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//
// System.Web.SessionState.SesionStateModule
//
// Authors:
// Gonzalo Paniagua Javier (gonzalo@ximian.com)
// Stefan Görling (stefan@gorling.se)
// Jackson Harper (jackson@ximian.com)
// Marek Habersack (grendello@gmail.com)
//
// Copyright (C) 2002-2006 Novell, Inc (http://www.novell.com)
// (C) 2003 Stefan Görling (http://www.gorling.se)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
using System.Collections.Specialized;
using System.ComponentModel;
using System.Web.Configuration;
using System.Web.Caching;
using System.Web.Util;
using System.Security.Permissions;
using System.Threading;
using System.Configuration;
using System.Diagnostics;
namespace System.Web.SessionState
{
// CAS - no InheritanceDemand here as the class is sealed
[AspNetHostingPermission (SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
public sealed class SessionStateModule : IHttpModule
{
class CallbackState
{
public readonly HttpContext Context;
public readonly AutoResetEvent AutoEvent;
public readonly string SessionId;
public readonly bool IsReadOnly;
public CallbackState (HttpContext context, AutoResetEvent e, string sessionId, bool isReadOnly) {
this.Context = context;
this.AutoEvent = e;
this.SessionId = sessionId;
this.IsReadOnly = isReadOnly;
}
}
internal const string HeaderName = "AspFilterSessionId";
internal const string CookielessFlagName = "_SessionIDManager_IsCookieLess";
static readonly object startEvent = new object ();
static readonly object endEvent = new object ();
SessionStateSection config;
SessionStateStoreProviderBase handler;
ISessionIDManager idManager;
bool supportsExpiration;
HttpApplication app;
// Store state
bool storeLocked;
TimeSpan storeLockAge;
object storeLockId;
SessionStateActions storeSessionAction;
bool storeIsNew;
// Session state
SessionStateStoreData storeData;
HttpSessionStateContainer container;
// config
TimeSpan executionTimeout;
//int executionTimeoutMS;
EventHandlerList events = new EventHandlerList ();
public event EventHandler Start {
add { events.AddHandler (startEvent, value); }
remove { events.RemoveHandler (startEvent, value); }
}
// This event is public, but only Session_[On]End in global.asax will be invoked if present.
public event EventHandler End {
add { events.AddHandler (endEvent, value); }
remove { events.RemoveHandler (endEvent, value); }
}
[SecurityPermission (SecurityAction.Demand, UnmanagedCode = true)]
public SessionStateModule () {
}
public void Dispose () {
app.BeginRequest -= new EventHandler (OnBeginRequest);
app.AcquireRequestState -= new EventHandler (OnAcquireRequestState);
app.ReleaseRequestState -= new EventHandler (OnReleaseRequestState);
app.EndRequest -= new EventHandler (OnEndRequest);
handler.Dispose ();
}
[EnvironmentPermission (SecurityAction.Assert, Read = "MONO_XSP_STATIC_SESSION")]
public void Init (HttpApplication app)
{
config = (SessionStateSection) WebConfigurationManager.GetSection ("system.web/sessionState");
ProviderSettings settings;
switch (config.Mode) {
case SessionStateMode.Custom:
settings = config.Providers [config.CustomProvider];
if (settings == null)
throw new HttpException (String.Format ("Cannot find '{0}' provider.", config.CustomProvider));
break;
case SessionStateMode.Off:
return;
case SessionStateMode.InProc:
settings = new ProviderSettings (null, typeof (SessionInProcHandler).AssemblyQualifiedName);
break;
case SessionStateMode.SQLServer:
settings = new ProviderSettings (null, typeof (SessionSQLServerHandler).AssemblyQualifiedName);
break;
case SessionStateMode.StateServer:
settings = new ProviderSettings (null, typeof (SessionStateServerHandler).AssemblyQualifiedName);
break;
default:
throw new NotImplementedException (String.Format ("The mode '{0}' is not implemented.", config.Mode));
}
