const debug = require("debug")("streamroller:fileNameParser"); const ZIP_EXT = ".gz"; const format = require("date-format"); const DEFAULT_FILENAME_SEP = "."; module.exports = ({ file, keepFileExt, pattern, fileNameSep }) => { let FILENAME_SEP = fileNameSep || DEFAULT_FILENAME_SEP; // All these functions take two arguments: f, the filename, and p, the result placeholder // They return the filename with any matching parts removed. // The "zip" function, for instance, removes the ".gz" part of the filename (if present) const zip = (f, p) => { if (f.endsWith(ZIP_EXT)) { debug("it is gzipped"); p.isCompressed = true; return f.slice(0, -1 * ZIP_EXT.length); } return f; }; const __NOT_MATCHING__ = "__NOT_MATCHING__"; const extAtEnd = f => { if (f.startsWith(file.name) && f.endsWith(file.ext)) { debug("it starts and ends with the right things"); return f.slice(file.name.length + 1, -1 * file.ext.length); } return __NOT_MATCHING__; }; const extInMiddle = f => { if (f.startsWith(file.base)) { debug("it starts with the right things"); return f.slice(file.base.length + 1); } return __NOT_MATCHING__; }; const dateAndIndex = (f, p) => { const items = f.split(FILENAME_SEP); let indexStr = items[items.length - 1]; debug("items: ", items, ", indexStr: ", indexStr); let dateStr = f; if (indexStr !== undefined && indexStr.match(/^\d+$/)) { dateStr = f.slice(0, -1 * (indexStr.length + 1)); debug(`dateStr is ${dateStr}`); if (pattern && !dateStr) { dateStr = indexStr; indexStr = "0"; } } else { indexStr = "0"; } try { // Two arguments for new Date() are intentional. This will set other date // components to minimal values in the current timezone instead of UTC, // as new Date(0) will do. const date = format.parse(pattern, dateStr, new Date(0, 0)); if (format.asString(pattern, date) !== dateStr) return f; p.index = parseInt(indexStr, 10); p.date = dateStr; p.timestamp = date.getTime(); return ""; } catch (e) { //not a valid date, don't panic. debug(`Problem parsing ${dateStr} as ${pattern}, error was: `, e); return f; } }; const index = (f, p) => { if (f.match(/^\d+$/)) { debug("it has an index"); p.index = parseInt(f, 10); return ""; } return f; }; let parts = [ zip, keepFileExt ? extAtEnd : extInMiddle, pattern ? dateAndIndex : index ]; return filename => { let result = { filename, index: 0, isCompressed: false }; // pass the filename through each of the file part parsers let whatsLeftOver = parts.reduce( (remains, part) => part(remains, result), filename ); // if there's anything left after parsing, then it wasn't a valid filename return whatsLeftOver ? null : result; }; };