Large project reorder and consolidation

1 files changed, 139 insertions, 0 deletions

diff --git a/libs/VNLib.Plugins.Sessions.VNCache/src/WebSessionProvider.cs b/libs/VNLib.Plugins.Sessions.VNCache/src/WebSessionProvider.cs
new file mode 100644
index 0000000..44fb936
--- /dev/null
+++ b/libs/VNLib.Plugins.Sessions.VNCache/src/WebSessionProvider.cs
@@ -0,0 +1,139 @@
+/*
+* Copyright (c) 2022 Vaughn Nugent
+* 
+* Library: VNLib
+* Package: VNLib.Plugins.Essentials.Sessions.VNCache
+* File: WebSessionProvider.cs 
+*
+* WebSessionProvider.cs is part of VNLib.Plugins.Essentials.Sessions.VNCache which is part of the larger 
+* VNLib collection of libraries and utilities.
+*
+* VNLib.Plugins.Essentials.Sessions.VNCache is free software: you can redistribute it and/or modify 
+* it under the terms of the GNU Affero General Public License as 
+* published by the Free Software Foundation, either version 3 of the
+* License, or (at your option) any later version.
+*
+* VNLib.Plugins.Essentials.Sessions.VNCache is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+* GNU Affero General Public License for more details.
+*
+* You should have received a copy of the GNU Affero General Public License
+* along with this program.  If not, see https://www.gnu.org/licenses/.
+*/
+
+using System;
+
+using VNLib.Net.Http;
+using VNLib.Plugins.Essentials;
+using VNLib.Plugins.Essentials.Sessions;
+using VNLib.Plugins.Extensions.Loading;
+using VNLib.Plugins.Sessions.Cache.Client;
+
+namespace VNLib.Plugins.Sessions.VNCache
+{
+    /// <summary>
+    /// The implementation of a VNCache web based session
+    /// </summary>
+    [ConfigurationName("web")]
+    internal sealed class WebSessionProvider : SessionCacheClient, ISessionProvider
+    {
+        static readonly TimeSpan BackgroundUpdateTimeout = TimeSpan.FromSeconds(10);
+
+        private readonly IWebSessionIdFactory factory;
+        private readonly uint MaxConnections;
+
+        /// <summary>
+        /// Initializes a new <see cref="WebSessionProvider"/> 
+        /// </summary>
+        /// <param name="client">The cache client to make cache operations against</param>
+        /// <param name="maxCacheItems">The max number of items to store in cache</param>
+        /// <param name="maxWaiting">The maxium number of waiting session events before 503s are sent</param>
+        /// <param name="factory">The session-id factory</param>
+        public WebSessionProvider(IRemoteCacheStore client, int maxCacheItems, uint maxWaiting, IWebSessionIdFactory factory) : base(client, maxCacheItems)
+        {
+            this.factory = factory;
+            MaxConnections = maxWaiting;
+        }
+
+        private string UpdateSessionId(IHttpEvent entity, string oldId)
+        {
+            //Generate and set a new sessionid
+            string newid = factory.GenerateSessionId(entity);
+            //Aquire lock on cache
+            lock (CacheLock)
+            {
+                //Change the cache lookup id
+                if (CacheTable.Remove(oldId, out RemoteSession? session))
+                {
+                    CacheTable.Add(newid, session);
+                }
+            }
+            return newid;
+        }
+        
+        protected override RemoteSession SessionCtor(string sessionId) => new WebSession(sessionId, Store, BackgroundUpdateTimeout, UpdateSessionId);
+
+        public async ValueTask<SessionHandle> GetSessionAsync(IHttpEvent entity, CancellationToken cancellationToken)
+        {
+            //Callback to close the session when the handle is closeed
+            static ValueTask HandleClosedAsync(ISession session, IHttpEvent entity)
+            {
+                return (session as SessionBase)!.UpdateAndRelease(true, entity);
+            }
+            
+            try
+            {
+                //Get session id
+                if (!factory.TryGetSessionId(entity, out string? sessionId))
+                {
+                    //Id not allowed/found, so do not attach a session
+                    return SessionHandle.Empty;
+                }
+
+                //Limit max number of waiting clients
+                if (WaitingConnections > MaxConnections)
+                {
+                    //Set 503 for temporary unavail
+                    entity.CloseResponse(System.Net.HttpStatusCode.ServiceUnavailable);
+                    return new SessionHandle(null, FileProcessArgs.VirtualSkip, null);
+                }
+
+                //Get session
+                RemoteSession session = await GetSessionAsync(entity, sessionId, cancellationToken);
+
+                //If the session is new (not in cache), then overwrite the session id with a new one as user may have specified their own
+                if (session.IsNew)
+                {
+                    session.RegenID();
+                }
+
+                //Make sure the session has not expired yet
+                if (session.Created.Add(factory.ValidFor) < DateTimeOffset.UtcNow)
+                {
+                    //Invalidate the session, so its technically valid for this request, but will be cleared on this handle close cycle
+                    session.Invalidate();
+                    //Clear basic login status
+                    session.Token = null;
+                    session.UserID = null;
+                    session.Privilages = 0;
+                    session.SetLoginToken(null);
+                }
+                
+                return new SessionHandle(session, HandleClosedAsync);
+            }
+            catch (OperationCanceledException)
+            {
+                throw;
+            }
+            catch (SessionException)
+            {
+                throw;
+            }
+            catch (Exception ex)
+            {
+                throw new SessionException("Exception raised while retreiving or loading Web session", ex);
+            }
+        }
+    }
+}