English

Español

English

Español

Appearance

The ApplicationBuilder struct ​

Sword uses a Builder pattern to construct web applications. This pattern is implemented in the ApplicationBuilder struct, which allows you to configure various aspects of your application in a fluid way before finally building the Application instance.

Application Construction ​

The construction flow is straightforward: you call Application::builder() to get an ApplicationBuilder, configure your application components by chaining methods, and finally call .build() to obtain the final Application instance:

rust
let app = Application::builder()
    .with_module::<SomeModule>()
    .build();

How does the Builder pattern work? ​

Application::builder(): Creates a new ApplicationBuilder that initializes:

  • The application's internal runtime.
  • The shared application state.
  • Configuration loading from the .toml file.

Key Methods and Attributes ​

The struct has key fields and methods that allow you to customize your application:

config Attribute ​

A public attribute that allows access to the application configuration loaded from the configuration file.

with_module::<M>() Method ​

A method that registers a module implementing the Module trait. Modules define entry points to group related controllers, components, and providers.

Parameters ​
  • M: A type that implements the Module trait.

Learn more about modules in the Modules section.

with_layer::<L>(layer: L) Method ​

Registers a Tower Layer globally in the application.

Parameters ​
  • layer: An instance that implements the Layer trait.
Example ​
rust
use tower_http::cors::*;

let cors_layer = CorsLayer::new()
    .allow_origin(Any)
    .allow_methods(vec!["GET", "POST"]);

let app = Application::builder()
    .with_layer(cors_layer)
    .build();

For more details on Tower, check the Tower Layers section.

from_config_path<P: AsRef<Path>>(path: P) Method ​

Allows loading the application configuration from a .toml file located at a custom path.

from_config(config: Config) Method ​

Allows loading the application configuration from a manually created Config instance.

build() Method ​

Finalizes the ApplicationBuilder construction and returns an Application instance ready to be executed.