Migrating to 3.0.0

The return type for ServiceRequest::app_data::<T>() was changed from returning a Data<T> to simply a T. To access a Data<T> use ServiceRequest::app_data::<Data<T>>().
Cookie handling has been offloaded to the cookie crate:
- USERINFO_ENCODE_SET is no longer exposed. Percent-encoding is still supported; check docs.
- Some types now require lifetime parameters.
The time crate was updated to v0.2, a major breaking change to the time crate, which affects any actix-web method previously expecting a time v0.1 input.
Setting a cookie's SameSite property, explicitly, to SameSite::None will now result in SameSite=None being sent with the response Set-Cookie header. To create a cookie without a SameSite attribute, remove any calls setting same_site.
actix-http support for Actors messages was moved to actix-http crate and is enabled with feature actors
content_length function is removed from actix-http. You can set Content-Length by normally setting the response body or calling no_chunking function.
BodySize::Sized64 variant has been removed. BodySize::Sized now receives a u64 instead of a usize.

Code that was using path.<index> to access a web::Path<(A, B, C)>s elements now needs to use destructuring or .into_inner(). For example:

rust

// Previously:
async fn some_route(path: web::Path<(String, String)>) -> String {
  format!("Hello, {} {}", path.0, path.1)
}

// Now (this also worked before):
async fn some_route(path: web::Path<(String, String)>) -> String {
  let (first_name, last_name) = path.into_inner();
  format!("Hello, {} {}", first_name, last_name)
}
// Or (this wasn't previously supported):
async fn some_route(web::Path((first_name, last_name)): web::Path<(String, String)>) -> String {
  format!("Hello, {} {}", first_name, last_name)
}

middleware::NormalizePath can now also be configured to trim trailing slashes instead of always keeping one. It will need middleware::normalize::TrailingSlash when being constructed with NormalizePath::new(...), or for an easier migration you can replace wrap(middleware::NormalizePath) with wrap(middleware::NormalizePath::new(TrailingSlash::MergeOnly)).
HttpServer::maxconn is renamed to the more expressive HttpServer::max_connections.
HttpServer::maxconnrate is renamed to the more expressive HttpServer::max_connection_rate.