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1 files changed, 310 insertions, 0 deletions

diff --git a/VNLib.Data.Caching/src/ClientExtensions.cs b/VNLib.Data.Caching/src/ClientExtensions.cs
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+++ b/VNLib.Data.Caching/src/ClientExtensions.cs
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+using System;
+using System.IO;
+using System.Linq;
+using System.Buffers;
+using System.Text.Json;
+using System.Threading;
+using System.Threading.Tasks;
+using System.Collections.Generic;
+using System.Text.Json.Serialization;
+using System.Runtime.CompilerServices;
+
+using VNLib.Utils.Logging;
+using VNLib.Net.Messaging.FBM;
+using VNLib.Net.Messaging.FBM.Client;
+using VNLib.Net.Messaging.FBM.Server;
+using VNLib.Data.Caching.Exceptions;
+
+using static VNLib.Data.Caching.Constants;
+
+namespace VNLib.Data.Caching
+{
+
+    /// <summary>
+    /// Provides caching extension methods for <see cref="FBMClient"/>
+    /// </summary>
+    public static class ClientExtensions
+    {
+        private static readonly JsonSerializerOptions LocalOptions = new()
+        {
+            DictionaryKeyPolicy = JsonNamingPolicy.CamelCase,
+            NumberHandling = JsonNumberHandling.Strict,
+            ReadCommentHandling = JsonCommentHandling.Disallow,
+            WriteIndented = false,
+            DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
+            IgnoreReadOnlyFields = true,
+            PropertyNameCaseInsensitive = true,
+            IncludeFields = false,
+
+            //Use small buffers
+            DefaultBufferSize = 128
+        };
+
+
+        private static readonly ConditionalWeakTable<FBMClient, SemaphoreSlim> GetLock = new();
+        private static readonly ConditionalWeakTable<FBMClient, SemaphoreSlim> UpdateLock = new();
+
+        private static SemaphoreSlim GetLockCtor(FBMClient client) => new (50);
+
+        private static SemaphoreSlim UpdateLockCtor(FBMClient client) => new (25);
+
+        /// <summary>
+        /// Gets an object from the server if it exists
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="client"></param>
+        /// <param name="objectId">The id of the object to get</param>
+        /// <param name="cancellationToken">A token to cancel the operation</param>
+        /// <returns>A task that completes to return the results of the response payload</returns>
+        /// <exception cref="JsonException"></exception>
+        /// <exception cref="OutOfMemoryException"></exception>
+        /// <exception cref="InvalidStatusException"></exception>
+        /// <exception cref="ObjectDisposedException"></exception>
+        /// <exception cref="InvalidResponseException"></exception>
+        public static async Task<T?> GetObjectAsync<T>(this FBMClient client, string objectId, CancellationToken cancellationToken = default)
+        {
+            client.Config.DebugLog?.Debug("[DEBUG] Getting object {id}", objectId);
+            SemaphoreSlim getLock = GetLock.GetValue(client, GetLockCtor);
+            //Wait for entry
+            await getLock.WaitAsync(cancellationToken);
+            //Rent a new request
+            FBMRequest request = client.RentRequest();
+            try
+            {
+                //Set action as get/create
+                request.WriteHeader(HeaderCommand.Action, Actions.Get);
+                //Set session-id header
+                request.WriteHeader(Constants.ObjectId, objectId);
+                
+                //Make request
+                using FBMResponse response = await client.SendAsync(request, cancellationToken);
+
+                response.ThrowIfNotSet();
+                //Get the status code
+                ReadOnlyMemory<char> status = response.Headers.FirstOrDefault(static a => a.Key == HeaderCommand.Status).Value;
+                if (status.Span.Equals(ResponseCodes.Okay, StringComparison.Ordinal))
+                {
+                    return JsonSerializer.Deserialize<T>(response.ResponseBody, LocalOptions);
+                }
+                //Session may not exist on the server yet
+                if (status.Span.Equals(ResponseCodes.NotFound, StringComparison.Ordinal))
+                {
+                    return default;
+                }
+                throw new InvalidStatusException("Invalid status code recived for object get request", status.ToString());
+            }
+            finally
+            {
+                getLock.Release();
+                client.ReturnRequest(request);
+            }
+        }
+
+        /// <summary>
+        /// Updates the state of the object, and optionally updates the ID of the object. The data 
+        /// parameter is serialized, buffered, and streamed to the remote server
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="client"></param>
+        /// <param name="objectId">The id of the object to update or replace</param>
+        /// <param name="newId">An optional parameter to specify a new ID for the old object</param>
