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搜尋 Async 結果：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>BLE Printer Test</title>
<script src="https://cdn.jsdelivr.net/npm/iconv-lite-umd@0.6.10/lib/iconv-lite-umd.js"></script>
</head>
<body>
<h1>BLE Printer Test 123</h1>
<button id="printTestButton">Test Print</button>
<button id="printAgain">Print Again</button>
<pre id="log"></pre>
<script>
// Function to log messages on the page
function logMessage(message) {
const logElement = document.getElementById('log');
logElement.textContent += message + '\n';
}
var device;
var server;
var service;
var characteristic;
var name = 'T58_6752'; // 藍芽設備的名稱
var uuid = 0x1800; //service UUID (用 BLE Scanner 找到的)
var characteristicUuid = 0x2A00; // characteristic UUID (用 BLE Scanner 找到的)
// Function to connect to BLE printer and send test data
async function connectAndTestPrint() {
try {
logMessage("Requesting Bluetooth device...");
// Request the BLE device
device = await navigator.bluetooth.requestDevice({
//acceptAllDevices: true,
filters: [
{ name: name }
],
optionalServices: [uuid] // Replace with the correct service UUID
});
logMessage(`Device selected: ${device.name}`);
logMessage(`Device uuid: ${device.id}`);
await printAgain();
} catch (error) {
logMessage(`Error: ${error.message}`);
}
}
// 转码方法
function stringToGbk(str) {
const ranges = [
[0xA1, 0xA9, 0xA1, 0xFE],
[0xB0, 0xF7, 0xA1, 0xFE],
[0x81, 0xA0, 0x40, 0xFE],
[0xAA, 0xFE, 0x40, 0xA0],
[0xA8, 0xA9, 0x40, 0xA0],
[0xAA, 0xAF, 0xA1, 0xFE],
[0xF8, 0xFE, 0xA1, 0xFE],
[0xA1, 0xA7, 0x40, 0xA0],
]
const codes = new Uint16Array(23940)
let i = 0
for (const [b1Begin, b1End, b2Begin, b2End] of ranges) {
for (let b2 = b2Begin; b2 <= b2End; b2++) {
if (b2 !== 0x7F) {
for (let b1 = b1Begin; b1 <= b1End; b1++) {
codes[i++] = b2 << 8 | b1
}
}
}
}
const cstr = new TextDecoder('gbk').decode(codes)
// 编码表
const table = new Uint16Array(65536)
for (let i = 0; i < cstr.length; i++) {
table[cstr.charCodeAt(i)] = codes[i]
}
const buf = new Uint8Array(str.length * 2)
let n = 0
for (let i = 0; i < str.length; i++) {
const code = str.charCodeAt(i)
if (code < 0x80) {
buf[n++] = code
} else {
const gbk = table[code]
buf[n++] = gbk & 0xFF
buf[n++] = gbk >> 8
}
}
u8buf = buf.subarray(0, n)
// console.log(u8buf);
return u8buf
}
async function printAgain() {
// Connect to the GATT server
server = await device.gatt.connect();
logMessage("Connected to GATT server.");
// Get the printer service
service = await server.getPrimaryService(uuid); // Replace with your printer's service UUID
logMessage("Printer service retrieved.");
// Get the characteristic for writing data
characteristic = await service.getCharacteristic(characteristicUuid); // Replace with the correct characteristic UUID
logMessage("Printer characteristic retrieved.");
// Prepare test print data
const encoder = new TextEncoder();
const testData = encoder.encode("TEST PRINT: Hello from Web Bluetooth!\n");
const finalData = encoder.encode("--\n--\n \n \n");
const setFontSize = new Uint8Array([0x1D, 0x21, 0x11]); // GS ! n
const setFontSize2 = new Uint8Array([0x1D, 0x21, 0x22]); // GS ! n
const setFontSize3 = new Uint8Array([0x1D, 0x21, 0x33]); // GS ! n
// Write test data to the printer
logMessage("Sending test data to printer...");
await characteristic.writeValue(new Uint8Array([0x1D, 0x21, 0x00]));
await characteristic.writeValue(encoder.encode("1x1!\n"));
await characteristic.writeValue(setFontSize);
await characteristic.writeValue(encoder.encode("2x2!\n"));
await characteristic.writeValue(setFontSize2);
await characteristic.writeValue(encoder.encode("3x3!\n"));
await characteristic.writeValue(setFontSize3);
await characteristic.writeValue(encoder.encode("4x4!\n"));
const initPrinter = new Uint8Array([0x1B, 0x40]); // ESC @
await characteristic.writeValue(initPrinter);
// 3. 設置字符集為 GBK
