Sorting¶
While InvenTree supports arbitrary text values in the serial number fields, behind the scenes it attempts to "coerce" these values into an integer representation for more efficient sorting.
A custom plugin can implement the
convert_serial_to_int method to determine how a particular serial number is converted to an integer representation.
If this method is not implemented, or the serial number cannot be converted to an integer, then the sorting algorithm falls back to the text (string) value
Serial Number Incrementing¶
A core component of the InvenTree serial number system is the ability to increment serial numbers - to determine the next serial number value in a sequence.
For custom serial number schemes, it is important to provide a method to generate the next serial number given a current value. The
increment_serial_number method can be implemented by a plugin to achieve this.
If the provided number cannot be incremented (or an error occurs) the method should return
Continuing with the hexadecimal example as above, the method may be implemented as follows:
def increment_serial_number(self, serial: str): """Provide the next hexadecimal number in sequence""" try: val = int(serial, 16) + 1 val = hex(val).upper()[2:] except ValueError: val = None return val