Azure 函数 - 调整存储在 blob 容器中的图像大小

Question

我已经回答了与 Azure Webjob 和调整存储为 blob 的图像相关的 this question，因此我正在尝试使用 Function App 来做同样的事情

每次上传新的 blob 时，我都会发送一条新的队列消息。 我的函数由队列消息触发并绑定到上传的 blob。我还有一个绑定到另一个 CloudBlobContainer 的第二个输入绑定，以便能够将新调整大小的图像上传到另一个 blob 容器。

我的函数是这样的：

#r "System.Web"
using System.IO;
using System.Web;
using ImageResizer;
using Microsoft.Azure.WebJobs;
using Microsoft.WindowsAzure;
using Microsoft.WindowsAzure.Storage;
using Microsoft.WindowsAzure.Storage.Blob;

private static readonly int[] Sizes = { 800, 500, 250 };

public static void Run(string filename, Stream blobStream, CloudBlobContainer container, TraceWriter log)
{
    log.Verbose($"C# Queue trigger function processed: {filename}");
    // Extract the filename  and the file extension
    var name = Path.GetFileNameWithoutExtension(filename);
    var ext = Path.GetExtension(filename);

    // Get the mime type to set the content type
    var mimeType = MimeMapping.GetMimeMapping(filename);

    foreach (var width in Sizes)
    {
        // Set the position of the input stream to the beginning.
        blobStream.Seek(0, SeekOrigin.Begin);

        // Get the output stream
        var outputStream = new MemoryStream();
        ResizeImage(blobStream, outputStream, width);

        // Get the blob reference
        CloudBlockBlob blob = container.GetBlockBlobReference($"{name}-w{width}.{ext}");

        // Set the position of the output stream to the beginning.
        outputStream.Seek(0, SeekOrigin.Begin);
        blob.UploadFromStream(outputStream);

        // Update the content type =>  don't know if required
        blob.Properties.ContentType = mimeType;
        blob.SetProperties();
    }               
}

private static void ResizeImage(Stream input, Stream output, int width)
{
    var instructions = new Instructions
    {
        Width = width,
        Mode = FitMode.Carve,
        Scale = ScaleMode.Both
    };
    var imageJob = new ImageJob(input, output, instructions);

    // Do not dispose the source object
    imageJob.DisposeSourceObject = false;
    imageJob.Build();
}

关联的function.json 文件：

{
"bindings": [
  {
    "queueName": "newfileuploaded",
    "connection": "crazytunastorageaccount_STORAGE",
    "name": "filename",
    "type": "queueTrigger",
    "direction": "in"
  },
  {
    "path": "input-images/{queueTrigger}",
    "connection": "crazytunastorageaccount_STORAGE",
    "name": "blobStream",
    "type": "blob",
    "direction": "in"
  },
  {
    "name": "container",
    "type": "blob",
    "path": "output-images",
    "connection": "crazytunastorageaccount_STORAGE",
    "direction": "in"
  }
],
"disabled": false
}

还有project.json 文件：

{
"frameworks": {
  "net46":{
    "dependencies": {
      "ImageResizer": "4.0.5",
      "WindowsAzure.Storage": "4.3.0"
    }
  }
 }
}

现在当我编译函数时，我总是得到这个错误：

Microsoft.Azure.WebJobs.Host：索引方法“Functions.ResizeBlobImage”出错。 Microsoft.Azure.WebJobs.Host：无法将 Blob 绑定到类型“Microsoft.WindowsAzure.Storage.Blob.CloudBlobContainer”。

目前是否支持这种类型？

Answer 1

支持CloudBlobContainer。我现在自己尝试了一个快速示例，下面的函数对我有用，使用与上面显示的相同的绑定元数据。我也在 project.json 中使用相同版本的 WebJobs SDK。

using System;
using Microsoft.WindowsAzure.Storage.Blob;

public static void Run(
    string blobTrigger, Stream inputBlob, Stream outputBlob,
    CloudBlobContainer container, TraceWriter log)
{
    log.Info($"Container name: {container.Name}");

    log.Info($"C# Blob trigger function processed {blobTrigger}");
    inputBlob.CopyTo(outputBlob);        
}

不知道为什么这对您不起作用。我不时看到一些 Portal 故障（我们正在修复的错误），这些故障有时会导致问题。