const setGBK = new Uint8Array([0x1B, 0x74, 0x11]); // ESC t 0x11 (GBK)
await characteristic.writeValue(setGBK);
const text = "繁體中文測試\n \n";
const encodedText = stringToGbk(text);
await characteristic.writeValue(encodedText);
logMessage("Test data sent successfully!");
// QrCode 列印
const qrData = "https://example.com"; // Your QR code data
const qrDataLength = qrData.length + 3;
const pL = qrDataLength & 0xFF; // Low byte
const pH = (qrDataLength >> 8) & 0xFF; // High byte
const commands = [
0x1B, 0x40, // Initialize printer
0x1D, 0x28, 0x6B, pL, pH, 0x31, 0x50, 0x30, ...new TextEncoder().encode(qrData), // Store data
0x1D, 0x28, 0x6B, 0x03, 0x00, 0x31, 0x51, 0x30 // Print QR code
];
const buffer = new Uint8Array(commands);
await characteristic.writeValue(buffer);
logMessage("QrCode sent successfully!");
await characteristic.writeValue(finalData);
logMessage("finalData sent successfully!");
// Disconnect the GATT server
server.disconnect();
logMessage("Disconnected from printer.");
}
// Bind the function to the button
document.getElementById('printTestButton').addEventListener('click', connectAndTestPrint);
document.getElementById('printAgain').addEventListener('click', printAgain);
</script>
</body>
</html>
Bike, 2025/1/2 下午 02:20:15
Restful 的 API 範例，比較特別的是取得單一筆資料時，不是用一般常見的 {id} 而是用 get?id=xxx 的方式，以避免 XXS 的功擊。(不要把原網頁中的參數拼入 API 網址，要改用 Query String 的方式傳給 API)
再增加一個同步範例(只例出 action)
using Ds;
using Ds.Gv;
using iText.Kernel.Geom;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using NPOI.SS.Formula.Functions;
using NPOI.SS.Util;
using Su;
using System.Linq.Expressions;
namespace CallCampaign.Api
{
/// <summary>
/// 行銷活動
/// </summary>
[Route("api/call-campaign")]
[ApiController]
[SetAuthorizationFilter(Sh.AuthCode.不設限)]
public class ReserveCampaignController : Controller
{
/// <summary>
/// 取得行銷活動列表
/// </summary>
/// <param name="reserveCampaignName"></param>
/// <param name="currentPage"></param>
/// <param name="pageSize"></param>
/// <param name="orderByName"></param>
/// <param name="sort"></param>
/// <returns></returns>
/// <exception cref="Exception"></exception>
[HttpGet("")]
public async Task<object> ListAsync([FromQuery] string reserveCampaignName = "", [FromQuery] int? currentPage = 1, [FromQuery] int? pageSize = 20, [FromQuery] string orderByName = "OrderNo", [FromQuery] string sort = "asc")
{
if (pageSize > 500)
{
pageSize = 500;
}
if (!(sort == "asc" || sort == "desc"))
{
throw new CustomException(System.Net.HttpStatusCode.BadRequest, "sort只能是asc或desc");
}
var temp = new V_ReserveCampaign().GetType().GetProperty(orderByName);
if (temp == null)
{
throw new CustomException(System.Net.HttpStatusCode.BadRequest, "不存在欄位");
}
Expression<Func<V_ReserveCampaign, bool>> q = p => p.Is_Deleted == "N"
&& (string.IsNullOrEmpty(reserveCampaignName) || (p.ReserveCampaignName != null && p.ReserveCampaignName.Contains(reserveCampaignName)))
;
if (orderByName.ToLower().Trim() != "id")
{
orderByName += " " + sort + ", id desc";
}
else
{
orderByName += " " + sort;
}
var ct = NewContext.GvContext;
var list = await ct.GetPageListAsync(q, columns: "Id, ReserveCampaignName, OrderNo, StartAt, EndAt, ModifierName, ModifyDate, CreatorName, CreateDate", page: currentPage ?? 1, pageSize: pageSize ?? 20, orderByName);
//var list = await ct.GetPageListAsync(q, page: currentPage ?? 1, pageSize: pageSize ?? 20, orderByName + " " + sort);
return list;
}
/// <summary>
/// 取得行銷活動
/// </summary>
/// <param name="Id"></param>
/// <returns></returns>
/// <exception cref="Exception"></exception>
[HttpGet("get")]
public async Task<dynamic> GetAsync([FromQuery] int Id)
{
var res = await Ds.NewContext.GvContext.ReserveCampaigns.Where(r => r.Id == Id)
.FirstOrDefaultAsync();
if (res == null)
{
throw new CustomException(System.Net.HttpStatusCode.BadRequest, "查無資料 " + Id.ToString());
}
return res;
}
/// <summary>
/// 建立行銷活動
/// </summary>
/// <param name="dto"></param>
