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Newtonsoft.Json.JsonConvert.DeserializeObject 失敗的情況
test...more
dotnet ef dbcontext scaffold
...more
[ASP.NET] 利用 aspnet_regiis 加密 web.config
...more
IIS ARR (reverse proxy) 服務安裝
...more
[錯誤訊息] 請加入 ScriptResourceMapping 命名的 jquery (區分大小寫)
...more
用 Javascript 跨網頁讀取 cookie (Cookie cross page, path of cookie)
...more
線上客服 - MSN
本人信箱被盜用以致資料外洩，是否可以請貴平台予以協助刪除該信箱之使用謝謝囉...more
插入文字到游標或選取處
aaaaa...more
IIS 配合 AD (Active Directory) 認証, 使用 .Net 6.0
太感謝你了~~~你救了我被windows 認證卡了好幾天QQ...more
PostgreSQL 的 monitor trigger
FOR EACH ROW 可能要改為 FOR EACH STATEMENT ...more

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搜尋 for 結果：

AWS SES 建立 SNS 通知

在 powershell 執行以下的指令



# List of SES identities

$identities = @(

    "wztech.com.tw",

    "s3.com.tw",

    "jdcard.com.tw",

    "mskcable.com",

    "uwinfo.com.tw",

    "bike.idv.tw",

    "richwave.com.tw",

    "ctcn.com.tw",

    "jcard.com.tw",

    "bike@bike.idv.tw",

    "ee@ier.org.tw"

)



foreach ($identity in $identities) {

    # Convert identity to a valid topic name by replacing '@' and '.' with '_'

    $safeIdentity = $identity -replace "@", "_" -replace "\.", "_"

    $topicName = "SES_NOTIFY_$safeIdentity"

    $endpoint = "https://working.uwinfo.com.tw/aws/api/sns/receive?topic=$topicName"



    # Validate topic name format

    if ($topicName -notmatch '^[a-zA-Z0-9_\-\$]+$') {

        Write-Host "❌ Invalid topic name: $topicName"

        continue

    }



    # 1. Create SNS topic

    $topicArn = aws sns create-topic `

        --name $topicName `

        --query 'TopicArn' `

        --output text



    Write-Host "✔ Created topic: $topicArn"



    # 2. Subscribe webhook

    aws sns subscribe `

        --topic-arn $topicArn `

        --protocol https `

        --notification-endpoint $endpoint



    Write-Host "✔ Subscribed webhook: $endpoint"



    # 3. Link SES notifications

    foreach ($type in @("Delivery", "Bounce", "Complaint")) {

        aws ses set-identity-notification-topic `

            --identity $identity `

            --notification-type $type `

            --sns-topic $topicArn

        Write-Host "✔ $type linked to $topicName"

    }



    Write-Host "✅ Setup complete for $identity\n"

}



Write-Host "🎉 All identities processed."

收到的 log 會放在這裡: E:\WebBackup\195\ASP.NET Project\working\Data\Log\sns

More...

Bike, 2025/4/16 上午 10:40:39

AWS SES 建立 SNS 通知

在 powershell 執行以下的指令

# List of SES identities
$identities = @(
"wztech.com.tw",
"s3.com.tw",
"jdcard.com.tw",
"mskcable.com",
"uwinfo.com.tw",
"bike.idv.tw",
"richwave.com.tw",
"ctcn.com.tw",
"jcard.com.tw",
"bike@bike.idv.tw",
"ee@ier.org.tw"
)

foreach ($identity in $identities) {
# Convert identity to a valid topic name by replacing '@' and '.' with '_'
$safeIdentity = $identity -replace "@", "_" -replace "\.", "_"
$topicName = "SES_NOTIFY_$safeIdentity"
$endpoint = "https://working.uwinfo.com.tw/aws/api/sns/receive?topic=$topicName"

# Validate topic name format
if ($topicName -notmatch '^[a-zA-Z0-9_\-\$]+$') {
Write-Host "❌ Invalid topic name: $topicName"
continue
}

