基于MongoDB打造.Net的分布式Session子系统
Taobao有她自己的分布式session框架，.net阵营也不能落后了，在下做了个基于MongoDB的支持最多26台MongoDB的分布式Session框架。
先看看配置文件：
<?xml version="1.0" encoding="utf-8" ?>
<MongoDBSession>
<DbName>SessionDB</DbName>
<IdentityMap Identity="A">mongodb://localhost</IdentityMap>
<IdentityMap Identity="B">mongodb://localhost</IdentityMap>
<IdentityMap Identity="C">mongodb://localhost</IdentityMap>
<IdentityMap Identity="D">mongodb://localhost</IdentityMap>
<IdentityMap Identity="E">mongodb://localhost</IdentityMap>
<IdentityMap Identity="F">mongodb://localhost</IdentityMap>
<IdentityMap Identity="G">mongodb://localhost</IdentityMap>
<IdentityMap Identity="H">mongodb://localhost</IdentityMap>
<IdentityMap Identity="I">mongodb://localhost</IdentityMap>
<IdentityMap Identity="J">mongodb://localhost</IdentityMap>
<IdentityMap Identity="K">mongodb://localhost</IdentityMap>
<IdentityMap Identity="L">mongodb://localhost</IdentityMap>
<IdentityMap Identity="M">mongodb://localhost</IdentityMap>
<IdentityMap Identity="N">mongodb://localhost</IdentityMap>
<IdentityMap Identity="O">mongodb://localhost</IdentityMap>
<IdentityMap Identity="P">mongodb://localhost</IdentityMap>
<IdentityMap Identity="Q">mongodb://localhost</IdentityMap>
<IdentityMap Identity="R">mongodb://localhost</IdentityMap>
<IdentityMap Identity="S">mongodb://localhost</IdentityMap>
<IdentityMap Identity="T">mongodb://localhost</IdentityMap>
<IdentityMap Identity="U">mongodb://localhost</IdentityMap>
<IdentityMap Identity="V">mongodb://localhost</IdentityMap>
<IdentityMap Identity="W">mongodb://localhost</IdentityMap>
<IdentityMap Identity="X">mongodb://localhost</IdentityMap>
<IdentityMap Identity="Y">mongodb://localhost</IdentityMap>
<IdentityMap Identity="Z">mongodb://localhost</IdentityMap>
</MongoDBSession>
从Identity A一直到Z，默认分成了26个Map，具体的C#应用代码：
protected void btnTest_Click(object sender, EventArgs e)
{
Session["A"] = DateTime.Now;
Session["B"] = 1111111111111;
Session["C"] = "fffffffffffffff";
} protected void btnGetSession_Click(object sender, EventArgs e)
{
Response.Write(Session["A"].ToString());
Response.Write("<br />");
Response.Write(Session["B"].ToString());
Response.Write("<br />");
Response.Write(Session["C"].ToString());
}
protected void btnAbandon_Click(object sender, EventArgs e)
{
Session.Abandon();
}
呵呵，就是普通的Session用法。
这个要配置web.config：
<system.web>
<sessionState mode="Custom" customProvider="A2DSessionProvider" sessionIDManagerType="A2DFramework.SessionService.MongoDBSessionIDManager">
<providers>
<add name="A2DSessionProvider" type="A2DFramework.SessionService.MongoDBSessionStateStore"/>
</providers>
</sessionState>
</system.web>
这里会牵扯出2个类：
- A2DFramework.SessionService.MongoDBSessionIDManager
- A2DFramework.SessionService.MongoDBSessionStateStore
MongoDBSessionIDManager
- 自定义生成的cookie值（也就是SessionID），在这个sample中，会生成如“E.asadfalkasdfjal”这样的SessionID，其中前缀E代表这个Session的信息会映射到哪台MongoDB上。
- 关键代码
public class MongoDBSessionIDManager : SessionIDManager
{
private Random rnd = new Random();
private object oLock = new object(); public override string CreateSessionID(System.Web.HttpContext context)
{
int index = 0;
lock(this.oLock)
{
index = rnd.Next(SessionConfiguration.SessionServerIdentities.Length);
}
string sessionId = string.Format("{0}.{1}", SessionConfiguration.SessionServerIdentities[index], base.CreateSessionID(context));
