Add resource_exists method

CHANGELOG.md

@@ -13,6 +13,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
   [conjur-api-python#30](https://github.com/cyberark/conjur-api-python/pull/30)
 - Add support for Show Resource endpoint
   [conjur-api-python#31](https://github.com/cyberark/conjur-api-python/pull/31)
+- Add `resource_exists` method
+  [conjur-api-python#32](https://github.com/cyberark/conjur-api-python/pull/32)
 - Add support for LDAP authentication
   [conjur-api-python#22](https://github.com/cyberark/conjur-api-python/pull/22)
 

README.md

@@ -197,6 +197,10 @@ For example: `client.list({'kind': 'user', 'inspect': True})`
 
 Gets a resource based on its kind and ID. Resource is json data that contains metadata about the resource.
 
+#### `resource_exists(kind, resource_id)`
+
+Check the existence of a resource based on its kind and ID. Returns a boolean.
+
 #### `get_role(kind, role_id)`
 
 Gets a role based on its kind and ID. Role is json data that contains metadata about the role.

conjur_api/client.py

@@ -111,6 +111,12 @@ async def get_resource(self, kind: str, resource_id: str) -> json:
         """
         return await self._api.get_resource(kind, resource_id)
 
+    async def resource_exists(self, kind: str, resource_id: str) -> bool:
+        """
+        Check for the existance of a resource based on its kind and ID
+        """
+        return await self._api.resource_exists(kind, resource_id)
+
     async def get_role(self, kind: str, role_id: str) -> json:
         """
         Gets a role based on its kind and ID

conjur_api/http/api.py

@@ -16,7 +16,7 @@
 from conjur_api.interface.authentication_strategy_interface import AuthenticationStrategyInterface
 from conjur_api.wrappers.http_response import HttpResponse
 from conjur_api.wrappers.http_wrapper import HttpVerb, invoke_endpoint
-from conjur_api.errors.errors import InvalidResourceException, MissingRequiredParameterException
+from conjur_api.errors.errors import HttpStatusError, InvalidResourceException, MissingRequiredParameterException
 # pylint: disable=too-many-instance-attributes
 from conjur_api.models import Resource, ConjurConnectionInfo, ListPermittedRolesData, \
     ListMembersOfData, CreateHostData, CreateTokenData, SslVerificationMetadata, SslVerificationMode
@@ -179,6 +179,33 @@ async def get_resource(self, kind: str, resource_id: str) -> dict:
         # ?tocpath=Developer%7CREST%C2%A0APIs%7C_____19
         return resource
 
+    async def resource_exists(self, kind: str, resource_id: str) -> bool:
+        """
+        This method is used to check whether a specific resource exists.
+        """
+        params = {
+            'account': self._account,
+            'kind': kind,
+            'identifier': resource_id
+        }
+        params.update(self._default_params)
+
+        try:
+            await invoke_endpoint(HttpVerb.HEAD, ConjurEndpoint.RESOURCE,
+                                  params,
+                                  api_token=await self.api_token,
+                                  ssl_verification_metadata=self.ssl_verification_data)
+        except HttpStatusError as err:
+            if err.status == 404:
+                return False
+
+            if err.status == 403:
+                return True
+
+            raise
+
+        return True
+
     async def get_role(self, kind: str, resource_id: str) -> dict:
         """
         This method is used to fetch a specific role.

conjur_api/wrappers/http_wrapper.py

@@ -37,6 +37,7 @@ class HttpVerb(Enum):
     PUT = 3
     DELETE = 4
     PATCH = 5
+    HEAD = 6
 
 
 # pylint: disable=too-many-locals,consider-using-f-string,too-many-arguments

tests/https/test_unit_client.py

@@ -237,6 +237,17 @@ async def test_client_get_resource_invokes_api(self, mock_api_token, mock_invoke
         self.assertTrue(exists_in_args('dummy', args))
         mock_invoke_endpoint.assert_called_once()
 
+    @patch.object(Api, '_api_token', new_callable=PropertyMock)  
+    async def test_client_resource_exists_invokes_api(self, mock_api_token, mock_invoke_endpoint):
+        mock_api_token.return_value = 'test_token'
+        await self.client.resource_exists('role', 'dummy')
+
+        args, kwargs = mock_invoke_endpoint.call_args
+        self.assertEqual('test_token', kwargs.get('api_token'))
+        self.assertTrue(exists_in_args('role', args))
+        self.assertTrue(exists_in_args('dummy', args))
+        mock_invoke_endpoint.assert_called_once()
+
     @patch.object(Api, '_api_token', new_callable=PropertyMock)  
     async def test_client_get_many_invokes_api(self, mock_api_token, mock_invoke_endpoint):
         mock_api_token.return_value = 'test_token'

tests/https/test_unit_http.py

@@ -46,6 +46,7 @@ def test_http_verb_has_all_the_verbs_expected(self):
         self.assertTrue(HttpVerb.POST)
         self.assertTrue(HttpVerb.DELETE)
         self.assertTrue(HttpVerb.PATCH)
+        self.assertTrue(HttpVerb.HEAD)
 
 
 def create_ssl_verification_metadata(mode=SslVerificationMode.TRUST_STORE, cert_path=None):