# 1. Create SNS topic
$topicArn = aws sns create-topic `
--name $topicName `
--query 'TopicArn' `
--output text

Write-Host "✔ Created topic: $topicArn"

# 2. Subscribe webhook
aws sns subscribe `
--topic-arn $topicArn `
--protocol https `
--notification-endpoint $endpoint

Write-Host "✔ Subscribed webhook: $endpoint"

# 3. Link SES notifications
foreach ($type in @("Delivery", "Bounce", "Complaint")) {
aws ses set-identity-notification-topic `
--identity $identity `
--notification-type $type `
--sns-topic $topicArn
Write-Host "✔ $type linked to $topicName"
}

Write-Host "✅ Setup complete for $identity\n"
}

Write-Host "🎉 All identities processed."

--

收到的 log 會放在這裡: E:\WebBackup\195\ASP.NET Project\working\Data\Log\sns

More...

Bike, 2025/4/16 上午 10:40:31

IIS ARR (reverse proxy) 服務安裝

IIS 如果要使用 reverse proxy server 服務，其實網路上已經有很多文章可以參考
這篇文章只是記錄一下安裝上要注意的事

過去安裝 IIS 套件可以透過 Web Platform Installer 搜尋下載
但現在 IIS 的 Web Platform Installer 已經不讓人搜尋下載可安裝的套件
所以要直接去微軟網站找相關套件可以用 IIS ARR 搜尋
https://www.iis.net/downloads/microsoft/application-request-routing
下載 requestRouter_amd64.msi 安裝這個 (3.0版 2021 年以後就沒有更新了)
安裝前，IIS也要預先安裝 URLRewrite 2 套件

安裝很簡單，msi 安裝後，IIS重啟就可以看到
IIS 的主機設定，可以看到 "Application Reuest Routing Cache" --> 點進後右邊有 Server Proxy Settings
proxy 的設定有一些地方要注意一下，避免未來採到雷

首先當然先開啟 Enable proxy，下面針對一些要注意的屬性說明一下

1. Time-out : 預設120秒，如果你後端的站台有一些操作可能超過兩分鐘(例如處理報表)，這個就調長一點
2. Reverse rewrite host in response header: 這個勾勾預設是開的，他的好意是同站台redirect(302) 到其他網頁，可以覆蓋
host 讓 client端能跑到正常的網址。但如果你是 redirect 到其他站台，建議把它關掉，不然後端網站如果下
redirect (302) 到別的站台，他會主動把 redirect網址 host 改為本站 (被雷過，所以要特別記下來)
3. Include TCP port from client IP: 這是一個 X-Forwarded-For 設定，預設是打開，這樣後端主機抓 client 來源 IP就會類似
"112.121.100.100:443" ，但後端網站在抓 client端IP通常不會管 port number，因此就會造成比對 IP 發生錯誤
所以建議還是把它關閉
4. Enable disk cache: 預設是勾勾打開，如果後端是靜態網站，例如圖片server，這個打開沒有問題，但如果後端網站是動態網站
那還是關掉

More...

darren, 2025/1/10 上午 11:01:38

Chrome 連接藍芽 BLE 印表機(出單機)，使用 ESC / POS 列印繁體中文和 Qrcode

<!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>

More...

Bike, 2025/1/2 下午 02:20:15

前端頁面讀入 API取值工具



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

More...

梨子, 2023/11/24 上午 11:05:08

AddPath優化

改寫成可輸入多參數，效能也比較好的版本。
以下為測試碼，請自行依照專案需求做修改。

var root = "C://wdqd/qwewq";

var addPath = @"//\\/fwef/qwf";

var addPath2 = @"5fwfef/qwf";

var addPath3 = @"//fwef/qwf";

var addPath4 = @"\\\fwef/qwf";

var addPath5 = @"\\\\\/fwef/qwf";





var result = root.AddPath(addPath, addPath2, addPath3, addPath4, addPath5);



Console.WriteLine(result);



public static class Helper

{

    public static string AddPath(this string value, params string[] addPaths)

    {

        if (string.IsNullOrEmpty(value))

        {

            throw new Exception("起始目錄不可以為空字串");

        }



        if (value.Contains("..") || addPaths.Any(x => x.Contains("..")))

