flask demo: don't provide a meaningless default server

README.md

@@ -176,9 +176,13 @@ print(patient.name[0].given)
 Take a look at
 [flask_app.py](https://github.com/smart-on-fhir/client-py/blob/main/demos/flask/flask_app.py)
 to see how you can use the client in a simple (Flask) app.
-This app starts a web server,
-listening on [_localhost:8000_](http://localhost:8000),
-and prompts you to log in to our sandbox server and select a patient.
+
+This demo requires a server that is capable of SMART OAuth logins for patients,
+so make sure you have such a server ready first.
+
+This app will start a web server,
+listen on [_localhost:8000_](http://localhost:8000),
+and prompt you to log in to our sandbox server and select a patient.
 It then retrieves the selected patient's demographics and med prescriptions
 and lists them on a simple HTML page.
 
@@ -192,6 +196,7 @@ and install the needed packages as shown:
     python3 -m venv env
     . env/bin/activate
     pip install -r requirements.txt
+    # Edit flask_app.py and put your own server's URL as api_base.
     ./flask_app.py
 
 

demos/flask/flask_app.py

@@ -10,13 +10,7 @@
 # app setup
 smart_defaults = {
     'app_id': 'my_web_app',
-    # The CapabilityStatement being returned from the new test server,
-    # r4.smarthealthit.org, is currently missing a required field in the
-    # description of one of the search params. So you may see a
-    # 'Non-optional property "type"' error message when running this with
-    # the default config. We'll remove this message once that has been
-    # fixed and tested.
-    'api_base': 'https://r4.smarthealthit.org/',
+    'api_base': None,
     'redirect_uri': 'http://localhost:8000/fhir-app/',
 }
 
@@ -29,8 +23,10 @@ def _get_smart():
     state = session.get('state')
     if state:
         return client.FHIRClient(state=state, save_func=_save_state)
-    else:
+    elif smart_defaults['api_base']:
         return client.FHIRClient(settings=smart_defaults, save_func=_save_state)
+    else:
+        return None
 
 def _logout():
     if 'state' in session:
@@ -80,8 +76,13 @@ def index():
     """
     smart = _get_smart()
     body = "<h1>Hello</h1>"
-
-    if smart.ready and smart.patient is not None:       # "ready" may be true but the access token may have expired, making smart.patient = None
+
+    if smart is None:
+        body += """<p>Please edit flask_app.py and set a value for 'api_base', """
+        body += """pointing at your own OAuth-capable server.</p>"""
+
+    # "ready" may be true but the access token may have expired, making smart.patient = None
+    elif smart.ready and smart.patient is not None:
         name = smart.human_name(smart.patient.name[0] if smart.patient.name and len(smart.patient.name) > 0 else 'Unknown')
 
         # generate simple body text
@@ -92,6 +93,7 @@ def index():
         else:
             body += "<p>(There are no prescriptions for {0})</p>".format("him" if 'male' == smart.patient.gender else "her")
         body += """<p><a href="/logout">Change patient</a></p>"""
+
     else:
         auth_url = smart.authorize_url
         if auth_url is not None: