This commit introduces TLS support, provided by `rustls` and a fork of
`hyper-rustls`. TLS support is enabled via the `tls` feature and
activated when the `tls` configuration parameter is set. A new
`hello_tls` example illustrates its usage.
This commit also introduces more robust and complete configuration
settings via environment variables. In particular, quoted string,
array, and table (dictionaries) based configuration parameters can now
be set via environment variables.
Resolves#28.
This commit includes the following additions:
* A `session` example was added.
* `Config::take_session_key` was removed.
* If a `session_key` is not supplied, one is automatically generated.
* The `Session` type implements signed, encrypted sessions.
* A `Session` can be retrieved via its request guard.
This commit involves several breaking changes:
* `session_key` config param must be a 256-bit base64 encoded string.
* `FromRequest` is implemented for `Cookies`, not `Cookie`.
* Only a single `Cookies` instance can be retrieved at a time.
* `Config::take_session_key` returns a `Vec<u8>`.
* `Into<Header>` is implemented for `&Cookie`, not `Cookie`.
A few interesting notes on this breakage:
* `Cookie` how has a lifetime. It should be `'static'` everywhere.
* The `SetCookie` header is no longer reexported.
* Instead, `Cookie` implements `Into<Header>` for Set-Cookie.
* Add Config::new() and Config::build() for simpler Config creation.
* Add set_{param} methods to Config.
* Add ConfigBuilder type for easy building of configurations.
* Remove builder methods from Config.
* PartialEq in Config doesn't consider path or session key.
* Rocket::custom takes Config by value.
* Rocket::custom takes second (enable_logging) boolean argument.
* Rocket::custom properly sets the custom config as the active config.