Attribute Macro constructor

#[constructor]

Mark a function (or method) as a constructor.

Pavex will use the annotated function whenever it needs to create a new instance of its output type.

Imports

The annotated function must be imported via Blueprint::import, otherwise it won’t be considered by Pavex.

Guide

Check out the “Dependency injection” section of Pavex’s guide for a thorough introduction to dependency injection in Pavex applications.

Example

use pavex::constructor;

pub struct MyType {
    // [...]
}

impl MyType {
    #[constructor(request_scoped)]
    pub fn new() -> Self {
        Self {
            // [...]
        }
    }
}

MyType::new will be called whenever a new instance of MyType is needed.

Shortcuts

#[constructor] requires you to specify the lifetime of the instance it creates (i.e. request_scoped in the example above). If you prefer a more concise syntax, you can use the lifetime-specific shortcuts:

use pavex::request_scoped;

pub struct MyType {
    // [...]
}

impl MyType {
    // Equivalent to #[constructor(request_scoped)]
    #[request_scoped]
    pub fn new() -> Self {
        Self {
            // [...]
        }
    }
}

#[request_scoped] is equivalent to #[constructor(request_scoped)].
#[singleton] is equivalent to #[constructor(singleton)].
#[transient] is equivalent to #[constructor(transient)].