This has the following positive effects:
1) The lifetime retrieved through 'Deref' is now long-lived.
2) An '&State<T>` can be created via an '&T'.
3) '&State<T>' is shorter to type than 'State<'_, T>'.
Sentinels resolve a long-standing usability and functional correctness
issue in Rocket: starting an application with guards and/or responders
that depend on state that isn't available. The canonical example is the
'State' guard. Prior to this commit, an application with routes that
queried unmanaged state via 'State' would fail at runtime. With this
commit, the application refuses to launch with a detailed error message.
The 'Sentinel' docs explains it as:
A sentinel, automatically run on ignition, can trigger a launch
abort should an instance fail to meet arbitrary conditions. Every
type that appears in a mounted route's type signature is eligible to
be a sentinel. Of these, those that implement 'Sentinel' have their
'abort()' method invoked automatically, immediately after ignition,
once for each unique type. Sentinels inspect the finalized instance
of 'Rocket' and can trigger a launch abort by returning 'true'.
The following types are now sentinels:
* 'contrib::databases::Connection' (any '#[database]' type)
* 'contrib::templates::Metadata'
* 'contrib::templates::Template'
* 'core::State'
The following are "specialized" sentinels, which allow sentinel
discovery even through type aliases:
* 'Option<T>', 'Debug<T>' if 'T: Sentinel'
* 'Result<T, E>', 'Either<T, E>' if 'T: Sentinel', 'E: Sentinel'
Closes#464.
The core 'Rocket' type is parameterized: 'Rocket<P: Phase>', where
'Phase' is a newly introduced, sealed marker trait. The trait is
implemented by three new marker types representing the three launch
phases: 'Build', 'Ignite', and 'Orbit'. Progression through these three
phases, in order, is enforced, as are the invariants guaranteed by each
phase. In particular, an instance of 'Rocket' is guaranteed to be in its
final configuration after the 'Build' phase and represent a running
local or public server in the 'Orbit' phase. The 'Ignite' phase serves
as an intermediate, enabling inspection of a finalized but stationary
instance. Transition between phases validates the invariants required
by the transition.
All APIs have been adjusted appropriately, requiring either an instance
of 'Rocket' in a particular phase ('Rocket<Build>', 'Rocket<Ignite>', or
'Rocket<Orbit>') or operating generically on a 'Rocket<P>'.
Documentation is also updated and substantially improved to mention
required and guaranteed invariants.
Additionally, this commit makes the following relevant changes:
* 'Rocket::ignite()' is now a public interface.
* 'Rocket::{build,custom}' methods can no longer panic.
* 'Launch' fairings are now 'ignite' fairings.
* 'Liftoff' fairings are always run, even in local mode.
* All 'ignite' fairings run concurrently at ignition.
* Launch logging occurs on launch, not any point prior.
* Launch log messages have improved formatting.
* A new launch error kind, 'Config', was added.
* A 'fairing::Result' type alias was introduced.
* 'Shutdown::shutdown()' is now 'Shutdown::notify()'.
Some internal changes were also introduced:
* Fairing 'Info' name for 'Templates' is now 'Templating'.
* Shutdown is implemented using 'tokio::sync::Notify'.
* 'Client::debug()' is used nearly universally in tests.
Resolves#1154.
Resolves#1136.
...because loading up a Rocket while it's ignited is a bad idea.
More seriously, because 'Rocket.ignite()' will become an "execute
everything up to here" method.
While offering some utility, the lifetime did not carry its weight, and
in practice offered no further ability to borrow. This greatly
simplifies request guard implementations.
So. Many. Changes.
This is an insane commit: simultaneously one of the best (because of all
the wonderful improvements!) and one of the worst (because it is just
massive) in the project's history.
Routing:
* All UTF-8 characters are accepted everywhere in route paths. (#998)
* `path` is now `uri` in `route` attribute: `#[route(GET, path = "..")]`
becomes `#[route(GET, uri = "..")]`.
Forms Revamp
* All form related types now reside in a new `form` module.
* Multipart forms are supported. (resolves#106)
* Collections are supported in forms and queries. (resolves#205)
* Nested structures in forms and queries are supported. (resolves#313)
* Form fields can be ad-hoc validated with `#[field(validate = expr)]`.
* `FromFormValue` is now `FromFormField`, blanket implements `FromForm`.
