From e677a57bf1cedc55214b0e457778311b8f1ea5ac Mon Sep 17 00:00:00 2001
From: Luke Pulverenti <luke.pulverenti@gmail.com>
Date: Mon, 17 Jun 2013 16:35:43 -0400
Subject: switch to flat file storage

---
 .../JsonDisplayPreferencesRepository.cs            | 164 ++++++++++++++
 .../Persistence/JsonItemRepository.cs              | 235 ++++++++++++++++++++
 .../Persistence/JsonUserDataRepository.cs          | 246 +++++++++++++++++++++
 .../Persistence/JsonUserRepository.cs              | 189 ++++++++++++++++
 4 files changed, 834 insertions(+)
 create mode 100644 MediaBrowser.Server.Implementations/Persistence/JsonDisplayPreferencesRepository.cs
 create mode 100644 MediaBrowser.Server.Implementations/Persistence/JsonItemRepository.cs
 create mode 100644 MediaBrowser.Server.Implementations/Persistence/JsonUserDataRepository.cs
 create mode 100644 MediaBrowser.Server.Implementations/Persistence/JsonUserRepository.cs

(limited to 'MediaBrowser.Server.Implementations/Persistence')

diff --git a/MediaBrowser.Server.Implementations/Persistence/JsonDisplayPreferencesRepository.cs b/MediaBrowser.Server.Implementations/Persistence/JsonDisplayPreferencesRepository.cs
new file mode 100644
index 0000000000..6ac2ff07a6
--- /dev/null
+++ b/MediaBrowser.Server.Implementations/Persistence/JsonDisplayPreferencesRepository.cs
@@ -0,0 +1,164 @@
+using MediaBrowser.Common.Configuration;
+using MediaBrowser.Controller.Persistence;
+using MediaBrowser.Model.Entities;
+using MediaBrowser.Model.Logging;
+using MediaBrowser.Model.Serialization;
+using System;
+using System.Collections.Concurrent;
+using System.IO;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace MediaBrowser.Server.Implementations.Persistence
+{
+    public class JsonDisplayPreferencesRepository : IDisplayPreferencesRepository
+    {
+        private readonly ConcurrentDictionary<string, SemaphoreSlim> _fileLocks = new ConcurrentDictionary<string, SemaphoreSlim>();
+
+        private SemaphoreSlim GetLock(string filename)
+        {
+            return _fileLocks.GetOrAdd(filename, key => new SemaphoreSlim(1, 1));
+        }
+
+        /// <summary>
+        /// Gets the name of the repository
+        /// </summary>
+        /// <value>The name.</value>
+        public string Name
+        {
+            get
+            {
+                return "Json";
+            }
+        }
+
+        /// <summary>
+        /// The _json serializer
+        /// </summary>
+        private readonly IJsonSerializer _jsonSerializer;
+
+        private readonly string _dataPath;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="JsonUserDataRepository" /> class.
