非同期処理とデッドロックについて

デッドロックの原因になったファイル

SlackAPI.cs

using Microsoft.VisualBasic;
using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;

namespace SlackTool
{
    /// <summary>
    /// C# から Slack へ送信する軽量ヘルパー
    /// - chat.postMessage（メッセージ送信）
    /// - files.upload     （ファイル送信）
    /// - Incoming Webhook（最短で試せる）
    ///
    /// 既定は環境変数を参照:
    ///   SLACK_BOT_TOKEN   : xoxb-...（Bot Token）
    ///   SLACK_CHANNEL_ID  : 例 "C0123456789"
    ///   SLACK_WEBHOOK_URL : Incoming Webhook のURL
    /// </summary>
    public sealed class SlackAPI : IDisposable
    {
        private readonly HttpClient _http;
        private readonly bool _disposeClient;
        private readonly string? _botToken;
        private readonly string? _defaultChannel;
        private readonly string? _defaultWebhookUrl;

        public SlackAPI(
            string? botToken,
            string? defaultChannel,
            string? defaultWebhookUrl)
        {
            _http = new HttpClient();
            _disposeClient = _http is null;

            _botToken = botToken;
            _defaultChannel = defaultChannel;
            _defaultWebhookUrl = defaultWebhookUrl;
        }

        /// <summary>
        /// chat.postMessage でメッセージ送信
        /// </summary>
        public async Task<SlackResponse> PostMessageAsync(
            string? channel,
            string text,
            object? blocks = null,
            string? threadTs = null,
            CancellationToken ct = default)
        {
            channel ??= _defaultChannel ?? throw new ArgumentNullException(nameof(channel),
                       "channel を指定するか、環境変数 SLACK_CHANNEL_ID を設定してください。");
            var token = RequireToken();

            return await SendWithRetryAsync(() =>
            {
                var req = new HttpRequestMessage(HttpMethod.Post, "https://slack.com/api/chat.postMessage");
                req.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);

                var body = new Dictionary<string, object?>
                {
                    ["channel"] = channel,
                    ["text"] = text
                };
                if (blocks is not null) body["blocks"] = blocks;
                if (threadTs is not null) body["thread_ts"] = threadTs;

                req.Content = JsonContent(body);
                return req;
            }, ct);
        }

        /// <summary>
        /// files.upload でファイル送信（channels へ共有）
        /// </summary>
        public async Task<SlackResponse> UploadFileAsync(
            string? channel,
            string filePath,
            string? initialComment = null,
            string? threadTs = null,
            string? title = null,
            CancellationToken ct = default)
        {
            channel ??= _defaultChannel ?? throw new ArgumentNullException(nameof(channel),
                       "channel を指定するか、環境変数 SLACK_CHANNEL_ID を設定してください。");
            if (!File.Exists(filePath)) throw new FileNotFoundException("File not found", filePath);
            var token = RequireToken();

            return await SendWithRetryAsync(() =>
            {
                var req = new HttpRequestMessage(HttpMethod.Post, "https://slack.com/api/files.upload");
                req.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);

                var form = new MultipartFormDataContent();
                form.Add(new StringContent(channel), "channels");
                if (initialComment is not null) form.Add(new StringContent(initialComment), "initial_comment");
                if (threadTs is not null) form.Add(new StringContent(threadTs), "thread_ts");
                if (title is not null) form.Add(new StringContent(title), "title");

                // 各リトライで新しい StreamContent を作る（再送で失敗しないように）
                var stream = File.OpenRead(filePath);
                var fileContent = new StreamContent(stream);
                fileContent.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
                form.Add(fileContent, "file", Path.GetFileName(filePath));

                req.Content = form;
                return req;
            }, ct);
        }

        /// <summary>
        /// Incoming Webhook でシンプル送信
        /// </summary>
        public async Task<HttpResponseMessage> PostWebhookAsync(
            string? webhookUrl,
            string text,
            object? blocks = null,
            CancellationToken ct = default)
        {
            webhookUrl ??= _defaultWebhookUrl ?? throw new ArgumentNullException(nameof(webhookUrl),
                          "webhookUrl を指定するか、環境変数 SLACK_WEBHOOK_URL を設定してください。");

            using var req = new HttpRequestMessage(HttpMethod.Post, webhookUrl);
            var body = new Dictionary<string, object?> { ["text"] = text };
            if (blocks is not null) body["blocks"] = blocks;

            req.Content = JsonContent(body);
            return await _http.SendAsync(req, ct);
        }

