Use httpcontext in a .NET core class library

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We are now dealing with converting our .NET Framework C# code to .NET Core and having some difficulty in the following:
A very generic method we have in a class library (DLL) is this:

C#

public static (string, string) InitMethod(bool SetWocContentType = true, [CallerMemberName] string callerName = "", bool printLog = true, bool setThreadName = false)
        {
            const string WocContentType = "application/json; charset=utf-8";

            string caller = Generic.GetSessionParam(SessionParams.Caller);
            string callerText = $"{caller} {callerName}".Trim();

            if (setThreadName)
            {
                string userId = System.Web.HttpContext.Current?.Request?.Params["UserId"] ?? Generic.GetSessionParam(SessionParams.TenantUID); 
                if (string.IsNullOrEmpty(System.Threading.Thread.CurrentThread.Name))
                {
                    System.Threading.Thread.CurrentThread.Name = !string.IsNullOrEmpty(userId ) ? $"{userId } ({callerName})" : $"({callerName})";
                }
            }

            if (printLog) NLogger.Instance.Debug($"{callerText} Starting");

            if (SetWocContentType && System.ServiceModel.Web.WebOperationContext.Current != null && System.ServiceModel.Web.WebOperationContext.Current.OutgoingResponse != null && System.ServiceModel.Web.WebOperationContext.Current.OutgoingResponse.ContentType != null)
            {                System.ServiceModel.Web.WebOperationContext.Current.OutgoingResponse.ContentType = WocContentType;
            }

            return (caller, callerText);
        }
        public static string GetSessionParam(SessionParams param)
        {
            string myName = "GetSessionParam"; //Cannot call InitMethod as it call GetSessionParam within and will result in StackOverflow..
            NLogger.Instance.Trace($"{myName} Asking for value ({param})");
            
            string value = "";
            if (HttpContext.Current != null && HttpContext.Current.Items.Contains(param.ToString()))
            {
                value = HttpContext.Current.Items[param.ToString()] as string;
            }
            if (!param.Equals(SessionParams.Config))
            {
                NLogger.Instance.Trace($"{myName} Returning with ({value})");                
            }
            else
            {
                NLogger.Instance.Trace($"{myName} Returning with ({value.CutByPrefixSuffix(3, 3)})");                
            }
            return value;
        }

I need to convert this code to .NET Core 6.0 but encounter a problem when working with HttpContext and WebOperationContext.
Can anyone please help me with this?

What I have tried:

I managed to convert the code to this but passing HttpContext as parameter - I don't think it's possible from lots of places in the code:

C#

public static (string?, string?) InitMethod(HttpContext httpContext, bool SetWocContentType = true, [CallerMemberName] string callerName = "", bool printLog = true, bool setThreadName = false)
        { 
            const string WocContentType = "application/json; charset=utf-8";

            string? caller = GetSessionParam(httpContext, SessionParams.Caller);
            string callerText = $"{caller} {callerName}".Trim();

            if (setThreadName)
            {
                string? userId = null;
                if (!string.IsNullOrEmpty(httpContext.Request.Query["UserID"]))
                {
                    userId = httpContext.Request.Query["UserID"];
                }
                else
                {
                    userId = Generic.GetSessionParam(httpContext, SessionParams.UserUID);
                }
                
                if (string.IsNullOrEmpty(Thread.CurrentThread.Name))
                {
                    Thread.CurrentThread.Name = !string.IsNullOrEmpty(userId ) ? $"{userId } ({callerName})" : $"({callerName})";
                }
            }

            if (printLog) NLogger.Instance.Debug($"{callerText} Starting");

            if (SetWocContentType && OperationContext.Current != null && httpContext.Response != null && httpContext.Response.ContentType != null)
            {
                httpContext.Response.ContentType = WocContentType;
            }

            return (caller, callerText);
        }

        private static string? GetSessionParam(HttpContext context, SessionParams param)
        {
            string myName = "GetSessionParam"; //Cannot call InitMethod as 
            // it calls GetSessionParam within and will result 
            // in StackOverflow..
            NLogger.Instance.Trace($"{myName} Asking for value ({param})");

            // Get the session object from the context.
            var session = context.Session;

            byte[] value;
            // Check if the session param exists.
            if (!session.TryGetValue(param.GetDescription(), out value))
            {
                // The session param does not exist.
                return null;
            }
            string? result = Encoding.UTF8.GetString(value);
            if (!param.Equals(SessionParams.Config))
            {
                NLogger.Instance.Trace
                    ($"{myName} Returning with ({result})");
            }
            else
            {
                NLogger.Instance.Trace($"{myName} 
                Returning with ({result.CutByPrefixSuffix(3, 3)})");
            }
            return result;
        }

Posted 6-Aug-23 11:07am

oronsultan

Updated 10-Aug-23 10:18am

Deeksha Shenoy

v2

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Comments

Graeme_Grant 6-Aug-23 20:32pm

with Asp.Net Core, alot of this is now done in middleware. ref: ASP.NET Core Middleware | Microsoft Learn[^]

oronsultan 7-Aug-23 2:43am

Can you please elaborate?
We have web services exposing nothing but API's. The web service is reference with a set of DLLs (class library) that are generic.
Is it possible to access request url params or current session params from a class library?

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Richard Deeming · Answer 1 · 2023-08-06T22:46:00

If your service really needs access to the full HttpContext, then you can inject the IHttpContextAccessor[^] service and use that to access the current context. However, you cannot inject services into a static method; you would need to inject the service into the caller, and pass the context as a parameter.

It would be better to create specific service interface(s) for your class library's exact requirements, and inject/pass an implementation that delegates to the current context. That way, you make your code more testable. Eg:

Class library:

C#

public interface ISessionParamProvider
{
    string? GetSessionParam(string name);
}

private static string? GetSessionParam(ISessionParamProvider provider, SessionParams param)
{
    string myName = "GetSessionParam"; //Cannot call InitMethod as it call GetSessionParam within and will result in StackOverflow..
    NLogger.Instance.Trace($"{myName} Asking for value ({param})");
    
    string? result = provider.GetSessionParam(param.GetDescription());
    if (result is null)
    {
        // The session param does not exist.
        return null;
    }
    
    if (!param.Equals(SessionParams.Config))
    {
        NLogger.Instance.Trace($"{myName} Returning with ({result})");
    }
    else
    {
        NLogger.Instance.Trace($"{myName} Returning with ({result.CutByPrefixSuffix(3, 3)})");
    }
    
    return result;
}

Web application:

C#

public class SessionParamProvider : ISessionParamProvider
{
    private readonly IHttpContextAccessor _contextAccessor;
    
    public SessionParamProvider(IHttpContextAccessor contextAccessor)
    {
        ArgumentNullException.ThrowIfNull(contextAccessor);
        _contextAccessor = contextAccessor;
    }
    
    public string? GetSessionParam(string name)
    {
        var session = _contextAccessor.HttpContext?.Session;
        if (session is null)
        {
            // There is no current context, or session state is disabled:
            return null;
        }

        byte[] value;
        // Check if the session param exists.
        if (!session.TryGetValue(name, out value))
        {
            // The session param does not exist.
            return null;
        }
        
        return Encoding.UTF8.GetString(value);   
    }
}

var builder = WebApplication.CreateBuilder(args);
...
builder.Services.AddHttpContextAccessor();
builder.Services.AddTransient<ISessionParamProvider, SessionParamProvider>();
...

Access HttpContext in ASP.NET Core | Microsoft Learn[^]