Update demo_server to fix import error. (#502)

Bumped versions for flask and dependencies,
and added workaround for an import error.

Author: marina-p

demo_server/demo_server/api/blog/endpoints/posts.py

@@ -4,7 +4,15 @@
 import logging
 
 from flask import request
-from flask_restplus import Resource
+# Workaround for import error
+#    ImportError: cannot import name 'cached_property' from 'werkzeug'
+try:
+    from flask_restplus import Resource
+except ImportError:
+    import werkzeug, flask.scaffold
+    werkzeug.cached_property = werkzeug.utils.cached_property
+    flask.helpers._endpoint_from_view_func = flask.scaffold._endpoint_from_view_func
+    from flask_restplus import Resource
 from demo_server.api.blog.business import create_blog_post, update_post, delete_post, get_post
 from demo_server.api.blog.serializers import blog_post, blog_post_public,\
     page_of_blog_posts

demo_server/demo_server/api/restplus.py

@@ -4,7 +4,15 @@
 import logging
 import traceback
 
-from flask_restplus import Api
+# Workaround for import error
+#    ImportError: cannot import name 'cached_property' from 'werkzeug'
+try:
+    from flask_restplus import Api
+except ImportError:
+    import werkzeug, flask.scaffold
+    werkzeug.cached_property = werkzeug.utils.cached_property
+    flask.helpers._endpoint_from_view_func = flask.scaffold._endpoint_from_view_func
+    from flask_restplus import Api
 from demo_server import settings
 from sqlalchemy.orm.exc import NoResultFound
 

demo_server/requirements.txt

@@ -1,6 +1,4 @@
-flask==1.1.2
+flask==2.1.0
 flask-restplus==0.13.0
 Flask-SQLAlchemy==2.5.1
-itsdangerous==2.0.1
-Werkzeug==0.16.0
-
+werkzeug==2.0.2