chain4all-service/app.js

import 'dotenv/config'
import express from "express"
import bodyParser from "body-parser"
import basicAuth from "express-basic-auth"

const app = express();
app.use(bodyParser.json());
app.use(basicAuth({
    users : { 'admin' : 'superPasswd' },
    challange : true
}));

const CHAIN4ALL_SERVICE_PORT = process.env.CHAIN4ALL_SERVICE_PORT || 3000;
const IROHA_API_HOST = process.env.IROHA_API_HOST || "http://localhost";
const IROHA_API_PORT = process.env.IROHA_API_PORT || 5000;

const IROHA_DOMAIN = process.env.IROHA_DOMAIN || "test";
const IROHA_ASSET = process.env.IROHA_ASSET || "coin";
const DATA_OWNER = process.env.DATA_OWNER || "admin"
const PRICE_MODIFIER = process.env.PRICE_MODIFIER || 0.5;

app.get("/", (req, res) => {
    res.send("Chain4All Blockchain service");
});

app.post("/price", (req, res) => {
    if (req.body && req.body.extent) {
        res.send({ price: getPrice(req.body.extent) });
    }
    else {
        res.status(400);
        throw Error(JSON.stringify({ error: { name: "Error, request has no body with \"extent\" property!" } }));
    }
});

app.post("/buy", async (req, res, next) => {

    try {
        if (!req.body) {
            res.status(400);
            throw Error(JSON.stringify({ error: { name: "Error, request has no body!" } }));
        }

        if (!req.body.txHash) {
            res.status(400);
            throw Error(JSON.stringify({ error: { name: "Error, request body has no \"txHash\" property!" } }));
        }                
    }
    catch (err) {
        next(err);
    }
});

function getArea(extent) {
    let y1 = extent[0][1];
    let y4 = extent[3][1];

    let x1 = extent[0][0];
    let x2 = extent[1][0];

    let height = Math.abs(y1 - y4);
    let width = Math.abs(x1 - x2);

    return height * width;
}

function getPrice(extent) {
    return getArea(extent) * PRICE_MODIFIER;
}

function errorMiddleware(err, req, res, next) { //TODO: add custom Exception class
    console.log(err);
    res.status(500);
    res.send(err.message);
}

app.use(errorMiddleware);

app.listen(CHAIN4ALL_SERVICE_PORT, () => {
    console.log(`Listening at http://localhost:${CHAIN4ALL_SERVICE_PORT}`)
});