Value Mappers

Modify and transform data before storing or displaying it in KtorAdmin using ValueMappers.

Value mappers allow modifying data before saving and before displaying it. For example, passwords need to be encrypted before storage.

Important: This feature is not supported for MongoDB at this time.

To define a custom ValueMapper, create an object implementing KtorAdminValueMapper:

object PasswordValueMapper : KtorAdminValueMapper {
    val cryptoManager = CryptManager()
    
    override fun map(value: Any?): Any? {
        return value?.let { cryptoManager.encrypt(value) }
    }

    override fun restore(value: Any?): Any? {
        return value
    }

    override val key: String
        get() = "password"
}

• map(value: Any?) → Transforms the value before storing it in the database. In this case, it encrypts the password.

• restore(value: Any?) → Restores the value when retrieving it from the database. Since passwords do not need to be displayed in the admin panel, decryption is not performed.

• key: String → A unique identifier for the ValueMapper.

Note: Since passwords do not need to be displayed in the admin panel, we do not decrypt the stored value.

Registering the ValueMapper

install(KtorAdmin){
    registerValueMapper(PasswordValueMapper)
}

Using @ValueMapper on Fields

Apply @ValueMapper to fields requiring transformation:

@ValueMapper(key = "password")
val password = text("password")

This ensures passwords are encrypted before saving while keeping them hidden in the admin panel.