bokeh server with data update and plot endpoints

bokeh_server.py

from bokeh.embed import components
from bokeh.core.templates import FILE
from bokeh.models import ColumnDataSource, DataRange1d, Plot
from bokeh.models.glyphs import Line
from bokeh.resources import INLINE
from bokeh.util.string import encode_utf8
from flask import Flask, request, jsonify
import numpy as np


"""
Very basic flask server to display and update a bokeh line plot.
This could be extended for more plots or changed for live updates to plots.

Example update:
>> curl -X POST -d '{"x": [0, 1, 2], "y": [2, 1, 0]}' \
    http://localhost:5000/update --header "Content-Type:application/json"
"""

app = Flask(__name__)
data = dict()


def init():
    N = 30
    data['x'] = np.linspace(-2, 2, N)
    data['y'] = data['x']**2


@app.route("/update", methods=['POST'])
def update_data():
    data_read = False
    req_data = request.get_json()
    if req_data is not None:
        data_read = True
        data['x'] = req_data['x']
        data['y'] = req_data['y']
    return jsonify({
        'OK': True,
        'updated': data_read,
        'x': str(data['x']),
        'y': str(data['y'])
    })


@app.route("/", methods=['GET'])
def line_plot():
    source = ColumnDataSource(dict(x=data['x'], y=data['y']))

    xdr = DataRange1d()
    ydr = DataRange1d()

    plot = Plot(
        title=None, x_range=xdr, y_range=ydr,
        plot_width=300, plot_height=300,
        h_symmetry=False, v_symmetry=False, min_border=0,
        toolbar_location=None
    )

    glyph = Line(
        x="x", y="y", line_color="#f46d43", line_width=6, line_alpha=0.6
    )
    plot.add_glyph(source, glyph)
    script, div = components(plot, INLINE)
    html = FILE.render(
        plot_script=script,
        plot_div=div,
        bokeh_js=INLINE.render_js(),
        bokeh_css=INLINE.render_css(),
    )
    return encode_utf8(html)


init()
app.run(debug=True)