        // ===== 内部共通処理 =====

        private static readonly JsonSerializerOptions JsonOptions = new()
        {
            PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
            DefaultIgnoreCondition = System.Text.Json.Serialization.JsonIgnoreCondition.WhenWritingNull
        };

        private static StringContent JsonContent(object body) =>
            new StringContent(JsonSerializer.Serialize(body, JsonOptions), Encoding.UTF8, "application/json");

        private string RequireToken() =>
            _botToken ?? throw new InvalidOperationException("Slack Bot Token がありません。SLACK_BOT_TOKEN を設定するかコンストラクタ引数で渡してください。");

        /// <summary>
        /// 429 レート制限時に Retry-After を待ってリトライ。
        /// 各試行で新しい HttpRequestMessage を生成する factory を受け取る。
        /// </summary>
        private async Task<SlackResponse> SendWithRetryAsync(
            Func<HttpRequestMessage> requestFactory,
            CancellationToken ct)
        {
            const int maxAttempts = 5;

            for (int attempt = 0; attempt < maxAttempts; attempt++)
            {
                using var req = requestFactory();
                var res = await _http.SendAsync(req, ct);

                // 429: 待ってから再試行
                if ((int)res.StatusCode == 429)
                {
                    var wait = res.Headers.RetryAfter?.Delta
                               ?? TimeSpan.FromSeconds(Math.Min(60, 2 + (int)Math.Pow(2, attempt)));
                    await Task.Delay(wait, ct);
                    continue;
                }

                // 通常の HTTP エラーは例外
                res.EnsureSuccessStatusCode();

                var json = await res.Content.ReadAsStringAsync(ct);
                var ok = false;
                string? error = null;

                try
                {
                    using var doc = JsonDocument.Parse(json);
                    var root = doc.RootElement;
                    ok = root.TryGetProperty("ok", out var okEl) && okEl.GetBoolean();
                    error = root.TryGetProperty("error", out var errEl) ? errEl.GetString() : null;
                } catch
                {
                    // Slack っぽい JSON でなければそのまま返す（Webhookなど）
                    return new SlackResponse(true, null, json);
                }

                return new SlackResponse(ok, error, json);
            }

            throw new Exception("Slack API: レート制限により最大試行回数を超えました。");
        }

        // SlackTool.SlackAPI クラス内に追記
        public async Task<SlackResponse> UploadFileV2Async(
            string? channel,
            string filePath,
            string? title = null,
            string? initialComment = null,
            CancellationToken ct = default)
        {
            channel ??= _defaultChannel ?? throw new ArgumentNullException(nameof(channel),
                       "channel を指定するか、環境変数 SLACK_CHANNEL_ID を設定してください。");
            if (!File.Exists(filePath)) throw new FileNotFoundException("File not found", filePath);

            var token = RequireToken();
            var fileName = Path.GetFileName(filePath);
            var length = new FileInfo(filePath).Length;

            // --- Step 1: 署名付き upload_url と file_id を取得 ---
            using var req1 = new HttpRequestMessage(HttpMethod.Post, "https://slack.com/api/files.getUploadURLExternal");
            req1.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
            // ※ getUploadURLExternal は application/x-www-form-urlencoded が安定
            req1.Content = new FormUrlEncodedContent(new[]
            {
        new KeyValuePair<string,string>("filename", fileName),
        new KeyValuePair<string,string>("length", length.ToString())
    });

            var r1 = await _http.SendAsync(req1, ct);
            r1.EnsureSuccessStatusCode();
            var s1 = await r1.Content.ReadAsStringAsync(ct);

            using var d1 = JsonDocument.Parse(s1);
            var root = d1.RootElement;
            if (!root.TryGetProperty("ok", out var okEl) || !okEl.GetBoolean())
            {
                var err = root.TryGetProperty("error", out var e) ? e.GetString() : "unknown_error";
                throw new InvalidOperationException($"files.getUploadURLExternal failed: {err}");
            }
            var uploadUrl = root.GetProperty("upload_url").GetString()!;
            var fileId = root.GetProperty("file_id").GetString()!;

