Added blob exists method

sdk/storage/azure-storage-blob/azure/storage/blob/_blob_client.py

@@ -918,6 +918,28 @@ def undelete_blob(self, **kwargs):
         except StorageErrorException as error:
             process_storage_error(error)
 
+    @distributed_trace()
+    def exists(self, timeout=None, version_id=None):
+        # type: (**Any) -> bool
+        """
+        Returns True if a blob exists with the defined parameters, and returns
+        False otherwise.
+
+        :param str version_id:
+            The version id parameter is an opaque DateTime
+            value that, when present, specifies the version of the blob to check if it exists.
+        :param int timeout:
+            The timeout parameter is expressed in seconds.
+        :returns: boolean
+        """
+        try:
+            self._client.blob.get_properties(
+                timeout=timeout,
+                version_id=version_id)
+            return True
+        except StorageErrorException:
+            return False
+
     @distributed_trace
     def get_blob_properties(self, **kwargs):
         # type: (**Any) -> BlobProperties

sdk/storage/azure-storage-blob/tests/recordings/test_blob_access_conditions.test_if_blob_exists.yaml

@@ -0,0 +1,237 @@
+interactions:
+- request:
+    body: null
+    headers:
+      Accept:
+      - '*/*'
+      Accept-Encoding:
+      - gzip, deflate
+      Connection:
+      - keep-alive
+      Content-Length:
+      - '0'
+      User-Agent:
+      - azsdk-python-storage-blob/12.4.0 Python/3.8.5 (Windows-10-10.0.18362-SP0)
+      x-ms-date:
+      - Wed, 19 Aug 2020 20:52:58 GMT
+      x-ms-version:
+      - '2019-12-12'
+    method: PUT
+    uri: https://storagename.blob.core.windows.net/utcontainerccc51342?restype=container
+  response:
+    body:
+      string: ''
+    headers:
+      content-length:
+      - '0'
+      date:
+      - Wed, 19 Aug 2020 20:52:58 GMT
+      etag:
+      - '"0x8D84481DAA59725"'
+      last-modified:
+      - Wed, 19 Aug 2020 20:52:58 GMT
+      server:
+      - Windows-Azure-Blob/1.0 Microsoft-HTTPAPI/2.0
+      x-ms-version:
+      - '2019-12-12'
+    status:
+      code: 201
+      message: Created
+- request:
+    body: hello world
+    headers:
+      Accept:
+      - '*/*'
+      Accept-Encoding:
+      - gzip, deflate
+      Connection:
+      - keep-alive
+      Content-Length:
+      - '11'
+      Content-Type:
+      - application/octet-stream
+      If-None-Match:
+      - '*'
+      User-Agent:
+      - azsdk-python-storage-blob/12.4.0 Python/3.8.5 (Windows-10-10.0.18362-SP0)
+      x-ms-blob-type:
+      - BlockBlob
+      x-ms-date:
+      - Wed, 19 Aug 2020 20:52:58 GMT
+      x-ms-version:
+      - '2019-12-12'
+    method: PUT
+    uri: https://storagename.blob.core.windows.net/utcontainerccc51342/blob1
+  response:
+    body:
+      string: ''
+    headers:
+      content-length:
+      - '0'
+      content-md5:
+      - XrY7u+Ae7tCTyyK7j1rNww==
+      date:
+      - Wed, 19 Aug 2020 20:52:58 GMT
+      etag:
+      - '"0x8D84481DABA7742"'
+      last-modified:
+      - Wed, 19 Aug 2020 20:52:58 GMT
+      server:
+      - Windows-Azure-Blob/1.0 Microsoft-HTTPAPI/2.0
+      x-ms-content-crc64:
+      - vo7q9sPVKY0=
+      x-ms-request-server-encrypted:
+      - 'true'
+      x-ms-version:
+      - '2019-12-12'
+      x-ms-version-id:
+      - '2020-08-19T20:52:58.4048450Z'
+    status:
+      code: 201
+      message: Created
+- request:
+    body: null
+    headers:
+      Accept:
+      - '*/*'
+      Accept-Encoding:
+      - gzip, deflate
+      Connection:
+      - keep-alive
+      User-Agent:
+      - azsdk-python-storage-blob/12.4.0 Python/3.8.5 (Windows-10-10.0.18362-SP0)
+      x-ms-date:
+      - Wed, 19 Aug 2020 20:52:58 GMT
+      x-ms-version:
+      - '2019-12-12'
+    method: HEAD
+    uri: https://storagename.blob.core.windows.net/utcontainerccc51342/blob1
+  response:
+    body:
+      string: ''
+    headers:
+      accept-ranges:
+      - bytes
+      content-length:
+      - '11'
+      content-md5:
+      - XrY7u+Ae7tCTyyK7j1rNww==
+      content-type:
+      - application/octet-stream
+      date:
+      - Wed, 19 Aug 2020 20:52:58 GMT
+      etag:
+      - '"0x8D84481DABA7742"'
+      last-modified:
+      - Wed, 19 Aug 2020 20:52:58 GMT
+      server:
+      - Windows-Azure-Blob/1.0 Microsoft-HTTPAPI/2.0
+      x-ms-access-tier:
+      - Hot
+      x-ms-access-tier-inferred:
+      - 'true'
+      x-ms-blob-type:
+      - BlockBlob
+      x-ms-creation-time:
+      - Wed, 19 Aug 2020 20:52:58 GMT
+      x-ms-is-current-version:
+      - 'true'
+      x-ms-lease-state:
+      - available
+      x-ms-lease-status:
+      - unlocked
+      x-ms-server-encrypted:
+      - 'true'
+      x-ms-version:
+      - '2019-12-12'
+      x-ms-version-id:
+      - '2020-08-19T20:52:58.4048450Z'
+    status:
+      code: 200
+      message: OK
+- request:
+    body: null
+    headers:
+      Accept:
+      - '*/*'
+      Accept-Encoding:
+      - gzip, deflate
+      Connection:
+      - keep-alive
+      User-Agent:
+      - azsdk-python-storage-blob/12.4.0 Python/3.8.5 (Windows-10-10.0.18362-SP0)
+      x-ms-date:
+      - Wed, 19 Aug 2020 20:52:58 GMT
+      x-ms-version:
+      - '2019-12-12'
+    method: HEAD
+    uri: https://storagename.blob.core.windows.net/utcontainerccc51342/blob1?versionid=2020-08-19T20%3A52%3A58.4048450Z
+  response:
+    body:
+      string: ''
+    headers:
+      accept-ranges:
+      - bytes
+      content-length:
+      - '11'
+      content-md5:
+      - XrY7u+Ae7tCTyyK7j1rNww==
+      content-type:
+      - application/octet-stream
+      date:
+      - Wed, 19 Aug 2020 20:52:58 GMT
+      etag:
+      - '"0x8D84481DABA7742"'
+      last-modified:
+      - Wed, 19 Aug 2020 20:52:58 GMT
+      server:
+      - Windows-Azure-Blob/1.0 Microsoft-HTTPAPI/2.0
+      x-ms-access-tier:
+      - Hot
+      x-ms-access-tier-inferred:
+      - 'true'
+      x-ms-blob-type:
+      - BlockBlob
+      x-ms-creation-time:
+      - Wed, 19 Aug 2020 20:52:58 GMT
+      x-ms-is-current-version:
+      - 'true'
+      x-ms-server-encrypted:
+      - 'true'
+      x-ms-version:
+      - '2019-12-12'
+      x-ms-version-id:
+      - '2020-08-19T20:52:58.4048450Z'
+    status:
+      code: 200
+      message: OK
+- request:
+    body: null
+    headers:
+      Accept:
+      - '*/*'
+      Accept-Encoding:
+      - gzip, deflate
+      Connection:
+      - keep-alive
+      User-Agent:
+      - azsdk-python-storage-blob/12.4.0 Python/3.8.5 (Windows-10-10.0.18362-SP0)
+      x-ms-date:
+      - Wed, 19 Aug 2020 20:52:59 GMT
+      x-ms-version:
+      - '2019-12-12'
+    method: HEAD
+    uri: https://storagename.blob.core.windows.net/utcontainerccc51342/blob1?versionid=bad_version_id
+  response:
+    body:
+      string: ''
+    headers:
+      date:
+      - Wed, 19 Aug 2020 20:52:58 GMT
+      server:
+      - Windows-Azure-Blob/1.0 Microsoft-HTTPAPI/2.0
+    status:
+      code: 400
+      message: Value for one of the query parameters specified in the request URI
+        is invalid.
+version: 1

