Creating Signed JWTs (JWS) with Ruby
When you're working with JSON Web Tokens (JWTs), you'll almost certainly be validating that the contents of the token is sent by the correct service by verifying the token's signature.
However, it's also helpful to be able to create these signed JWTs for yourself, which we can do with either of the two popular JWT libraries in Ruby.
With both of these approaches, the expectation is that you can run them as the following:
ruby sign.rb payload.json 'hmac-key-here'
ruby sign.rb payload.json 'hmac-key-here' 'HS256'
ruby sign.rb payload.json '/path/to/key.pem' 'RS256'
ruby sign.rb payload.json '/path/to/key.pem' 'ES256'
With JSON::JWT
Using JSON::JWT, we can use the following:
require 'json/jwt'
payload = JSON.parse(File.read ARGV[0])
maybe_secret = ARGV[1]
algorithm = ARGV[2] || 'HS256'
if File.exists? maybe_secret
maybe_secret = OpenSSL::PKey.read(File.read maybe_secret)
end
puts JSON::JWT.new(payload).sign(maybe_secret, algorithm.to_sym)
With ruby-jwt
Using ruby-jwt, we have the following code:
require 'jwt'
payload = JSON.parse(File.read ARGV[0])
maybe_secret = ARGV[1]
algorithm = ARGV[2] || 'HS256'
if File.exists? maybe_secret
maybe_secret = OpenSSL::PKey.read(File.read maybe_secret)
end
puts JWT.encode payload, maybe_secret, algorithm
