using System.Collections.Immutable; using System.Net.Http.Json; using System.Text.Json; using Phantom.Common.Data.Minecraft; using Phantom.Utils.Cryptography; using Phantom.Utils.IO; using Phantom.Utils.Logging; using Phantom.Utils.Runtime; using Serilog; namespace Phantom.Controller.Minecraft; sealed class MinecraftVersionApi : IDisposable { private static readonly ILogger Logger = PhantomLogger.Create<MinecraftVersionApi>(); private const string VersionManifestUrl = "https://launchermeta.mojang.com/mc/game/version_manifest.json"; private readonly HttpClient http = new (); public void Dispose() { http.Dispose(); } public async Task<ImmutableArray<MinecraftVersion>> GetVersions(CancellationToken cancellationToken) { return await FetchVersions(cancellationToken) ?? ImmutableArray<MinecraftVersion>.Empty; } private async Task<ImmutableArray<MinecraftVersion>?> FetchVersions(CancellationToken cancellationToken) { return await FetchOrFailSilently(async () => { var versionManifest = await FetchJson(VersionManifestUrl, "version manifest", cancellationToken); return GetVersionsFromManifest(versionManifest); }); } public async Task<FileDownloadInfo?> GetServerExecutableInfo(ImmutableArray<MinecraftVersion> versions, string version, CancellationToken cancellationToken) { var versionObject = versions.FirstOrDefault(v => v.Id == version); if (versionObject == null) { Logger.Error("Version {Version} was not found in version manifest.", version); return null; } return await FetchOrFailSilently(async () => { var versionMetadata = await FetchJson(versionObject.MetadataUrl, "version metadata", cancellationToken); return GetServerExecutableInfoFromMetadata(versionMetadata); }); } private static async Task<T?> FetchOrFailSilently<T>(Func<Task<T?>> task) { try { return await task(); } catch (StopProcedureException) { return default; } catch (Exception e) { Logger.Error(e, "An unexpected error occurred."); return default; } } private async Task<JsonElement> FetchJson(string url, string description, CancellationToken cancellationToken) { Logger.Debug("Fetching {Description} JSON from: {Url}", description, url); try { return await http.GetFromJsonAsync<JsonElement>(url, cancellationToken); } catch (HttpRequestException e) { Logger.Error(e, "Unable to download {Description}.", description); throw StopProcedureException.Instance; } catch (Exception e) { Logger.Error(e, "Unable to parse {Description} as JSON.", description); throw StopProcedureException.Instance; } } private static ImmutableArray<MinecraftVersion> GetVersionsFromManifest(JsonElement versionManifest) { JsonElement versionsElement = GetJsonPropertyOrThrow(versionManifest, "versions", JsonValueKind.Array, "version manifest"); var foundVersions = ImmutableArray.CreateBuilder<MinecraftVersion>(versionsElement.GetArrayLength()); foreach (var versionElement in versionsElement.EnumerateArray()) { try { foundVersions.Add(GetVersionFromManifestEntry(versionElement)); } catch (StopProcedureException) {} } return foundVersions.MoveToImmutable(); } private static MinecraftVersion GetVersionFromManifestEntry(JsonElement versionElement) { JsonElement idElement = GetJsonPropertyOrThrow(versionElement, "id", JsonValueKind.String, "version entry in version manifest"); string id = idElement.GetString() ?? throw new InvalidOperationException(); JsonElement typeElement = GetJsonPropertyOrThrow(versionElement, "type", JsonValueKind.String, "version entry in version manifest"); string? typeString = typeElement.GetString(); var type = MinecraftVersionTypes.FromString(typeString); if (type == MinecraftVersionType.Other) { Logger.Warning("Unknown version type: {Type} ({Version})", typeString, id); } JsonElement urlElement = GetJsonPropertyOrThrow(versionElement, "url", JsonValueKind.String, "version entry in version manifest"); string? url = urlElement.GetString(); if (!Uri.TryCreate(url, UriKind.Absolute, out var uri)) { Logger.Error("The \"url\" key in version entry in version manifest does not contain a valid URL: {Url}", url); throw StopProcedureException.Instance; } if (uri.Scheme != "https" || !uri.AbsolutePath.EndsWith(".json", StringComparison.OrdinalIgnoreCase)) { Logger.Error("The \"url\" key in version entry in version manifest does not contain an accepted URL: {Url}", url); throw StopProcedureException.Instance; } return new MinecraftVersion(id, type, url); } private static FileDownloadInfo GetServerExecutableInfoFromMetadata(JsonElement versionMetadata) { JsonElement downloadsElement = GetJsonPropertyOrThrow(versionMetadata, "downloads", JsonValueKind.Object, "version metadata"); JsonElement serverElement = GetJsonPropertyOrThrow(downloadsElement, "server", JsonValueKind.Object, "downloads object in version metadata"); JsonElement urlElement = GetJsonPropertyOrThrow(serverElement, "url", JsonValueKind.String, "downloads.server object in version metadata"); string? url = urlElement.GetString(); if (!Uri.TryCreate(url, UriKind.Absolute, out var uri)) { Logger.Error("The \"url\" key in downloads.server object in version metadata does not contain a valid URL: {Url}", url); throw StopProcedureException.Instance; } if (uri.Scheme != "https" || !uri.AbsolutePath.EndsWith(".jar", StringComparison.OrdinalIgnoreCase)) { Logger.Error("The \"url\" key in downloads.server object in version metadata does not contain a accepted URL: {Url}", url); throw StopProcedureException.Instance; } JsonElement sizeElement = GetJsonPropertyOrThrow(serverElement, "size", JsonValueKind.Number, "downloads.server object in version metadata"); ulong size; try { size = sizeElement.GetUInt64(); } catch (FormatException) { Logger.Error("The \"size\" key in downloads.server object in version metadata contains an invalid file size: {Size}", sizeElement); throw StopProcedureException.Instance; } JsonElement sha1Element = GetJsonPropertyOrThrow(serverElement, "sha1", JsonValueKind.String, "downloads.server object in version metadata"); Sha1String hash; try { hash = Sha1String.FromString(sha1Element.GetString()); } catch (Exception) { Logger.Error("The \"sha1\" key in downloads.server object in version metadata does not contain a valid SHA-1 hash: {Sha1}", sha1Element.GetString()); throw StopProcedureException.Instance; } return new FileDownloadInfo(url, hash, new FileSize(size)); } private static JsonElement GetJsonPropertyOrThrow(JsonElement parentElement, string propertyKey, JsonValueKind expectedKind, string location) { if (!parentElement.TryGetProperty(propertyKey, out var valueElement)) { Logger.Error("Missing \"{Property}\" key in " + location + ".", propertyKey); throw StopProcedureException.Instance; } if (valueElement.ValueKind != expectedKind) { Logger.Error("The \"{Property}\" key in " + location + " does not contain a JSON {ExpectedType}. Actual type: {ActualType}", propertyKey, expectedKind, valueElement.ValueKind); throw StopProcedureException.Instance; } return valueElement; } }