Serve template CSS files per Document (#1479)

panel/io/resources.py

@@ -45,7 +45,7 @@ def js_files(self):
         if any('ace' in jsf for jsf in js_files):
             js_files.append('/panel_dist/post_require.js')
     return js_files
-                    
+
 def css_files(self):
     from ..config import config
     files = super(Resources, self).css_files
@@ -58,10 +58,30 @@ def css_files(self):
 def conffilter(value):
     return json.dumps(OrderedDict(value)).replace('"', '\'')
 
-Resources.css_raw = property(css_raw)
-Resources.js_files = property(js_files)
-Resources.css_files = property(css_files)
+
+class PanelResources(Resources):
+
+    def __init__(self, extra_css_files=None, **kwargs):
+        super(PanelResources, self).__init__(**kwargs)
+        self._extra_css_files = extra_css_files
+
+    @property
+    def css_raw(self):
+        raw = super(PanelResources, self).css_raw
+        for cssf in self._extra_css_files:
+            if not os.path.isfile(cssf):
+                continue
+            with open(cssf) as f:
+                css_txt = f.read()
+                if css_txt not in raw:
+                    raw.append(css_txt)
+        return raw
+
 
 _env = get_env()
 _env.filters['json'] = lambda obj: Markup(json.dumps(obj))
 _env.filters['conffilter'] = conffilter
+
+Resources.css_raw = property(css_raw)
+Resources.js_files = property(js_files)
+Resources.css_files = property(css_files)

panel/io/server.py

@@ -14,11 +14,17 @@
 from types import FunctionType, MethodType
 
 from bokeh.document.events import ModelChangedEvent
+from bokeh.embed.server import server_html_page_for_session
 from bokeh.server.server import Server
+from bokeh.server.views.session_handler import SessionHandler
+from bokeh.server.views.static_handler import StaticHandler
+from bokeh.server.urls import per_app_patterns
+from bokeh.settings import settings
 from tornado.websocket import WebSocketHandler
-from tornado.web import RequestHandler, StaticFileHandler
+from tornado.web import RequestHandler, StaticFileHandler, authenticated
 from tornado.wsgi import WSGIContainer
 
+from .resources import PanelResources
 from .state import state
 
 
@@ -61,6 +67,39 @@ def _eval_panel(panel, server_id, title, location, doc):
             doc = as_panel(panel)._modify_doc(server_id, title, doc, location)
         return doc
 
+
+class PanelDocHandler(SessionHandler):
+    """
+    Implements a custom Tornado handler for document display page
+    overriding the default bokeh DocHandler to replace the default
+    resources with a Panel resources object.
+    """
+
+    @authenticated
+    async def get(self, *args, **kwargs):
+        session = await self.get_session()
+
+        mode = settings.resources(default="server")
+        css_files = session.document.template_variables.get('template_css_files')
+        resource_opts = dict(mode=mode, extra_css_files=css_files)
+        if mode == "server":
+            resource_opts.update({
+                'root_url': self.application._prefix,
+                'path_versioner': StaticHandler.append_version
+            })
+        resources = PanelResources(**resource_opts)
+
+        page = server_html_page_for_session(
+            session, resources=resources, title=session.document.title,
+            template=session.document.template,
+            template_variables=session.document.template_variables
+        )
+
+        self.set_header("Content-Type", 'text/html')
+        self.write(page)
+
+per_app_patterns[0] = (r'/?', PanelDocHandler)
+
 #---------------------------------------------------------------------
 # Public API
 #---------------------------------------------------------------------
@@ -368,18 +407,9 @@ def do_stop(*args, **kwargs):
 class StoppableThread(threading.Thread):
     """Thread class with a stop() method."""
 
-    def __init__(self, io_loop=None, timeout=1000, **kwargs):
-        from tornado import ioloop
+    def __init__(self, io_loop=None, **kwargs):
         super(StoppableThread, self).__init__(**kwargs)
-        self._stop_event = threading.Event()
         self.io_loop = io_loop
-        self._cb = ioloop.PeriodicCallback(self._check_stopped, timeout)
-        self._cb.start()
-
-    def _check_stopped(self):
-        if self.stopped:
-            self._cb.stop()
-            self.io_loop.stop()
 
     def run(self):
         if hasattr(self, '_target'):
@@ -400,8 +430,4 @@ def run(self):
                 del self._Thread__target, self._Thread__args, self._Thread__kwargs
 
     def stop(self):
-        self._stop_event.set()
-
-    @property
-    def stopped(self):
-        return self._stop_event.is_set()
+        self.io_loop.add_callback(self.io_loop.stop)

