MVP for a server that runs Brightway2-calc calculations

bw2calc_alone.py

from bw2calc import IndepentLCAMixin, LCA as _LCA
from flask import request, Flask, jsonify
from io import TextIOWrapper
import csv
import numpy as np
import os
import tempfile

"""Run bw2calc without using a backend - instead, send LCI/A data as CSV files in a web request.

To run: Install dependencies, and gunicorn, then do `gunicorn bw2calc_alone:application`."""


class LCA(IndepentLCAMixin, _LCA):
    pass


application = Flask(__name__)


LCI_DTYPE = [
    ('input', np.uint32),
    ('output', np.uint32),
    ('row', np.uint32),
    ('col', np.uint32),
    ('type', np.uint8),
    ('amount', np.float32),
]
LCIA_DTYPE = [
    ('flow', np.uint32),
    ('geo', np.uint32),
    ('row', np.uint32),
    ('amount', np.float32),
]
MAX_INT_32 = 4294967295


@application.route("/", methods=['POST'])
def lca_calculation():
    with tempfile.TemporaryDirectory() as dirpath:
        arr = np.array([
            (int(inp), int(outp), MAX_INT_32, MAX_INT_32, int(typ), float(amnt))
            for inp, outp, typ, amnt in csv.reader(TextIOWrapper(request.files['lci']))
        ], dtype=LCI_DTYPE)
        np.save(os.path.join(dirpath, "lci.npy"), arr, allow_pickle=False)

        arr = np.array([
            (int(flow), 1, MAX_INT_32, float(amnt))
            for flow, amnt in csv.reader(TextIOWrapper(request.files['lcia']))
        ], dtype=LCIA_DTYPE)
        np.save(os.path.join(dirpath, "lcia.npy"), arr, allow_pickle=False)

        config = {'demand': {
            int(request.form['activity']): float(request.form['amount'])},
            'database_filepath': [os.path.join(dirpath, "lci.npy")],
            'method': [os.path.join(dirpath, "lcia.npy")],
        }

        lca = LCA(**config)
        lca.lci()
        lca.lcia()

    return jsonify({'score': lca.score})