            // --- Step 2: 取得した upload_url へ生バイトをPOST（認証ヘッダ不要） ---
            using (var fs = File.OpenRead(filePath))
            using (var content = new StreamContent(fs))
            {
                content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
                var r2 = await _http.PostAsync(uploadUrl, content, ct);
                r2.EnsureSuccessStatusCode(); // 200 以外は失敗
            }

            // --- Step 3: complete（チャネルへ共有 & コメント） ---
            return await SendWithRetryAsync(() =>
            {
                var req3 = new HttpRequestMessage(HttpMethod.Post, "https://slack.com/api/files.completeUploadExternal");
                req3.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);

                var files = new[] { new Dictionary<string, string?> { ["id"] = fileId, ["title"] = title ?? fileName } };
                var body3 = new Dictionary<string, object?>
                {
                    ["files"] = files,
                    ["channel_id"] = channel
                };
                if (!string.IsNullOrWhiteSpace(initialComment))
                    body3["initial_comment"] = initialComment;

                req3.Content = JsonContent(body3);
                return req3;
            }, ct);
        }


        public void Dispose()
        {
            if (_disposeClient) _http.Dispose();
        }

        /// <summary>
        /// Slack Web API の戻り（ok/error と生JSON）
        /// </summary>
        public record SlackResponse(bool Ok, string? Error, string RawJson);

        public void SlackMessage_Send(string moji)
        {
            var text = moji;//Interaction.InputBox("送信するテキストを入力してください：", "Slack にメッセージ送信", "テスト投稿");
            if (string.IsNullOrWhiteSpace(text)) return;

            try
            {
                // 非同期を同期呼び出しに変更
                var res = PostMessageAsync(channel: null, text: text).GetAwaiter().GetResult();

            } catch (Exception ex)
            {
                MessageBox.Show($"送信中にエラー: {ex.Message}", "例外", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }

        // 画像送信ボタン（新方式ファイルアップロード）
        public void SlackImage_Send(string path)
        {
            if (!File.Exists(path))
            {
                //MessageBox.Show("ファイルが見つかりません。", "エラー", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }

            try
            {
                var title = Path.GetFileName(path);

                // 非同期を同期呼び出しに変更
                var res = UploadFileV2Async(
                    channel: null,   // 省略で .env の SLACK_CHANNEL_ID
                    filePath: path,
                    title: title,
                    initialComment: "画像を共有します"
                ).GetAwaiter().GetResult();

            } catch (Exception ex)
            {
                MessageBox.Show($"送信中にエラー: {ex.Message}", "例外", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }

    }
}

修正方法：

ライブラリ側で ConfigureAwait(false) を付けて同期呼び出しを許容

SlackAPI.cs

using Microsoft.VisualBasic;
using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;

namespace SlackTool
{
    public sealed class SlackAPI : IDisposable
    {
        private readonly HttpClient _http;
        private readonly bool _disposeClient;
        private readonly string? _botToken;
        private readonly string? _defaultChannel;
        private readonly string? _defaultWebhookUrl;

        public SlackAPI(string? botToken, string? defaultChannel, string? defaultWebhookUrl)
        {
            _http = new HttpClient { Timeout = TimeSpan.FromSeconds(30) }; // ★ 追加: タイムアウト
            _disposeClient = true;                                         // ★ 修正: 自前生成なので true

            _botToken = botToken;
            _defaultChannel = defaultChannel;
            _defaultWebhookUrl = defaultWebhookUrl;
        }

        // ===== Public API =====

        public async Task<SlackResponse> PostMessageAsync(
            string? channel,
            string text,
            object? blocks = null,
            string? threadTs = null,
            CancellationToken ct = default)
        {
            channel ??= _defaultChannel ?? throw new ArgumentNullException(nameof(channel),
                       "channel を指定するか、環境変数 SLACK_CHANNEL_ID を設定してください。");
            var token = RequireToken();

            return await SendWithRetryAsync(() =>
            {
                var req = new HttpRequestMessage(HttpMethod.Post, "https://slack.com/api/chat.postMessage");
                req.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);

                var body = new Dictionary<string, object?>
                {
                    ["channel"] = channel,
                    ["text"] = text
                };
                if (blocks is not null) body["blocks"] = blocks;
                if (threadTs is not null) body["thread_ts"] = threadTs;

