Next.js应用从Azure Blob存储下载Word文件损坏问题求助

你遇到的核心问题是下载后的Word文件损坏，无法被MS Word正常识别，即使调整了Content-Type也未解决。以下是针对性的修复方案：

问题分析 #

1. API层直接返回可读流（readableStreamBody）可能导致数据传输不完整或格式异常，Next.js API路由对原始流的处理存在兼容性问题
2. 前端重复包装Blob对象，可能破坏了原始文件的二进制结构

修复步骤 #

1. 修改API路由代码（转换流为Buffer） #

将Azure Blob返回的可读流转换为Buffer后再返回，确保数据完整传递：

import { dataFound, dataNotFound } from '@/helpers/api-result';
import { BlobServiceClient } from '@azure/storage-blob';
import { Readable } from 'stream';

export const GET = async (request: any) => {
  try {
    const url = new URL(request.url);
    const fileName = url.searchParams.get('fileName') as string;  
    const connectionString = process.env.NEXT_PUBLIC_AZURE_BLOB_STORAGE_CONNECTION_STRING;
    const containerName = "xxxxxxxx";
    
    const blobServiceClient = BlobServiceClient.fromConnectionString(connectionString!);
    const containerClient = blobServiceClient.getContainerClient(containerName);
    const blobClient = containerClient.getBlobClient(fileName);
    const blobDownloadResponse = await blobClient.download();
    
    // 将可读流转换为Buffer，确保数据完整性
    const stream = blobDownloadResponse.readableStreamBody as Readable;
    const chunks: Uint8Array[] = [];
    for await (const chunk of stream) {
      chunks.push(chunk);
    }
    const buffer = Buffer.concat(chunks);

    const headers = {
      'Content-Disposition': `attachment; filename="${fileName}"`,
      'Content-Type': 'application/vnd.openxmlformats-officedocument.wordprocessingml.document'
    };
    
    return dataFound({
      status: 200,
      headers,
      body: buffer
    });
   
  } catch (error) {
    return {
      status: 500,
      body: 'An error occurred while downloading the file.'
    };
  }
}

2. 简化前端下载代码 #

axios已指定responseType: "blob"，返回的data.data已是合法Blob对象，无需重复包装：

const data = await axios.get("/api/download", { 
  params: { fileName: originalFileName },  // 移除未使用的attachmentPath参数
  responseType: "blob",
});

if (data.status === 200) {
  const blobUrl = URL.createObjectURL(data.data);
  
  const a = document.createElement('a');
  a.href = blobUrl;
  a.download = originalFileName;
  a.click();
  URL.revokeObjectURL(blobUrl);
}

额外检查项 #

• 确认Azure Blob存储中的原始Word文件可正常打开，排除上传阶段的损坏问题
• 检查文件名是否包含特殊字符，若有可尝试在Content-Disposition中使用filename*=UTF-8''${encodeURIComponent(fileName)}编码格式

内容的提问来源于stack exchange，提问作者Ponmani Chinnaswamy