古い非 OWIN API では、MessageHanlder を使用してすべての HttpRequests と HttpResponses をログに記録します。MessageHandler は次のとおりです。
public class MessageHandler : DelegatingHandler
{
private static readonly ILog RequestApiLogger = LogManager.GetLogger("RequestApiPacketLogger");
private static readonly ILog ResponseApiLogger = LogManager.GetLogger("ResponseApiPacketLogger");
protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
{
var correlationId = Guid.NewGuid();
RequestApiLogger.LogHttpRequest(request, correlationId);
return await base.SendAsync(request, cancellationToken).ContinueWith(
task =>
{
var response = task.Result;
response.Headers.Add("http-tracking-id", correlationId.ToString("D"));
ResponseApiLogger.LogHttpResponse(response, correlationId);
return response;
}, cancellationToken);
}
}
ただし、私の新しいプロジェクトでは、カスタム OWIN ミドルウェアを作成して、次のように OwinContext を使用して同様のことを行うことができます。
//use an alias for the OWIN AppFunc
using AppFunc = Func<IDictionary<string, object>, Task>;
public class LoggingMiddleware
{
private readonly AppFunc _next;
public LoggingMiddleware(AppFunc next)
{
_next = next;
}
public async Task Invoke(IDictionary<string, object> environment)
{
IOwinContext context = new OwinContext(environment);
// Get the identity
var identity = (context.Request.User != null && context.Request.User.Identity.IsAuthenticated)
? context.Request.User.Identity.Name
: "(anonymous)";
// Buffer the request (body is a string, we can use this to log the request later
var requestBody = new StreamReader(context.Request.Body).ReadToEnd();
var requestData = Encoding.UTF8.GetBytes(requestBody);
context.Request.Body = new MemoryStream(requestData);
var apiPacket = new ApiPacket
{
CallerIdentity = identity,
Request = requestBody,
RequestLength = context.Request.Body.Length
};
// Buffer the response
var responseBuffer = new MemoryStream();
var responseStream = context.Response.Body;
context.Response.Body = responseBuffer;
// add the "http-tracking-id" response header so the user can correlate back to this entry
var responseHeaders = (IDictionary<string, string[]>)environment["owin.ResponseHeaders"];
responseHeaders["http-tracking-id"] = new[] { apiPacket.TrackingId.ToString("d") };
await _next.Invoke(environment);
responseBuffer.Seek(0, SeekOrigin.Begin);
var reader = new StreamReader(responseBuffer);
apiPacket.Response = await reader.ReadToEndAsync();
apiPacket.ResponseLength = context.Response.ContentLength ?? 0;
WriteRequestHeaders(context.Request, apiPacket);
WriteResponseHeaders(context.Response, apiPacket);
// You need to do this so that the response we buffered is flushed out to the client application.
responseBuffer.Seek(0, SeekOrigin.Begin);
await responseBuffer.CopyToAsync(responseStream);
//TODO: persist the ApiPacket in the database
}
private static void WriteRequestHeaders(IOwinRequest request, ApiPacket packet)
{
packet.Verb = request.Method;
packet.RequestUri = request.Uri;
packet.RequestHeaders = "{\r\n" + string.Join(Environment.NewLine, request.Headers.Select(kv => "\t" + kv.Key + "=" + string.Join(",", kv.Value))) + "\r\n}";
}
private static void WriteResponseHeaders(IOwinResponse response, ApiPacket packet)
{
packet.StatusCode = response.StatusCode;
packet.ReasonPhrase = response.ReasonPhrase;
packet.ResponseHeaders = "{\r\n" + string.Join(Environment.NewLine, response.Headers.Select(kv => "\t" + kv.Key + "=" + string.Join(",", kv.Value))) + "\r\n}";
}
}
log4net を使用して情報を SQL2012 データベースに書き込みます。どちらの方法でも私の目標を達成できます。ただし、ある方法を他の方法よりも使用する理由を探しています。カスタム OWIN ミドルウェアまたは MessageHandler を使用する必要がありますか? その理由は? 前もって感謝します。