如何在 AWS Lambda 上讀取和寫入條碼

安裝

本文將使用 S3 儲存桶，因此需要AWSSDK.S3包。

var awsTmpPath = @"/tmp/";
IronBarCode.Installation.DeploymentPath = awsTmpPath;

var awsTmpPath = @"/tmp/";
IronBarCode.Installation.DeploymentPath = awsTmpPath;

建立 AWS Lambda 項目

使用 Visual Studio，建立容器化的 AWS Lambda 函數非常簡單：

• 安裝適用於 Visual Studio 的 AWS 工具包
• 選擇"AWS Lambda 專案（.NET Core - C#）"
• 選擇".NET 8（容器映像）"藍圖，然後選擇"完成"。

！選擇容器影像

新增包依賴項

.NET 8 中的 IronBarcode 庫無需額外相依性即可在 AWS Lambda 上運作。 若要進行設置，請如下更新專案的 Dockerfile：

FROM public.ecr.aws/lambda/dotnet:8

# Install necessary packages
RUN dnf update -y

WORKDIR /var/task

# This COPY command copies the .NET Lambda project's build artifacts from the host machine into the image. 
# The source of the COPY should match where the .NET Lambda project publishes its build artifacts. If the Lambda function is being built 
# with the AWS .NET Lambda Tooling, the `--docker-host-build-output-dir` switch controls where the .NET Lambda project
# will be built. The .NET Lambda project templates default to having `--docker-host-build-output-dir`
# set in the aws-lambda-tools-defaults.json file to "bin/Release/lambda-publish".
#
# Alternatively Docker multi-stage build could be used to build the .NET Lambda project inside the image.
# For more information on this approach check out the project's README.md file.
COPY "bin/Release/lambda-publish"  .

修改函數處理程序程式碼

此範例產生 EAN8 條碼，將其上傳到 S3 儲存桶，並讀取新建立的條碼。 使用 IronBarcode ZIP 時，配置臨時資料夾至關重要，因為該程式庫需要寫入權限才能從 DLL 複製執行時間資料夾。

using Amazon.Lambda.Core;
using Amazon.S3;
using Amazon.S3.Model;
using IronBarCode;

// Assembly attribute to enable the Lambda function's JSON input to be converted into a .NET class.
[assembly: LambdaSerializer(typeof(Amazon.Lambda.Serialization.SystemTextJson.DefaultLambdaJsonSerializer))]

namespace IronBarcodeZipAwsLambda;

public class Function
{
    private static readonly IAmazonS3 _s3Client = new AmazonS3Client(Amazon.RegionEndpoint.APSoutheast1);

    /// <summary>
    /// AWS Lambda Function Handler. It generates a barcode, uploads it to S3, and then reads it.
    /// </summary>
    /// <param name="context">The ILambdaContext that provides methods for logging and describing the Lambda environment.</param>
    public async Task FunctionHandler(ILambdaContext context)
    {
        var awsTmpPath = @"/tmp/";
        IronBarCode.Installation.DeploymentPath = awsTmpPath;

        // Set your IronBarcode license key here
        IronBarCode.License.LicenseKey = "IRONBARCODE-MYLICENSE-KEY-1EF01";

        string filename = Guid.NewGuid().ToString();
        string bucketName = "deploymenttestbucket";
        string objectKey = $"IronBarcodeZip/{filename}.png";

        try
        {
            // Creating a barcode with EAN8 encoding
            var myBarcode = BarcodeWriter.CreateBarcode("1212345", BarcodeWriterEncoding.EAN8);

            context.Logger.LogLine($"Barcode created.");

            // Upload the PNG image of the barcode to the specified S3 bucket
            await UploadPngToS3Async(bucketName, objectKey, myBarcode.ToPngBinaryData());
            context.Logger.LogLine($"Barcode uploaded successfully to {bucketName}/{objectKey}");

            // Read and log the barcode value from the PNG binary data
            var resultFromByte = BarcodeReader.Read(myBarcode.ToPngBinaryData());
            foreach (var item in resultFromByte)
            {
                context.Logger.LogLine($"Barcode value is = {item.Value}");
            }
        }
        catch (Exception e)
        {
            context.Logger.LogLine($"[ERROR] FunctionHandler: {e.Message}");
        }
    }

    /// <summary>
    /// Uploads a PNG byte array to the specified S3 bucket.
    /// </summary>
    /// <param name="bucketName">The name of the S3 bucket.</param>
    /// <param name="objectKey">The object key for the uploaded file in the bucket.</param>
    /// <param name="pdfBytes">Byte array of the PNG to be uploaded.</param>
    private async Task UploadPngToS3Async(string bucketName, string objectKey, byte[] pdfBytes)
    {
        using (var memoryStream = new MemoryStream(pdfBytes))
        {
            var request = new PutObjectRequest
            {
                BucketName = bucketName,
                Key = objectKey,
                InputStream = memoryStream,
                ContentType = "image/png",
            };

            await _s3Client.PutObjectAsync(request);
        }
    }
}

using Amazon.Lambda.Core;
using Amazon.S3;
using Amazon.S3.Model;
using IronBarCode;

