You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
113 lines
4.6 KiB
JavaScript
113 lines
4.6 KiB
JavaScript
const fs = require("fs"),
|
|
path = require("path"),
|
|
cache_dir = "./.cache";
|
|
let cache = {};
|
|
let logger = require("winston");
|
|
|
|
/**
|
|
* Sets the logger for logging
|
|
* @param {Object} newLogger
|
|
*/
|
|
exports.setLogger = function (newLogger) {
|
|
logger = newLogger;
|
|
};
|
|
|
|
/**
|
|
* Returns the data from files that were cached
|
|
* @param {String} filename The name of the file that has been cached
|
|
* @return {String} The data stored in the file
|
|
*/
|
|
exports.getCached = function (filename) {
|
|
let cf = cache[filename];
|
|
let call_passed = (Date.now() - cf.last_call) / 1000; // calculate the time since the last call of the file
|
|
if (cf.call_count > 10 && call_passed < 60) {
|
|
cf.data = fs.readFileSync(cf.path); // store the file's data into the json
|
|
} else if (call_passed > 3600) {
|
|
cf.call_count = 0; // reset the counter when an hour has passed since the last call
|
|
cf.data = null; // reset the data to free memory
|
|
}
|
|
cf.last_call = Date.now(); // set the last call to now
|
|
cf.call_count += 1; // increase the call count
|
|
if (cf.data != null) return cf.data;
|
|
logger.debug("Returning cached data for %s : %s", filename, cf.path);
|
|
return fs.readFileSync(cf.path); // return either the data or read the file
|
|
};
|
|
|
|
/**
|
|
* Safes the file with it's corresponding data in the cache directory
|
|
* @param {String} filename The name of the file
|
|
* @param {String} data The data form the file
|
|
*/
|
|
exports.cache = function (filename, data) {
|
|
logger.verbose("Creating cache entry for %s", filename);
|
|
if (!fs.existsSync("./.cache")) fs.mkdirSync("./.cache"); // if the cache folder doesn't exist, create it
|
|
let cache_fn = filename.replace(/[^\w.]/g, "__"); // remove invalid path characters
|
|
let count = 0;
|
|
while (fs.existsSync(filename + count + ".cache")) count++; // check if a file with the same name already exists and increase count
|
|
let cache_path = path.join(cache_dir, cache_fn + count + ".cache"); // create the final file path. Cachedir + cached filename (without invalid) + count + .cache
|
|
logger.debug("Creating file %s", cache_path);
|
|
fs.writeFile(cache_path, data, (err) => {
|
|
if (err !== null) logger.error(err);
|
|
else {
|
|
logger.debug("Created file cache entry for %s", filename);
|
|
cache[filename] = { // create a cache-entry with the file's path when the file is written (so it won't be accessed before)
|
|
"path": cache_path, // the last call to the file, the count of calls and an
|
|
"last_call": null, // empty data field to store the file's data if the file
|
|
"call_count": 0, // was called often
|
|
"data": null,
|
|
"creation_time": Date.now(),
|
|
"changed": false
|
|
}
|
|
}
|
|
fs.watch(filename, (eventType) => { // watch the file for changes
|
|
logger.debug("Change detected on %s", filename);
|
|
if (eventType === 'change') cache[filename].changed = true; // if the event change is detected set the change attribute to true
|
|
});
|
|
}); // write the data asynchronously to the file
|
|
};
|
|
|
|
/**
|
|
* Returns if the file is already cached. It returns false if changes were detected in the file
|
|
* @param {String} filename The filename to check
|
|
* @return {Boolean} Is it cached or not
|
|
*/
|
|
exports.isCached = function (filename) {
|
|
return false
|
|
let cached_entry = cache[filename];
|
|
if (cached_entry) { // check if the cache entry exists
|
|
logger.debug("Found cache entry for %s", filename);
|
|
if (cached_entry.changed) return false; // if a change was detected recache the file
|
|
if (cached_entry.path) { // check if the path variable is set
|
|
logger.debug("Found path entry for %s", filename);
|
|
return fs.existsSync(cached_entry.path); // return if the file exists
|
|
}
|
|
}
|
|
logger.debug("Found no cache entry for %s", filename);
|
|
return false; // return false if the cache entry doesn't exist
|
|
}
|
|
|
|
/**
|
|
* A function that clears the ./.cache directory
|
|
*/
|
|
exports.cleanup = function () {
|
|
deleteFolder(cache_dir); // delte the cache folder and it's contents
|
|
};
|
|
|
|
/**
|
|
* Deletes a folder with it's contents recursive
|
|
* @param {string} p the path to the folder
|
|
*/
|
|
var deleteFolder = function(p) {
|
|
if( fs.existsSync(p) ) {
|
|
fs.readdirSync(p).forEach(function(file){ // get the contents of the directory
|
|
var curPath = path.join(p, file); // create path by joining
|
|
if(fs.lstatSync(curPath).isDirectory()) { // recurse
|
|
deleteFolder(curPath); // call recursive
|
|
} else { // delete file
|
|
fs.unlinkSync(curPath); // delete file
|
|
}
|
|
});
|
|
fs.rmdirSync(p); // delete directory
|
|
}
|
|
};
|