Ejemplo de grupo de recursos de BrightSign

este script muestra cómo se puede usar brightsign asset pool desde javascript funciona tanto desde nodejs como desde chromium no está pensado como una aplicación completa y no hace nada con los assets que se descargan // mit license // // copyright (c) 2020 brightsign // // permission is hereby granted, free of charge, to any person obtaining a copy // of this software and associated documentation files (the "software"), to deal // in the software without restriction, including without limitation the rights // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell // copies of the software, and to permit persons to whom the software is // furnished to do so, subject to the following conditions // // the above copyright notice and this permission notice shall be included in all // copies or substantial portions of the software // // the software is provided "as is", without warranty of any kind, express or // implied, including but not limited to the warranties of merchantability, // fitness for a particular purpose and noninfringement in no event shall the // authors or copyright holders be liable for any claim, damages or other // liability, whether in an action of contract, tort or otherwise, arising from, // out of or in connection with the software or the use or other dealings in the // software // customise these settings for your environment const storagepath = "/storage/sd/"; const poolpath = storagepath + "examplepool"; const serverprefix = "https //github com/brightsign/javascript assetpoolfetcher/blob/video training/"; const fs = require('fs'); const assetpool = require("@brightsign/assetpool"); const assetpoolfiles = require("@brightsign/assetpoolfiles"); const assetfetcher = require("@brightsign/assetfetcher"); const assetrealizer = require("@brightsign/assetrealizer"); // create the asset collection array to be used by the rest of the // program the asset collection will usually come either directly or // indirectly from a server somewhere rather than being generated in // code like this function makeassetcollection() { // assets must have a name and a link everything else is // optional you can add your own properties if required for // example, the "osupdate" property here is only used by this // script let videoasset1 = { 	name "brightlink mp4", 	hash { method "sha256", 	 hex "82e5e800ff4b2608ae996b6c9fce78c0d84b82cba0da270251846324f48fb076" }, 	link serverprefix + "brightlink%201min mp4?raw=true", 	size 17219989, }; let videoasset2 = { 	name "cmscontrol mp4", 	hash { method "sha512", 	 hex "d476296b114fda612917b1568a9f7ffe6f54f3f927b2d1ecc932816e912619eeef980e1adc16d8b1d7914d3f172cd6a2ef17172ea3251ddcdbb3d151faa6818f" }, 	link serverprefix + "cms%2bcontrol%201%20min mp4?raw=true", 	size 5633877, }; // we don't want to risk actually changing the os version on the // brightsign running this example cript, so this is not a real // brightsignos file it will be realized into the root of the // storage device, but the os will fail to find the expected // header and rename it to placeholder bsfw invalid let osupdateasset = { 	name "placeholder bsfw", 	hash { method "sha1", hex "20e89c9ba0491590e3c34bc704171c0c02e643c3" }, 	link serverprefix + "placeholder bsfw?raw=true", 	size 43, 	osupdate true, }; let assetcollection = \[ 	videoasset1, 	videoasset2, 	osupdateasset, ]; return assetcollection; } // convert a progress event to a useful string for reporting function progressstring(event) { if (event currentfiletotal === undefined) { 	// if the size of the asset was not specified in the asset collection, then the total size may not be reported 	// during the fetch 	return event currentfiletransferred tostring() + " of unknown"; } else { 	return event currentfiletransferred tostring() + " of " + event currentfiletotal tostring() + " " 	 \+ (100 event currentfiletransferred / event currentfiletotal) tofixed(0) + "%"; } } // download any assets that aren't already in the pool into the pool // whilst reporting progress async function fetchassets(assetpool, assetcollection) { console log("fetch " + json stringify(assetcollection map(asset => asset name))); let assetfetcher = new assetfetcher(assetpool); assetfetcher addeventlistener("fileevent", (event) => { 	// this is called each time the fetcher has finished trying to 	// download an asset, whether successful or not it is not 	// called for any assets that are already in the pool 	console log("asset \[" + (event index + 1) tostring() + "] " 	 \+ event filename + " complete " + event responsecode tostring() + " " + event error); }); assetfetcher addeventlistener("progressevent", (event) => { 	// this is called at approximately the progress interval 	// specified in the options to indicate how far through the 	// download 	console log("asset \[" + (event index + 1) tostring() + "/" + event total tostring() + "] " + event filename 	 \+ " progress " + progressstring(event)); }); const fetchoptions = { 	// receive asset progress events about every five seconds 	progressinterval 5, 	// try to download each asset three times before giving up 	fileretrycount 3, 	// give up if we fail to download at least 1024 bytes in each 	// ten second period 	minimumtransferrate { bytespersecond 1024, periodinseconds 10 }, }; try { 	await assetfetcher start(assetcollection, fetchoptions); } catch (err) { 	console log("fetch failed " + err message); 	throw(err); } } // in order to make use of an asset from the pool you need to look up // its pool filename so you can refer to it there async function useassets(assetpool, assetcollection) { let files = new assetpoolfiles(assetpool, assetcollection); for (const filename of \[ 'brightlink mp4', 'cmscontrol mp4' ]) { 	const path = await files getpath(filename); 	console log("asset " + filename + " is at " + path); } } // some files need to appear in the filesystem outside the pool for // example, brightsignos update files must be written to the root of // a storage device for them to be found realizing will copy files, // so can be slow on large files async function realizeassets(assetpool, assetcollection) { let realizer = new assetrealizer(assetpool, storagepath); // we only want to realize the files that we have to const assetstorealize = assetcollection filter(asset => asset osupdate); console log("realize " + json stringify(assetstorealize map(asset => asset name))); await realizer realize(assetstorealize); } function ensuredirectoryexists(path) { try { 	fs mkdirsync(path); } catch (err) { 	if (err code != 'eexist') 	 throw(err); } } function exceptiontostring(err) { if (err instanceof error) return err name + " " + err message; else if (typeof(err) === "string") return err; else return json stringify(err); } async function runexample() { console log("start"); ensuredirectoryexists(poolpath); // only one assetpool instance should be created for a given pool // path having multiple instances risks them disagreeing over // which assets are protected during pruning let assetpool = new assetpool(poolpath); // don't let the pool grow any larger than 500mib await assetpool setmaximumpoolsize(500 1024 1024); // don't let free space on the storage device fall below 100mib await assetpool reservestorage(100 1024 1024); const assetcollection = makeassetcollection(); // we need to stop the fetcher from pruning any of the assets we // currently care about in order to make space for fetching new // assets or realizing existing ones assets are protected until // the assetpool instance is destroyed or unprotectassets is // called for the same name await assetpool protectassets("collection1", assetcollection); await fetchassets(assetpool, assetcollection); // in this case any failure to fetch the assets will cause // fetchassets to have thrown an exception, so we won't get this // far however, in a larger script it may be more convenient to // call areassetsready to determine whether the asset collection // is ready for use if (await assetpool areassetsready(assetcollection)) { 	await useassets(assetpool, assetcollection); 	await realizeassets(assetpool, assetcollection); } else { 	console log("assets were not downloaded successfully"); } } runexample() then(() => { 	console log("complete"); 	process exit(0); }) catch((err) => { 	console log("failed " + exceptiontostring(err)); 	process exit(1); });