extracting key generation out of author

app/models/author.rb

@@ -90,19 +90,7 @@ def reset_key_lease
 
   # Retrieves a valid RSA::KeyPair for the Author's public key
   def retrieve_public_key
-    # Create the public key from the key stored
-
-    # Retrieve the exponent and modulus from the key string
-    public_key.match /^RSA\.(.*?)\.(.*)$/
-    modulus = Base64::urlsafe_decode64($1)
-    exponent = Base64::urlsafe_decode64($2)
-
-    modulus = modulus.bytes.inject(0) {|num, byte| (num << 8) | byte }
-    exponent = exponent.bytes.inject(0) { |num, byte| (num << 8) | byte }
-
-    # Create the public key instance
-    key = RSA::Key.new(modulus, exponent)
-    keypair = RSA::KeyPair.new(nil, key)
+    Crypto.make_rsa_keypair(public_key, nil)
   end
 
   # Returns a locally useful url for the Author

app/models/user.rb

@@ -60,8 +60,8 @@ def generate_rsa_pair
   end
 
   # Retrieves a valid RSA::KeyPair for the User's private key
-  def self.to_rsa_key
-    Crypto.make_rsa_key(nil, private_key)
+  def self.to_rsa_keypair
+    Crypto.make_rsa_keypair(nil, private_key)
   end
 
   # After a user is created, create the feed and reset the token
@@ -169,7 +169,7 @@ def send_follow_notification to_feed_id
 
     salmon = OStatus::Salmon.from_follow(author.to_atom, f.author.to_atom)
 
-    envelope = salmon.to_xml self.to_rsa_key
+    envelope = salmon.to_xml self.to_rsa_keypair
 
     # Send envelope to Author's Salmon endpoint
     uri = URI.parse(f.author.salmon_url)
@@ -197,7 +197,7 @@ def send_unfollow_notification to_feed_id
 
     salmon = OStatus::Salmon.from_unfollow(author.to_atom, f.author.to_atom)
 
-    envelope = salmon.to_xml self.to_rsa_key
+    envelope = salmon.to_xml self.to_rsa_keypair
 
     # Send envelope to Author's Salmon endpoint
     uri = URI.parse(f.author.salmon_url)
@@ -213,7 +213,7 @@ def send_mention_notification update_id, to_feed_id
     base_uri = "http://#{author.domain}/"
     salmon = OStatus::Salmon.new(u.to_atom(base_uri))
 
-    envelope = salmon.to_xml self.to_rsa_key
+    envelope = salmon.to_xml self.to_rsa_keypair
 
     # Send envelope to Author's Salmon endpoint
     uri = URI.parse(f.author.salmon_url)

lib/crypto.rb

@@ -54,17 +54,28 @@ def self.generate_keypair
 
   # We don't yet do anything with the public key, but I added it so that when we
   # need to, it'll be there.
-  def self.make_rsa_key(public_key, private_key)
-    # Retrieve the exponent and modulus from the key string
-    private_key.match /^RSA\.(.*?)\.(.*)$/
-    modulus = Base64::urlsafe_decode64($1)
-    exponent = Base64::urlsafe_decode64($2)
-
-    modulus = modulus.bytes.inject(0) {|num, byte| (num << 8) | byte }
-    exponent = exponent.bytes.inject(0) { |num, byte| (num << 8) | byte }
-
-    # Create the public key instance
-    key = RSA::Key.new(modulus, exponent)
-    RSA::KeyPair.new(key, nil)
+  def self.make_rsa_keypair(public_key, private_key)
+    private_key = generate_key(private_key)
+    public_key = generate_key(public_key)
+
+    RSA::KeyPair.new(private_key, public_key)
+  end
+
+  private
+
+  def generate_key(key_string)
+    return nil unless key_string
+
+    key_string.match /^RSA\.(.*?)\.(.*)$/
+
+    modulus = decode_key($1)
+    exponent = decode_key($2)
+
+    RSA::Key.new(modulus, exponent)
+  end
+
+  def decode_key(encoded_key_part)
+    modulus = Base64::urlsafe_decode64(encoded_key_part)
+    modulus.bytes.inject(0) {|num, byte| (num << 8) | byte }
   end
 end