                req.Content = JsonContent(body);
                return req;
            }, ct).ConfigureAwait(false); // ★ 追加
        }

        public async Task<SlackResponse> UploadFileAsync(
            string? channel,
            string filePath,
            string? initialComment = null,
            string? threadTs = null,
            string? title = null,
            CancellationToken ct = default)
        {
            channel ??= _defaultChannel ?? throw new ArgumentNullException(nameof(channel),
                       "channel を指定するか、環境変数 SLACK_CHANNEL_ID を設定してください。");
            if (!File.Exists(filePath)) throw new FileNotFoundException("File not found", filePath);
            var token = RequireToken();

            return await SendWithRetryAsync(() =>
            {
                var req = new HttpRequestMessage(HttpMethod.Post, "https://slack.com/api/files.upload");
                req.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);

                var form = new MultipartFormDataContent();
                form.Add(new StringContent(channel), "channels");
                if (initialComment is not null) form.Add(new StringContent(initialComment), "initial_comment");
                if (threadTs is not null) form.Add(new StringContent(threadTs), "thread_ts");
                if (title is not null) form.Add(new StringContent(title), "title");

                // 各リトライで新しい StreamContent を作る（再送で失敗しないように）
                var stream = File.OpenRead(filePath);
                var fileContent = new StreamContent(stream);
                fileContent.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
                form.Add(fileContent, "file", Path.GetFileName(filePath));

                req.Content = form;
                return req;
            }, ct).ConfigureAwait(false); // ★ 追加
        }

        public async Task<HttpResponseMessage> PostWebhookAsync(
            string? webhookUrl,
            string text,
            object? blocks = null,
            CancellationToken ct = default)
        {
            webhookUrl ??= _defaultWebhookUrl ?? throw new ArgumentNullException(nameof(webhookUrl),
                          "webhookUrl を指定するか、環境変数 SLACK_WEBHOOK_URL を設定してください。");

            using var req = new HttpRequestMessage(HttpMethod.Post, webhookUrl);
            var body = new Dictionary<string, object?> { ["text"] = text };
            if (blocks is not null) body["blocks"] = blocks;

            req.Content = JsonContent(body);
            return await _http.SendAsync(req, ct).ConfigureAwait(false); // ★ 追加
        }

        // ===== 内部共通処理 =====

        private static readonly JsonSerializerOptions JsonOptions = new()
        {
            PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
            DefaultIgnoreCondition = System.Text.Json.Serialization.JsonIgnoreCondition.WhenWritingNull
        };

        private static StringContent JsonContent(object body) =>
            new StringContent(JsonSerializer.Serialize(body, JsonOptions), Encoding.UTF8, "application/json");

        private string RequireToken() =>
            _botToken ?? throw new InvalidOperationException("Slack Bot Token がありません。SLACK_BOT_TOKEN を設定するかコンストラクタ引数で渡してください。");

        private async Task<SlackResponse> SendWithRetryAsync(
            Func<HttpRequestMessage> requestFactory,
            CancellationToken ct)
        {
            const int maxAttempts = 5;

            for (int attempt = 0; attempt < maxAttempts; attempt++)
            {
                using var req = requestFactory();
                var res = await _http.SendAsync(req, ct).ConfigureAwait(false); // ★ 追加

                if ((int)res.StatusCode == 429)
                {
                    var wait = res.Headers.RetryAfter?.Delta
                               ?? TimeSpan.FromSeconds(Math.Min(60, 2 + (int)Math.Pow(2, attempt)));
                    await Task.Delay(wait, ct).ConfigureAwait(false); // ★ 追加
                    continue;
                }

                res.EnsureSuccessStatusCode();

                var json = await res.Content.ReadAsStringAsync(ct).ConfigureAwait(false); // ★ 追加
                var ok = false;
                string? error = null;

                try
                {
                    using var doc = JsonDocument.Parse(json);
                    var root = doc.RootElement;
                    ok = root.TryGetProperty("ok", out var okEl) && okEl.GetBoolean();
                    error = root.TryGetProperty("error", out var errEl) ? errEl.GetString() : null;
                } catch
                {
                    return new SlackResponse(true, null, json);
                }

                return new SlackResponse(ok, error, json);
            }

            throw new Exception("Slack API: レート制限により最大試行回数を超えました。");
        }

        public async Task<SlackResponse> UploadFileV2Async(
            string? channel,
            string filePath,
            string? title = null,
            string? initialComment = null,
            CancellationToken ct = default)
        {
            channel ??= _defaultChannel ?? throw new ArgumentNullException(nameof(channel),
                       "channel を指定するか、環境変数 SLACK_CHANNEL_ID を設定してください。");
            if (!File.Exists(filePath)) throw new FileNotFoundException("File not found", filePath);

            var token = RequireToken();
            var fileName = Path.GetFileName(filePath);
            var length = new FileInfo(filePath).Length;

