Add basic implement for cognito-idp create_resource_server (#3153)

* Add basic implement for cognito-idp create_resource_server

* lint

moto/cognitoidp/exceptions.py

@@ -2,6 +2,7 @@ from __future__ import unicode_literals
 
 import json
 from werkzeug.exceptions import BadRequest
+from moto.core.exceptions import JsonRESTError
 
 
 class ResourceNotFoundError(BadRequest):
@@ -42,3 +43,11 @@ class NotAuthorizedError(BadRequest):
         self.description = json.dumps(
             {"message": message, "__type": "NotAuthorizedException"}
         )
+
+
+class InvalidParameterException(JsonRESTError):
+    def __init__(self, msg=None):
+        self.code = 400
+        super(InvalidParameterException, self).__init__(
+            "InvalidParameterException", msg or "A parameter is specified incorrectly."
+        )

moto/cognitoidp/models.py

@@ -21,6 +21,7 @@ from .exceptions import (
     ResourceNotFoundError,
     UserNotFoundError,
     UsernameExistsException,
+    InvalidParameterException,
 )
 
 UserStatus = {
@@ -83,6 +84,7 @@ class CognitoIdpUserPool(BaseModel):
         self.identity_providers = OrderedDict()
         self.groups = OrderedDict()
         self.users = OrderedDict()
+        self.resource_servers = OrderedDict()
         self.refresh_tokens = {}
         self.access_tokens = {}
         self.id_tokens = {}
@@ -337,6 +339,27 @@ class CognitoIdpUser(BaseModel):
         self.attributes = expand_attrs(flat_attributes)
 
 
+class CognitoResourceServer(BaseModel):
+    def __init__(self, user_pool_id, identifier, name, scopes):
+
+        self.user_pool_id = user_pool_id
+        self.identifier = identifier
+        self.name = name
+        self.scopes = scopes
+
+    def to_json(self):
+        res = {
+            "UserPoolId": self.user_pool_id,
+            "Identifier": self.identifier,
+            "Name": self.name,
+        }
+
+        if len(self.scopes) != 0:
+            res.update({"Scopes": self.scopes})
+
+        return res
+
+
 class CognitoIdpBackend(BaseBackend):
     def __init__(self, region):
         super(CognitoIdpBackend, self).__init__()
@@ -768,6 +791,20 @@ class CognitoIdpBackend(BaseBackend):
         user = user_pool.users[username]
         user.update_attributes(attributes)
 
+    def create_resource_server(self, user_pool_id, identifier, name, scopes):
+        user_pool = self.user_pools.get(user_pool_id)
+        if not user_pool:
+            raise ResourceNotFoundError(user_pool_id)
+
+        if identifier in user_pool.resource_servers:
+            raise InvalidParameterException(
+                "%s already exists in user pool %s." % (identifier, user_pool_id)
+            )
+
+        resource_server = CognitoResourceServer(user_pool_id, identifier, name, scopes)
+        user_pool.resource_servers[identifier] = resource_server
+        return resource_server
+
 
 cognitoidp_backends = {}
 for region in Session().get_available_regions("cognito-idp"):

moto/cognitoidp/responses.py

@@ -379,6 +379,17 @@ class CognitoIdpResponse(BaseResponse):
         )
         return ""
 
+    # Resource Server
+    def create_resource_server(self):
+        user_pool_id = self._get_param("UserPoolId")
+        identifier = self._get_param("Identifier")
+        name = self._get_param("Name")
+        scopes = self._get_param("Scopes")
+        resource_server = cognitoidp_backends[self.region].create_resource_server(
+            user_pool_id, identifier, name, scopes
+        )
+        return json.dumps({"ResourceServer": resource_server.to_json()})
+
 
 class CognitoIdpJsonWebKeyResponse(BaseResponse):
     def __init__(self):