DTO Validation

The go-mod-core-contracts leverage the go-playground/validator for DTO validation as it provides common validation function and customization mechanism.

Tag usage

EdgeX verifies the struct fields by using go-playground/validator validation tags or custom validation tags, for example:

type Device struct {
    DBTimestamp    `json:",inline"`
    Id             string                        `json:"id,omitempty" validate:"omitempty,uuid"`
    Name           string                        `json:"name" validate:"required,edgex-dto-none-empty-string,edgex-dto-rfc3986-unreserved-chars"`
    Description    string                        `json:"description,omitempty"`
    AdminState     string                        `json:"adminState" validate:"oneof='LOCKED' 'UNLOCKED'"`
    OperatingState string                        `json:"operatingState" validate:"oneof='UP' 'DOWN' 'UNKNOWN'"`
    ...
}

• required validation tag ensures the value is not zero, empty string, or nil
• edgex-dto-none-empty-string validation tag trims white space and ensures the value is not an empty string
• edgex-dto-rfc3986-unreserved-chars validation tag checks the value that does not contain reserved characters

You can find more validations in the go-playground/validator and EdgeX custom validations in the go-mod-core-contracts.

Character restriction

The EdgeX uses the custom validation edgex-dto-rfc3986-unreserved-chars to prevent the user inputting the reserved characters.

This validation allows for only the following characters:

• alphabet: a-z, A-Z
• digital number: 0-9
• special character: - _ ~ : ; =