AzureBlob Schemas

AzureBlob Schemas

The @tundraconnect/azure-blob/schemas subpath exports Guardian validators and inferred types. Client methods validate every response (or the header-derived object built from one) before returning it.

import {
  type BlobItemSchema,
  BlobItemSchemaObject,
} from '@tundraconnect/azure-blob/schemas';

const payload: unknown = {
  name: 'photos/cat.png',
  lastModified: 'Tue, 01 Jan 2019 12:00:00 GMT',
  etag: '"0x8D1234567890ABC"',
  contentLength: '12345',
  contentType: 'image/png',
};

const [error, item] = BlobItemSchemaObject.safeParse(payload);
if (error || !item) throw error;

const typed: BlobItemSchema = item;
console.log(typed.lastModified.toISOString());

Response Schemas

Schema	Used by
PutObjectResultSchemaObject	putObject()
GetObjectResultSchemaObject	getObject()
HeadObjectResultSchemaObject	headObject()
ListBlobsResponseSchemaObject	listObjects()
ErrorSchemaObject	Vendor XML <Error> envelopes

Component Schemas

Schema	Purpose
BlobItemSchemaObject	One normalized entry from a List Blobs response
BlobPropertiesSchemaObject	Header-derived properties shared by Get Blob and Get Blob Properties

XML Response Handling

Azure's Blob Storage REST API is XML-based (List Blobs, and every error envelope) rather than JSON. RESTler auto-parses an application/xml response body into an object keyed by the root tag name — for example, List Blobs surfaces as { EnumerationResults: { Blobs: { Blob: [...] }, ... } }, and a single <Blob> flattens to an object while two or more become an array. ListBlobsResponseSchemaObject uses Guardian.preprocess() to normalize that ambiguous shape into a flat { blobs: BlobItemSchema[], nextMarker?: string } before validating the normalized fields — see schema/response/ListBlobsResponse.ts for the exact flattening logic, and its co-located test for fixtures verified directly against the XML parser's real output.

The normalization is tolerant of elements the parser drops or nulls (an empty <Blobs/> or <NextMarker/>, even an empty root), but it requires the <EnumerationResults> root itself: a body without one is rejected with RESPONSE_ERROR rather than being read as an empty container, so a malformed response can never pass for "no blobs".

Get Blob's binary body is requested with responseType: 'BLOB' and validated with Guardian.instanceof(Blob).

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