Initial arguments (#32)

* Added intial_arguments handling for all apps

* Improve demo pages - better css would help

* Fix urls

* Move initial arguments example into the initial state demo page

* Another demo tweak

* Tidy up use of route names to ensure trailing slash

* Added separate test script and increased test coverage

* Refactor test

* Added documentation for initial_arguments template argument

Author: delsim

check_code

@@ -2,5 +2,6 @@
 #
 ./check_code_dpd
 ./check_code_demo
+./check_code_demo_test
 #
 

check_code_demo

@@ -3,5 +3,4 @@
 source env/bin/activate
 pushd demo
 pylint demo --rcfile=../pylintrc
-pytest demo --cov=demo --cov=django_plotly_dash --cov-report term-missing
 popd

check_code_demo_test

@@ -0,0 +1,6 @@
+#!/usr/bin/env bash
+#
+source env/bin/activate
+pushd demo
+pytest demo --cov=demo --cov=django_plotly_dash --cov-report term-missing
+popd

demo/demo/plotly_apps.py

@@ -187,7 +187,7 @@ def callback_liveIn_button_press(red_clicks, blue_clicks, green_clicks,
                                                                                              datetime.fromtimestamp(0.001*timestamp))
 
 liveOut = DjangoDash("LiveOutput",
-                     )#serve_locally=True)
+                    )#serve_locally=True)
 
 def _get_cache_key(state_uid):
     return "demo-liveout-s6-%s" % state_uid

demo/demo/templates/demo_four.html

@@ -54,4 +54,5 @@ <h1>Live Updating</h1>
     curl http://localhost:8000/dpd/views/poke/ -d'{"channel_name":"live_button_counter","label":"named_counts","value":{"click_colour":"red"}}'
   </div>
 </div>
+<p></p>
 {%endblock%}

demo/demo/templates/demo_one.html

@@ -31,5 +31,5 @@ <h1>Simple App Embedding</h1>
     </div>
   </div>
 </div>
+<p></p>
 {%endblock%}
-

demo/demo/templates/demo_three.html

@@ -39,4 +39,5 @@ <h1>Enhanced Callback Functionality</h1>
     {%plotly_app slug="ex2-3" ratio=0.15 %}
   </div>
 </div>
+<p></p>
 {%endblock%}

demo/demo/templates/demo_two.html

@@ -14,17 +14,29 @@ <h1>Initial State</h1>
   state is persisted in a standard
   Django <a href="{%url "admin:django_plotly_dash_dashapp_changelist" %}">model</a>.
 </p>
+<p>
+  It is also possible to specify intial arguments in the template. These override the values specifed in
+  the code defining the app, and also take priority over any stored state.
+</p>
 <div class="card bg-light border-dark">
   <div class="card-body">
     <p><span>{</span>% load plotly_dash %}</p>
-    <p><span>{</span>% plotly_app slug="simpleexample-1" ratio=0.2 %}</p>
+    <p><span>{</span>% plotly_app slug="simpleexample-1" ratio=0.1 %}</p>
+    <p><span>{</span>% plotly_app name="simpleexample-1" initial_arguments='{"dropdown-color": {"value": "green"}}' %}</p>
   </div>
 </div>
 <p>
 </p>
 <div class="card border-dark">
   <div class="card-body">
-    {%plotly_app slug="simpleexample-1" ratio=0.2 %}
+    {%plotly_app slug="simpleexample-1" ratio=0.1 %}
+  </div>
+</div>
+<p></p>
+<div class="card border-dark">
+  <div class="card-body">
+    {%plotly_app slug="simpleexample-1" initial_arguments='{"dropdown-color": {"value": "green"}}' %}
   </div>
 </div>
+<p></p>
 {%endblock%}

demo/demo/tests/test_dpd_demo.py

@@ -4,16 +4,26 @@
 
 import pytest
 
+from django.urls import reverse
+
 @pytest.mark.django_db
 def test_template_tag_use(client):
     'Check use of template tag'
 
-    from django.urls import reverse
-
     for name in ['demo-one', 'demo-two', 'demo-three', 'demo-four',]:
         url = reverse(name, kwargs={})
 
         response = client.get(url)
 
         assert response.content
         assert response.status_code == 200
+
+@pytest.mark.django_db
+def test_add_to_session(client):
+    'Check use of session variable access helper'
+
+    url = reverse('session-variable-example')
+    response = client.get(url)
+
+    assert response.content
+    assert response.status_code == 200

django_plotly_dash/dash_wrapper.py

@@ -100,11 +100,11 @@ def __init__(self, name=None, serve_locally=False,
             bootstrap_source = css_url()['href']
             self.css.append_script({'external_url':[bootstrap_source,]})
 
