node-savas/components/update_service.js

a node.js integration to communicate with the savas http-service

const axios = require('axios')
const fs = require('fs')
const _ = require('lodash')

module.exports = class UpdateService {

    constructor (settings) {
        let me = this

        me.defaultConfig = {
            host: '',
            ssl: false,
            id: null,
            channel: null,
            platform: null,
            version: null,
            token: null
        }

        me.opts = _.extend(me.defaultConfig, settings)
        me.http = axios.create({
            baseURL: (me.opts.ssl ? 'https://' : 'http://') + me.opts.host
        })
    }

    getUpdate () {
        let me = this
        let params = {
            id: me.opts.id,
            channel: me.opts.channel,
            platform: me.opts.platform,
            version: me.opts.version,
            token: me.opts.token
        }

        return new Promise ((resolve, reject) => {
            me.http.get('api/v1/updates', { params })
                .then(response => response.data)
                .then(response => {
                    if (response.isNewer) {
                        delete response.isNewer

                        resolve(response)
                    } else {
                        reject()
                    }
                })
                .catch(error => {
                    reject(error)
                })
        })
    }

    download (update, settings) {
        let me = this
        let opts = _.extend({
            /**
             * The filename where the file should be downloaded to (required)
             *
             * @var {string}
             */
            destination: '',
            /**
             * The listener which gets called when the download finished (required)
             *
             * @var {function}
             */
            resolve: () => {},
            /**
             * The listener which gets called when the download fails (required)
             *
             * @var {function}
             */
            reject: () => {},
            /**
             * The listener which gets called on download-progress (optional)
             *
             * @var {function}
             */
            progress: () => {}
        }, settings)

        me.http.get(update.filename, { responseType: 'stream' })
            .then(response => {
                let total = response.headers['content-length']
                let received = 0
                let percentage = 0

                response.data.on('data', (chunk) => {
                    if (total > 0) {
                        received += chunk.length

                        let _percentage = Math.round(received / total * 100)

                        if (_percentage !== percentage) {
                            percentage = _percentage

                            if (typeof opts.progress === 'function') {
                                opts.progress({
                                    total,
                                    current: received,
                                    percentage
                                })
                            }
                        }
                    }
                })

                response.data.on('end', () => {
                    opts.resolve({
                        filename: opts.destination
                    })
                })

                response.data.pipe(fs.createWriteStream(opts.destination))
            })
            .catch(opts.reject || (() => {}))
    }

}