+        /// </summary>
+        /// <param name="appPaths">The app paths.</param>
+        /// <param name="jsonSerializer">The json serializer.</param>
+        /// <param name="logManager">The log manager.</param>
+        /// <exception cref="System.ArgumentNullException">
+        /// jsonSerializer
+        /// or
+        /// appPaths
+        /// </exception>
+        public JsonDisplayPreferencesRepository(IApplicationPaths appPaths, IJsonSerializer jsonSerializer, ILogManager logManager)
+        {
+            if (jsonSerializer == null)
+            {
+                throw new ArgumentNullException("jsonSerializer");
+            }
+            if (appPaths == null)
+            {
+                throw new ArgumentNullException("appPaths");
+            }
+
+            _jsonSerializer = jsonSerializer;
+            _dataPath = Path.Combine(appPaths.DataPath, "display-preferences");
+        }
+
+        /// <summary>
+        /// Opens the connection to the database
+        /// </summary>
+        /// <returns>Task.</returns>
+        public Task Initialize()
+        {
+            return Task.FromResult(true);
+        }
+
+        /// <summary>
+        /// Save the display preferences associated with an item in the repo
+        /// </summary>
+        /// <param name="displayPreferences">The display preferences.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <returns>Task.</returns>
+        /// <exception cref="System.ArgumentNullException">item</exception>
+        public async Task SaveDisplayPreferences(DisplayPreferences displayPreferences, CancellationToken cancellationToken)
+        {
+            if (displayPreferences == null)
+            {
+                throw new ArgumentNullException("displayPreferences");
+            }
+            if (displayPreferences.Id == Guid.Empty)
+            {
+                throw new ArgumentNullException("displayPreferences.Id");
+            }
+            if (cancellationToken == null)
+            {
+                throw new ArgumentNullException("cancellationToken");
+            }
+
+            cancellationToken.ThrowIfCancellationRequested();
+
+            if (!Directory.Exists(_dataPath))
+            {
+                Directory.CreateDirectory(_dataPath);
+            }
+
+            var path = Path.Combine(_dataPath, displayPreferences.Id + ".json");
+
+            var semaphore = GetLock(path);
+
+            await semaphore.WaitAsync(cancellationToken).ConfigureAwait(false);
+
+            try
+            {
+                _jsonSerializer.SerializeToFile(displayPreferences, path);
+            }
+            finally
+            {
+                semaphore.Release();
+            }
+        }
+
+        /// <summary>
+        /// Gets the display preferences.
+        /// </summary>
+        /// <param name="displayPreferencesId">The display preferences id.</param>
+        /// <returns>Task{DisplayPreferences}.</returns>
+        /// <exception cref="System.ArgumentNullException">item</exception>
+        public Task<DisplayPreferences> GetDisplayPreferences(Guid displayPreferencesId)
+        {
+            if (displayPreferencesId == Guid.Empty)
+            {
+                throw new ArgumentNullException("displayPreferencesId");
+            }
+
+            return Task.Run(() =>
+            {
+                var path = Path.Combine(_dataPath, displayPreferencesId + ".json");
+
+                try
+                {
+                    return _jsonSerializer.DeserializeFromFile<DisplayPreferences>(path);
+                }
+                catch (IOException)
+                {
+                    // File doesn't exist or is currently bring written to
+                    return null;
+                }
+            });
+        }
+
+        public void Dispose()
+        {
+            // Wait up to two seconds for any existing writes to finish
+            var locks = _fileLocks.Values.ToList()
+                                  .Where(i => i.CurrentCount == 1)
+                                  .Select(i => i.WaitAsync(2000));
+
+            var task = Task.WhenAll(locks);
+
+            Task.WaitAll(task);
+        }
+    }
+}
diff --git a/MediaBrowser.Server.Implementations/Persistence/JsonItemRepository.cs b/MediaBrowser.Server.Implementations/Persistence/JsonItemRepository.cs
new file mode 100644
index 0000000000..d0333e334e
--- /dev/null
+++ b/MediaBrowser.Server.Implementations/Persistence/JsonItemRepository.cs
@@ -0,0 +1,235 @@
+using MediaBrowser.Common.Configuration;
+using MediaBrowser.Common.IO;
+using MediaBrowser.Controller.Entities;
+using MediaBrowser.Controller.Persistence;
+using MediaBrowser.Model.Entities;
+using MediaBrowser.Model.Logging;
+using MediaBrowser.Model.Serialization;
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace MediaBrowser.Server.Implementations.Persistence
+{
+    public class JsonItemRepository : IItemRepository
+    {
+        private readonly ConcurrentDictionary<string, SemaphoreSlim> _fileLocks = new ConcurrentDictionary<string, SemaphoreSlim>();
+
+        private SemaphoreSlim GetLock(string filename)
+        {
+            return _fileLocks.GetOrAdd(filename, key => new SemaphoreSlim(1, 1));
+        }
+        
+        /// <summary>
+        /// Gets the name of the repository
+        /// </summary>
+        /// <value>The name.</value>
+        public string Name
+        {
+            get
+            {
+                return "Json";
+            }
+        }
+
+        /// <summary>
+        /// Gets the json serializer.