            // Step 1: getUploadURLExternal
            using var req1 = new HttpRequestMessage(HttpMethod.Post, "https://slack.com/api/files.getUploadURLExternal");
            req1.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
            req1.Content = new FormUrlEncodedContent(new[]
            {
                new KeyValuePair<string,string>("filename", fileName),
                new KeyValuePair<string,string>("length", length.ToString())
            });

            var r1 = await _http.SendAsync(req1, ct).ConfigureAwait(false);     // ★ 追加
            r1.EnsureSuccessStatusCode();
            var s1 = await r1.Content.ReadAsStringAsync(ct).ConfigureAwait(false); // ★ 追加

            using var d1 = JsonDocument.Parse(s1);
            var root = d1.RootElement;
            if (!root.TryGetProperty("ok", out var okEl) || !okEl.GetBoolean())
            {
                var err = root.TryGetProperty("error", out var e) ? e.GetString() : "unknown_error";
                throw new InvalidOperationException($"files.getUploadURLExternal failed: {err}");
            }
            var uploadUrl = root.GetProperty("upload_url").GetString()!;
            var fileId = root.GetProperty("file_id").GetString()!;

            // Step 2: upload bytes
            using (var fs = File.OpenRead(filePath))
            using (var content = new StreamContent(fs))
            {
                content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
                var r2 = await _http.PostAsync(uploadUrl, content, ct).ConfigureAwait(false); // ★ 追加
                r2.EnsureSuccessStatusCode();
            }

            // Step 3: complete
            return await SendWithRetryAsync(() =>
            {
                var req3 = new HttpRequestMessage(HttpMethod.Post, "https://slack.com/api/files.completeUploadExternal");
                req3.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);

                var files = new[] { new Dictionary<string, string?> { ["id"] = fileId, ["title"] = title ?? fileName } };
                var body3 = new Dictionary<string, object?>
                {
                    ["files"] = files,
                    ["channel_id"] = channel
                };
                if (!string.IsNullOrWhiteSpace(initialComment))
                    body3["initial_comment"] = initialComment;

                req3.Content = JsonContent(body3);
                return req3;
            }, ct).ConfigureAwait(false); // ★ 追加
        }

        public void Dispose()
        {
            if (_disposeClient) _http.Dispose();
        }

        public record SlackResponse(bool Ok, string? Error, string RawJson);

        // ===== 同期で呼びたい場合のラッパー（UIスレッドからの使用はブロックに注意） =====

        public void SlackMessage_Send(string moji)
        {
            var text = moji;
            if (string.IsNullOrWhiteSpace(text)) return;

            try
            {
                var res = PostMessageAsync(channel: null, text: text).GetAwaiter().GetResult();
                // 必要なら res.Ok など確認してメッセージ表示
            } catch (Exception ex)
            {
                // UI ライブラリに依存しないようにするなら例外を上に投げるでもOK
                System.Windows.Forms.MessageBox.Show($"送信中にエラー: {ex.Message}", "例外",
                    System.Windows.Forms.MessageBoxButtons.OK, System.Windows.Forms.MessageBoxIcon.Error);
            }
        }

        public void SlackImage_Send(string path)
        {
            if (!File.Exists(path)) return;

            try
            {
                var title = Path.GetFileName(path);
                var res = UploadFileV2Async(
                    channel: null,
                    filePath: path,
                    title: title,
                    initialComment: "画像を共有します"
                ).GetAwaiter().GetResult();
            } catch (Exception ex)
            {
                System.Windows.Forms.MessageBox.Show($"送信中にエラー: {ex.Message}", "例外",
                    System.Windows.Forms.MessageBoxButtons.OK, System.Windows.Forms.MessageBoxIcon.Error);
            }
        }
    }
}