/// <returns></returns>
/// <exception cref="CustomException"></exception>
[HttpPost("")]
public async Task<object> CreateAsync(Dtos.CreateReserveCampaign dto)
{
var ct = NewContext.GvContext;
var res = await Models.ReserveCampaignHelper.CreateReserveCampaignAsync(ct, dto);
return res;
}
/// <summary>
/// 編輯行銷活動
/// </summary>
/// <param name="dto"></param>
/// <returns></returns>
/// <exception cref="CustomException"></exception>
[HttpPatch("")]
public async Task<object> UpdateAsync(Dtos.UpdateReserveCampaign dto)
{
var ct = NewContext.GvContext;
var res = await Models.ReserveCampaignHelper.UpdateReserveCampaignAsync(ct, dto);
return res;
}
/// <summary>
/// 刪除行銷活動
/// </summary>
/// <param name="id"></param>
/// <returns></returns>
/// <exception cref="CustomException"></exception>
[HttpDelete("")]
public async Task<object> DeleteAsync([FromQuery] int id)
{
var res = await Ds.NewContext.GvContext.MarkDeleteAsync<Ds.Gv.ReserveCampaign>(id, Sh.ModifyInfo);
return res;
}
}
}
再增加一個同步範例(只例出 action)
/// <summary>
/// 取得列表
/// </summary>
/// <param name="name"></param>
/// <param name="currentPage"></param>
/// <param name="pageSize"></param>
/// <param name="orderByName"></param>
/// <param name="sort"></param>
/// <returns></returns>
[HttpGet("")]
public object List([FromQuery] string name = "", [FromQuery] int? currentPage = 1, [FromQuery] int? pageSize = 20, [FromQuery] string orderByName = "OrderNo", [FromQuery] string sort = "asc")
{
return "";
}
/// <summary>
/// 取得明細資料
/// </summary>
/// <param name="Id"></param>
/// <returns></returns>
/// <exception cref="Exception"></exception>
[HttpGet("get")]
public object Get([FromQuery] int id)
{
return "";
}
/// <summary>
/// 建立
/// </summary>
/// <param name="dto"></param>
/// <returns></returns>
/// <exception cref="CustomException"></exception>
[HttpPost("")]
public object Create(Dtos.PhysicalCheckUpType dto)
{
return "";
}
/// <summary>
/// 編輯
/// </summary>
/// <param name="dto"></param>
/// <returns></returns>
/// <exception cref="CustomException"></exception>
[HttpPatch("")]
public object Update(Dtos.PhysicalCheckUpType dto)
{
return "";
}
/// <summary>
/// 刪除
/// </summary>
/// <param name="id"></param>
/// <returns></returns>
/// <exception cref="CustomException"></exception>
[HttpDelete("")]
public object Delete([FromQuery] int id)
{
return 1;
}
Bike, 2023/12/13 上午 08:54:28
PromiseAll: async function (array) {
let taskList = [];
let propList = [];
for (let obj of array) {
for (let prop in obj) {
taskList.push(obj[prop]);
propList.push(prop);
}
}
let resp = await Promise.all(taskList);
let result = {};
let counter = 0;
for (let prop of propList) {
result[prop] = resp[counter];
counter += 1;
}
return result;
}
PromiseAll 是將API一次發送並接收回傳值的工具
使用方法範例:
const taskList = [{
adPosition : BannerPositionDataService.GetList(),
big : BannerDataService.GetList(100),
smallTop : BannerDataService.GetOne(200),
smallBottom : BannerDataService.GetOne(300),
section2 : BannerDataService.GetList(400),
section3 : BannerDataService.GetList(500),
section4 : BannerDataService.GetList(600),
recommends : ProductDataService.GetRndList()
}];
let resps = await UJ.PromiseAll(taskList);
要特別記得TaskList中的Method不需要做await,不然就沒有意義了
DeepBinding: function (vueData, data) {
if (Array.isArray(data)) {
if (!Array.isArray(vueData)) {
vueData = [];
} else {
vueData.splice(0);
}
for (let prop in data) {
vueData.push(data[prop]);
}
}
else if (typeof (data) === 'object') {
if (Object.keys(data).length === 0) {
return;
}
for (let prop in data) {
if (vueData[prop] === undefined || data[prop] === null ||
(!Array.isArray(vueData[prop] && vueData !== null && typeof (data) !== 'object'))) {
vueData[prop] = data[prop];
} else {
this.DeepBinding(vueData[prop], data[prop]);
}
}
} else {
vueData = data;
}
}
在資料回傳後要Binding到Vue Data上面或是任意Object的Property上可以使用這個,
不使用DeepBinding是因為瀏覽器版本限制,這個方式不受瀏覽器版本限制,但是只有提供一階,需要多階請自行改寫.