+        /// <param name="data">The payload data to serialize and set as the data state of the session</param>
+        /// <param name="cancellationToken">A token to cancel the operation</param>
+        /// <returns>A task that resolves when the server responds</returns>
+        /// <exception cref="JsonException"></exception>
+        /// <exception cref="OutOfMemoryException"></exception>
+        /// <exception cref="InvalidStatusException"></exception>
+        /// <exception cref="ObjectDisposedException"></exception>
+        /// <exception cref="InvalidResponseException"></exception>
+        /// <exception cref="MessageTooLargeException"></exception>
+        /// <exception cref="ObjectNotFoundException"></exception>
+        public static async Task AddOrUpdateObjectAsync<T>(this FBMClient client, string objectId, string? newId, T data, CancellationToken cancellationToken = default)
+        {
+            client.Config.DebugLog?.Debug("[DEBUG] Updating object {id}, newid {nid}", objectId, newId);
+            SemaphoreSlim updateLock = UpdateLock.GetValue(client, UpdateLockCtor);
+            //Wait for entry
+            await updateLock.WaitAsync(cancellationToken);
+            //Rent a new request
+            FBMRequest request = client.RentRequest();
+            try
+            {
+                //Set action as get/create
+                request.WriteHeader(HeaderCommand.Action, Actions.AddOrUpdate);
+                //Set session-id header
+                request.WriteHeader(Constants.ObjectId, objectId);
+                //if new-id set, set the new-id header
+                if (!string.IsNullOrWhiteSpace(newId))
+                {
+                    request.WriteHeader(Constants.NewObjectId, newId);
+                }
+                //Get the body writer for the message
+                IBufferWriter<byte> bodyWriter = request.GetBodyWriter();
+                //Write json data to the message
+                using (Utf8JsonWriter jsonWriter = new(bodyWriter))
+                {
+                    JsonSerializer.Serialize(jsonWriter, data, LocalOptions);
+                }
+
+                //Make request
+                using FBMResponse response = await client.SendAsync(request, cancellationToken);
+
+                response.ThrowIfNotSet();
+                //Get the status code
+                ReadOnlyMemory<char> status = response.Headers.FirstOrDefault(static a => a.Key == HeaderCommand.Status).Value;
+                //Check status code
+                if (status.Span.Equals(ResponseCodes.Okay, StringComparison.OrdinalIgnoreCase))
+                {
+                    return;
+                }
+                else if(status.Span.Equals(ResponseCodes.NotFound, StringComparison.OrdinalIgnoreCase))
+                {
+                    throw new ObjectNotFoundException($"object {objectId} not found on remote server");
+                }
+                //Invalid status
+                throw new InvalidStatusException("Invalid status code recived for object upsert request", status.ToString());
+            }
+            finally
+            {
+                updateLock.Release();
+                //Return the request(clears data and reset)
+                client.ReturnRequest(request);
+            }
+        }
+        
+        /// <summary>
+        /// Asynchronously deletes an object in the remote store
+        /// </summary>
+        /// <param name="client"></param>
+        /// <param name="objectId">The id of the object to update or replace</param>
+        /// <param name="cancellationToken">A token to cancel the operation</param>
+        /// <returns>A task that resolves when the operation has completed</returns>
+        /// <exception cref="InvalidStatusException"></exception>
+        /// <exception cref="ObjectDisposedException"></exception>
+        /// <exception cref="InvalidResponseException"></exception>
+        /// <exception cref="ObjectNotFoundException"></exception>
+        public static async Task DeleteObjectAsync(this FBMClient client, string objectId, CancellationToken cancellationToken = default)
+        {
+            client.Config.DebugLog?.Debug("[DEBUG] Deleting object {id}", objectId);
+
+            SemaphoreSlim updateLock = UpdateLock.GetValue(client, UpdateLockCtor);
+            //Wait for entry
+            await updateLock.WaitAsync(cancellationToken);
+            //Rent a new request
+            FBMRequest request = client.RentRequest();
+            try
+            {
+                //Set action as delete
+                request.WriteHeader(HeaderCommand.Action, Actions.Delete);
+                //Set session-id header
+                request.WriteHeader(Constants.ObjectId, objectId);
+
+                //Make request
+                using FBMResponse response = await client.SendAsync(request, cancellationToken);
+
+                response.ThrowIfNotSet();
+                //Get the status code
