helpers.js

const fs = require('fs');

// a function to log stuff onto the console.
const log = (message, style) => {
    output = "";
    switch (style) {
        case ('box'):
            let horizontals = ''
            let mLength = message.length;
            for (let i = 0; i < (mLength + 2); i++) {
                horizontals += '═';
            }
            output += '\n╔' + horizontals + '╗\n' + '║ ' + message + ' ║' + '\n╚' + horizontals + '╝';
            break;
        case 'm':
            output += '\n- ' + message;
            break;
        default:
            output = '  ' + message;
    }
    console.log(output);
};

// a function to format the output of diverse scrapes and formats onto the format required by the output feed
const formatJson = (json, what) => {
    log('Formatting json for ' + what.id);
    const findItems = (route) => {
        var branches = route.split('>');
        let obj = json;
        for (let i = 0; i < branches.length; i++) {
            obj = obj[branches[i].trim()];
        }
        return obj;
    };
    let sourceArray = findItems(what.itemsPath);
    let output = { items: [] };
    let sourceItem, outputItem;
    for (let i = 0; i < sourceArray.length; i++) {
        sourceItem = sourceArray[i]
        outputItem = {};
        for (let key in what.items) {
            outputItem[key] = what.items[key](sourceItem);
        }
        output.items.push(outputItem);
    }
    return output;
};

// https get with promises
const getContent = (url) => {
    // return new pending promise
    return new Promise((resolve, reject) => {
        // select http or https module, depending on reqested url
        const lib = url.startsWith('https') ? require('https') : require('http');
        const request = lib.get(url, (response) => {
            log('Retrieveing content from ' + url);
            // handle http errors
            if (response.statusCode < 200 || response.statusCode > 299) {
                reject(new Error('Failed to load page, status code: ' + response.statusCode));
            }
            // temporary data holder
            const body = [];
            // on every content chunk, push it to the data array
            response.on('data', (chunk) => body.push(chunk));
            // we are done, resolve promise with those joined chunks
            response.on('end', () => resolve(body.join('')));
        });
        // handle connection errors of the request
        request.on('error', (err) => reject(err))
    });
};

// read files asynchronously and return data in a promise
const readFileAsync = function(filename) {
    return new Promise(function(resolve, reject) {
        fs.readFile(filename, function(err, data){
            if (err) 
                reject(err); 
            else 
                resolve(data);
        });
    });
};
// writes files asynchronously and returns written value in promise
const writeFileAsync = function(filename,contents){
    return new Promise(function(resolve, reject) {
        fs.writeFile(filename, contents, function (err) {
            if (err) reject(err);
            resolve(true);
        });
    });
};

// create directories asynchronously
const makeDirSync = function(path){
    if (!fs.existsSync(path)) fs.mkdirSync(path);
    return true;
}

// name says it all, comverts xml onto json
const xmlToJson = function (xml) {
    return new Promise((resolve, reject) => {
        let parseString = require('xml2js').parseString;
        let output = parseString(xml, function (err, result) {
            if (err) {
                reject(err);
            } else {
                resolve(result);
            }
        });
    });
};

module.exports = {
    log: log,
    getContent: getContent,
    xmlToJson: xmlToJson,
    formatJson: formatJson,
    readFileAsync: readFileAsync,
    writeFileAsync: writeFileAsync,
    makeDirSync: makeDirSync
}