使用方法範例:
UJ.DeepBinding(this, resp);
這邊的this代表的是Vue的Data
梨子, 2023/11/24 上午 11:05:08
Entity Framework 提供了 ExecuteSqlRawAsync 和 FromSqlRaw 之後，可以和 Dapper 非常類似的用法。
我們在用 Dapper 時。最常用的就是 sql command 加上一個物件做為參數，就可以執行 CRUD 的動作。
其實用 Entity Framework 的 ExecuteSqlRawAsync 和 FromSqlRaw 也可以逹到幾乎一樣的效果。
ExecuteSqlRawAsync 和 FromSqlRaw 接受的參數是 object array (其實是 Microsoft.Data.SqlClient.SqlParameter 的 array)
所以我們先做一個 Object to Microsoft.Data.SqlClient.SqlParameter Array 的擴充, 可參考: https://gist.github.com/aliozgur/75182b2e9b0a58b83443
不過很奇怪的是，原作者提供的擴充轉出來的會是 System.Data.SqlClient.SqlParameter Array 無法直接使用於 ExecuteSqlRawAsync 和 FromSqlRaw，所以要稍微改一下，把 using System.Data.SqlClient; 改為 using Microsoft.Data.SqlClient; 即可:
另外，我們再自行 對 DbContext 做一個擴充如下:
最後的結果可以做到以下的效果: (res3 和 res4 是配合 FormattableString 的範例 )
範例程式碼:
我們在用 Dapper 時。最常用的就是 sql command 加上一個物件做為參數，就可以執行 CRUD 的動作。
其實用 Entity Framework 的 ExecuteSqlRawAsync 和 FromSqlRaw 也可以逹到幾乎一樣的效果。
ExecuteSqlRawAsync 和 FromSqlRaw 接受的參數是 object array (其實是 Microsoft.Data.SqlClient.SqlParameter 的 array)
所以我們先做一個 Object to Microsoft.Data.SqlClient.SqlParameter Array 的擴充, 可參考: https://gist.github.com/aliozgur/75182b2e9b0a58b83443
不過很奇怪的是，原作者提供的擴充轉出來的會是 System.Data.SqlClient.SqlParameter Array 無法直接使用於 ExecuteSqlRawAsync 和 FromSqlRaw，所以要稍微改一下，把 using System.Data.SqlClient; 改為 using Microsoft.Data.SqlClient; 即可:
另外，我們再自行 對 DbContext 做一個擴充如下:
/// <summary>
/// 會把物件 Parameter 的各 Property 帶入 SQL 中.