return sessionId;
} public override string Encode(string id)
{
return DESEncryptor.Encode(id, SessionConfiguration.DESKey);
}
public override string Decode(string id)
{
return DESEncryptor.Decode(id, SessionConfiguration.DESKey);
} public override bool Validate(string id)
{
string prefix;
string realId; if (!Helper.ParseSessionID(id, out prefix, out realId))
return false; return base.Validate(realId);
}
}
MongoDBSessionStateStore
- 自定义Session过程中最核心的一个类，代码如下（较多）：
public sealed class MongoDBSessionStateStore : SessionStateStoreProviderBase
{
private SessionStateSection pConfig;
private string pApplicationName; public override void Initialize(string name, System.Collections.Specialized.NameValueCollection config)
{
base.Initialize(name, config); pApplicationName =System.Web.Hosting.HostingEnvironment.ApplicationVirtualPath;
System.Configuration.Configuration cfg = WebConfigurationManager.OpenWebConfiguration(pApplicationName);
pConfig =(SessionStateSection)cfg.GetSection("system.web/sessionState");
} public override SessionStateStoreData CreateNewStoreData(System.Web.HttpContext context, int timeout)
{
return new SessionStateStoreData(new SessionStateItemCollection(), SessionStateUtility.GetSessionStaticObjects(context), timeout);
} public override void CreateUninitializedItem(System.Web.HttpContext context, string id, int timeout)
{
//insert to db
MongoDBSessionEntity session = new MongoDBSessionEntity();
session.ApplicationName = this.pApplicationName;
session.SessionId = id;
session.Created = DateTime.Now;
session.Expires = DateTime.Now.AddMinutes(pConfig.Timeout.Minutes);
session.LockDate = DateTime.Now;
session.LockId = 0;
session.Timeout = timeout;
session.Locked = false;
session.Flags = (int)SessionStateActions.InitializeItem; MongoCollection<MongoDBSessionEntity> collection = Helper.GetMongoDBCollection(id);
collection.Save(session);
} public override void Dispose()
{
} public override void EndRequest(System.Web.HttpContext context)
{
} public override SessionStateStoreData GetItem(System.Web.HttpContext context, string id, out bool locked, out TimeSpan lockAge, out object lockId, out SessionStateActions actions)
{
return GetSessionStoreItem(false, context, id, out locked, out lockAge, out lockId, out actions);
} public override SessionStateStoreData GetItemExclusive(System.Web.HttpContext context, string id, out bool locked, out TimeSpan lockAge, out object lockId, out SessionStateActions actions)
{
return GetSessionStoreItem(true, context, id, out locked, out lockAge, out lockId, out actions);
} public override void InitializeRequest(System.Web.HttpContext context)
{
} public override void ReleaseItemExclusive(System.Web.HttpContext context, string id, object lockId)
{
//update locked=0, expired=, where lockId=?
MongoCollection<MongoDBSessionEntity> collection = Helper.GetMongoDBCollection(id); var query = Query.And( Query.EQ("LockId", int.Parse(lockId.ToString())),
Query.EQ("_id", id),
Query.EQ("ApplicationName", pApplicationName));
var update = Update.Set("Locked", false)
.Set("Expires", DateTime.Now.AddMinutes(pConfig.Timeout.Minutes)); collection.Update(query, update);
} public override void RemoveItem(System.Web.HttpContext context, string id, object lockId, SessionStateStoreData item)
{
//delete where sessionId=? and lockId=? and applicationname=?
