## Migration from 0.5 to 0.6
* `Path<T>` extractor return `ErrorNotFound` on failure instead of `ErrorBadRequest`
* `ws::Message::Close` now includes optional close reason.
`ws::CloseCode::Status` and `ws::CloseCode::Empty` have been removed.
* `HttpServer::threads()` renamed to `HttpServer::workers()`.
* `HttpServer::start_ssl()` and `HttpServer::start_tls()` deprecated.
Use `HttpServer::bind_ssl()` and `HttpServer::bind_tls()` instead.
* `HttpRequest::extensions()` returns read only reference to the request's Extension
`HttpRequest::extensions_mut()` returns mutable reference.
* Instead of
`use actix_web::middleware::{
CookieSessionBackend, CookieSessionError, RequestSession,
Session, SessionBackend, SessionImpl, SessionStorage};`
use `actix_web::middleware::session`
`use actix_web::middleware::session{CookieSessionBackend, CookieSessionError,
RequestSession, Session, SessionBackend, SessionImpl, SessionStorage};`
* `FromRequest::from_request()` accepts mutable reference to a request
* `FromRequest::Result` has to implement `Into<Reply<Self>>`
* [`Responder::respond_to()`](
https://actix.rs/actix-web/actix_web/trait.Responder.html#tymethod.respond_to)
is generic over `S`
* Use `Query` extractor instead of HttpRequest::query()`.
```rust
fn index(q: Query<HashMap<String, String>>) -> Result<..> {
...
}
```
or
```rust
let q = Query::<HashMap<String, String>>::extract(req);
```
* Websocket operations are implemented as `WsWriter` trait.
you need to use `use actix_web::ws::WsWriter`
## Migration from 0.4 to 0.5
* `HttpResponseBuilder::body()`, `.finish()`, `.json()`
methods return `HttpResponse` instead of `Result<HttpResponse>`
* `actix_web::Method`, `actix_web::StatusCode`, `actix_web::Version`
moved to `actix_web::http` module
* `actix_web::header` moved to `actix_web::http::header`
* `NormalizePath` moved to `actix_web::http` module
* `HttpServer` moved to `actix_web::server`, added new `actix_web::server::new()` function,
shortcut for `actix_web::server::HttpServer::new()`
* `DefaultHeaders` middleware does not use separate builder, all builder methods moved to type itself
* `StaticFiles::new()`'s show_index parameter removed, use `show_files_listing()` method instead.
* `CookieSessionBackendBuilder` removed, all methods moved to `CookieSessionBackend` type
* `actix_web::httpcodes` module is deprecated, `HttpResponse::Ok()`, `HttpResponse::Found()` and other `HttpResponse::XXX()`
functions should be used instead
* `ClientRequestBuilder::body()` returns `Result<_, actix_web::Error>`
instead of `Result<_, http::Error>`
* `Application` renamed to a `App`
* `actix_web::Reply`, `actix_web::Resource` moved to `actix_web::dev`