/// </summary>
/// <param name="dbct"></param>
/// <param name="sql"></param>
/// <param name="parameters"></param>
/// <returns></returns>
public static async Task<int> ExecuteParameterSqlAsync(this DbContext dbct, string sql, object parameters)
{
return await dbct.Database.ExecuteSqlRawAsync(sql, parameters.ToSqlParamsArray());
}
最後的結果可以做到以下的效果: (res3 和 res4 是配合 FormattableString 的範例 )
範例程式碼:
public async Task<object> EfTest()
{
var dbct = Ds.NewContext.GvContext;
var insertSql = @"Insert into ProfileEvent(JobId,[Name],GvShoplineId,LiShoplineId,Phone,Email,LineId,GaClientId)
Values(@JobId, @Name, null , null , null , @Email, @GaClientId , @GaClientId )";
//執行 SQL 的原生寫法
await dbct.Database.ExecuteSqlRawAsync(insertSql, new object[]
{
new SqlParameter("@JobId", 10),
new SqlParameter("@Email", "XX'TT"),
new SqlParameter("@Name", "AA'BB"),
new SqlParameter("@GaClientId", "GaClientId"),
});
//執行 SQL 的擴充寫法
await dbct.ExecuteParameterSqlAsync(insertSql, new
{
JobId = 10,
Email = "XX'TT",
Name = "AA'BB",
GaClientId = "GaClientId"
});
//關於查詢
string name = "%'B%";
//原生寫法
var res1 = await dbct.ProfileEvents.FromSqlRaw("Select top 100 * from ProfileEvent where Name like @name",
new object[]
{
new SqlParameter("@name", "%'B%")
})
.ToListAsync();
//擴充, object to SqlParameter array
var res2 = await dbct.ProfileEvents.FromSqlRaw("Select top 100 * from ProfileEvent where Name like @name",
new { name }.ToSqlParamsArray())
.ToListAsync();
var res3 = await dbct.ProfileEvents.FromSql($"Select top 100 * from ProfileEvent where Name like {name}")
.ToListAsync();
var res4 = await dbct.ProfileEvents.FromSqlInterpolated($"Select top 100 * from ProfileEvent where Name like {name}")
.ToListAsync();
return new { res1, res2, res3, res4 };
}
Bike, 2023/5/6 下午 05:37:19
這個指令還是會把所有的資料 Select 出來，再更新
原指令:
UPDATE Job Set En_Status = 200 Where En_Status = 100 and LastTouchAt < '2023-05-06 12:34:56'
其中 '2023-05-06 12:34:56' 是 DateTime.Now.AddMinutes(-2) 的結果(Web Server 端的時間扣 2 分鐘)
但，若是改使用 UpdateFromQueryAsync 如下:
var c = await Ds.NewContext.GvContext.Jobs.Where(j => j.En_Status == Cst.Job.Status.Running && j.LastTouchAt < DateTime.Now.AddMinutes(-2))
.UpdateFromQueryAsync(j => new Ds.Gv.Job { En_Status = Cst.Job.Status.ReStarting });
產生的 SQL 如下:
UPDATE A
SET A.[En_Status] = @zzz_BatchUpdate_0
FROM [Job] AS A
INNER JOIN ( SELECT [j].[Id], [j].[CancelledAt], [j].[CancelledBy], [j].[En_Status], [j].[EndAt], [j].[Exception], [j].[Filename], [j].[InformationJson], [j].[InitAt], [j].[Is_CheckOnly], [j].[LastTouchAt], [j].[LastTouchMessage], [j].[LoopStartAt], [j].[Name], [j].[ScheduleId], [j].[TotalTouch], [j].[TouchCount]
FROM [Job] AS [j]
WHERE [j].[En_Status] = 100 AND [j].[LastTouchAt] < DATEADD(minute, CAST(-2.0E0 AS int), GETDATE())
) AS B ON A.[Id] = B.[Id]
有兩個要注意的地方:
1. 它會先 Select 全欄位，再做更新
2. 它的時間是 DB Server 的現在時間。不是 Web Server 端的時間。
順便記錄一下。若是要執行 Update xx Ser cc = cc + 1 Where ...
