Custom MongoDB listener¶

In the following example, we will create a custom ILogListener which saves the logs to MongoDB database.

To start, we define two entities which will store the logs data, respectively RequestLog and Message.

namespace MyApp.Models
{
    public class RequestLog
    {
        public string Id { get; private set; }
        public DateTime DateTime { get; set; }
        public string UserAgent { get; set; }
        public string HttpMethod { get; set; }
        public string AbsoluteUri { get; set; }
        public double DurationInMilliseconds { get; set; }

        public IEnumerable<Message> Messages { get; set; }

        public RequestLog()
        {
            Id = Guid.NewGuid().ToString();
            Messages = new List<Message>();
        }
    }
}

namespace MyApp.Models
{
    public class Message
    {
        public string Category { get; set; }
        public DateTime DateTime { get; set; }
        public string LogLevel { get; set; }
        public string LogMessage { get; set; }
    }
}

Next, we create the MongoDbContext, which will help us query the MongoDB database.

using MongoDB.Driver;
using MyApp.Models;

namespace MyApp.MongoDb
{
    public class MongoDbContext
    {
        private readonly IMongoDatabase _db;
        public MongoDbContext()
        {
            var mongoClient = new MongoClient("mongodb://localhost:27017");
            _db = mongoClient.GetDatabase("CustomLogsDatabase");
        }

        // we define a "RequestLog" collection
        public IMongoCollection<RequestLog> RequestLogs => _db.GetCollection<RequestLog>("RequestLog");
    }
}

Finally, we create the MongoDbListener, which will save the logs to MongoDB.

using MyApp.Models;
using KissLog;
using KissLog.Web;

namespace MyApp.MongoDb
{
    public class MongoDbListener : ILogListener
    {
        public int MinimumResponseHttpStatusCode { get; set; } = 0;
        public LogLevel MinimumLogMessageLevel { get; set; } = LogLevel.Trace;
        public LogListenerParser Parser { get; set; } = new LogListenerParser();

        public void OnBeginRequest(HttpRequest httpRequest, ILogger logger)
        {
            // do nothing
        }

        public void OnMessage(LogMessage message, ILogger logger)
        {
            // do nothing
        }

        public void OnFlush(FlushLogArgs args, ILogger logger)
        {
            var logMessages = args.MessagesGroups.SelectMany(p => p.Messages).OrderBy(p => p.DateTime).ToList();

            // create the entities
            RequestLog requestLog = ToModel(args.WebProperties);
            requestLog.Messages = logMessages.Select(p => ToModel(p)).ToList();

            // save the entities to MongoDB
            MongoDbContext dbContext = new MongoDbContext();
            dbContext.RequestLogs.InsertOne(requestLog);
        }

        private Message ToModel(LogMessage logMessage)
        {
            return new Message
            {
                Category = logMessage.CategoryName,
                DateTime = logMessage.DateTime,
                LogLevel = logMessage.LogLevel.ToString(),
                LogMessage = logMessage.Message
            };
        }

        private RequestLog ToModel(WebProperties webProperties)
        {
            HttpRequest request = webProperties.Request;
            HttpResponse response = webProperties.Response;

            double durationInMs = (response.EndDateTime - request.StartDateTime).TotalMilliseconds;

            return new RequestLog
            {
                UserAgent = request.UserAgent,
                HttpMethod = request.HttpMethod,
                AbsoluteUri = request.Url.AbsoluteUri,
                DurationInMilliseconds = durationInMs
            };
        }
    }
}

Last step is to register the newly created MongoDbListener.

using KissLog;
using MyApp.MongoDb

namespace MyApp
{
    public class MvcApplication : System.Web.HttpApplication
    {
        // [...]

        private void RegisterKissLogListeners()
        {
            KissLogConfiguration.Listeners.Add(new MongoDbListener());
        }
    }
}

Result

MongoDbListener output¶

Inspecting the request log entity¶