handler = (SessionStateStoreProviderBase) ProvidersHelper.InstantiateProvider (settings, typeof (SessionStateStoreProviderBase));
if (String.IsNullOrEmpty(config.SessionIDManagerType)) {
idManager = new SessionIDManager ();
} else {
Type idManagerType = HttpApplication.LoadType (config.SessionIDManagerType, true);
idManager = (ISessionIDManager)Activator.CreateInstance (idManagerType);
}
try {
idManager.Initialize ();
} catch (Exception ex) {
throw new HttpException ("Failed to initialize session ID manager.", ex);
}
supportsExpiration = handler.SetItemExpireCallback (OnSessionExpired);
HttpRuntimeSection runtime = HttpRuntime.Section;
executionTimeout = runtime.ExecutionTimeout;
//executionTimeoutMS = executionTimeout.Milliseconds;
this.app = app;
app.BeginRequest += new EventHandler (OnBeginRequest);
app.AcquireRequestState += new EventHandler (OnAcquireRequestState);
app.ReleaseRequestState += new EventHandler (OnReleaseRequestState);
app.EndRequest += new EventHandler (OnEndRequest);
}
internal static bool IsCookieLess (HttpContext context, SessionStateSection config) {
if (config.Cookieless == HttpCookieMode.UseCookies)
return false;
if (config.Cookieless == HttpCookieMode.UseUri)
return true;
object cookieless = context.Items [CookielessFlagName];
if (cookieless == null)
return false;
return (bool) cookieless;
}
void OnBeginRequest (object o, EventArgs args)
{
HttpApplication application = (HttpApplication) o;
HttpContext context = application.Context;
string file_path = context.Request.FilePath;
string base_path = VirtualPathUtility.GetDirectory (file_path);
string id = UrlUtils.GetSessionId (base_path);
if (id == null)
return;
string new_path = UrlUtils.RemoveSessionId (base_path, file_path);
context.Request.SetFilePath (new_path);
context.Request.SetHeader (HeaderName, id);
context.Response.SetAppPathModifier (id);
}
void OnAcquireRequestState (object o, EventArgs args) {
Trace.WriteLine ("SessionStateModule.OnAcquireRequestState (hash " + this.GetHashCode ().ToString ("x") + ")");
HttpApplication application = (HttpApplication) o;
HttpContext context = application.Context;
if (!(context.Handler is IRequiresSessionState)) {
Trace.WriteLine ("Handler (" + context.Handler + ") does not require session state");
return;
}
bool isReadOnly = (context.Handler is IReadOnlySessionState);
bool supportSessionIDReissue;
if (idManager.InitializeRequest (context, false, out supportSessionIDReissue))
return; // Redirected, will come back here in a while
string sessionId = idManager.GetSessionID (context);
handler.InitializeRequest (context);
storeData = GetStoreData (context, sessionId, isReadOnly);
storeIsNew = false;
if (storeData == null && !storeLocked) {
storeIsNew = true;
sessionId = idManager.CreateSessionID (context);
Trace.WriteLine ("New session ID allocated: " + sessionId);
bool redirected;
bool cookieAdded;
idManager.SaveSessionID (context, sessionId, out redirected, out cookieAdded);
if (redirected) {
if (supportSessionIDReissue)
handler.CreateUninitializedItem (context, sessionId, (int)config.Timeout.TotalMinutes);
context.Response.End ();
return;
}
else
storeData = handler.CreateNewStoreData (context, (int)config.Timeout.TotalMinutes);
}
else if (storeData == null && storeLocked) {
WaitForStoreUnlock (context, sessionId, isReadOnly);
}
else if (storeData != null &&
!storeLocked &&
storeSessionAction == SessionStateActions.InitializeItem &&
IsCookieLess (context, config)) {
storeData = handler.CreateNewStoreData (context, (int)config.Timeout.TotalMinutes);
}
container = CreateContainer (sessionId, storeData, storeIsNew, isReadOnly);
SessionStateUtility.AddHttpSessionStateToContext (app.Context, container);
if (storeIsNew) {
OnSessionStart ();
HttpSessionState hss = app.Session;
if (hss != null)
storeData.Timeout = hss.Timeout;
}
// Whenever a container is abandoned, we temporarily disable the expire call back.