+        /// </summary>
+        /// <value>The json serializer.</value>
+        private readonly IJsonSerializer _jsonSerializer;
+
+        private readonly string _criticReviewsPath;
+
+        private readonly FileSystemRepository _itemRepo;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="JsonUserDataRepository" /> class.
+        /// </summary>
+        /// <param name="appPaths">The app paths.</param>
+        /// <param name="jsonSerializer">The json serializer.</param>
+        /// <param name="logManager">The log manager.</param>
+        /// <exception cref="System.ArgumentNullException">appPaths</exception>
+        public JsonItemRepository(IApplicationPaths appPaths, IJsonSerializer jsonSerializer, ILogManager logManager)
+        {
+            if (appPaths == null)
+            {
+                throw new ArgumentNullException("appPaths");
+            }
+            if (jsonSerializer == null)
+            {
+                throw new ArgumentNullException("jsonSerializer");
+            }
+
+            _jsonSerializer = jsonSerializer;
+
+            _criticReviewsPath = Path.Combine(appPaths.DataPath, "critic-reviews");
+
+            _itemRepo = new FileSystemRepository(Path.Combine(appPaths.DataPath, "library"));
+        }
+
+        /// <summary>
+        /// Opens the connection to the database
+        /// </summary>
+        /// <returns>Task.</returns>
+        public Task Initialize()
+        {
+            return Task.FromResult(true);
+        }
+
+        /// <summary>
+        /// Save a standard item in the repo
+        /// </summary>
+        /// <param name="item">The item.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <returns>Task.</returns>
+        /// <exception cref="System.ArgumentNullException">item</exception>
+        public async Task SaveItem(BaseItem item, CancellationToken cancellationToken)
+        {
+            if (item == null)
+            {
+                throw new ArgumentNullException("item");
+            }
+
+            if (!Directory.Exists(_criticReviewsPath))
+            {
+                Directory.CreateDirectory(_criticReviewsPath);
+            }
+
+            var path = _itemRepo.GetResourcePath(item.Id + ".json");
+
+            var parentPath = Path.GetDirectoryName(path);
+            if (!Directory.Exists(parentPath))
+            {
+                Directory.CreateDirectory(parentPath);
+            }
+
+            var semaphore = GetLock(path);
+
+            await semaphore.WaitAsync(cancellationToken).ConfigureAwait(false);
+
+            try
+            {
+                _jsonSerializer.SerializeToFile(item, path);
+            }
+            finally
+            {
+                semaphore.Release();
+            }
+        }
+
+        /// <summary>
+        /// Saves the items.
+        /// </summary>
+        /// <param name="items">The items.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <returns>Task.</returns>
+        /// <exception cref="System.ArgumentNullException">
+        /// items
+        /// or
+        /// cancellationToken
+        /// </exception>
+        public Task SaveItems(IEnumerable<BaseItem> items, CancellationToken cancellationToken)
+        {
+            if (items == null)
+            {
+                throw new ArgumentNullException("items");
+            }
+
+            if (cancellationToken == null)
+            {
+                throw new ArgumentNullException("cancellationToken");
+            }
+
+            var tasks = items.Select(i => SaveItem(i, cancellationToken));
+
+            return Task.WhenAll(tasks);
+        }
+
+        /// <summary>
+        /// Retrieves the item.