* Form field values are always percent-decoded apriori.
Temporary Files
* A new `TempFile` data and form guard allows streaming data directly to a
file which can then be persisted.
* A new `temp_dir` config parameter specifies where to store `TempFile`.
* The limits `file` and `file/$ext`, where `$ext` is the file extension,
determines the data limit for a `TempFile`.
Capped
* A new `Capped` type is used to indicate when data has been truncated due to
incoming data limits. It allows checking whether data is complete or
truncated.
* `DataStream` methods return `Capped` types.
* `DataStream` API has been revamped to account for `Capped` types.
* Several `Capped<T>` types implement `FromData`, `FromForm`.
* HTTP 413 (Payload Too Large) errors are now returned when data limits are
exceeded. (resolves#972)
Hierarchical Limits
* Data limits are now hierarchical, delimited with `/`. A limit of `a/b/c`
falls back to `a/b` then `a`.
Core
* `&RawStr` no longer implements `FromParam`.
* `&str` implements `FromParam`, `FromData`, `FromForm`.
* `FromTransformedData` was removed.
* `FromData` gained a lifetime for use with request-local data.
* The default error HTML is more compact.
* `&Config` is a request guard.
* The `DataStream` interface was entirely revamped.
* `State` is only exported via `rocket::State`.
* A `request::local_cache!()` macro was added for storing values in
request-local cache without consideration for type uniqueness by using a
locally generated anonymous type.
* `Request::get_param()` is now `Request::param()`.
* `Request::get_segments()` is now `Request::segments()`, takes a range.
* `Request::get_query_value()` is now `Request::query_value()`, can parse any
`FromForm` including sequences.
* `std::io::Error` implements `Responder` like `Debug<std::io::Error>`.
* `(Status, R)` where `R: Responder` implements `Responder` by overriding the
`Status` of `R`.
* The name of a route is printed first during route matching.
* `FlashMessage` now only has one lifetime generic.
HTTP
* `RawStr` implements `serde::{Serialize, Deserialize}`.
* `RawStr` implements _many_ more methods, in particular, those related to the
`Pattern` API.
* `RawStr::from_str()` is now `RawStr::new()`.
* `RawStr::url_decode()` and `RawStr::url_decode_lossy()` only allocate as
necessary, return `Cow`.
* `Status` implements `Default` with `Status::Ok`.
* `Status` implements `PartialEq`, `Eq`, `Hash`, `PartialOrd`, `Ord`.
* Authority and origin part of `Absolute` can be modified with new
`Absolute::{with,set}_authority()`, `Absolute::{with,set}_origin()` methods.
* `Origin::segments()` was removed in favor of methods split into query and
path parts and into raw and decoded versions.
* The `Segments` iterator is smarter, returns decoded `&str` items.
* `Segments::into_path_buf()` is now `Segments::to_path_buf()`.
* A new `QuerySegments` is the analogous query segment iterator.
* Once set, `expires` on private cookies is not overwritten. (resolves#1506)
* `Origin::path()` and `Origin::query()` return `&RawStr`, not `&str`.
Codegen
* Preserve more spans in `uri!` macro.
* Preserve spans `FromForm` field types.
* All dynamic parameters in a query string must typecheck as `FromForm`.
* `FromFormValue` derive removed; `FromFormField` added.
* The `form` `FromForm` and `FromFormField` field attribute is now named
`field`. `#[form(field = ..)]` is now `#[field(name = ..)]`.
Contrib
* `Json` implements `FromForm`.
* `MsgPack` implements `FromForm`.
* The `json!` macro is exported as `rocket_contrib::json::json!`.
* Added clarifying docs to `StaticFiles`.
Examples
* `form_validation` and `form_kitchen_sink` removed in favor of `forms`.
* The `hello_world` example uses unicode in paths.
* The `json` example only allocates as necessary.
Internal
* Codegen uses new `exports` module with the following conventions:
- Locals starts with `__` and are lowercased.
- Rocket modules start with `_` and are lowercased.
- `std` types start with `_` and are titlecased.
- Rocket types are titlecased.
* A `header` module was added to `http`, contains header types.
* `SAFETY` is used as doc-string keyword for `unsafe` related comments.
* The `Uri` parser no longer recognizes Rocket route URIs.
Sergio Benitez