eddy-geek · March 10, 2022 19:01 · Mar 10, 2022 · Mar 22, 2020 · Mar 22, 2020 · Mar 22, 2020
diff --git a/dash_state_demo_datepicker.py b/dash_state_demo_datepicker.py
@@ -1,3 +1,8 @@
+# Copyright (C) 2022 by Edward O.
+# Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without l> imitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+# The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE
+
 import ast
 import re
 

diff --git a/dash_state_demo_datepicker.py b/dash_state_demo_datepicker.py
@@ -1,6 +1,8 @@
 import ast
 import re
 
+import flask
+
 import dash
 import dash_core_components as dcc
 import dash_html_components as html
@@ -9,15 +11,13 @@
 
 app = dash.Dash()
 
-app.config.suppress_callback_exceptions = True
-
-
-app.layout = html.Div([
+url_bar_and_content_div = html.Div([
     dcc.Location(id='url', refresh=False),
     html.Div(id='page-layout')
 ])
 
 
+
 def apply_default_value(params):
     """
     :param params: the state decoded from url
@@ -32,7 +32,9 @@ def apply_value(*args, **kwargs):
     return wrapper
 
 
-def build_layout(params):
+def page_layout(params=None):
+
+    params = params or {}
     layout = [
         html.H2('URL State demo', id='state'),
         apply_default_value(params)(dcc.DatePickerRange)(
@@ -61,6 +63,19 @@ def build_layout(params):
     return layout
 
 
+def app_layout():
+    if flask.has_request_context():  # for real
+        return url_bar_and_content_div
+    # validation only
+    return html.Div([
+        url_bar_and_content_div,
+        *page_layout()
+    ])
+
+
+app.layout = app_layout
+
+
 ID_PARAM_SEP = '::'
 
 
@@ -76,7 +91,6 @@ def parse_state(url):
             id, param = key, 'value'
         state.setdefault(id, {})[param] = ast.literal_eval(value)
 
-    print('state', state)
     return state
 
 
@@ -86,7 +100,7 @@ def page_load(href):
     if not href:
         return []
     state = parse_state(href)
-    return build_layout(state)
+    return page_layout(state)
 
 
 component_ids = {

diff --git a/dash_state_demo_datepicker.py b/dash_state_demo_datepicker.py
@@ -68,8 +68,6 @@ def parse_state(url):
     parse_result = urlparse(url)
     query_string = parse_qsl(parse_result.query)
 
-    print(query_string)
-
     state = {}
     for key, value in query_string:
         if ID_PARAM_SEP in key:

diff --git a/dash_state_demo_datepicker.py b/dash_state_demo_datepicker.py
@@ -0,0 +1,124 @@
+import ast
+import re
+
+import dash
+import dash_core_components as dcc
+import dash_html_components as html
+from urllib.parse import urlparse, parse_qsl, urlencode, quote
+from dash.dependencies import Input, Output
+
+app = dash.Dash()
+
+app.config.suppress_callback_exceptions = True
+
+
+app.layout = html.Div([
+    dcc.Location(id='url', refresh=False),
+    html.Div(id='page-layout')
+])
+
+
+def apply_default_value(params):
+    """
+    :param params: the state decoded from url
+    """
+    def wrapper(func):
+        def apply_value(*args, **kwargs):
+            if 'id' in kwargs and kwargs['id'] in params:
+                param_key_dict = params[kwargs['id']]
+                kwargs.update(param_key_dict)
+            return func(*args, **kwargs)
+        return apply_value
+    return wrapper
+
+
+def build_layout(params):
+    layout = [
+        html.H2('URL State demo', id='state'),
+        apply_default_value(params)(dcc.DatePickerRange)(
+            id='picker',
+        ),
+        apply_default_value(params)(dcc.Dropdown)(
+            id='dropdown',
+            options=[{'label': i, 'value': i} for i in ['LA', 'NYC', 'MTL']],
+            value='LA'
+        ),
+        apply_default_value(params)(dcc.Input)(
+            id='input',
+            placeholder='Enter a value...',
+            value=''
+        ),
+        apply_default_value(params)(dcc.Slider)(
+            id='slider',
+            min=0,
+            max=9,
+            marks={i: 'Label {}'.format(i) for i in range(10)},
+            value=5,
+        ),
+        html.Br(),
+    ]
+
+    return layout
+
+
+ID_PARAM_SEP = '::'
+
+
+def parse_state(url):
+    parse_result = urlparse(url)
+    query_string = parse_qsl(parse_result.query)
+
+    print(query_string)
+
+    state = {}
+    for key, value in query_string:
+        if ID_PARAM_SEP in key:
+            id, param = key.split(ID_PARAM_SEP)
+        else:
+            id, param = key, 'value'
+        state.setdefault(id, {})[param] = ast.literal_eval(value)
+
+    print('state', state)
+    return state
+
+
+@app.callback(Output('page-layout', 'children'),
+              inputs=[Input('url', 'href')])
+def page_load(href):
+    if not href:
+        return []
+    state = parse_state(href)
+    return build_layout(state)
+
+
+component_ids = {
+    'picker': ['start_date', 'end_date'],
+    'dropdown': ['value'],
+    'input': ['value'],
+    'slider': ['value'],
+}
+
+
+def param_string(id, p):
+    return id if p == 'value' else id + ID_PARAM_SEP + p
+
+
+RE_SINGLE_QUOTED = re.compile("^'|'$")
+def myrepr(o):
+    """Optional but chrome URL bar hates "'" """
+    return RE_SINGLE_QUOTED.sub('"', repr(o))
+
+
+@app.callback(Output('url', 'search'),
+              inputs=[Input(id, p) for id, param in component_ids.items() for p in param])
+def update_url_state(*values):
+    """Updates URL from component values."""
+
+    keys = [param_string(id, p) for id, param in component_ids.items() for p in param]
+    state = dict(zip(keys, map(myrepr, values)))
+    params = urlencode(state, safe="%/:?~#+!$,;'@()*[]\"", quote_via=quote)
+    return f'?{params}'
+
+
+if __name__ == '__main__':
+    app.run_server(debug=True)
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