+        /// </summary>
+        /// <param name="id">The id.</param>
+        /// <param name="type">The type.</param>
+        /// <returns>BaseItem.</returns>
+        /// <exception cref="System.ArgumentNullException">id</exception>
+        public BaseItem RetrieveItem(Guid id, Type type)
+        {
+            if (id == Guid.Empty)
+            {
+                throw new ArgumentNullException("id");
+            }
+
+            var path = _itemRepo.GetResourcePath(id + ".json");
+
+            try
+            {
+                return (BaseItem)_jsonSerializer.DeserializeFromFile(type, path);
+            }
+            catch (IOException)
+            {
+                // File doesn't exist or is currently bring written to
+                return null;
+            }
+        }
+
+        /// <summary>
+        /// Gets the critic reviews.
+        /// </summary>
+        /// <param name="itemId">The item id.</param>
+        /// <returns>Task{IEnumerable{ItemReview}}.</returns>
+        public Task<IEnumerable<ItemReview>> GetCriticReviews(Guid itemId)
+        {
+            return Task.Run<IEnumerable<ItemReview>>(() =>
+            {
+                var path = Path.Combine(_criticReviewsPath, itemId + ".json");
+
+                try
+                {
+                    return _jsonSerializer.DeserializeFromFile<List<ItemReview>>(path);
+                }
+                catch (IOException)
+                {
+                    // File doesn't exist or is currently bring written to
+                    return new List<ItemReview>();
+                }
+            });
+        }
+
+        /// <summary>
+        /// Saves the critic reviews.
+        /// </summary>
+        /// <param name="itemId">The item id.</param>
+        /// <param name="criticReviews">The critic reviews.</param>
+        /// <returns>Task.</returns>
+        public Task SaveCriticReviews(Guid itemId, IEnumerable<ItemReview> criticReviews)
+        {
+            return Task.Run(() =>
+            {
+                if (!Directory.Exists(_criticReviewsPath))
+                {
+                    Directory.CreateDirectory(_criticReviewsPath);
+                }
+
+                var path = Path.Combine(_criticReviewsPath, itemId + ".json");
+
+                _jsonSerializer.SerializeToFile(criticReviews.ToList(), path);
+            });
+        }
+
+        public void Dispose()
+        {
+            // Wait up to two seconds for any existing writes to finish
+            var locks = _fileLocks.Values.ToList()
+                                  .Where(i => i.CurrentCount == 1)
+                                  .Select(i => i.WaitAsync(2000));
+
+            var task = Task.WhenAll(locks);
+
+            Task.WaitAll(task);
+        }
+    }
+}
diff --git a/MediaBrowser.Server.Implementations/Persistence/JsonUserDataRepository.cs b/MediaBrowser.Server.Implementations/Persistence/JsonUserDataRepository.cs
new file mode 100644
index 0000000000..2f1129bebc
--- /dev/null
+++ b/MediaBrowser.Server.Implementations/Persistence/JsonUserDataRepository.cs
@@ -0,0 +1,246 @@
+using MediaBrowser.Common.Configuration;
+using MediaBrowser.Common.Extensions;
+using MediaBrowser.Controller.Entities;
+using MediaBrowser.Controller.Persistence;
+using MediaBrowser.Model.Logging;
+using MediaBrowser.Model.Serialization;
+using System;
+using System.Collections.Concurrent;
+using System.IO;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace MediaBrowser.Server.Implementations.Persistence
+{
+    public class JsonUserDataRepository : IUserDataRepository
+    {
+        private readonly ConcurrentDictionary<string, SemaphoreSlim> _fileLocks = new ConcurrentDictionary<string, SemaphoreSlim>();
+
+        private SemaphoreSlim GetLock(string filename)
+        {
+            return _fileLocks.GetOrAdd(filename, key => new SemaphoreSlim(1, 1));
+        }
+        
+        private readonly ConcurrentDictionary<string, UserItemData> _userData = new ConcurrentDictionary<string, UserItemData>();
+
+        /// <summary>
+        /// Gets the name of the repository
+        /// </summary>
+        /// <value>The name.</value>
+        public string Name
+        {
+            get
+            {
+                return "Json";
+            }
+        }
+
+        private readonly IJsonSerializer _jsonSerializer;
+
+        private readonly string _dataPath;
+
+        private readonly ILogger _logger;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="JsonUserDataRepository" /> class.
