Unable to download blob from my container as shown in the @azure/storage-blob documentation

Question

I am unable to download blob from azure storage account. I have done exactly as shown in there official documentation here.

DOCUMENTATION CODE

const { BlobServiceClient } = require("@azure/storage-blob");
 
const account = "<account name>";
const sas = "<service Shared Access Signature Token>";
const containerName = "<container name>";
const blobName = "<blob name>"
 
const blobServiceClient = new BlobServiceClient(
  `https://${account}.blob.core.windows.net${sas}`
);
 
async function main() {
  const containerClient = blobServiceClient.getContainerClient(containerName);
  const blobClient = containerClient.getBlobClient(blobName);
 
  // Get blob content from position 0 to the end
  // In browsers, get downloaded data by accessing downloadBlockBlobResponse.blobBody
  const downloadBlockBlobResponse = await blobClient.download();
  const downloaded = await blobToString(await downloadBlockBlobResponse.blobBody);
  console.log(
    "Downloaded blob content",
    downloaded
  );

My Code

exports.downloadBlob = async (req, res, next)=>{
    const ref = req.params.id;
    try{
         const containerClient = blobServiceClient.getContainerClient('xxxxxxxxx');
         const blobClient = containerClient.getBlobClient(ref);
   
         // Get blob content from position 0 to the end
          // In Node.js, get downloaded data by accessing downloadBlockBlobResponse.readableStreamBody
          const downloadBlockBlobResponse = await blobClient.download();
          const downloaded = await streamToString(downloadBlockBlobResponse.readableStreamBody);
            console.log("Downloaded blob content:", downloaded);
            return res.send(downloaded)

    }
    catch(err){
        return res.send(err)
    }
}

I have passed the name of the blob as well the reference number it sends back when we save any blob

Answer 1

According to my understanding, you want to get the blob content. Please refer to the following code. Besides，please note that you need to provide the right blob name.

var storage = require("@azure/storage-blob")
async function readBlob() {

    const accountname ="";
    const key = "";
    const cerds = new storage.StorageSharedKeyCredential(accountname,key);

    const blobServiceClient =new storage.BlobServiceClient( `https://${accountname}.blob.core.windows.net`,cerds)
    const containerName="test";
    
    var client =blobServiceClient.getContainerClient(containerName)
    
    // download blob(read)
    const blobClient = client.getBlobClient("test.json");
    const downloadBlockBlobResponse = await blobClient.download(0);
    console.log(
      "Downloaded blob content",
      await streamToString(downloadBlockBlobResponse.readableStreamBody)
    );
   
        
}
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);
  });
}

readBlob()
  .then(() => {
    console.log("Successfully executed sample.");
  })
  .catch((err) => {
    console.log(err.message);
  });

---

Update

If you want to download the picture, you can use the method dowlodToFile. For more details, please refer to https://learn.microsoft.com/en-us/javascript/api/@azure/storage-blob/blobclient?view=azure-node-latest#downloadtofile-string--undefined---number--undefined---number--blobdownloadoptions-.