Added preferences backend (#465)

* Added preferences backend

* Gender -> Sex

* ClientPreferencesManager properties

* Username validation

* Fixed client init

* WIP db

* Actually working sqlite db

* Dropped shitty sqlite libraries, dropped DbUp, added MigrationManager

* Added profile deletion, test

* Docs, sanity, tests, cleanup

* Cleaned up profile and appearance, fixed running on .net core

Co-authored-by: Pieter-Jan Briers <pieterjan.briers@gmail.com>

Content.Server/Preferences/Migrations/MigrationManager.cs

@@ -0,0 +1,169 @@
+using System.Collections.Generic;
+using System.Data;
+using System.IO;
+using System.Linq;
+using System.Reflection;
+using System.Text.RegularExpressions;
+using Dapper;
+using JetBrains.Annotations;
+using Microsoft.Data.Sqlite;
+using Robust.Shared.Log;
+
+namespace Content.Server.Preferences.Migrations
+{
+    /// <summary>
+    /// Ensures database schemas are up to date.
+    /// </summary>
+    public static class MigrationManager
+    {
+        /// <summary>
+        /// Ensures the database schema for the given connection string is up to date.
+        /// </summary>
+        public static void PerformUpgrade(string connectionString)
+        {
+            using (var connection = new SqliteConnection(connectionString))
+            {
+                EnsureSchemaVersionTableExists(connection);
+                foreach (var migrationToRun in MigrationsToRun(connection))
+                {
+                    Logger.InfoS("db", "Running migration {0}", migrationToRun.Id);
+                    migrationToRun.Run(connection);
+                }
+            }
+        }
+
+        /// <summary>
+        /// Generated for each SQL file found.
+        /// </summary>
+        private class Migration
+        {
+            public readonly string Id;
+            private readonly string _sql;
+
+            public Migration(string id, string sql)
+            {
+                Id = id;
+                _sql = sql;
+            }
+
+            /// <summary>
+            /// Executes the query in <see cref="_sql"/> and logs this in the SchemaVersion table.
+            /// </summary>
+            public void Run(IDbConnection connection)
+            {
+                connection.Execute(_sql);
+                InsertMigrationLog(connection, Id);
+            }
+        }
+
+        private const string InsertMigrationLogQuery =
+            @"INSERT INTO SchemaVersion (Id) VALUES (@Id)";
+        /// <summary>
+        /// Inserts a <see cref="MigrationLog"/> in the SchemaVersion table.
+        /// </summary>
+        private static void InsertMigrationLog(IDbConnection connection, string id)
+        {
+            Logger.InfoS("db", "Completing migration {0}", id);
+            connection.Execute(InsertMigrationLogQuery, new {Id = id});
+        }
+
+        /// <summary>
+        /// An entry in the SchemaVersion table.
+        /// </summary>
+        [UsedImplicitly]
+        private class MigrationLog
+        {
+            public string Id;
+            public string Timestamp;
+        }
+
+        private const string GetRanMigrationsQuery =
+            @"SELECT Id, Timestamp FROM SchemaVersion ORDER BY Id COLLATE NOCASE";
+        /// <summary>
+        /// Fetches a collection of <see cref="MigrationLog"/> from the SchemaVersion table and returns it.
+        /// </summary>
+        private static IEnumerable<MigrationLog> RanMigrations(IDbConnection connection)
+        {
+            return connection.Query<MigrationLog>(GetRanMigrationsQuery);
+        }
+
+        /// <summary>
+        /// Finds all available migrations, returns those that haven't been run yet.
+        /// </summary>
+        private static List<Migration> MigrationsToRun(IDbConnection connection)
+        {
+            var discoveredMigrations = DiscoverMigrations(connection);
+            if (discoveredMigrations.Count == 0)
+            {
+                // No migrations found.
+                return null;
+            }
+
+            var ranMigrations = RanMigrations(connection);
+
+            // Filter out migrations that have already been executed
+            discoveredMigrations
+                .RemoveAll(migration => ranMigrations.Any(ranMigration => migration.Id == ranMigration.Id));
+            return discoveredMigrations;
+        }
+
+        /// <summary>
+        /// Given an embedded resource's full path returns its contents as a string.
+        /// </summary>
+        private static string ResourceAssemblyToString(string resourceName)
+        {
+            using (var stream = Assembly.GetExecutingAssembly()
+                .GetManifestResourceStream(resourceName))
+            using (var reader = new StreamReader(stream))
+            {
+                return reader.ReadToEnd();
+            }
+        }
+
+        /// <summary>
+        /// Searches the current assembly for SQL migration files.
+        /// TODO: Filter by subfolder so that different databases use different sets of migrations.
+        /// </summary>
+        [NotNull]
+        private static List<Migration> DiscoverMigrations(IDbConnection connection)
+        {
+            var results = new List<Migration>();
+            var assembly = Assembly.GetExecutingAssembly();
+            foreach (var sqlResourceName in assembly
+                .GetManifestResourceNames()
+                .Where(IsValidMigrationFileName))
+            {
+                var splitName = sqlResourceName.Split('.');
+                // The second to last string in the list is the actual file name without the final ".sql"
+                var migrationId = splitName[splitName.Length - 2];
+                var sqlContents = ResourceAssemblyToString(sqlResourceName);
+                results.Add(new Migration(migrationId, sqlContents));
+            }
+
+            return results;
+        }
+
+        /// <summary>
+        /// A valid file name is "000_Initial.sql". A dot (from the path, not to be included in the filename itself),
+        /// three digits, a mandatory underscore, any number of characters, a mandatory ".sql".
+        /// </summary>
+        private static bool IsValidMigrationFileName(string name)
+        {
+            return Regex.IsMatch(name, @"\.\d\d\d_[a-zA-Z]+\.sql$");
+        }
+
+        private const string EnsureSchemaVersionTableExistsQuery =
+            @"CREATE TABLE IF NOT EXISTS SchemaVersion (
+              Id TEXT NOT NULL UNIQUE,
+              Timestamp TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP
+              )";
+
+        /// <summary>
+        /// Creates the SchemaVersion table if it doesn't exist.
+        /// </summary>
+        private static void EnsureSchemaVersionTableExists(IDbConnection connection)
+        {
+            connection.Execute(EnsureSchemaVersionTableExistsQuery);
+        }
+    }
+}