+        /// </summary>
+        /// <param name="appPaths">The app paths.</param>
+        /// <param name="jsonSerializer">The json serializer.</param>
+        /// <param name="logManager">The log manager.</param>
+        /// <exception cref="System.ArgumentNullException">
+        /// jsonSerializer
+        /// or
+        /// appPaths
+        /// </exception>
+        public JsonUserDataRepository(IApplicationPaths appPaths, IJsonSerializer jsonSerializer, ILogManager logManager)
+        {
+            if (jsonSerializer == null)
+            {
+                throw new ArgumentNullException("jsonSerializer");
+            }
+            if (appPaths == null)
+            {
+                throw new ArgumentNullException("appPaths");
+            }
+
+            _logger = logManager.GetLogger(GetType().Name);
+            _jsonSerializer = jsonSerializer;
+            _dataPath = Path.Combine(appPaths.DataPath, "userdata");
+        }
+
+        /// <summary>
+        /// Opens the connection to the database
+        /// </summary>
+        /// <returns>Task.</returns>
+        public Task Initialize()
+        {
+            return Task.FromResult(true);
+        }
+
+        /// <summary>
+        /// Saves the user data.
+        /// </summary>
+        /// <param name="userId">The user id.</param>
+        /// <param name="key">The key.</param>
+        /// <param name="userData">The user data.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <returns>Task.</returns>
+        /// <exception cref="System.ArgumentNullException">userData
+        /// or
+        /// cancellationToken
+        /// or
+        /// userId
+        /// or
+        /// userDataId</exception>
+        public async Task SaveUserData(Guid userId, string key, UserItemData userData, CancellationToken cancellationToken)
+        {
+            if (userData == null)
+            {
+                throw new ArgumentNullException("userData");
+            }
+            if (cancellationToken == null)
+            {
+                throw new ArgumentNullException("cancellationToken");
+            }
+            if (userId == Guid.Empty)
+            {
+                throw new ArgumentNullException("userId");
+            }
+            if (string.IsNullOrEmpty(key))
+            {
+                throw new ArgumentNullException("key");
+            }
+
+            cancellationToken.ThrowIfCancellationRequested();
+
+            try
+            {
+                await PersistUserData(userId, key, userData, cancellationToken).ConfigureAwait(false);
+
+                // Once it succeeds, put it into the dictionary to make it available to everyone else
+                _userData.AddOrUpdate(GetInternalKey(userId, key), userData, delegate { return userData; });
+            }
+            catch (Exception ex)
+            {
+                _logger.ErrorException("Error saving user data", ex);
+
+                throw;
+            }
+        }
+
+        /// <summary>
+        /// Gets the internal key.
+        /// </summary>
+        /// <param name="userId">The user id.</param>
+        /// <param name="key">The key.</param>
+        /// <returns>System.String.</returns>
+        private string GetInternalKey(Guid userId, string key)
+        {
+            return userId + key;
+        }
+
+        /// <summary>
+        /// Persists the user data.
+        /// </summary>
+        /// <param name="userId">The user id.</param>
+        /// <param name="key">The key.</param>
+        /// <param name="userData">The user data.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <returns>Task.</returns>
+        public async Task PersistUserData(Guid userId, string key, UserItemData userData, CancellationToken cancellationToken)
+        {
+            cancellationToken.ThrowIfCancellationRequested();
+
+            var path = GetUserDataPath(userId, key);
+
+            var parentPath = Path.GetDirectoryName(path);
+            if (!Directory.Exists(parentPath))
+            {
+                Directory.CreateDirectory(parentPath);
+            }
+
+            var semaphore = GetLock(path);
+
+            await semaphore.WaitAsync(cancellationToken).ConfigureAwait(false);
+
+            try
+            {
+                _jsonSerializer.SerializeToFile(userData, path);
+            }
+            finally
+            {
+                semaphore.Release();
+            }
+        }
+
+        /// <summary>
+        /// Gets the user data.
