Add a helper function to verify webhook requests

The new `request::verified()` takes POST params as a string as does all
the work needed to call `paddle::verify_signature()`.

This involves extracting the `p_signature` POST parameter to get the
signature, and getting the public key PEM.

Change `params::parse()` to return a
`BTreeMap<Cow<'a, str>, Cow<'a, str>>` instead of `String` keys &
values. This is because `paddle::verify_signature()` needs a `(<&str,
&str)` iterator. Actually, it still doesn't solve the problem because
the types don't match. We need to modify the input type of
`verify_signature()`, but at least this change gives us references.

Make `params` private to the crate because we no longer need to use it
in `main()`.

1 files changed, 4 insertions, 1 deletions

diff --git a/license-generator/src/lib.rs b/license-generator/src/lib.rs
index 64d96e9..bf3ed57 100644
--- a/license-generator/src/lib.rs
+++ b/license-generator/src/lib.rs
@@ -2,12 +2,15 @@
 extern crate error_chain;
 extern crate log;
 extern crate mysql;
+extern crate paddle;
 extern crate rand;
 extern crate sha1;
 extern crate url;
 
 
+mod params;
+
 pub mod database;
 pub mod errors;
-pub mod params;
 pub mod purchaser;
+pub mod request;