        {

            throw new Exception($"value: {value}, addPaths: {addPaths.Where(x => x.Contains("..")).ToOneString()} 檔名與路徑不可包含 ..");

        }



        var paths = addPaths.Select(x => x.Substring(x.FindLastContinuousCharPosition('/', '\\') + 1).SafeFilename()).ToList();



        if (paths.Any(x => System.IO.Path.IsPathRooted(x)))

        {

            throw new Exception("不可併入完整路徑 ..");

        }



        paths.Insert(0, value.SafeFilename());



        return System.IO.Path.Combine(paths.ToArray());

    }



    public static string ToOneString<T>(this IEnumerable<T> list, string separator = ",")

    {

        var strList = list.Select(x => x.ToString());

        return string.Join(separator, strList);

    }



    public static int FindLastContinuousCharPosition(this string input, params char[] targets)

    {

        int lastPosition = -1;



        for (int i = 0; i < input.Length; i++)

        {

            if (targets.Contains(input[i]))

            {

                lastPosition = i;

            }

            else

            {

                break;

            }

        }



        return lastPosition;

    }



    public static string SafeFilename(this string value)

    {

        return GetValidFilename(value);

    }



    public static string GetValidFilename(string value)

    {

        string ValidFilenameCharacters = @"0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ\-_$.@:/# ";

        if (value.Contains(".."))

        {

            throw new Exception("路徑中不可包含 .. ");

        }



        string newUrl = "";

        for (int i = 0; i < value.Length; i++)

        {

            var c = value.Substring(i, 1);

            int k = ValidFilenameCharacters.IndexOf(c);

            if (k < 0)

            {

                throw new Exception($"檔名 '{value}' 中有非法的字元 '" + c + "'。");

            }

            newUrl += ValidFilenameCharacters.Substring(k, 1);

        }



        return newUrl;

    }

}

More...

梨子, 2023/8/28 上午 09:43:49

sessionStorage 跨分頁無法讀取

問題：
在開出新分頁後，無法讀取 sessionStorage 的資料

可能原因：
Chrome 某個版本，Stop cloning sessionStorage for windows opened with noopener
a标签_blank默认 rel="noopener" ，所以a标签需要加入rel=“opener” 而才能像window.open("同源页面")这种方式新开的页面会复制之前的sessionStorage

解決方法：
開新分頁前，加入 rel=“opener”參數即可。
例：

<a href="http://..." target="_blank" rel="opener">Link</a>

$(".hlkPrint").click(function () {

    $("form").setPostDataToStorage();



    $("form").attr("rel", "opener");

    $("form").attr("target", "_blank");

    $("form").attr("action", "xxxxx.aspx");

    $("form").submit();

});

參考：
面试官：你确定多窗口之间sessionStorage不能共享状态吗？？？

More...

Reiko, 2022/12/1 下午 05:57:23

關於 PostgreSQL

-- 自動更新某個欄位

CREATE OR REPLACE FUNCTION before_market_update ()
RETURNS TRIGGER AS
$$
BEGIN
NEW.LMDT = LocalTimeStamp;
RETURN NEW;
END;
$$
LANGUAGE 'plpgsql';

CREATE TRIGGER updt_market
BEFORE UPDATE
ON "Market"
FOR EACH ROW
EXECUTE PROCEDURE before_market_update();

More...