// Assembly attribute to enable the Lambda function's JSON input to be converted into a .NET class.
[assembly: LambdaSerializer(typeof(Amazon.Lambda.Serialization.SystemTextJson.DefaultLambdaJsonSerializer))]

namespace IronBarcodeZipAwsLambda;

public class Function
{
    private static readonly IAmazonS3 _s3Client = new AmazonS3Client(Amazon.RegionEndpoint.APSoutheast1);

    /// <summary>
    /// AWS Lambda Function Handler. It generates a barcode, uploads it to S3, and then reads it.
    /// </summary>
    /// <param name="context">The ILambdaContext that provides methods for logging and describing the Lambda environment.</param>
    public async Task FunctionHandler(ILambdaContext context)
    {
        var awsTmpPath = @"/tmp/";
        IronBarCode.Installation.DeploymentPath = awsTmpPath;

        // Set your IronBarcode license key here
        IronBarCode.License.LicenseKey = "IRONBARCODE-MYLICENSE-KEY-1EF01";

        string filename = Guid.NewGuid().ToString();
        string bucketName = "deploymenttestbucket";
        string objectKey = $"IronBarcodeZip/{filename}.png";

        try
        {
            // Creating a barcode with EAN8 encoding
            var myBarcode = BarcodeWriter.CreateBarcode("1212345", BarcodeWriterEncoding.EAN8);

            context.Logger.LogLine($"Barcode created.");

            // Upload the PNG image of the barcode to the specified S3 bucket
            await UploadPngToS3Async(bucketName, objectKey, myBarcode.ToPngBinaryData());
            context.Logger.LogLine($"Barcode uploaded successfully to {bucketName}/{objectKey}");

            // Read and log the barcode value from the PNG binary data
            var resultFromByte = BarcodeReader.Read(myBarcode.ToPngBinaryData());
            foreach (var item in resultFromByte)
            {
                context.Logger.LogLine($"Barcode value is = {item.Value}");
            }
        }
        catch (Exception e)
        {
            context.Logger.LogLine($"[ERROR] FunctionHandler: {e.Message}");
        }
    }

    /// <summary>
    /// Uploads a PNG byte array to the specified S3 bucket.
    /// </summary>
    /// <param name="bucketName">The name of the S3 bucket.</param>
    /// <param name="objectKey">The object key for the uploaded file in the bucket.</param>
    /// <param name="pdfBytes">Byte array of the PNG to be uploaded.</param>
    private async Task UploadPngToS3Async(string bucketName, string objectKey, byte[] pdfBytes)
    {
        using (var memoryStream = new MemoryStream(pdfBytes))
        {
            var request = new PutObjectRequest
            {
                BucketName = bucketName,
                Key = objectKey,
                InputStream = memoryStream,
                ContentType = "image/png",
            };

            await _s3Client.PutObjectAsync(request);
        }
    }
}

在 try 程式碼區塊之前，檔案目標位置設定為 IronBarcodeZip 目錄，檔案名稱由全域唯一識別碼 (GUID) 產生。 CreateBarcode方法用於產生條碼。 之後，將 PNG 位元組數組傳遞給Read方法來讀取條碼。 這證明 AWS Lambda 函數能夠讀取條碼。

Read方法也接受一個BarcodeReaderOptions對象，您可以對其進行自訂以啟用讀取多個條碼、定位特定區域、使用非同步和多執行緒處理、套用影像校正濾鏡等功能。

增加記憶體和超時

Lambda 函數中分配的記憶體量將根據正在處理的文件的大小和同時處理的文件數量而變化。 作為基準，在aws-lambda-tools-defaults.json中將記憶體設為 512 MB，逾時設為 300 秒。

{
    "function-memory-size": 512,
    "function-timeout": 300
}

當記憶體不足時，程式會拋出錯誤："運行時錯誤退出：訊號：終止"。增加記憶體大小可以解決此問題。 如需更多詳細信息，請參閱故障排除文章： AWS Lambda - 運行時退出訊號：已終止。

發布

若要在 Visual Studio 中發布，請右鍵按一下專案並選擇"發佈到 AWS Lambda..."，然後配置必要的設定。 您可以在AWS 網站上閱讀更多關於發布 Lambda 函數的資訊。

試試看！

您可以透過Lambda 控制台或 Visual Studio 啟動 Lambda 函數。