How to map a string property to a binary column in the database? - postgresql

Question

I have a class for a user entity. One of the properties is the user's password (a hash, actually). I made it a string (streamlined code):
public class User
{
public virtual int Id { get; set; }
public virtual string Password { get; set; }
}
There's also a Fluent NHibernate mapping (streamlined code):
public class UserMap : ClassMap<User>
{
public UserMap()
{
Table("users");
Id(x => x.Id).GeneratedBy.Sequence("users_id_seq");
Map(x => x.Password); // what do I put here???
}
}
The database column is of bytea data type on PostgreSQL. The above mapping doesn't work, because the property is string (text). What should I do?

Answer 1

you can Make Password a public property, which is only used to reference to the underlying private property HashedPassword.
something like so:
protected virtual byte[] /*or whatever the type is*/ HashedPassword {get; set;}
public virtual string Password
get
{
return (string)(HashedPassword); //or however you want to cast it to string...
}
set
//...
you can then tell fluent nHib to ignore your Password property.

Answer 2

Here is the final solution which works both ways (read & write), what I tried earlier didn't work properly. Hope this will help somebody.
public class User
{
private byte[] _password;
public virtual int Id { get; private set; }
public virtual string Password
{
get { return System.Text.Encoding.Unicode.GetString(_password); }
set { _password = System.Text.Encoding.Unicode.GetBytes(value); }
}
}
public class UserMap : ClassMap<User>
{
public UserMap()
{
Table("users");
Id(x => x.Id).GeneratedBy.Sequence("users_id_seq");
Map(x => x.Password)
.Access.LowerCaseField(Prefix.Underscore)
.CustomType<byte[]>();
}
}