iframe is now loaded when using google colab (#9)

Part of fix for #3

Added logic to check if the script is being ran in google colab, then replace the server url with proxied url for the specified port if that is the case
Tested in google colab, created a widget and verified that the iframe appeared
!apt-get install openjdk-11-jdk-headless

import os
from google.colab.output import eval_js
os.environ["JAVA_HOME"] = "/usr/lib/jvm/java-11-openjdk-amd64"

from google.colab import drive
drive.mount('/content/drive')

!pip install --upgrade pip setuptools wheel
!pip install deephaven-core deephaven-server
!pip install '/content/drive/MyDrive/deephaven_ipywidgets-0.2.0-py2.py3-none-any.whl'

import deephaven_server
from deephaven_server import Server
import portpicker
from google.colab.output import eval_js

dh_port = portpicker.pick_unused_port()
s = Server(port=dh_port, jvm_args=["-Xmx4g", "-Dhttp.requireHttp2=false"], dh_args={'http.requireHttp2': False})
s.start()

from google.colab import output
output.enable_custom_widget_manager()

from deephaven import empty_table
t = empty_table(10).update("x=i")

from deephaven_ipywidgets import DeephavenWidget
DeephavenWidget(t)

deephaven_ipywidgets/_version.py

@@ -4,5 +4,5 @@
 # Copyright (c) Deephaven Data Labs LLC.
 # Distributed under the terms of the Modified BSD License.
 
-version_info = (0, 2, 0)
+version_info = (0, 2, 1)
 __version__ = ".".join(map(str, version_info))

deephaven_ipywidgets/deephaven.py

@@ -15,19 +15,21 @@
 from uuid import uuid4
 from ._frontend import module_name, module_version
 
+
 def _str_object_type(obj):
-  """Returns the object type as a string value"""
-  return f"{obj.__class__.__module__}.{obj.__class__.__name__}"
+    """Returns the object type as a string value"""
+    return f"{obj.__class__.__module__}.{obj.__class__.__name__}"
+
 
 def _path_for_object(obj):
-  """Return the iframe path for the specified object. Inspects the class name to determine."""
-  name = _str_object_type(obj)
+    """Return the iframe path for the specified object. Inspects the class name to determine."""
+    name = _str_object_type(obj)
 
-  if name in ('deephaven.table.Table', 'pandas.core.frame.DataFrame'):
-    return 'table'
-  if name == 'deephaven.plot.figure.Figure':
-    return 'chart'
-  raise TypeError(f"Unknown object type: {name}")
+    if name in ('deephaven.table.Table', 'pandas.core.frame.DataFrame'):
+        return 'table'
+    if name == 'deephaven.plot.figure.Figure':
+        return 'chart'
+    raise TypeError(f"Unknown object type: {name}")
 
 
 class DeephavenWidget(DOMWidget):
@@ -60,9 +62,17 @@ def __init__(self, deephaven_object, height=600, width=0):
         # Generate a new table ID using a UUID prepended with a `t_` prefix
         object_id = f"t_{str(uuid4()).replace('-', '_')}"
 
+        port = Server.instance.port
+        server_url = f"http://localhost:{Server.instance.port}/"
+
+        try:
+            from google.colab.output import eval_js
+            server_url = eval_js(f"google.colab.kernel.proxyPort({port})")
+        except ImportError:
+            pass
+
         # Generate the iframe_url from the object type
-        server_url = f"http://localhost:{Server.instance.port}"
-        iframe_url = f"{server_url}/iframe/{_path_for_object(deephaven_object)}/?name={object_id}"
+        iframe_url = f"{server_url}iframe/{_path_for_object(deephaven_object)}/?name={object_id}"
 
         # Add the table to the main modules globals list so it can be retrieved by the iframe
         __main__.__dict__[object_id] = deephaven_object
@@ -72,4 +82,4 @@ def __init__(self, deephaven_object, height=600, width=0):
         self.set_trait('object_id', object_id)
         self.set_trait('object_type', _str_object_type(deephaven_object))
         self.set_trait('width', width)
-        self.set_trait('height', height)
+        self.set_trait('height', height)

deephaven_ipywidgets/tests/test_table.py

@@ -19,5 +19,5 @@ def test_example_creation_blank(MockTableClass):
     mock_table.__class__.__module__ = 'deephaven.table'
     mock_table.__class__.__name__ = 'Table'
     w = DeephavenWidget(mock_table)
-    assert w.server_url == 'http://localhost:9876'
+    assert w.server_url == 'http://localhost:9876/'
     assert str(w.iframe_url).startswith('http://localhost:9876/iframe/table/?name=t_')