Bokeh server APIs

It can be useful to embed the Bokeh Server in a larger Tornado application, or a Jupyter notebook, and use the already existing Tornado IOloop. Here is the basis for integration of Bokeh in such a scenario:

from bokeh.server.server import Server

server = Server(
    bokeh_applications,  # list of Bokeh applications
    io_loop=loop,        # Tornado IOLoop
    **server_kwargs      # port, num_procs, etc.
)

# start timers and services and immediately return
server.start()

You can also create and control an IOLoop directly. This can be useful when creating standalone “normal” Python scripts that serve Bokeh apps or embedding a Bokeh application in a framework like Flask or Django without having to run a separate Bokeh server process. You can find some examples of this technique in the examples directory:

• examples/server/api/flask_embed.py

• examples/server/api/notebook_embed.ipynb

• examples/server/api/standalone_embed.py

• examples/server/api/tornado_embed.py

Also note that every command line argument for bokeh serve has a corresponding keyword argument for Server. For instance, using the --allow-websocket-origin command line argument is equivalent to passing allow_websocket_origin as a parameter.

Connecting with bokeh.client

You can directly interact with the Bokeh server via a client API, which you can use to make modifications to Bokeh documents in existing sessions on a Bokeh server.

Typically, web browsers connect to the Bokeh server, but you can make a connection from Python by using the bokeh.client module.

This can be useful, for example, to make user-specific customizations to a Bokeh app that is embedded by another web framework, such as Flask or Django. In the following example, a Flask endpoint embeds a “sliders” app already running on the server but changes the plot title before passing the output to the user.

from flask import Flask, render_template

from bokeh.client import pull_session
from bokeh.embed import server_session

app = Flask(__name__)

@app.route('/', methods=['GET'])
def bkapp_page():

    with pull_session(url="http://localhost:5006/sliders") as session:

        # update or customize that session
        session.document.roots[0].children[1].title.text = "Special sliders for a specific user!"

        # generate a script to load the customized session
        script = server_session(session_id=session.id, url='http://localhost:5006/sliders')

        # use the script in the rendered page
        return render_template("embed.html", script=script, template="Flask")

if __name__ == '__main__':
    app.run(port=8080)