server.py

"""
Diapason RESTful API.
"""
import inspect
import configparser
from io import BytesIO

from flask import Flask
from flask import abort
from flask import request
from flask import jsonify
from flask import send_file

import numpy
from numpy import linspace,sin,pi,int16
from scipy.io import wavfile

from diapason import note_frequency
from diapason import generate_wav
from diapason.dub import convert_wav


app = Flask('Diapason')


def list_routes(app, starting=''):
    output = []
    for rule in app.url_map.iter_rules():
        if rule.endpoint.startswith('_'):
            continue
        if not str(rule).startswith(starting):
            continue
        output.append(dict(
            name=rule.endpoint,
            rule=rule.rule,
            methods=','.join(rule.methods),
            doc=inspect.getdoc(app.view_functions[rule.endpoint])
        ))
    return output


def error_information(error):
    info = {}
    info['code'] = error.code
    info['name'] = error.name
    if error.response:
        info['response'] = error.response
    if error.description:
        info['description'] = error.description
    return jsonify(error=info), error.code


@app.errorhandler(400)
def handle_400(error):
    return error_information(error)


@app.errorhandler(404)
def handle_404(error):
    return error_information(error)


@app.route('/')
def root():
    versions = dict(v0=request.url+'v0')
    return jsonify(title='Diapason RESTful API', versions=versions)


@app.route('/v0')
def routes():
    return jsonify(routes=list_routes(app, '/v0'))


@app.route('/v0/reverse/<string:query>')
def reverse(query):
    """
    Return the reversed query string provided (for testing purposes).
    """
    return jsonify(reverse=query[::-1])


@app.route('/v0/<note>')
def get(note):
    """
    Get a note.
    """
    coding_format = request.args.get('format', 'wav')
    rate = int(request.args.get('rate', 44100))
    duration = float(request.args.get('duration', 2))
    octave = int(request.args.get('octave', 4))
    sharp = int(request.args.get('sharp', 0))
    flat = int(request.args.get('flat', 0))

    mimetype = 'audio/' + coding_format

    if '.' in note:
        note = note.split('.')[0]

    note = note.upper()
    frequency = note_frequency(note, sharp=sharp, flat=flat, octave=octave)
    note = generate_wav(frequency, duration, rate)

    if coding_format != 'wav':
        note = convert_wav(note, coding_format=coding_format,
                           **request.args.to_dict())

    return send_file(note, mimetype=mimetype,
                     # For developing purposes only
                     add_etags=False, cache_timeout=0)


@app.route('/v0/alexa/<note>')
def alexa(note):
    """
    Get a note in a convenient format to deal with Alexa.
    """
    coding_format = 'mpeg'
    rate = 16000
    duration = 5.
    octave = 4
    sharp = 0
    flat = 0
    extra = {'bitrate': '48k'}

    mimetype = 'audio/' + coding_format

    if '.' in note:
        note = note.split('.')[0]

    note = note.upper()
    frequency = note_frequency(note, sharp=sharp, flat=flat, octave=octave)
    note = generate_wav(frequency, duration, rate)

    note = convert_wav(note, coding_format=coding_format, **extra)

    return send_file(note, mimetype=mimetype)


@app.route('/<path:path>', methods=['GET', 'POST'])
def _catch_all(path):
    abort(404, 'Requested API call does not exist')


if __name__ == '__main__':
    config = configparser.ConfigParser()
    config.read('server.ini')
    app.run(host=config['server']['host'],
            port=int(config['server']['port']),
            threaded=True, debug=True)