WME/aufgabe3/app.js

// DO NOT CHANGE!
//init app with express, util, body-parser, csv2json
var express = require('express');
var app = express();
var sys = require('util');
var path = require('path');
var bodyParser = require('body-parser');
var Converter = require("csvtojson").Converter;

//register body-parser to handle json from res / req
app.use(bodyParser.json());

//register public dir to serve static files (html, css, js)
app.use(express.static(path.join(__dirname, "public")));

// END DO NOT CHANGE!


/**************************************************************************
****************************** csv2json *********************************
**************************************************************************/

const csv = require('csvtojson')

var json;

csv()
    .fromFile("world_data.csv")
    .then((jsonObj) => {
        json = jsonObj;
    })

/**************************************************************************
********************** handle HTTP METHODS ***********************
**************************************************************************/

// ------------------------------ GET ------------------------------
app.get("/items", function (req, res) {
    console.log(json);
    res.send(json);
});

app.get("/items/:id", function (req, res) {
    var requested_id = parseInt(req.params.id);
    var answer = ["Err", "No such id " + requested_id + " in database"];

    for (var i = 0; i < json.length; i++) {
        if (json[i].id == requested_id) {
            answer = [json[i]];
        }
    }

    res.send(answer);
});

app.get("/items/:id1/:id2", function (req, res) {
    var first_requested_id = parseInt(req.params.id1);
    var second_requested_id = parseInt(req.params.id2);
    var answer = ["Err", "Range not possible"];

    // check that first id is bigger than 0
    // and the second one is the bigger one
    if (first_requested_id >= 0 && second_requested_id > first_requested_id) {
        var enable_push = false;

        for (var i; i < json.length; i++) {
            // enable push when the first id is found
            if (parseInt(json[i].id) == first_requested_id) {
                enable_push = true;
            }

            // push key when enabled
            if (enable_push) {
                answer.push(json[i]);
            }

            // break when second id is found
            if (parseInt(json[i].id) == second_requested_id) {
                break;
            }
        }
    }

    res.send(answer);
});

app.get("/properties", function (req, res) {
    var answer = [];

    for (var key in json[0]) {
        answer.push(key);
    }

    res.send(answer);
});

app.get("/properties/:num", function (req, res) {
    let num = parseInt(req.params.num);
    var answer = ["Err", "No such property available"];

    var i = 0;

    for (var key in json[0]) {
        if (i == num) {
            answer = [key];
            break;
        }

        i++;
    }

    res.send(answer);
})

// ----------------------------- POST ------------------------------
app.post("/items", function (req, res) {
    var new_entry = req.body;

    // set id
    var last_id = parseInt(json[json.length - 1].id);
    new_entry["id"] = (last_id + 1).toString();

    // add entry to json
    json.push(new_entry);

    res.send("Added country " + new_entry.name + " to list!");
});

// ---------------------------- DELETE -----------------------------
app.delete("/items", function (req, res) {
    var name = json[json.length - 1].name;

    json.splice(-1, 1);

    res.send("Deleted last country " + name + "!");
});

app.delete("/items/id", function (req, res) {
    var requested_id = parseInt(req.params.id);
    var answer = ["Err", "No such id " + requested_id + "in database"];

    for (var i = 0; i < json.length; i++) {
        if (json[i].id == requested_id) {
            json.splice(i, 1);
            answer = ["Item " + requested_id + " deleted successfully."];

            break;
        }
    }

    res.send(answer);
});

// DO NOT CHANGE!
// bind server to port
var server = app.listen(3000, function () {
    var host = server.address().address;
    var port = server.address().port;
    console.log('Example app listening at http://%s:%s', host, port);
});