NextId

Strongly-typed, K-Sortable globally unique identifier with checksum for .NET 7+.

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Example

Example value:

user-4B4XH7BnCp68CCY8mzVbNT5X

• Left from - is type (max 11 characters)
• Right from - is id value

id is componsed of:

• First 8 chars, Unix timestamp in milliseconds
• Next 2 chars, microseconds of the timestamp
• Next 11 chars, random value
• Final 3 chars, checksum value

Checksum can be used to validate id before going to database to detect malicious or unexpected activities by clients.

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NumberValue can be used to avoid displaying Id as random string which can unintentionally contain words.

Example number value:

user-020802261305083909400406090927063849243018230326

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How to use it

Install nuget package

dotnet add package NextId

Inherit NextId.Identifier class:

public class UserId : Identifier<UserId>, IParsable<UserId>
{
    private const string PrefixConst = "user";
    private const string SaltConst = "99AAB45utg";
    protected override string Prefix => PrefixConst;
    protected override string Salt => SaltConst;

    private UserId() { }
    
    // constructor with time component
    public UserId(DateTimeOffset dt) : base(dt) { }

    // constructor for parsing
    private UserId(string value) : base(value) { }

    public static UserId NewId() => new();

    public static UserId Parse(string s) => Parse(s, null);

    public static UserId Parse(string s, IFormatProvider? provider) => new(s);

    public static bool TryParse(string? s, IFormatProvider? provider, [NotNullWhen(true)]out UserId? result)
    {
        try
        {
            result = Parse(s!, provider);
            return true;
        }
        catch
        {
            result = null;
            return false;
        }
    }

    public static bool IsValid(string value) => IsValid(value, PrefixConst, SaltConst);
}

UserId id1 = UserId.NewId();
UserId id2 = UserId.Parse(id1.Value);
UserId id3 = UserId.Parse(id1.NumberValue);

(id1 == id2).Should().BeTrue();
(id1 == id3).Should().BeTrue();

You can get string value of identifier by calling Value property or ToString() method.

Prefix will be set as identifier prefix (user in this case). Value must have less than 12 characters and can contain only ASCII letters and digits.

Salt must be less than 33 characters and should be set to random value to each type. Once set, it must not be changed.

Serialization

System.Text.Json serializer options are available.

First add package reference:

dotnet add package NextId.Serialization.Json

var options = new JsonSerializerOptions();
options.AddIdentifierConverters();

User user1 = User.NewRandomUser();
string json = JsonSerializer.Serialize(user1, options);
User user2 = JsonSerializer.Deserialize<User>(json, options)!;

Performance

• ~866,551 generated ids per second per core
• ~369,822 parsed ids per second per core

BenchmarkDotNet=v0.13.5, OS=Windows 10 (10.0.19045.3086/22H2/2022Update)
AMD Ryzen 7 2700X, 1 CPU, 16 logical and 8 physical cores
.NET SDK=7.0.304
  [Host]     : .NET 7.0.7 (7.0.723.27404), X64 RyuJIT AVX2
  DefaultJob : .NET 7.0.7 (7.0.723.27404), X64 RyuJIT AVX2


|     Method |     Mean |     Error |    StdDev |
|----------- |---------:|----------:|----------:|
| NewId_1000 | 1.154 ms | 0.0054 ms | 0.0050 ms |
| Parse_1000 | 2.704 ms | 0.0309 ms | 0.0258 ms |

Changes

• 1.1.1

  • Fix bug where IsValid method returns false for NumberValue

• 1.1.0

  • Fixed bug when verifying validity of value
  • Added support for NumberValue

• 1.0.0

  • Initial version