+        /// </summary>
+        /// <param name="userId">The user id.</param>
+        /// <param name="key">The key.</param>
+        /// <returns>Task{UserItemData}.</returns>
+        /// <exception cref="System.ArgumentNullException">
+        /// userId
+        /// or
+        /// key
+        /// </exception>
+        public UserItemData GetUserData(Guid userId, string key)
+        {
+            if (userId == Guid.Empty)
+            {
+                throw new ArgumentNullException("userId");
+            }
+            if (string.IsNullOrEmpty(key))
+            {
+                throw new ArgumentNullException("key");
+            }
+
+            return _userData.GetOrAdd(GetInternalKey(userId, key), keyName => RetrieveUserData(userId, key));
+        }
+
+        /// <summary>
+        /// Retrieves the user data.
+        /// </summary>
+        /// <param name="userId">The user id.</param>
+        /// <param name="key">The key.</param>
+        /// <returns>Task{UserItemData}.</returns>
+        private UserItemData RetrieveUserData(Guid userId, string key)
+        {
+            var path = GetUserDataPath(userId, key);
+
+            try
+            {
+                return _jsonSerializer.DeserializeFromFile<UserItemData>(path);
+            }
+            catch (IOException)
+            {
+                // File doesn't exist or is currently bring written to
+                return new UserItemData { UserId = userId };
+            }
+        }
+
+        private string GetUserDataPath(Guid userId, string key)
+        {
+            var userFolder = Path.Combine(_dataPath, userId.ToString());
+
+            var keyHash = key.GetMD5().ToString();
+
+            var prefix = keyHash.Substring(0, 1);
+
+            return Path.Combine(userFolder, prefix, keyHash + ".json");
+        }
+
+        public void Dispose()
+        {
+            // Wait up to two seconds for any existing writes to finish
+            var locks = _fileLocks.Values.ToList()
+                                  .Where(i => i.CurrentCount == 1)
+                                  .Select(i => i.WaitAsync(2000));
+
+            var task = Task.WhenAll(locks);
+
+            Task.WaitAll(task);
+        }
+    }
+}
\ No newline at end of file
diff --git a/MediaBrowser.Server.Implementations/Persistence/JsonUserRepository.cs b/MediaBrowser.Server.Implementations/Persistence/JsonUserRepository.cs
new file mode 100644
index 0000000000..0573c6e2ef
--- /dev/null
+++ b/MediaBrowser.Server.Implementations/Persistence/JsonUserRepository.cs
@@ -0,0 +1,189 @@
+using MediaBrowser.Common.Configuration;
+using MediaBrowser.Controller.Entities;
+using MediaBrowser.Controller.Persistence;
+using MediaBrowser.Model.Logging;
+using MediaBrowser.Model.Serialization;
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace MediaBrowser.Server.Implementations.Persistence
+{
+    public class JsonUserRepository : IUserRepository
+    {
+        private readonly ConcurrentDictionary<string, SemaphoreSlim> _fileLocks = new ConcurrentDictionary<string, SemaphoreSlim>();
+
+        private SemaphoreSlim GetLock(string filename)
+        {
+            return _fileLocks.GetOrAdd(filename, key => new SemaphoreSlim(1, 1));
+        }
+        
+        /// <summary>
+        /// Gets the name of the repository
+        /// </summary>
+        /// <value>The name.</value>
+        public string Name
+        {
+            get
+            {
+                return "Json";
+            }
+        }
+
+        /// <summary>
+        /// Gets the json serializer.
+        /// </summary>
+        /// <value>The json serializer.</value>
+        private readonly IJsonSerializer _jsonSerializer;
+
+        private readonly string _dataPath;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="JsonUserRepository"/> class.
