chain4all-service/app.ts

import 'dotenv/config'
import grpc from "grpc"
import express from "express"
import bodyParser from "body-parser"
import basicAuth from "express-basic-auth"
import {
    CommandService_v1Client as CommandService,
    QueryService_v1Client as QueryService
} from 'iroha-helpers/lib/proto/endpoint_grpc_pb'
import { queries } from 'iroha-helpers'
import util from 'util'
import { exec } from 'child_process'
import cors from 'cors'
import * as sql from 'sqlite3'
import fs from 'fs'

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

//TODO is cors package necesary? basic middleware could suffice 
app.use(cors()); //TODO: set only safe origins
app.use(basicAuth({
    users: { admin: 'superPasswd' }
}));



const asyncExec = util.promisify(exec);

const IROHA_ADMIN_PRIV = "f101537e319568c765b2cc89698325604991dca57b9716b58016b253506cab70";
const IROHA_ADMIN = "admin@test";
const IROHA_ADDRESS = process.env.IROHA_ADDRESS || "localhost:50051";
const queryService = new QueryService(IROHA_ADDRESS, grpc.credentials.createInsecure());


const CHAIN4ALL_RASTER_CLIP_SCRIPT_PATH = process.env.CHAIN4ALL_RASTER_CLIP_SCRIPT_PATH || '/home/kunickyd/Documents/chain4all/chain4all_raster_clip.sh';
const CHAIN4ALL_SERVICE_PORT = process.env.CHAIN4ALL_SERVICE_PORT || 3000;
const PRICE_MODIFIER: number = parseFloat(process.env.PRICE_MODIFIER || "0.5");

const DB_FILE_NAME: string = "data/transfers.db";

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

app.get("/transfers/:userId", async (req, res, next) => {
    let db = await getDbConnection();

    db.all(
        "SELECT hash " +
        "FROM transfers " +
        "WHERE user=? " +
        "ORDER BY id DESC " +
        "LIMIT 10;",
        [req.params.userId],
        (err, rows) => {
            if (err) {
                next(err);
                return;
            }
                        
            res.send(rows);
        }
    );

    db.close();
});

app.post("/transfer", 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!" } }));
        }

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

        let db = await getDbConnection();

        db.run(
            "INSERT INTO transfers (hash, user)" +
            "VALUES (?, ?);",
            [req.body.txHash, req.body.user],
            (err) => {
                if (err) {
                    next(err);
                    return;
                }
                res.status(201);
                res.send();
            }
        );

        db.close();
    }
    catch (err) {
        next(err);
    }
});

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

        //TODO load from http headers, or something like that??
        if (!req.body.user) {
            res.status(400);
            throw Error(JSON.stringify({ error: { name: "Error, request body has no \"user\" property!" } }));
        }

        //TODO validate this properly
        let txDetail = await getTransactionDetail(req.body.txHash, req.body.user);

        let extent: number[] = JSON.parse(txDetail.description).extent as number[];
        let dataFileId: string = Date.now().toString();

        let dataCommand = CHAIN4ALL_RASTER_CLIP_SCRIPT_PATH + ' ' + extent[0] + ' ' + extent[1] + ' ' + extent[2] + ' ' + extent[3] + ' ' + dataFileId;
        console.debug(dataCommand);

        const { stdout, stderr } = await asyncExec(dataCommand);

        console.debug(stdout);

        if (stderr) {
            console.warn(stderr);
        }

        res.send({ dataUrl: "https://gis.lesprojekt.cz/chain4all/raster_" + dataFileId + ".tif" });
    }
    catch (err) {
        next(err);
    }
});

function getDbConnection(): Promise<sql.Database> {

    return new Promise<sql.Database>((resolve, reject) => {
        if(!fs.existsSync("./data")){
            fs.mkdirSync("data");
        };
        
        let db = new sql.Database(DB_FILE_NAME);       

        db.run(
            "CREATE TABLE IF NOT EXISTS transfers( " +
            "id INTEGER PRIMARY KEY, " +
            "hash TEXT NOT NULL, " +
            "user TEXT NOT NULL " +
            ");",
            (err) => {
                if (err) {
                    reject(err);
                }
                else{
                    resolve(db);
                }
            }
        );
    });
}

async function getTransactionDetail(txHash: string, user: string) {
    let quer: any = await queries.getAccountTransactions({
        privateKey: IROHA_ADMIN_PRIV,
        creatorAccountId: IROHA_ADMIN,
        queryService,
        timeoutLimit: 5000
    }, {
        accountId: user,
        pageSize: 10,
        firstTxHash: txHash,
        ordering: {
            field: undefined,
            direction: undefined
        },
        firstTxTime: undefined,
        lastTxTime: undefined,
        firstTxHeight: 1,
        lastTxHeight: 3
    });

    //TODO find better way to look for transferAssets command in transaction
    return quer.transactionsList[0].payload.reducedPayload.commandsList[0].transferAsset;
}

function getPrice(area: number): number {
    return area * PRICE_MODIFIER;
}

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

app.use(errorMiddleware);

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