-    def as_dash_instance(self):
+    def as_dash_instance(self, cache_id=None):
         '''
         Form a dash instance, for stateless use of this app
         '''
-        return self.do_form_dash_instance()
+        return self.do_form_dash_instance(cache_id=cache_id)
 
     def handle_current_state(self):
         'Do nothing impl - only matters if state present'
@@ -116,7 +116,7 @@ def have_current_state_entry(self, wid, key):
         'Do nothing impl - only matters if state present'
         pass
 
-    def get_base_pathname(self, specific_identifier):
+    def get_base_pathname(self, specific_identifier, cache_id):
         'Base path name of this instance, taking into account any state or statelessness'
         if not specific_identifier:
             app_pathname = "%s:app-%s"% (app_name, main_view_label)
@@ -125,13 +125,21 @@ def get_base_pathname(self, specific_identifier):
             app_pathname = "%s:%s" % (app_name, main_view_label)
             ndid = specific_identifier
 
-        full_url = reverse(app_pathname, kwargs={'ident':ndid})
+        kwargs = {'ident': ndid}
+
+        if cache_id:
+            kwargs['cache_id'] = cache_id
+            app_pathname = app_pathname + "--args"
+
+        full_url = reverse(app_pathname, kwargs=kwargs)
+        if full_url[-1] != '/':
+            full_url = full_url + '/'
         return ndid, full_url
 
-    def do_form_dash_instance(self, replacements=None, specific_identifier=None):
+    def do_form_dash_instance(self, replacements=None, specific_identifier=None, cache_id=None):
         'Perform the act of constructing a Dash instance taking into account state'
 
-        ndid, base_pathname = self.get_base_pathname(specific_identifier)
+        ndid, base_pathname = self.get_base_pathname(specific_identifier, cache_id)
         return self.form_dash_instance(replacements, ndid, base_pathname)
 
     def form_dash_instance(self, replacements=None, ndid=None, base_pathname=None):
@@ -242,16 +250,24 @@ def use_dash_layout(self):
         '''
         return self._use_dash_layout
 
-    def augment_initial_layout(self, base_response):
+    def augment_initial_layout(self, base_response, initial_arguments=None):
         'Add application state to initial values'
-        if self.use_dash_layout() and False:
+        if self.use_dash_layout() and not initial_arguments and False:
             return base_response.data, base_response.mimetype
+
         # Adjust the base layout response
         baseDataInBytes = base_response.data
         baseData = json.loads(baseDataInBytes.decode('utf-8'))
+
+        # Also add in any initial arguments
+        if initial_arguments:
+            if isinstance(initial_arguments, str):
+                initial_arguments = json.loads(initial_arguments)
+
         # Walk tree. If at any point we have an element whose id
         # matches, then replace any named values at this level
-        reworked_data = self.walk_tree_and_replace(baseData)
+        reworked_data = self.walk_tree_and_replace(baseData, initial_arguments)
+
         response_data = json.dumps(reworked_data,
                                    cls=PlotlyJSONEncoder)
 
@@ -274,7 +290,7 @@ def walk_tree_and_extract(self, data, target):
             for element in data:
                 self.walk_tree_and_extract(element, target)
 
-    def walk_tree_and_replace(self, data):
+    def walk_tree_and_replace(self, data, overrides):
         '''
         Walk the tree. Rely on json decoding to insert instances of dict and list
         ie we use a dna test for anatine, rather than our eyes and ears...
@@ -285,17 +301,19 @@ def walk_tree_and_replace(self, data):
             # look for id entry
             thisID = data.get('id', None)
             if thisID is not None:
-                replacements = self._replacements.get(thisID, {})
+                replacements = overrides.get(thisID, None) if overrides else None
+                if not replacements:
+                    replacements = self._replacements.get(thisID, {})
             # walk all keys and replace if needed
             for k, v in data.items():
                 r = replacements.get(k, None)
                 if r is None:
-                    r = self.walk_tree_and_replace(v)
+                    r = self.walk_tree_and_replace(v, overrides)
                 response[k] = r
             return response
         if isinstance(data, list):
             # process each entry in turn and return
-            return [self.walk_tree_and_replace(x) for x in data]
+            return [self.walk_tree_and_replace(x, overrides) for x in data]
         return data
 
     def flask_app(self):
@@ -328,7 +346,7 @@ def locate_endpoint_function(self, name=None):
     # pylint: disable=no-member
     @Dash.layout.setter
     def layout(self, value):
-        'Overloaded layoyt function to fix component names as needed'
+        'Overloaded layout function to fix component names as needed'
 
         if self._adjust_id:
             self._fix_component_id(value)