EF 可寫為:
var c = await Ds.NewContext.GvContext.Jobs.Where(j => j.En_Status == Cst.Job.Status.Running && j.LastTouchAt < DateTime.Now.AddMinutes(-2))
.UpdateFromQueryAsync(j => new Ds.Gv.Job { TotalTouch = j.TotalTouch + 1 });
轉換的 SQL 為:
UPDATE A
SET A.[TotalTouch] = B.[TotalTouch] + 1
FROM [Job] AS A
INNER JOIN ( SELECT [j].[Id], [j].[CancelledAt], [j].[CancelledBy], [j].[En_Status], [j].[EndAt], [j].[Exception], [j].[Filename], [j].[InformationJson], [j].[InitAt], [j].[Is_CheckOnly], [j].[LastTouchAt], [j].[LastTouchMessage], [j].[LoopStartAt], [j].[Name], [j].[ScheduleId], [j].[TotalTouch], [j].[TouchCount]
FROM [Job] AS [j]
WHERE [j].[En_Status] = 100 AND [j].[LastTouchAt] < DATEADD(minute, CAST(-2.0E0 AS int), GETDATE())
) AS B ON A.[Id] = B.[Id]
原指令:
UPDATE Job Set En_Status = 200 Where En_Status = 100 and LastTouchAt < '2023-05-06 12:34:56'
其中 '2023-05-06 12:34:56' 是 DateTime.Now.AddMinutes(-2) 的結果(Web Server 端的時間扣 2 分鐘)
但，若是改使用 UpdateFromQueryAsync 如下:
var c = await Ds.NewContext.GvContext.Jobs.Where(j => j.En_Status == Cst.Job.Status.Running && j.LastTouchAt < DateTime.Now.AddMinutes(-2))
.UpdateFromQueryAsync(j => new Ds.Gv.Job { En_Status = Cst.Job.Status.ReStarting });
產生的 SQL 如下:
UPDATE A
SET A.[En_Status] = @zzz_BatchUpdate_0
FROM [Job] AS A
INNER JOIN ( SELECT [j].[Id], [j].[CancelledAt], [j].[CancelledBy], [j].[En_Status], [j].[EndAt], [j].[Exception], [j].[Filename], [j].[InformationJson], [j].[InitAt], [j].[Is_CheckOnly], [j].[LastTouchAt], [j].[LastTouchMessage], [j].[LoopStartAt], [j].[Name], [j].[ScheduleId], [j].[TotalTouch], [j].[TouchCount]
FROM [Job] AS [j]
WHERE [j].[En_Status] = 100 AND [j].[LastTouchAt] < DATEADD(minute, CAST(-2.0E0 AS int), GETDATE())
) AS B ON A.[Id] = B.[Id]
有兩個要注意的地方:
1. 它會先 Select 全欄位，再做更新
2. 它的時間是 DB Server 的現在時間。不是 Web Server 端的時間。
順便記錄一下。若是要執行 Update xx Ser cc = cc + 1 Where ...
EF 可寫為:
var c = await Ds.NewContext.GvContext.Jobs.Where(j => j.En_Status == Cst.Job.Status.Running && j.LastTouchAt < DateTime.Now.AddMinutes(-2))
.UpdateFromQueryAsync(j => new Ds.Gv.Job { TotalTouch = j.TotalTouch + 1 });
轉換的 SQL 為:
UPDATE A
SET A.[TotalTouch] = B.[TotalTouch] + 1
FROM [Job] AS A
INNER JOIN ( SELECT [j].[Id], [j].[CancelledAt], [j].[CancelledBy], [j].[En_Status], [j].[EndAt], [j].[Exception], [j].[Filename], [j].[InformationJson], [j].[InitAt], [j].[Is_CheckOnly], [j].[LastTouchAt], [j].[LastTouchMessage], [j].[LoopStartAt], [j].[Name], [j].[ScheduleId], [j].[TotalTouch], [j].[TouchCount]
FROM [Job] AS [j]
WHERE [j].[En_Status] = 100 AND [j].[LastTouchAt] < DATEADD(minute, CAST(-2.0E0 AS int), GETDATE())
) AS B ON A.[Id] = B.[Id]
Bike, 2023/4/29 下午 08:44:31
由於在使用Await時，系統的Thread並不保證會與該function使用同一個Thread。
因此使用lock將單一Thread鎖住會導致出現 'Cannot await in the body of a lock statement'的錯誤
將Lock物件改成使用SemaphoreSlim，於function起始與結束加入WaitAsync與Release即可達到Lock的效果。
SemaphoreSlim完整介紹 : 用 SemaphoreSlim 來做 async/await 的鎖定
使用如下圖↓
因此使用lock將單一Thread鎖住會導致出現 'Cannot await in the body of a lock statement'的錯誤
將Lock物件改成使用SemaphoreSlim，於function起始與結束加入WaitAsync與Release即可達到Lock的效果。
SemaphoreSlim完整介紹 : 用 SemaphoreSlim 來做 async/await 的鎖定
使用如下圖↓
梨子, 2023/3/23 下午 03:00:41
試了這兩個 Sample:
