UserActionLogMiddleware.cs

using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using Microsoft.Owin;

namespace SampleApp.Core.OwinMiddlewares
{
    public class UserActionLogMiddleware : OwinMiddleware
    {
        // このパスにアクセスが来たらログ採取開始
        private const string StartAction = "/api/Top/xxxxxxx";
        
        // 無視するパス。システム的なAPIとか
        private static readonly List<string> IgnoreActions = new List<string>
        {
            "/api/Debug/xxxxxxx",
            "/api/QuestSelect/xxxxxxx"
        };

        //ログ採取し続ける期間。過ぎたら離脱とみなす。もっと短くても良いかも
        private static readonly TimeSpan LoggingSpan = TimeSpan.FromHours(1);

        public UserActionLogMiddleware(OwinMiddleware next) : base(next)
        {
        }

        public override async Task Invoke(IOwinContext context)
        {
            await Next.Invoke(context);

            //ログインユーザーのID
            var uid = context.Get<int?>("LoginUid");
            if (uid == null)
            {
                return;
            }

            if (!context.Request.Path.HasValue || IgnoreActions.Contains(context.Request.Path.Value))
            {
                return;
            }

            //RedisクライアントはCloudStructuresをカスタマイズして使ってます
            var redis = RedisGroups.Cache.String<ActionLogState>("UserActionLog" + uid.Value);
            var now = DateTime.Now;

            //行動ログ採取開始
            if (context.Request.Path.Value == StartAction)
            {
                await redis.Set(new ActionLogState
                {
                    Index = 0,
                    BeforePath = StartAction
                }, LoggingSpan);

                //レコードをためてStream ImsertするためのUtilityクラス
                BigQueryStreaming.Enqueue<Statistics, ActionLog>(new ActionLog
                {
                    Timestamp = now,
                    Uid = uid.Value,
                    ToPath = StartAction,
                    Index = 0
                });
                return;
            }

            //Redisの値が取れない場合は行動ログ採取してない
            var state = await redis.Get();
            if (!state.HasValue)
            {
                return;
            }

            //行動ログ採取中
            var nextIndex = state.Value.Index + 1;
            var beforePath = state.Value.BeforePath;

            await redis.Set(new ActionLogState
            {
                Index = nextIndex,
                BeforePath = context.Request.Path.Value
            }, LoggingSpan);

            BigQueryStreaming.Enqueue<Statistics, ActionLog>(new ActionLog
            {
                Timestamp = now,
                Uid = uid.Value,
                FromPath = beforePath,
                ToPath = context.Request.Path.Value,
                Index = nextIndex
            });
        }
    }

    public class ActionLogState
    {
        public int Index { get; set; }
        public string BeforePath { get; set; }
    }
}