Generate a valid Authorization header for azure service bus/eventhubs - ruby

Question

I am trying to use SAS authenticaion in a ruby script and i keep getting 401 (Access denied) response from the event hub, it seems I am generating the SAS token incorrectly.
Below is the code I have used, it is based on https://azure.microsoft.com/en-us/documentation/articles/service-bus-sas-overview/ Javascript example that i have rewritten as ruby (please note it might be not idiomatic)
require "optparse"
require "CGI"
require 'openssl'
require "base64"
require "Faraday"
require 'Digest'
def generateToken(url,keyname,keyvalue)
encoded = CGI::escape(url)
ttl = (Time.now + 60*5).to_i
signature = "#{encoded}\n#{ttl}".encode('utf-8')
# puts signature
key = Base64.strict_decode64(keyvalue)
dig = OpenSSL::HMAC.digest('sha256', key, signature)
# dig = Digest::HMAC.digest(signature, key, Digest::SHA256)
hash = CGI.escape(Base64.strict_encode64(dig))
# puts hash
return "SharedAccessSignature sig=#{hash}&se=#{ttl}&skn=#{keyname}&sr=#{encoded}"
end
def build_connection(url,token)
conn = Faraday.new(:url => url) do |faraday|
faraday.request :url_encoded # form-encode POST params
faraday.response :logger # log requests to STDOUT
faraday.adapter Faraday.default_adapter # make requests with Net::HTTP
end
conn.headers['Content-Type'] = 'application/json'
conn.headers['Authorization'] = token
return conn
end
if __FILE__ == $0
ARGV << '-h' if ARGV.empty?
options = {}
OptionParser.new do |opts|
opts.banner = "Usage: generateSasToken.rb [options]"
opts.on('-u URL', '--url URL', 'url for access') { |v| options[:url] = v }
opts.on('--keyname NAME','set key name') { |v| options[:keyname] = v }
opts.on('--key KEY','set key value') { |v| options[:keyvalue] = v }
opts.on_tail("-h", "--help", "Show this message") do
puts opts
exit
end
end.parse!
token = generateToken(options[:url],options[:keyname],options[:keyvalue])
puts token
conn = build_connection(options[:url],token)
puts conn.headers
response = conn.post do |req|
req.body = '{"temprature":50}'
req.headers['content-length'] = req.body.length.to_s
end
puts response
end
any help in understanding why the token is incorrect would be great

Answer 1

After comparing my code against the python sdk this is the correct way to generate the token:
require "optparse"
require "CGI"
require 'openssl'
require "base64"
require "Faraday"
require 'Digest'
def generateToken(url,keyname,keyvalue)
encoded = CGI::escape(url)
ttl = (Time.now + 60*5).to_i
signature = "#{encoded}\n#{ttl}"
# puts signature
key = keyvalue
#dig = OpenSSL::HMAC.digest('sha256', key, signature)
dig = Digest::HMAC.digest(signature, key, Digest::SHA256)
hash = CGI.escape(Base64.strict_encode64(dig))
# puts hash
return "SharedAccessSignature sig=#{hash}&se=#{ttl}&skn=#{keyname}&sr=#{encoded}"
end
def build_connection(url,token)
conn = Faraday.new(:url => url) do |faraday|
faraday.request :url_encoded # form-encode POST params
faraday.response :logger # log requests to STDOUT
faraday.adapter Faraday.default_adapter # make requests with Net::HTTP
end
conn.headers['Content-Type'] = 'application/json'
conn.headers['Authorization'] = token
return conn
end
if __FILE__ == $0
ARGV << '-h' if ARGV.empty?
options = {}
OptionParser.new do |opts|
opts.banner = "Usage: generateSasToken.rb [options]"
opts.on('-u URL', '--url URL', 'url for access') { |v| options[:url] = v }
opts.on('--keyname NAME','set key name') { |v| options[:keyname] = v }
opts.on('--key KEY','set key value') { |v| options[:keyvalue] = v }
opts.on_tail("-h", "--help", "Show this message") do
puts opts
exit
end
end.parse!
token = generateToken(options[:url],options[:keyname],options[:keyvalue])
conn = build_connection(options[:url],token)
puts conn.headers
response = conn.post do |req|
req.body = '{"temprature":50}'
req.headers['content-length'] = req.body.length.to_s
end
puts response
end
this was much simpler than expected no need to encode to utf8 or to decode the key.