https://learn.microsoft.com/en-us/training/modules/store-local-data/4-exercise-store-data-locally-with-sqlite
和
https://blazorhelpwebsite.com/ViewBlogPost/61
結果專案在 Windows 環境下都可以正常執行，但切換到 Android Emulator 就無法存檔。
在查了很多資料後，發現需要裝額外的 Package，需安裝的 Package 如下:
其它的發現為:
1. 雙點專案，就可以開啟 csproj 檔案。下方的 ItemGroup 就是已安裝的 package
2. 可以把 chrome 連接到 Android Emulator 的方法，在網址列輸入以下指令:
chrome://inspect/#devices
https://learn.microsoft.com/en-us/training/modules/store-local-data/4-exercise-store-data-locally-with-sqlite
和
https://blazorhelpwebsite.com/ViewBlogPost/61
結果專案在 Windows 環境下都可以正常執行，但切換到 Android Emulator 就無法存檔。
在查了很多資料後，發現需要裝額外的 Package，需安裝的 Package 如下:
<ItemGroup>
<PackageReference Include="sqlite-net-pcl" Version="1.8.116" />
<PackageReference Include="SQLiteNetExtensions.Async" Version="2.1.0" />
<PackageReference Include="SQLitePCLRaw.bundle_green" Version="2.1.4" />
<PackageReference Include="SQLitePCLRaw.core" Version="2.1.4" />
<PackageReference Include="SQLitePCLRaw.lib.e_sqlite3" Version="2.1.4" />
<PackageReference Include="SQLitePCLRaw.provider.dynamic_cdecl" Version="2.1.4" />
<PackageReference Include="System.Data.DataSetExtensions" Version="4.5.0" />
</ItemGroup>
其它的發現為:
1. 雙點專案，就可以開啟 csproj 檔案。下方的 ItemGroup 就是已安裝的 package
2. 可以把 chrome 連接到 Android Emulator 的方法，在網址列輸入以下指令:
chrome://inspect/#devices
Bike, 2023/2/12 下午 05:09:11
產生 FileStreamResult 物件的 function 如下: (目前置於 SU 之中，以便轉移)
輸出用的 Controller 和 Action 如下:
static List<Brush> CaptchaBrushes = null;
public static FileStreamResult CreateCaptcha(string captcha)
{
if (CaptchaBrushes == null)
{
CaptchaBrushes = new List<Brush>();
CaptchaBrushes.Add(Brushes.White);
CaptchaBrushes.Add(Brushes.Gold);
CaptchaBrushes.Add(Brushes.LightSkyBlue);
CaptchaBrushes.Add(Brushes.LimeGreen);
CaptchaBrushes.Add(Brushes.AliceBlue);
CaptchaBrushes.Add(Brushes.AntiqueWhite);
CaptchaBrushes.Add(Brushes.BurlyWood);
CaptchaBrushes.Add(Brushes.Silver);
}
int width = 90;
int height = 45;
//https://stackoverflow.com/questions/61365732/cannot-access-a-closed-stream-when-returning-filestreamresult-from-c-sharp-netc
//Using statements close and unload the variable from memory set in the using statement which is why you are getting an error trying to access a closed memory stream.You don't need to use a using statement if you are just going to return the result at the end.
//這個 memory stream 不用關閉或 dispose
var ms = new MemoryStream();
// 釋放所有在 GDI+ 所佔用的記憶體空間 ( 非常重要!! )
using (Bitmap _bmp = new Bitmap(width, height))
using (Graphics _graphics = Graphics.FromImage(_bmp))
using (Font _font = new Font("Courier New", 24, FontStyle.Bold)) // _font 設定要出現在圖片上的文字字型、大小與樣式
{
// (封裝 GDI+ 繪圖介面) 所有繪圖作業都需透過 Graphics 物件進行操作
_graphics.Clear(Color.Black);
// 如果想啟用「反鋸齒」功能，可以將以下這行取消註解
//_graphics.TextRenderingHint = TextRenderingHint.AntiAlias;
// 將亂碼字串「繪製」到之前產生的 Graphics 「繪圖板」上
var x = 10;
for(var i = 0; i < captcha.Length; i++)
{
_graphics.DrawString(captcha.Substring(i, 1), _font, CaptchaBrushes[Su.MathUtil.GetRandomInt(CaptchaBrushes.Count)], x, Su.MathUtil.GetRandomInt(15));
x += 10 + Su.MathUtil.GetRandomInt(10);
}
// 畫線
_graphics.DrawLine(new Pen(CaptchaBrushes[Su.MathUtil.GetRandomInt(CaptchaBrushes.Count)], 1),
