如何解决如何在Node.js和TypeScript中构建可读流?
我通过Rest-API将打字稿功能连接到Azure Blobstorage,这对我来说很好。现在,我想获取每个blob的内容并读取每个blob的内容。
我在这里使用此代码尝试此操作,但它返回错误:
const blobServiceClient = new BlobServiceClient(`https://${accountName}.blob.core.windows.net?${sasToken}`,pipeline)
const containerClient = blobServiceClient.getContainerClient(containerName)
console.log(containerClient)
if (!containerClient.exists()) {
console.log("the container does not exit")
await containerClient.create()
}
const client = containerClient.getBlockBlobClient(this.currentFile.name)
//name of uploded blob
console.log(this.currentFile.name)
//metaata from the blob
console.log(client)
//List each blobs in the container
for await (const blob of containerClient.listBlobsFlat()) {
console.log('\t',blob.name);
const blockBlobClient = containerClient.getBlockBlobClient(blob.name);
const downloadBlockBlobResponse = await blockBlobClient.download(0);
console.log('\nDownloaded blob content...');
console.log('\t',await streamToString(downloadBlockBlobResponse.readableStreamBody));
//end of loop
}
async function 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);
});
}
错误是:
ERROR Error: Uncaught (in promise): TypeError: Cannot read property 'on' of undefined TypeError: Cannot read property 'on' of undefined
那么如何解决问题呢? 谢谢
解决方法
Download the official sample code.
它通常在我这边运行。检查您本地是否缺少依赖项,或者是否需要设置存储中的权限。
// Copyright (c) Microsoft Corporation.
// Licensed under the MIT license.
/*
Setup: Enter your storage account name and shared key in main()
*/
import {
BlobServiceClient,StorageSharedKeyCredential,BlobDownloadResponseModel
} from "@azure/storage-blob";
// Load the .env file if it exists
import * as dotenv from "dotenv";
dotenv.config();
export async function main() {
// Enter your storage account name and shared key
const account = process.env.ACCOUNT_NAME || "pans*****age";
const accountKey = process.env.ACCOUNT_KEY || "IHa48xxo+0anyKQ2GzQ2K*******ZBxgJ0VotCpGs/PMftkebb9UFqyg==";
// Use StorageSharedKeyCredential with storage account and account key
// StorageSharedKeyCredential is only available in Node.js runtime,not in browsers
const sharedKeyCredential = new StorageSharedKeyCredential(account,accountKey);
// ONLY AVAILABLE IN NODE.JS RUNTIME
// DefaultAzureCredential will first look for Azure Active Directory (AAD)
// client secret credentials in the following environment variables:
//
// - AZURE_TENANT_ID: The ID of your AAD tenant
// - AZURE_CLIENT_ID: The ID of your AAD app registration (client)
// - AZURE_CLIENT_SECRET: The client secret for your AAD app registration
//
// If those environment variables aren't found and your application is deployed
// to an Azure VM or App Service instance,the managed service identity endpoint
// will be used as a fallback authentication source.
// const defaultAzureCredential = new DefaultAzureCredential();
// You can find more TokenCredential implementations in the [@azure/identity](https://www.npmjs.com/package/@azure/identity) library
// to use client secrets,certificates,or managed identities for authentication.
// Use AnonymousCredential when url already includes a SAS signature
// const anonymousCredential = new AnonymousCredential();
// List containers
const blobServiceClient = new BlobServiceClient(
// When using AnonymousCredential,following url should include a valid SAS or support public access
`https://${account}.blob.core.windows.net`,sharedKeyCredential
);
let i = 1;
for await (const container of blobServiceClient.listContainers()) {
console.log(`Container ${i++}: ${container.name}`);
}
// Create a container
const containerName = `newcontainer${new Date().getTime()}`;
const containerClient = blobServiceClient.getContainerClient(containerName);
const createContainerResponse = await containerClient.create();
console.log(`Create container ${containerName} successfully`,createContainerResponse.requestId);
// Create a blob
const content = "hello,你好";
const blobName = "newblob" + new Date().getTime();
const blockBlobClient = containerClient.getBlockBlobClient(blobName);
const uploadBlobResponse = await blockBlobClient.upload(content,Buffer.byteLength(content));
console.log(`Upload block blob ${blobName} successfully`,uploadBlobResponse.requestId);
// List blobs
i = 1;
for await (const blob of containerClient.listBlobsFlat()) {
console.log(`Blob ${i++}: ${blob.name}`);
}
// Get blob content from position 0 to the end
// In Node.js,get downloaded data by accessing downloadBlockBlobResponse.readableStreamBody
// In browsers,get downloaded data by accessing downloadBlockBlobResponse.blobBody
const downloadBlockBlobResponse: BlobDownloadResponseModel = await blockBlobClient.download(0);
console.log(
"Downloaded blob content",await streamToString(downloadBlockBlobResponse.readableStreamBody!)
);
// Delete container
await containerClient.delete();
console.log("deleted container");
}
// A helper method used to read a Node.js readable stream into string
async function streamToString(readableStream: NodeJS.ReadableStream) {
return new Promise((resolve,reject) => {
const chunks: string[] = [];
readableStream.on("data",(data) => {
chunks.push(data.toString());
});
readableStream.on("end",() => {
resolve(chunks.join(""));
});
readableStream.on("error",reject);
});
}
main().catch((err) => {
console.error("Error running sample:",err.message);
});
版权声明:本文内容由互联网用户自发贡献,该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务,不拥有所有权,不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容, 请发送邮件至 dio@foxmail.com 举报,一经查实,本站将立刻删除。