Email answers allow checking signatures

Use Mail gem for receiving emails. Changed fixture email question to require a
valid signature. Tests for signatures validation.

1 files changed, 29 insertions, 0 deletions

diff --git a/lib/message.rb b/lib/message.rb
new file mode 100644
index 0000000..a860c59
--- /dev/null
+++ b/lib/message.rb
@@ -0,0 +1,29 @@
+# This must not be automagically included.
+# If this is included automatically Mail gem will not load properly and
+# things will break.
+module Mail
+  class Message
+    def signatures
+      boundary = content_type._?.match(/boundary="?([^;"]*)"?;?/)._?.captures._?.first
+      return [] unless boundary
+
+      boundary = Regexp.escape(boundary)
+      signed = body.decoded.match(/#{boundary}\n(.*?)\n\-*#{boundary}/m)._?.captures._?.first
+      return [] unless signed
+
+      result = []
+      for part in parts[1..-1]
+        begin
+          GPGME::verify(part.decoded, signed){ |signature| result.push signature.to_s}
+        rescue
+          # Some signatures break GPGME::Signature#to_s - report them
+          result = []
+          GPGME::verify(part.decoded, signed) do |signature|
+            result.push "Breaking signature"
+          end
+        end
+      end
+      result
+    end
+  end
+end