mirror of https://github.com/seald/nedb
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
38 lines
1.0 KiB
38 lines
1.0 KiB
var fs = require('fs')
|
|
, crypto = require('crypto')
|
|
, path = require('path')
|
|
, mkdirp = require('mkdirp')
|
|
;
|
|
|
|
|
|
/**
|
|
* Check if a directory exists and create it on the fly if it is not the case
|
|
* cb is optional, signature: err
|
|
*/
|
|
function ensureDirectoryExists (dir, cb) {
|
|
var callback = cb || function () {}
|
|
;
|
|
|
|
mkdirp(dir, function (err) { return callback(err); });
|
|
}
|
|
|
|
|
|
/**
|
|
* Return a random alphanumerical string of length len
|
|
* There is a very small probability (less than 1/1,000,000) for the length to be less than len
|
|
* (il the base64 conversion yields too many pluses and slashes) but
|
|
* that's not an issue here
|
|
* The probability of a collision is extremely small (need 3*10^12 documents to have one chance in a million of a collision)
|
|
* See http://en.wikipedia.org/wiki/Birthday_problem
|
|
*/
|
|
function uid (len) {
|
|
return crypto.randomBytes(Math.ceil(Math.max(8, len * 2)))
|
|
.toString('base64')
|
|
.replace(/[+\/]/g, '')
|
|
.slice(0, len);
|
|
}
|
|
|
|
|
|
|
|
module.exports.ensureDirectoryExists = ensureDirectoryExists;
|
|
module.exports.uid = uid;
|
|
|