Bike, 2022/8/12 下午 09:25:57

PostgreSQL 的 monitor trigger

--建立 table (要記得改 XXX)
CREATE TABLE IF NOT EXISTS public.table_monitor
(
table_name text COLLATE pg_catalog."default" NOT NULL,
update_at timestamp without time zone NOT NULL DEFAULT now(),
update_count bigint NOT NULL DEFAULT 0,
CONSTRAINT table_monitor_pkey PRIMARY KEY (table_name)
)

TABLESPACE pg_default;

ALTER TABLE IF EXISTS public.table_monitor
OWNER to XXX;

-- 這一段只要執行一次
CREATE OR REPLACE FUNCTION public.table_monitor_trigger_fnc()
RETURNS trigger
LANGUAGE 'plpgsql'
COST 100
VOLATILE NOT LEAKPROOF
AS $BODY$
BEGIN
Update public.table_monitor Set update_count = update_count + 1, update_at = now() Where table_name = TG_TABLE_NAME;
RETURN NEW;
END;
$BODY$;

ALTER FUNCTION public.table_monitor_trigger_fnc()
OWNER TO XXX;

-- 對於被監控的 table, 要執行以下的指令，記得 monitor_table_name 要改為 table 的名字(要符合大小寫)
INSERT INTO public.table_monitor (table_name, update_at, update_count) VALUES ('monitor_table_name', '2000-01-01', 0) ON CONFLICT DO NOTHING;

CREATE OR REPLACE TRIGGER table_monitor_trigger
AFTER INSERT OR DELETE OR UPDATE
ON monitor_table_name
FOR EACH STATEMENT
EXECUTE FUNCTION public.table_monitor_trigger_fnc();

監控用的程式碼:

public static void UpdateTableCache()

{

    //標記自已是正在執行的 Thread. 讓舊的 Thread 在執行完畢之後, 應該會自動結束. 以防舊的 Thread 執行超過 10 秒.

    CurrentThreadId = System.Threading.Thread.CurrentThread.ManagedThreadId;



    try

    {

        //確認自已是正在執行的 Thread, 重覆執行. (另一個 Thread 插入執行)

        while (CurrentThreadId == System.Threading.Thread.CurrentThread.ManagedThreadId)

        {

            LastUpdateDate = DateTime.Now;



            foreach (var dbId in CachedDbs)

            {

                var sql = @"select * from table_monitor";



                var dt = Su.PgSql.DtFromSql(sql, dbId);



                foreach (DataRow row in dt.Rows)

                {

                    string changeId = row["update_count"].DBNullToDefault();

                    string CacheKey = TableCacheKey(dbId, row["table_name"].DBNullToDefault());

                    ObjectCache cache = MemoryCache.Default;



                    string OldValue = (string)cache[CacheKey];



                    if (OldValue == null)

                    {

                        cache.Set(CacheKey, changeId, DateTime.MaxValue);

                    }

                    else

                    {

                        if (changeId != OldValue)

                        {

                            cache.Remove(CacheKey);

                            cache.Set(CacheKey, changeId, DateTime.MaxValue);

                        }

                    }

                }

            }



            //每兩秒檢查一次

            System.Threading.Thread.Sleep(2000);

        }

    }

    catch (Exception)

    {

        //依經驗, 只要 DB 能通, 這裡幾乎不會有問題, 所以這裡暫時不處理, 未來有問題時可以考慮寫入文字檔比較好.

    }

}

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Bike, 2022/7/20 上午 10:05:39

.Net Framework 的檔案檢查機制 Web API 和 MVC 5

我們的目標是在啟動時，掛一個 global filter 來檢查上傳的檔案附檔名，避免上傳未預期的可執行檔。使用 global filter 可以防止程式設計師忘了做檔案檢查，發生危險。我們目前用到的 .Net Framework 有兩個類別，一個是 System.Web.Http.ApiController，另一個是 System.Web.Mvc.Controller，兩個要分開處理。

1. Web API (System.Web.Http.ApiController)
.Net Framework 的 Web API 2 在接收檔案時，必需使用 Request.Content.ReadAsMultipartAsync 把上傳的資料存入 MultipartMemoryStreamProvider 之後再來處理。
範例如下:

    public class UploadController : ApiController

    {

        public async Task<object> PostFormData()

        {

            var provider = new MultipartMemoryStreamProvider();



            if (! Request.Content.IsMimeMultipartContent())

            {

                return "no file";

