dahlsailrunner · August 19, 2021 16:58 · Aug 19, 2021
diff --git a/CustomSerilogRequestLogging.md b/CustomSerilogRequestLogging.md
@@ -0,0 +1,79 @@
+# Central Code within a Library or other location
+
+You can create the following code in some central library or folder if desired:
+
+```csharp
+public static IApplicationBuilder UseCustomSerilogRequestLogging(this IApplicationBuilder app, bool includeHealthChecks = false)
+{
+    return app.UseSerilogRequestLogging(options =>
+    {
+        if (!includeHealthChecks)
+        {
+            options.GetLevel = ExcludeHealthChecks;
+        }
+        options.EnrichDiagnosticContext = (diagnosticContext, httpContext) =>
+        {
+            diagnosticContext.Set("RequestHost", httpContext.Request.Host.Value);
+            diagnosticContext.Set("RequestScheme", httpContext.Request.Scheme);
+            var user = httpContext.User.Identity;
+            if (user != null && user.IsAuthenticated)
+            {
+                var userInfo = GetUserInfoFromHttpContext(user as ClaimsIdentity);
+                var userInfoJson = JsonConvert.SerializeObject(userInfo, Formatting.Indented);
+                diagnosticContext.Set("UserInfo", userInfoJson);
+                diagnosticContext.Set("LoginName", userInfo.UserName);                
+            }
+        };
+    });
+}
+
+private static UserInfo GetUserInfoFromHttpContext(ClaimsIdentity user)
+{
+    var excluded = new List<string>
+    {
+        "nbf", "exp", "auth_time", "amr", "sub", "aud", "jti"
+    };
+    const string userIdClaimType = "sub";
+    const string userNameClaimType = "userName";
+    var userId = user.Claims.FirstOrDefault(a => a.Type == userIdClaimType)?.Value;
+    var userName = user.Claims.FirstOrDefault(a => a.Type == userNameClaimType)?.Value;
+    var userInfo = new UserInfo
+    {
+        UserName = userName,
+        UserId = userId,
+        UserClaims = new Dictionary<string, List<string>>()
+    };
+    foreach (var distinctClaimType in user.Claims
+        .Where(a => excluded.All(ex => ex != a.Type))
+        .Select(a => a.Type)
+        .Distinct())
+    {
+        userInfo.UserClaims[distinctClaimType] = user.Claims
+            .Where(a => a.Type == distinctClaimType)
+            .Select(c => c.Value)
+            .ToList();
+    }
+    return userInfo;
+}
+private static LogEventLevel ExcludeHealthChecks(HttpContext ctx, double _, Exception ex) =>
+    ex != null
+        ? LogEventLevel.Error
+        : ctx.Response.StatusCode > 499
+            ? LogEventLevel.Error
+            : IsHealthCheckEndpoint(ctx) // Not an error, check if it was a health check
+                ? LogEventLevel.Verbose // Was a health check, use Verbose
+                : LogEventLevel.Information;
+
+private static bool IsHealthCheckEndpoint(HttpContext ctx)
+{
+    var userAgent = ctx.Request.Headers["User-Agent"].FirstOrDefault() ?? "";
+    return ctx.Request.Path.Value.EndsWith("health", StringComparison.CurrentCultureIgnoreCase) ||
+           userAgent.Contains("HealthCheck", StringComparison.InvariantCultureIgnoreCase);
+}
+
+```
+
+Then in the Configure method of Startup.cs, add this line:
+```
+app.UseCustomSerilogRequestLogging();
+```