MongoCollection<MongoDBSessionEntity> collection = Helper.GetMongoDBCollection(id); var query = Query.And(Query.EQ("LockId", int.Parse(lockId.ToString())),
Query.EQ("_id", id),
Query.EQ("ApplicationName", pApplicationName));
collection.Remove(query);
} public override void ResetItemTimeout(System.Web.HttpContext context, string id)
{
//update expire date
MongoCollection<MongoDBSessionEntity> collection = Helper.GetMongoDBCollection(id); var query = Query.And(Query.EQ("_id", id),
Query.EQ("ApplicationName", pApplicationName));
var update = Update.Set("Expires", DateTime.Now.AddMinutes(pConfig.Timeout.Minutes));
collection.Update(query, update);
} public override void SetAndReleaseItemExclusive(System.Web.HttpContext context, string id, SessionStateStoreData item, object lockId, bool newItem)
{
MongoCollection<MongoDBSessionEntity> collection = Helper.GetMongoDBCollection(id);
if (newItem)
{
//delete expired items
var query = Query.And(Query.EQ("_id", id),
Query.EQ("ApplicationName", pApplicationName),
Query.LT("Expires", DateTime.Now)); collection.Remove(query); //insert new item
MongoDBSessionEntity session = new MongoDBSessionEntity();
session.ApplicationName = this.pApplicationName;
session.SessionId = id;
session.Created = DateTime.Now;
session.Expires = DateTime.Now.AddMinutes(pConfig.Timeout.Minutes);
session.LockDate = DateTime.Now;
session.LockId = 0;
session.Timeout = item.Timeout;
session.Locked = false;
session.Flags = (int)SessionStateActions.None;
session.SessionItems = Helper.Serialize((SessionStateItemCollection)item.Items); collection.Save(session);
}
else
{
//update item
var query = Query.And(Query.EQ("_id", id),
Query.EQ("ApplicationName", pApplicationName),
Query.EQ("LockId", int.Parse(lockId.ToString())));
MongoDBSessionEntity entity= collection.FindOne(query);
entity.Expires = DateTime.Now.AddMinutes(item.Timeout);
entity.SessionItems = Helper.Serialize((SessionStateItemCollection)item.Items);
entity.Locked = false;
collection.Save(entity);
}
} public override bool SetItemExpireCallback(SessionStateItemExpireCallback expireCallback)
{
return false;
} private SessionStateStoreData GetSessionStoreItem(bool lockRecord, System.Web.HttpContext context,
string id,
out bool locked,
out TimeSpan lockAge,
out object lockId,
out SessionStateActions actions)
{
SessionStateStoreData item = null;
lockAge = TimeSpan.Zero;
lockId = null;
locked = false;
actions = 0; bool foundRecord = false;
bool deleteData = false; MongoCollection<MongoDBSessionEntity> collection = Helper.GetMongoDBCollection(id); if (lockRecord)
{
//update db, set locked=1, lockdate=now
var query1 = Query.And(Query.EQ("_id", id),
Query.EQ("ApplicationName", pApplicationName),
Query.EQ("Locked", MongoDB.Bson.BsonValue.Create(false)),
Query.GT("Expires", DateTime.UtcNow)); long count = collection.Find(query1).Count();
if (count == 0)
{
locked = true;
}
else
{
var update = Update.Set("Locked", true).Set("LockDate", DateTime.Now);
collection.Update(query1, update);
locked = false;
}
}
//get item by id
var query2 = Query.And(Query.EQ("_id", id),
Query.EQ("ApplicationName", pApplicationName));
MongoDBSessionEntity entity=collection.FindOne(query2);
if (entity != null)
{
if (entity.Expires < DateTime.Now)
{
locked = false;
deleteData = true;
}
else
{
foundRecord = true;
}
} //delete item if session expired
if (deleteData)
{
var query3 = Query.And(Query.EQ("_id", id),
Query.EQ("ApplicationName", pApplicationName));
collection.Remove(query3);
} if (!foundRecord)
locked = false; if (foundRecord && !locked)
{
if (lockId == null)
lockId = 0;
lockId = (int)lockId + 1; var query4 = Query.And(Query.EQ("_id", id),
Query.EQ("ApplicationName", pApplicationName));
var update4 = Update.Set("LockId", (int)lockId)
.Set("Flags", (int)SessionStateActions.None);
collection.Update(query4, update4); if (actions == SessionStateActions.InitializeItem)
item = CreateNewStoreData(context, pConfig.Timeout.Minutes);
else
item = Helper.Deserialize(context, entity.SessionItems, entity.Timeout);
}
return item;
}
}
由于很多方法会用到MongoCollection，因此写了个static公用函数，如下：
public static MongoCollection<MongoDBSessionEntity> GetMongoDBCollection(string sessionId)
{
IPartitionResolver resolver = new MongoDBSessionPartitionResolver();
string mongoDbConnectionString = resolver.ResolvePartition(sessionId); MongoClient client = new MongoClient(mongoDbConnectionString);
MongoServer srv = client.GetServer();
MongoDatabase db = srv.GetDatabase(SessionConfiguration.MongoDBName);
if (!db.CollectionExists(SessionConfiguration.MongoDBCollectionName))
db.CreateCollection(SessionConfiguration.MongoDBCollectionName); MongoCollection<MongoDBSessionEntity> collection = db.GetCollection<MongoDBSessionEntity>(SessionConfiguration.MongoDBCollectionName); return collection;
}
运行效果：
点击Set Session后：
点击Get Session后：
点击Abandon后：
源代码已经更新到A2D Framework中了。