            }



            //要注意這裡的 await

            await Request.Content.ReadAsMultipartAsync(provider);



            foreach (var content in provider.Contents)

            {

                if (content.Headers.ContentDisposition.FileName != null)

                {

                    string localFilename = content.Headers.ContentDisposition.FileName.Replace("\"", "");

                    System.IO.Directory.CreateDirectory(HttpContext.Current.Server.MapPath(@"~/App_Data/Temp/"));

                    string filename = HttpContext.Current.Server.MapPath(@"~/App_Data/Temp/" + localFilename);

                    if (System.IO.File.Exists(filename))

                    {

                        System.IO.File.Delete(filename);

                    }



                    using (var fileStream = new FileStream(filename, FileMode.Create, FileAccess.Write))

                    {

                        var contentStream = await content.ReadAsStreamAsync();

                        await contentStream.CopyToAsync(fileStream);

                        Trace.WriteLine("Save To" + filename);

                    }

                }

            }

            return "OK";

        }

    }

程式碼中有個地方我沒有注意到。我一開始是用 Request.Content.ReadAsMultipartAsync(provider); 把資料讀進 provider，但前方沒有加上 await，造成有時讀不到檔案的情況，再次提醒自己 Async 和 Await 的關係。

直覺的想法是在 filter 中執行一樣的程式碼，不存檔，只要抓出檔名來檢查即可。但這時遇到一個問題 Request.Content.ReadAsMultipartAsync 不能執行兩次，Google 了一陣子，也沒找不到類似 seek(0) 的操作。所以只好自己寫一個暫存的機製。

這裡決定使用 System.Web.HttpContext.Current.Items 來暫存 provider，最後的 OnActionExecutingAsync 結果如下:

        /// <summary>

        /// 檔案檢查

        /// </summary>

        /// <param name="actionContext"></param>

        /// <param name="cancellationToken"></param>

        /// <returns></returns>

        public override async Task OnActionExecutingAsync(HttpActionContext actionContext, CancellationToken cancellationToken)

        {

            Trace.WriteLine("ApiCheckFile OnActionExecutingAsync");



            var request = actionContext.Request;

            if (!request.Content.IsMimeMultipartContent())

            {

                return;

            }



            var provider = new MultipartMemoryStreamProvider();

            await request.Content.ReadAsMultipartAsync(provider);



            //把 provider 存入 System.Web.HttpContext.Current.Items 之中，以便在 controller 中再度使用

            System.Web.HttpContext.Current.Items["MimeMultipartContentProvider"] = provider;



            foreach (var content in provider.Contents)

            {

                if (content.Headers.ContentDisposition.FileName != null)

                {

                    var filename = content.Headers.ContentDisposition.FileName.Replace("\"", "");

                    Trace.WriteLine(filename);



                    var ext = System.IO.Path.GetExtension(filename);

                    if (!".jpg,.jpeg,.png".Contains(ext.ToLower()))

                    {

                        throw new Exception("file format error.");

                    }

                }

            }



            return;

        }

而 controller 中的 Action 則改為以下的版本；本版本中，除了把上傳的檔案存檔以外，還有讀取 form data 中其它欄位的範例:

        public async Task<object> PostFormData()

        {

            //改由 HttpContext.Current.Items 中，讀取資料。

            MultipartMemoryStreamProvider provider = (MultipartMemoryStreamProvider)System.Web.HttpContext.Current.Items["MimeMultipartContentProvider"];



            //如果沒有經過 filter，provider會是 null, 這時就要直接由 Request.Content 讀入 provider

            if (provider == null)

            {

                provider = new MultipartMemoryStreamProvider();

                Request.Content.ReadAsMultipartAsync(provider);

            }



            foreach (var content in provider.Contents)

            {

                if (content.Headers.ContentDisposition.FileName != null)

                {

                    string localFilename = content.Headers.ContentDisposition.FileName.Replace("\"", "");

                    Trace.WriteLine("FileName: " + localFilename);

