secret-base62
Generate random token using base62 which is alphanumeric with uppercase and lowercase.
This is suitable for secret URLs, whereas base64 includes slash in its charset.
You can test my image on DockerHub:
docker run evanxsummers/secret-base62
It should output a random base62 string e.g. r2CKLsQ4HxfFevdl
It is implemented as follows:
const assert = require('assert');
const crypto = require('crypto');
const digits = '0123456789';
const letters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
const charset = [digits, letters, letters.toLowerCase()].join('');
assert.equal(charset.length, 62);
const length = parseInt(process.env.length || '16');
const string = crypto.randomBytes(length).map(
value => charset.charCodeAt(
Math.floor(value*charset.length/256)
)
).toString();
console.log(string);where we generate an array of random bytes (values 0 to 255 inclusive) of the desired length and then map each into our charset:
0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz
We can build using its Dockerfile as follows:
docker build -t secret-base62 https://github.com/evanx/secret-base62.git
where we tag the image so we can run by tag name:
docker run -t secret-base62
which gives random output e.g. zQPv2WXCuy43nueh
Use length envar to change from default 16
docker run -e length=32 secret-base62
which outputs length 32 token e.g. CMZRUgDU5RxwzhDFh7fV5EKAKz6HmXdb