Su.MathUtil.GetRandomInt(0, Convert.ToInt32((width * 0.9 / 2))), 0, Su.MathUtil.GetRandomInt(Convert.ToInt32(width / 2), Convert.ToInt32(width * 1.9 / 2)), height);
_graphics.DrawLine(new Pen(CaptchaBrushes[Su.MathUtil.GetRandomInt(CaptchaBrushes.Count)], 1),
Su.MathUtil.GetRandomInt(Convert.ToInt32(width / 2), Convert.ToInt32(width * 1.9 / 2)), 0, Su.MathUtil.GetRandomInt(0, Convert.ToInt32((width * 0.9 / 2))), height);
_graphics.DrawLine(new Pen(CaptchaBrushes[Su.MathUtil.GetRandomInt(CaptchaBrushes.Count)], 1),
0,
Su.MathUtil.GetRandomInt(height / 2),
width,
height / 2 + Su.MathUtil.GetRandomInt(height / 2)
);
_graphics.DrawLine(new Pen(CaptchaBrushes[Su.MathUtil.GetRandomInt(CaptchaBrushes.Count)], 1),
0,
height / 2 + Su.MathUtil.GetRandomInt(height / 2),
width,
Su.MathUtil.GetRandomInt(height / 2)
);
_bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
}
ms.Seek(0, SeekOrigin.Begin);
// Controller 的型別為 FileResult
return new FileStreamResult(ms, "image/jpeg")
{ FileDownloadName = $"{DateTime.Now.Ymdhmsf()}.jpg" };
}
輸出用的 Controller 和 Action 如下:
namespace Web.Controllers
{
public class CaptchaController : Controller
{
[Route("captcha")]
public async Task<FileStreamResult> Index()
{
//產生 Captcha 並存入 Session 之中。目前是四位數字
string captcha = (await Ah.ReGetAsync<object>("api/kol/create-captcha-code")).ToString();
//產生圖檔並回傳 FileStreamResult
return Su.Wu.CreateCaptcha(captcha);
}
}
}
Bike, 2022/9/25 下午 10:03:44
接到弱掃報告指出以下的程式碼會造成危害:
string Url = WebConfigurationManager.AppSettings["SkyShopCheckoutURL"] + $"/api/token/ {Su.Fsc.SessionId}"; ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
HttpClient client = Su.Wu.GetClient();
var response = await client.GetAsync(Url);
var message = await response.Content.ReadAsStringAsync(); result = JsonConvert.DeserializeObject(message);
沒想到吧...
string Url = WebConfigurationManager.AppSettings["SkyShopCheckoutURL"] + $"/api/token/ {Su.Fsc.SessionId}"; ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
HttpClient client = Su.Wu.GetClient();
var response = await client.GetAsync(Url);
var message = await response.Content.ReadAsStringAsync(); result = JsonConvert.DeserializeObject(message);
沒想到吧...
Bike, 2022/9/23 上午 05:40:51
在 Postgres 使用 TransactionScope 似乎很空易就會發生 Transaction Abort 的情況。所以必需自行實做 retry 的機制
int tries = 0;
while (tries < Su.PgSql.maxTransactionAborted)
{
try
{
using (var scop = new System.Transactions.TransactionScope(TransactionScopeAsyncFlowOption.Enabled))
{
var context = ShopBandContext.Context;
updateCount = await context.UpdateAsync<MarketDiscount>(dto, Sc.ModifyInfo,
onlyColumns: "StartAt,EndAt,NewPrice,FrontEndMemo,BackEndMemo");
scop.Complete();
break; //這個 Break 很重要
}
}
catch (Exception ex)
{
// 我發現因為是非同步模式，所以要檢查很多層的 InnerException
if (tries < Su.PgSql.maxTransactionAborted
&& ((ex.InnerException != null && ex.InnerException is Npgsql.PostgresException && ((Npgsql.PostgresException)ex.InnerException).SqlState == "40001")
|| (ex.InnerException.InnerException != null && ex.InnerException.InnerException is Npgsql.PostgresException && ((Npgsql.PostgresException)ex.InnerException.InnerException).SqlState == "40001")))
{
//隨機休息 10 ~ 20 ms, 等另一個 job 完工
System.Threading.Thread.Sleep(Su.MathUtil.Random.Next(10, 20));
tries++;
}
else
{
throw;
}
}
}
Bike, 2022/8/25 上午 09:19:35