                    Trace.WriteLine("FileName: " + @"~/App_Data/Temp/" + localFilename);

                    System.IO.Directory.CreateDirectory(HttpContext.Current.Server.MapPath(@"~/App_Data/Temp/"));

                    string filename = HttpContext.Current.Server.MapPath(@"~/App_Data/Temp/" + localFilename);

                    if (System.IO.File.Exists(filename))

                    {

                        System.IO.File.Delete(filename);

                    }



                    using (var fileStream = new FileStream(filename, FileMode.Create, FileAccess.Write))

                    {

                        var contentStream = await content.ReadAsStreamAsync();

                        await contentStream.CopyToAsync(fileStream);

                        Trace.WriteLine("Save To" + filename);

                    }

                }

                else

                {

                    var contentStream = await content.ReadAsStreamAsync();

                    var reader = new System.IO.StreamReader(contentStream);

                    var data = reader.ReadToEnd();

                    Trace.WriteLine("data: " + data);

                }

            }

            return "OK";

        }

以上是展示 Web Api 的 Filter。

如果是 MVC 的 Controller，就簡單多了，直接讀取 actionContext.HttpContext.Request.Files 裡面各檔案的 FileName 即可。不過也遇到了一個和直覺不同的地方，對 actionContext.HttpContext.Request.Files 居然不能用 foreach 請見下方註解掉的地方。也許是我的用法有問題，如果有人找到可以使用的方法也麻煩告知。

        public override void OnActionExecuting(ActionExecutingContext actionContext)

        {

            Debug.WriteLine("MvcCheckFileFilter OnActionExecuting");

            if (actionContext.HttpContext.Request.Files.Count > 0)

            {

                for (int i = 0; i < actionContext.HttpContext.Request.Files.Count; i++)

                {

                    System.Web.HttpPostedFileBase file = actionContext.HttpContext.Request.Files[i];

                    if (System.IO.Path.GetExtension(file.FileName) != ".jpg")

                    {

                        throw new Exception("file format error.");

                    }

                    Debug.WriteLine(i + "MvcCheckFileFilter OnActionExecuting File type: " + file.FileName.ToString());

                }

            }



            //以下寫法會發生錯誤: 無法將類型 'System.String' 的物件轉換為類型 'System.Web.HttpPostedFileBase'。

            //foreach (HttpPostedFileBase file in actionContext.HttpContext.Request.Files)

            //{

            //    if (System.IO.Path.GetExtension(file.FileName) != ".jpg")

            //    {

            //        throw new Exception("file format error.");

            //    }

            //}

        }

最後是把 filter 掛在 global filter 裡，如下:
Web API Controller 的部份:
在 WebApiConfig.cs 裡加上 config.Filters.Add(new ApiCheckFile()); 見下圖:

附帶一提，Register 是在 global.asax 裡被叫用的。微軟的架構常常這樣，硬是拉到另一個目錄的獨立檔案裡，如果 global.asax 沒有這一行，不知所以的人，在 App_Start 裡，建立了一個 WebApiConfig.cs 然後會發現完全沒做用... 見下圖

MVC Controller 的部份，
在 FilterConfig.cs 中，加上 filters.Add(new MvcCheckFileFilter()); 如下圖

一樣是在 global.asax 中呼叫 FilterConfig.RegisterGlobalFilters，見下圖:

不過有趣的地方是，在 global.asax 裡, WebApiConfig.Register 和 FilterConfig.RegisterGlobalFilters 的叫用方法不同，一個是把 function 當作變數，一個是直接呼叫 function, 大家可以比較一下。

附註 1, 關於 OnActionExecutingAsync 和 OnActionExecuting:

Web API 的 filter 中，提供了 OnActionExecutingAsync 和 OnActionExecuting 兩個 method 可以 override ，我實驗的結果是如果兩個 method 都 override 了，只有 OnActionExecutingAsync 會被呼叫。

MVC 的 filter 中，只有 OnActionExecuting 可以 override。

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Bike, 2022/5/15 上午 10:01:11