panel/template/base.py

@@ -158,6 +158,11 @@ def _init_doc(self, doc=None, comm=None, title=None, notebook=False, location=Tr
         else:
             doc.template = self.template
         doc._template_variables.update(self._render_variables)
+        doc._template_variables['template_css_files'] = css_files = (
+            doc._template_variables.get('template_css_files', [])
+        )
+        for cssf in self._css_files:
+            css_files.append(str(cssf))
         return doc
 
     def _repr_mimebundle_(self, include=None, exclude=None):
@@ -201,6 +206,10 @@ def _repr_mimebundle_(self, include=None, exclude=None):
 
         return render_template(doc, comm, manager)
 
+    @property
+    def _css_files(self):
+        return []
+
     #----------------------------------------------------------------
     # Public API
     #----------------------------------------------------------------
@@ -236,6 +245,7 @@ def save(self, filename, title=None, resources=None, embed=False,
         """
         if embed:
             raise ValueError("Embedding is not yet supported on Template.")
+
         return save(self, filename, title, resources, self.template,
                     self._render_variables, embed, max_states, max_opts,
                     embed_json, json_prefix, save_path, load_path)
@@ -320,8 +330,6 @@ class BasicTemplate(BaseTemplate):
     __abstract = True
 
     def __init__(self, **params):
-        if self._css and self._css not in config.css_files:
-            config.css_files.append(self._css)
         template = self._template.read_text()
         if 'header' not in params:
             params['header'] = ListLike()
@@ -330,17 +338,24 @@ def __init__(self, **params):
         if 'sidebar' not in params:
             params['sidebar'] = ListLike()
         super(BasicTemplate, self).__init__(template=template, **params)
-        if self.theme:
-            theme = self.theme.find_theme(type(self))
-            if theme and theme.css and theme.css not in config.css_files:
-                config.css_files.append(theme.css)
         self._update_vars()
         self.main.param.watch(self._update_render_items, ['objects'])
         self.sidebar.param.watch(self._update_render_items, ['objects'])
         self.header.param.watch(self._update_render_items, ['objects'])
         self.param.watch(self._update_vars, ['title', 'header_background',
                                              'header_color'])
 
+    @property
+    def _css_files(self):
+        css_files = []
+        if self._css and self._css not in config.css_files:
+            css_files.append(self._css)
+        if self.theme:
+            theme = self.theme.find_theme(type(self))
+            if theme and theme.css and theme.css not in config.css_files:
+                css_files.append(theme.css)
+        return css_files
+
     def _init_doc(self, doc=None, comm=None, title=None, notebook=False, location=True):
         doc = super(BasicTemplate, self)._init_doc(doc, comm, title, notebook, location)
         if self.theme:

panel/tests/test_server.py

@@ -1,6 +1,8 @@
 import os
 import time
 
+from tempfile import NamedTemporaryFile
+
 import pytest
 import requests
 
@@ -10,6 +12,7 @@
 from panel.models import HTML as BkHTML
 from panel.pane import Markdown
 from panel.io.server import StoppableThread
+from panel.template import Template
 
 
 def test_get_server(html_server_session):
@@ -73,6 +76,7 @@ def test_kill_all_servers(html_server_session, markdown_server_session):
     assert server_1._stopped
     assert server_2._stopped
 
+
 def test_multiple_titles(multiple_apps_server_sessions):
     """Serve multiple apps with a title per app."""
     session1, session2 = multiple_apps_server_sessions(
@@ -84,3 +88,27 @@ def test_multiple_titles(multiple_apps_server_sessions):
     with pytest.raises(KeyError):
         session1, session2 = multiple_apps_server_sessions(
             slugs=('app1', 'app2'), titles={'badkey': 'APP1', 'app2': 'APP2'})
+
+
+def test_template_css():
+    t = Template("{% extends base %}")
+    t.add_panel('A', 1)
+    css = ".test { color: 'green' }"
+    ntf = NamedTemporaryFile()
+    with open(ntf.name, 'w') as f:
+        f.write(css)
+    t.add_variable('template_css_files', [ntf.name])
+
+    loop = IOLoop()
+    server = StoppableThread(
+        target=t._get_server, io_loop=loop,
+        args=(5009, None, None, loop, False, True, None, False, None)
+    )
+    server.start()
+
+    # Wait for server to start
+    time.sleep(1)
+
+    r = requests.get("http://localhost:5009/")
+    assert css in r.content.decode('utf-8')
+    server.stop()