+                ReadOnlyMemory<char> status = response.Headers.FirstOrDefault(static a => a.Key == HeaderCommand.Status).Value;
+                if (status.Span.Equals(ResponseCodes.Okay, StringComparison.Ordinal))
+                {
+                    return;
+                }
+                else if(status.Span.Equals(ResponseCodes.NotFound, StringComparison.OrdinalIgnoreCase))
+                {
+                    throw new ObjectNotFoundException($"object {objectId} not found on remote server");
+                }
+                throw new InvalidStatusException("Invalid status code recived for object get request", status.ToString());
+            }
+            finally
+            {
+                updateLock.Release();
+                client.ReturnRequest(request);
+            }
+        }
+
+        /// <summary>
+        /// Dequeues a change event from the server event queue for the current connection, or waits until a change happens
+        /// </summary>
+        /// <param name="client"></param>
+        /// <param name="cancellationToken">A token to cancel the deuque operation</param>
+        /// <returns>A <see cref="KeyValuePair{TKey, TValue}"/> that contains the modified object id and optionally its new id</returns>
+        public static async Task<WaitForChangeResult> WaitForChangeAsync(this FBMClient client, CancellationToken cancellationToken = default)
+        {
+            //Rent a new request
+            FBMRequest request = client.RentRequest();
+            try
+            {
+                //Set action as event dequeue to dequeue a change event
+                request.WriteHeader(HeaderCommand.Action, Actions.Dequeue);
+
+                //Make request
+                using FBMResponse response = await client.SendAsync(request, cancellationToken);
+
+                response.ThrowIfNotSet();
+
+                return new()
+                {
+                    Status = response.Headers.FirstOrDefault(static a => a.Key == HeaderCommand.Status).Value.ToString(),
+                    CurrentId = response.Headers.SingleOrDefault(static v => v.Key == Constants.ObjectId).Value.ToString(),
+                    NewId = response.Headers.SingleOrDefault(static v => v.Key == Constants.NewObjectId).Value.ToString()
+                };
+            }
+            finally
+            {
+                client.ReturnRequest(request);
+            }
+        }
+
+        /// <summary>
+        /// Gets the Object-id for the request message, or throws an <see cref="InvalidOperationException"/> if not specified
+        /// </summary>
+        /// <param name="context"></param>
+        /// <returns>The id of the object requested</returns>
+        /// <exception cref="InvalidOperationException"></exception>
+        public static string ObjectId(this FBMContext context)
+        {
+            return context.Request.Headers.First(static kvp => kvp.Key == Constants.ObjectId).Value.ToString();
+        }
+        /// <summary>
+        /// Gets the new ID of the object if specified from the request. Null if the request did not specify an id update
+        /// </summary>
+        /// <param name="context"></param>
+        /// <returns>The new ID of the object if speicifed, null otherwise</returns>
+        public static string? NewObjectId(this FBMContext context)
+        {
+            return context.Request.Headers.FirstOrDefault(static kvp => kvp.Key == Constants.NewObjectId).Value.ToString();
+        }
+        /// <summary>
+        /// Gets the request method for the request
+        /// </summary>
+        /// <param name="context"></param>
+        /// <returns>The request method string</returns>
+        public static string Method(this FBMContext context)
+        {
+            return context.Request.Headers.First(static kvp => kvp.Key == HeaderCommand.Action).Value.ToString();
+        }
+        /// <summary>
+        /// Closes a response with a status code
+        /// </summary>
+        /// <param name="context"></param>
+        /// <param name="responseCode">The status code to send to the client</param>
+        public static void CloseResponse(this FBMContext context, string responseCode)
+        {
+            context.Response.WriteHeader(HeaderCommand.Status, responseCode);
+        }
+
+
+        /// <summary>
+        /// Initializes the worker for a reconnect policy and returns an object that can listen for changes
+        /// and configure the connection as necessary
+        /// </summary>
+        /// <param name="worker"></param>
+        /// <param name="retryDelay">The amount of time to wait between retries</param>
+        /// <param name="serverUri">The uri to reconnect the client to</param>
+        /// <returns>A <see cref="ClientRetryManager{T}"/> for listening for retry events</returns>
+        public static ClientRetryManager<T> SetReconnectPolicy<T>(this T worker, TimeSpan retryDelay, Uri serverUri) where T: IStatefulConnection
+        {
+            //Return new manager
+            return new (worker, retryDelay, serverUri);
+        }
+    }
+}