authors	title	description	lastmod	date	license	type	keywords	slug
dgmjr	Regex DTO Generator	This is a simple tool to generate DTOs from a regex. It is a work in progress.	2022-12-28-07:31:51	2022-12-28-07:31:50	MIT	readme	codegen roslyn source-generator roslyn-generator	regex-dto-generator

Regex DTO Generator

This is a simple tool to generate DTOs from a regex. It is a work in progress.

Usage

Simply decorate any class, record, struct, record class, or record struct with the attribute [RegexDtoAttribute] and provide a regular expression with names groups. You can extend the regular expression syntax by including the primitive data types in the name group separated from the name by a colon (:). The following data types are supported:

• string
• int
• long
• float
• double
• decimal
• bool
• DateTime
• DateTimeOffset
• TimeSpan
• Guid
• Uri
• Really, any type that implements IConvertible and is convertible to/from a string

Let's say you want to pull out the room number and password from a Zoom URL. You can do this with the following code:

[RegexDto("https://zoom.us/j/(?<RoomNumber:int>[0-9]{10,11})(?:&pwd=(?<Password:string?>[a-zA-Z0-9]{6,8}))?")]
public partial record struct ZoomRoomDto { }

This will generate the following code for you:

[System.CodeDom.Compiler.GeneratedCode("Dgmjr.RegexDtoGenerator", "0.0.1.0")]
public partial record struct ZoomRoom
{
    const RegexOptions RegexOptions = (RegexOptions)(IgnoreCase |  ExplicitCapture |  Compiled);

    #if NET7_0_OR_GREATER
    [StringSyntax(@StringSyntax.Regex)]
    #endif
    public const string RegexString = @"https://zoom.us/j/(?<RoomNumber>[0-9]{10,11})(?:&pwd=(?<Password>[a-zA-Z0-9]{6,8}))?";

    #if NET7_0_OR_GREATER
    [GeneratedRegex(RegexString, Compiled | CultureInvariant | IgnoreCase)]
    public static partial System.Text.RegularExpressions.Regex Regex();
    #else
    private static readonly System.Text.RegularExpressions.Regex _regex = new System.Text.RegularExpressions.Regex(RegexString, RegexOptions);
    public static System.Text.RegularExpressions.Regex Regex() => _regex;
    #endif

    public static ZoomRoom Parse(string s)
    {
        var match = Regex().Match(s);
        if (!match.Success)
        {
            throw new System.ArgumentException($"The string \"{s}\" does not match the regular expression \"{RegexString}\".", nameof(s));
        }

        return new ZoomRoom
        {
            RoomNumber = (int)System.Convert.ChangeType(match.Groups["RoomNumber"]?.Value, typeof(int)),
            Password = match.Groups["Password"]?.Value is null ? null : (string?)System.Convert.ChangeType(match.Groups["Password"]?.Value, typeof(string)),
        };
    }
    public  int RoomNumber { get; set; }
    public  string? Password { get; set; }

    public ZoomRoom () { }

    public ZoomRoom (string s)
    {
        var match = Regex().Match(s);
        if (!match.Success)
        {
            throw new System.ArgumentException($"The string \"{s}\" does not match the regular expression \"{RegexString}\".", nameof(s));
        }

        RoomNumber = (int)System.Convert.ChangeType(match.Groups["RoomNumber"]?.Value, typeof(int));
        Password = match.Groups["Password"]?.Value is null ? null : (string?)System.Convert.ChangeType(match.Groups["Password"]?.Value, typeof(string));
    }
}

Which can then be complemented by the partial definition below:

public partial record struct ZoomRoom
{
    public Uri Url => new Uri($"https://zoom.us/j/{RoomNumber}{(!string.IsNullOrEmpty(Password) ? $"?pwd={Password}" : "")}");
}