C# Code Generation doesn't validate patterns

[MaxHaertwig]

Hi everyone,

I noticed that the C# code generation doesn't validate patterns (on the client side). If I annotate a parameter of type string with a pattern (e.g. "^v[1-9]$"), I expect the Api method to throw an ApiException when the supplied string doesn't match the pattern.

I'd be happy to open a PR. Is that something this project could use?

[jeremyVignelles]

What code generation are you talking about? Controller code generation or client-side validation?

For controllers generation, I think that DataAnnotations are enough to validate such entries? doesn't that work? Could you send an example ?

[MaxHaertwig]

I'm referring to client-side code generation. I'd expect the client to validate URL parameters before sending the request. Even if the validation happens on the server, we can avoid this unnecessary network roundtrip.

[MaxHaertwig]

Example:

/api/test/{version}:
  get:
    parameters:
        name: version
        in: path
        schema:
          type: string
          pattern: "^\\d+(\\.\\d+)?(\\.\\d+)?$"
    responses:
      "200":
        description: Success
        content:
          text/plain:
            schema:
              type: string

generates the following client code:

public async System.Threading.Tasks.Task<string> TestAsync(string version, System.Threading.CancellationToken cancellationToken)
{
    var urlBuilder_ = new System.Text.StringBuilder();
    urlBuilder_.Append(BaseUrl != null ? BaseUrl.TrimEnd('/') : "").Append("/api/test/{version}");
    urlBuilder_.Replace("{version}", System.Uri.EscapeDataString(ConvertToString(version, System.Globalization.CultureInfo.InvariantCulture)));
    
    var client_ = _httpClient;
    var disposeClient_ = false;
    try
    {
        using (var request_ = new System.Net.Http.HttpRequestMessage())
        ...

I would expect to see a few lines like:

if (!Regex.IsMatch(version, @"^\d+(\.\d+)?(\.\d+)?$"))
{
    throw new ApiException($"Query parameter 'version' doesn't match the specified pattern.")
}

[RicoSuter]

This feature is currently not implemented.

[davidorbelian]

@RicoSuter Hello! Is this feature still not implemented? If so, I would be happy to try to implement it.

[MortenMeisler]

@RicoSuter @davidorbelian any updates on this? We're making wrappers at the moment to do simple validation on the client-side

Example:

        /// <summary>
        /// Gets or sets the value of ids
        /// </summary>
        [Newtonsoft.Json.JsonProperty("Ids", Required = Newtonsoft.Json.Required.Always)]
        [System.ComponentModel.DataAnnotations.Required]
        [System.ComponentModel.DataAnnotations.MinLength(1)]
        public System.Collections.Generic.ICollection<string> Ids { get; set; } = new 
        System.Collections.ObjectModel.Collection<string>();

The generated csharp client does not create any validation here. Or is there any options to enforce this?

Thanks

[IrinaSouth]

Hi, is there a plan to prioritise this? None of the System.ComponentModel.DataAnnotations that get generated seem to be respected when the generated client code is executed. Thanks