sdk/storage/azure-storage-blob/tests/test_blob_access_conditions.py

@@ -715,6 +715,20 @@ def test_get_blob_properties_with_if_modified(self, resource_group, location, st
         self.assertEqual(properties.size, 11)
         self.assertEqual(properties.lease.status, 'unlocked')
 
+    @GlobalStorageAccountPreparer()
+    def test_if_blob_exists(self, resource_group, location, storage_account, storage_account_key):
+        bsc = BlobServiceClient(self.account_url(storage_account, "blob"), storage_account_key, connection_data_block_size=4 * 1024)
+        self._setup()
+        self._create_container_and_block_blob(
+            self.container_name, 'blob1', b'hello world', bsc)
+        test_datetime = (datetime.utcnow() -
+                         timedelta(minutes=15))
+        # Act
+        blob = bsc.get_blob_client(self.container_name, 'blob1')
+        blob_version_id = blob.get_blob_properties().get("version_id")
+        self.assertEqual(blob.exists(version_id=blob_version_id), True)
+        self.assertEqual(blob.exists(version_id="bad_version_id"), False)
+
     @GlobalStorageAccountPreparer()
     def test_get_blob_properties_with_if_modified_fail(self, resource_group, location, storage_account, storage_account_key):
         bsc = BlobServiceClient(self.account_url(storage_account, "blob"), storage_account_key, connection_data_block_size=4 * 1024)