chain4all-service/app.js

import fetch from "node-fetch"
import express from "express"
import bodyParser from "body-parser"

const app = express();
app.use(bodyParser.json());

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 PRICE_MODIFIER = 0.5;

app.post("/price", (req, res) => {        
    if(req.body && req.body.extent){            
        req.body.price = getPrice(req.body.extent);
        res.send(req.body);
    }
    else{
        res.status(400);
        res.send();
    }    
});

app.get("/users/:userId/assets", async (req, res) => {
    let irohaResponse = await fetchUsersAssets(req.params.userId);

    res.status(irohaResponse.status);

    if(irohaResponse.headers.get("content-length") < 1){            
        res.send();
    }
    else{                        
        res.send(await irohaResponse.json());
    }            
});

app.get("/users/:userId/assets/:assetId", async (req, res) => {
    let assets = (await fetchUsersAssets(req.params.userId)).assets;
    
    let parsedAssetName = "";
    let i = 0;
    for(i; i < assets.length; i++){           
        parsedAssetName = assets[i].assetId.split('#')[0];
        if(parsedAssetName === req.params.assetId){
            res.status(200);
            res.send(assets[i]);
            return;
        }
    }

    res.status(204);
    res.send();   
});

app.post("/buy", (req, res) => {
    //TODO implement...
    res.status(201);
});

async function fetchUsersAssets(userId){        
    return await fetch(IROHA_API_HOST + ':' + IROHA_API_PORT + '/accounts/' + userId + '@' + IROHA_DOMAIN + '/assets/');    
}

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 error(err, req, res, next){
    console.log(err);
    res.status(500);
    res.send("Something went wrong. Here is the error message: " + err.message);
}

app.use(error);

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