+        /// </summary>
+        /// <param name="appPaths">The app paths.</param>
+        /// <param name="jsonSerializer">The json serializer.</param>
+        /// <param name="logManager">The log manager.</param>
+        /// <exception cref="System.ArgumentNullException">
+        /// appPaths
+        /// or
+        /// jsonSerializer
+        /// </exception>
+        public JsonUserRepository(IApplicationPaths appPaths, IJsonSerializer jsonSerializer, ILogManager logManager)
+        {
+            if (appPaths == null)
+            {
+                throw new ArgumentNullException("appPaths");
+            }
+            if (jsonSerializer == null)
+            {
+                throw new ArgumentNullException("jsonSerializer");
+            }
+
+            _jsonSerializer = jsonSerializer;
+
+            _dataPath = Path.Combine(appPaths.DataPath, "users");
+        }
+
+        /// <summary>
+        /// Opens the connection to the database
+        /// </summary>
+        /// <returns>Task.</returns>
+        public Task Initialize()
+        {
+            return Task.FromResult(true);
+        }
+
+        /// <summary>
+        /// Save a user in the repo
+        /// </summary>
+        /// <param name="user">The user.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <returns>Task.</returns>
+        /// <exception cref="System.ArgumentNullException">user</exception>
+        public async Task SaveUser(User user, CancellationToken cancellationToken)
+        {
+            if (user == null)
+            {
+                throw new ArgumentNullException("user");
+            }
+
+            if (cancellationToken == null)
+            {
+                throw new ArgumentNullException("cancellationToken");
+            }
+
+            cancellationToken.ThrowIfCancellationRequested();
+
+            if (!Directory.Exists(_dataPath))
+            {
+                Directory.CreateDirectory(_dataPath);
+            }
+
+            var path = Path.Combine(_dataPath, user.Id + ".json");
+
+            var semaphore = GetLock(path);
+
+            await semaphore.WaitAsync(cancellationToken).ConfigureAwait(false);
+
+            try
+            {
+                _jsonSerializer.SerializeToFile(user, path);
+            }
+            finally
+            {
+                semaphore.Release();
+            }
+        }
+
+        /// <summary>
+        /// Retrieve all users from the database
+        /// </summary>
+        /// <returns>IEnumerable{User}.</returns>
+        public IEnumerable<User> RetrieveAllUsers()
+        {
+            try
+            {
+                return Directory.EnumerateFiles(_dataPath, "*.json", SearchOption.TopDirectoryOnly)
+                    .Select(i => _jsonSerializer.DeserializeFromFile<User>(i));
+            }
+            catch (IOException)
+            {
+                return new List<User>();
+            }
+        }
+
+        /// <summary>
+        /// Deletes the user.
+        /// </summary>
+        /// <param name="user">The user.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <returns>Task.</returns>
+        /// <exception cref="System.ArgumentNullException">user</exception>
+        public async Task DeleteUser(User user, CancellationToken cancellationToken)
+        {
+            if (user == null)
+            {
+                throw new ArgumentNullException("user");
+            }
+
+            if (cancellationToken == null)
+            {
+                throw new ArgumentNullException("cancellationToken");
+            }
+
+            cancellationToken.ThrowIfCancellationRequested();
+
+            var path = Path.Combine(_dataPath, user.Id + ".json");
+
+            var semaphore = GetLock(path);
+
+            await semaphore.WaitAsync(cancellationToken).ConfigureAwait(false);
+
+            try
+            {
+                File.Delete(path);
+            }
+            finally
+            {
+                semaphore.Release();
+            }
+        }
+
+        public void Dispose()
+        {
+            // Wait up to two seconds for any existing writes to finish
+            var locks = _fileLocks.Values.ToList()
+                                  .Where(i => i.CurrentCount == 1)
+                                  .Select(i => i.WaitAsync(2000));
+
+            var task = Task.WhenAll(locks);
+
+            Task.WaitAll(task);
+        }
+    }
+}
-- 
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