在 Azure Functions 应用程序 blobtrigger 中设置 blob 的内容类型

问题描述

我正在尝试调整上传到我的容器的图像的大小，以便为我的网站创建缩略图和其他各种版本的图像.

I am trying to resize the images uploaded to my container in order to create thumbnails and various other versions of my images for my site.

我上传的图片必须更正内容类型image/jpeg"；但是当我使用下面的代码创建它们的新版本时，结果显示为application/octet-stream".

The images I upload have to correct content-type "image/jpeg" but when I create a new version of them using the code below it turns out as "application/octet-stream".

我在这里错过了什么?

using ImageResizer;
using ImageResizer.ExtensionMethods;
 
public static void Run(Stream myBlob, string blobname, string blobextension, Stream outputBlob, TraceWriter log)
{
    log.Info($"C# Blob trigger function Processed blob
 Name:{blobname} 
 Size: {myBlob.Length} Bytes");
    
    var instructions = new Instructions
    {
        Width = 570,
        Mode = FitMode.Crop,
        Scale = ScaleMode.Both,
    };
    ImageBuilder.Current.Build(new ImageJob(myBlob, outputBlob, instructions));
}

解决方案.

#r "Microsoft.WindowsAzure.Storage"
using ImageResizer;
using ImageResizer.ExtensionMethods;
using Microsoft.WindowsAzure.Storage.Blob;

public static void Run(Stream myBlob, string blobname, string blobextension, CloudBlockBlob outputBlob, TraceWriter log)
{
    log.Info($"C# Blob trigger function Processed blob
 Name:{blobname} 
 Size: {myBlob.Length} Bytes");
    
    var instructions = new Instructions
    {
        Width = 570,
        Mode = FitMode.Crop,
        Scale = ScaleMode.Both
    };

    Stream stream = new MemoryStream();
    ImageBuilder.Current.Build(new ImageJob(myBlob, stream, instructions));
    stream.Seek(0, SeekOrigin.Begin);
 
    outputBlob.Properties.ContentType = "image/jpeg";
    outputBlob.UploadFromStream(stream);
}

推荐答案

当你使用流输出时，函数会默认你的 content-type 为 application/octet-stream.

When you use the stream output, functions will default your content-type to application/octet-stream.

使用其中一种 ICloudBlob 类型，它应该允许您指定 blob 的内容类型.

Use one of the ICloudBlob types, which should allow you to specify the content type of your blob.

以下是可以作为参数绑定的类型的备忘单:https://jhaleyfiles2016.blob.core.windows.net/public/Azure%20WebJobs%20SDK%20Cheat%20Sheet%202014.pdf

Here's a cheatsheet of types you can bind to as parameters: https://jhaleyfiles2016.blob.core.windows.net/public/Azure%20WebJobs%20SDK%20Cheat%20Sheet%202014.pdf

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