// So in this case we are quite sure we have a brand new container, so we make sure it works again.
supportsExpiration = handler.SetItemExpireCallback (OnSessionExpired);
}
void OnReleaseRequestState (object o, EventArgs args) {
Trace.WriteLine ("SessionStateModule.OnReleaseRequestState (hash " + this.GetHashCode ().ToString ("x") + ")");
HttpApplication application = (HttpApplication) o;
HttpContext context = application.Context;
if (!(context.Handler is IRequiresSessionState))
return;
Trace.WriteLine ("\tsessionId == " + container.SessionID);
Trace.WriteLine ("\trequest path == " + context.Request.FilePath);
Trace.WriteLine ("\tHandler (" + context.Handler + ") requires session state");
try {
if (!container.IsAbandoned) {
Trace.WriteLine ("\tnot abandoned");
if (!container.IsReadOnly) {
Trace.WriteLine ("\tnot read only, storing and releasing");
handler.SetAndReleaseItemExclusive (context, container.SessionID, storeData, storeLockId, storeIsNew);
}
else {
Trace.WriteLine ("\tread only, releasing");
handler.ReleaseItemExclusive (context, container.SessionID, storeLockId);
}
handler.ResetItemTimeout (context, container.SessionID);
}
else {
handler.ReleaseItemExclusive (context, container.SessionID, storeLockId);
handler.RemoveItem (context, container.SessionID, storeLockId, storeData);
if (supportsExpiration)
// Make sure the expiration handler is not called after we will have raised
// the session end event.
handler.SetItemExpireCallback (null);
SessionStateUtility.RaiseSessionEnd (container, this, args);
}
SessionStateUtility.RemoveHttpSessionStateFromContext (context);
}
finally {
container = null;
storeData = null;
}
}
void OnEndRequest (object o, EventArgs args) {
if (handler == null)
return;
if (container != null)
OnReleaseRequestState (o, args);
HttpApplication application = o as HttpApplication;
if (application == null)
return;
if (handler != null)
handler.EndRequest (application.Context);
}
SessionStateStoreData GetStoreData (HttpContext context, string sessionId, bool isReadOnly) {
SessionStateStoreData item;
item = (isReadOnly) ?
handler.GetItem (context,
sessionId,
out storeLocked,
out storeLockAge,
out storeLockId,
out storeSessionAction)
:
handler.GetItemExclusive (context,
sessionId,
out storeLocked,
out storeLockAge,
out storeLockId,
out storeSessionAction);
if (storeLockId == null)
storeLockId = 0;
return item;
}
void WaitForStoreUnlock (HttpContext context, string sessionId, bool isReadonly) {
AutoResetEvent are = new AutoResetEvent (false);
TimerCallback tc = new TimerCallback (StoreUnlockWaitCallback);
CallbackState cs = new CallbackState (context, are, sessionId, isReadonly);
using (Timer timer = new Timer (tc, cs, 500, 500)) {
try {
are.WaitOne (executionTimeout, false);
}
catch {
storeData = null;
}
}
}
void StoreUnlockWaitCallback (object s) {
CallbackState state = (CallbackState) s;
SessionStateStoreData item = GetStoreData (state.Context, state.SessionId, state.IsReadOnly);
if (item == null && storeLocked && (storeLockAge > executionTimeout)) {
handler.ReleaseItemExclusive (state.Context, state.SessionId, storeLockId);
storeData = null; // Create new state
state.AutoEvent.Set ();
}
else if (item != null && !storeLocked) {
storeData = item;
state.AutoEvent.Set ();
}
}
HttpSessionStateContainer CreateContainer (string sessionId, SessionStateStoreData data, bool isNew, bool isReadOnly) {
if (data == null)
return new HttpSessionStateContainer (
sessionId, null, null, 0, isNew,
config.Cookieless, config.Mode, isReadOnly);
return new HttpSessionStateContainer (
sessionId,
data.Items,
data.StaticObjects,
data.Timeout,
isNew,
config.Cookieless,
config.Mode,
isReadOnly);
}
void OnSessionExpired (string id, SessionStateStoreData item) {
SessionStateUtility.RaiseSessionEnd (
CreateContainer (id, item, false, true),
this, EventArgs.Empty);
}
void OnSessionStart () {
EventHandler eh = events [startEvent] as EventHandler;
if (eh != null)
eh (this, EventArgs.Empty);
}
}
}
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