Azure Blob Node.js下载Blob文件

Question

我有一个前端在Angular中的node.js应用程序，我需要上传和下载文件到Azure blob/Azure存储

我遵循了这里给出的指示：https://github.com/Azure/azure-sdk-for-js/blob/master/sdk/storage/storage-blob/samples/typescript/src/basic.ts

现在，当我下载它读取可读流中的图像或文件时，我如何从azure blob 下载文件

下面是我的代码，列出了读到可读流的Blob

const { BlobServiceClient, StorageSharedKeyCredential, BlobDownloadResponseModel } = require('@azure/storage-blob');
const uuidv1 = require('uuid/v1');
async ListBlob(req,res){
const blobServiceClient = await BlobServiceClient.fromConnectionString(this.AZURE_STORAGE_CONNECTION_STRING);
const container = blobServiceClient.getContainerClient('mycontainer');
const containerClient = await blobServiceClient.getContainerClient(container.containerName);
let temp = Array();
// List the blob(s) in the container.
for await (const blob of containerClient.listBlobsFlat()) {
temp.push(blob.name);
}
const blockBlobClient = containerClient.getBlockBlobClient(temp[2]);
const downloadBlockBlobResponse = await blockBlobClient.download(0);
let result = await this.streamToString(downloadBlockBlobResponse.readableStreamBody!);
res.send(result);
}
async streamToString(readableStream) {
return new Promise((resolve, reject) => {
const chunks = [];
readableStream.on("data", (data) => {
chunks.push(data.toString());
});
readableStream.on("end", () => {
resolve(chunks.join(""));
});
readableStream.on("error", reject);
});
}

Answer 1

请尝试BlockBlobClient.downloadToFile()方法

const response = await blockBlobClient.downloadToFile("filePath");

Answer 2

如果您的目标是将流写入本地文件，那么您所需要做的就是将流读取为buffer，并使用Node中的fs模块将其保存在文件中。

本质上，你可以尝试这样的东西：

const fs = require('fs');
async streamToLocalFile(readableStream) {
return new Promise((resolve, reject) => {
let buffer = Buffer.from([]);
readableStream.on("data", (data) => {
buffer = Buffer.concat([buffer, data], buffer.length+data.length);//Add the data read to the existing buffer.
});
readableStream.on("end", () => {
fs.writeFileSync('your file path', buffer);//Write buffer to local file.
resolve('your file path);//Return that file path.  
});
readableStream.on("error", reject);
});
}