Generates a SAS token URL for a particular file in an Azure storage account

generateSasTokenUrl.js

const {
	BlobSASPermissions, generateBlobSASQueryParameters, StorageSharedKeyCredential,
} = require('@azure/storage-blob');

/**
 * Generate a secure token URL for a particular file in a storage account.
 *
 * @param {string} accountName The name of the storage account.
 * @param {string} accountKey The account key.
 * @param {string} container The container.
 * @param {string} blobName The file name.
 * @param {string} permissions The permissions granted by the secure token.
 * @param {integer} ttl The number of minutes that the token should remain valid.
 * @returns {object} Contains the SAS token and the URL.
 */
const generateSecureTokenUrl = async (accountName, accountKey, container, blobName, permissions = 'r', ttl = 60) => {
	// Create a SAS token that expires in an hour
	// Set start time to fifteen minutes ago to avoid clock skew.
	// This is recommended by Azure.
	const startDate = new Date();
	startDate.setMinutes(startDate.getMinutes() - 15);
	const expiryDate = new Date(startDate);
	expiryDate.setMinutes(startDate.getMinutes() + ttl);

	const sharedKeyCredential = new StorageSharedKeyCredential(accountName, accountKey);

	const sas = generateBlobSASQueryParameters({
		containerName: container,
		blobName,
		permissions: BlobSASPermissions.parse(permissions),
		startsOn: startDate,
		expiresOn: expiryDate,
		version: '2019-12-12',
	}, sharedKeyCredential).toString();

	const { url } = this.blobServiceClient.getContainerClient(container).getBlockBlobClient(blobName);

	return {
		token: sas,
		url: `${url}?${sas}`,
	};
}