C# API Endpoints

This plugin enables C# support for API endpoints.

Identifier: PowerShellUniversal.Language.CSharp

This plugin creates a C#-based environment that can be used to create API endpoints with C# code. APIs created with C# are much faster than PowerShell-based endpoints. Endpoints run directly in the PowerShell Universal service. Any exception thrown from your endpoint will be handled and a valid status code will be returned to the caller.

You must create endpoints with the -Path parameter and specify the C# environment for the endpoint to function properly.

New-PSUEndpoint -Url /csharp -Path csharp.cs -Environment 'C#'

Defining an Endpoint

Within the C# endpoint, there are two classes that are of interest. The first is the request variable that is passed to the endpoint. It is an ApiRequest object.

public class ApiRequest
{
    public long Id { get; set; }
    public ICollection<KeyValue> Variables { get; set; } = new List<KeyValue>();
    public IEnumerable<ApiFile> Files { get; set; } = new List<ApiFile>();
    public string Url { get; set; }
    public ICollection<KeyValue> Headers { get; set; } = new List<KeyValue>();
    public byte[] Data { get; set; }
    public int ErrorAction { get; set; }
    public ICollection<KeyValue> Parameters { get; set; } = new List<KeyValue>();
    public string Method { get; set; }
    public ICollection<KeyValue> Cookies { get; set; } = new List<KeyValue>();
    public string ClaimsPrincipal { get; set; }
    public string ContentType { get; set; }
    public string[] Roles { get; set; }
}

In your endpoint, you can access this variable automatically.

if (request.ContentType == "application/json")
{
     // Do some stuff with JSON
}

The endpoint must return an ApiResponse object. This object has the following definition.

public class ApiResponse
{
    public int StatusCode { get; set; } = 200;
    public string Body { get; set; }
    public List<KeyValue> Cookies { get; set; } = new List<KeyValue>();
    public byte[] Data { get; set; } = Array.Empty<byte>();
    public string ContentType { get; set; } = "text/plain";
    public List<KeyValue> Headers { get; set; } = new List<KeyValue>();
    public ApiFile File { get; set; }
}

You can return a response by creating a new object and returning it from your endpoint.

return new ApiResponse {
    StatusCode = 401
};

When defining an endpoint's content, understand that the code is being added to a dynamically named class with a single Execute function. Your code should be valid syntax for such a source file.

using PowerShellUniversal;

public class c{id} : ExecutionClass {{ 
    public static ApiResponse Execute(ApiRequest request) 
    {{ 
        {fileContents} 

        return new ApiResponse();
    }} 
}}";

You can access the PowerShell Universal service container within your endpoint by accessing the ServiceProvider property in your endpoint. We currently do not document the internal services of PowerShell Universal.

var database = ServiceProvider.GetService(typeof(IDatabase));

References

You can control which assemblies are referenced by using the #ref keyword. The value can be a DLL file in the PowerShell Universal installation directory, or the full path to another assembly.

#ref PowerShellUniversal.Apis.dll
#ref C:\assemblies\markdiag.dll

Namespace Using

You can reference a namespace using the #using keyword.

#using System.Management.Automation

Variables

You can access variables in C# endpoints with GetVariable, GetSecretString, and GetSecretCredential methods.

return new ApiResponse {
    StatusCode = 200
    Body = GetVariable("MyVar").ToString()
};

To access a PSCredential, you can do the following.

#ref System  
#ref System.Management.Automation

return new ApiResponse { 
    StatusCode = 200, 
    Body = GetSecretCredential("MyCred").UserName.ToString() 
};