Function downloadFromBlob

apps/sim/lib/uploads/providers/blob/client.ts:281–343

(
  key: string,
  customConfig?: BlobConfig,
  maxBytes?: number
)

): Promise<Buffer>

export async function downloadFromBlob(
  key: string,
  customConfig?: BlobConfig,
  maxBytes?: number
): Promise<Buffer> {
  const { BlobServiceClient, StorageSharedKeyCredential } = await import('@azure/storage-blob')
  let blobServiceClient: BlobServiceClientType
  let containerName: string

  if (customConfig) {
    if (customConfig.connectionString) {
      blobServiceClient = BlobServiceClient.fromConnectionString(customConfig.connectionString)
    } else if (customConfig.accountName && customConfig.accountKey) {
      const credential = new StorageSharedKeyCredential(
        customConfig.accountName,
        customConfig.accountKey
      )
      blobServiceClient = new BlobServiceClient(
        `https://${customConfig.accountName}.blob.core.windows.net`,
        credential
      )
    } else {
      throw new Error('Invalid custom blob configuration')
    }
    containerName = customConfig.containerName
  } else {
    blobServiceClient = await getBlobServiceClient()
    containerName = BLOB_CONFIG.containerName
  }

  const containerClient = blobServiceClient.getContainerClient(containerName)
  const blockBlobClient = containerClient.getBlockBlobClient(key)

  const downloadBlockBlobResponse = await blockBlobClient.download()
  if (maxBytes !== undefined && downloadBlockBlobResponse.contentLength !== undefined) {
    try {
      assertKnownSizeWithinLimit(
        downloadBlockBlobResponse.contentLength,
        maxBytes,
        'storage download'
      )
    } catch (error) {
      const stream = downloadBlockBlobResponse.readableStreamBody as
        | { destroy?: (error?: Error) => void }
        | undefined
      stream?.destroy?.(error instanceof Error ? error : undefined)
      throw error
    }
  }

  if (!downloadBlockBlobResponse.readableStreamBody) {
    throw new Error('Failed to get readable stream from blob download')
  }
  const downloaded = await readNodeStreamToBufferWithLimit(
    downloadBlockBlobResponse.readableStreamBody,
    {
      maxBytes: maxBytes ?? Number.MAX_SAFE_INTEGER,
      label: 'storage download',