Struct rocket::http::CookieJar

pub struct CookieJar<'a> { /* private fields */ }

Collection of one or more HTTP cookies.

CookieJar allows for retrieval of cookies from an incoming request. It also tracks modifications (additions and removals) and marks them as pending.

Pending

Changes to a CookieJar are not visible via the normal get() and get_private() methods. This is typically the desired effect as a CookieJar always reflects the cookies in an incoming request. In cases where this is not desired, the get_pending() method is available, which always returns the latest changes.

use rocket::http::{CookieJar, Cookie};

#[get("/message")]
fn message(jar: &CookieJar<'_>) {
    jar.add(("message", "hello!"));
    jar.add(Cookie::build(("session", "bye!")).expires(None));

    // `get()` does not reflect changes.
    assert!(jar.get("session").is_none());
    assert_eq!(jar.get("message").map(|c| c.value()), Some("hi"));

    // `get_pending()` does.
    let session_pending = jar.get_pending("session");
    let message_pending = jar.get_pending("message");
    assert_eq!(session_pending.as_ref().map(|c| c.value()), Some("bye!"));
    assert_eq!(message_pending.as_ref().map(|c| c.value()), Some("hello!"));
}

Usage

A type of &CookieJar can be retrieved via its FromRequest implementation as a request guard or via the Request::cookies() method. Individual cookies can be retrieved via the get() and get_private() methods. Pending changes can be observed via the get_pending() method. Cookies can be added or removed via the add(), add_private(), remove(), and remove_private() methods.

Examples

The following example shows &CookieJar being used as a request guard in a handler to retrieve the value of a “message” cookie.

use rocket::http::CookieJar;

#[get("/message")]
fn message<'a>(jar: &'a CookieJar<'_>) -> Option<&'a str> {
    jar.get("message").map(|cookie| cookie.value())
}

The following snippet shows &CookieJar being retrieved from a Request in a custom request guard implementation for User. A private cookie containing a user’s ID is retrieved. If the cookie exists and the ID parses as an integer, a User structure is validated. Otherwise, the guard forwards.

use rocket::http::Status;
use rocket::request::{self, Request, FromRequest};
use rocket::outcome::IntoOutcome;

// In practice, we'd probably fetch the user from the database.
struct User(usize);

#[rocket::async_trait]
impl<'r> FromRequest<'r> for User {
    type Error = std::convert::Infallible;

    async fn from_request(request: &'r Request<'_>) -> request::Outcome<Self, Self::Error> {
        request.cookies()
            .get_private("user_id")
            .and_then(|c| c.value().parse().ok())
            .map(|id| User(id))
            .or_forward(Status::Unauthorized)
    }
}

Private Cookies

Private cookies are just like regular cookies except that they are encrypted using authenticated encryption, a form of encryption which simultaneously provides confidentiality, integrity, and authenticity. This means that private cookies cannot be inspected, tampered with, or manufactured by clients. If you prefer, you can think of private cookies as being signed and encrypted.

Private cookies can be retrieved, added, and removed from a CookieJar collection via the get_private(), add_private(), and remove_private() methods.

Encryption Key

To encrypt private cookies, Rocket uses the 256-bit key specified in the secret_key configuration parameter. If one is not specified, Rocket will automatically generate a fresh key. Note, however, that a private cookie can only be decrypted with the same key with which it was encrypted. As such, it is important to set a secret_key configuration parameter when using private cookies so that cookies decrypt properly after an application restart. Rocket will emit a warning if an application is run in production mode without a configured secret_key.

Generating a string suitable for use as a secret_key configuration value is usually done through tools like openssl. Using openssl, for instance, a 256-bit base64 key can be generated with the command openssl rand -base64 32.

Implementations

impl<'a> CookieJar<'a>

pub fn get(&self, name: &str) -> Option<&Cookie<'static>>

Returns a reference to the original Cookie inside this container with the name name. If no such cookie exists, returns None.

Note: This method does not observe changes made via additions and removals to the cookie jar. To observe those changes, use CookieJar::get_pending().

Example

use rocket::http::CookieJar;

#[get("/")]
fn handler(jar: &CookieJar<'_>) {
    let cookie = jar.get("name");
}

pub fn get_private(&self, name: &str) -> Option<Cookie<'static>>

Available on crate feature secrets only.

Retrieves the original Cookie inside this collection with the name name and authenticates and decrypts the cookie’s value. If the cookie cannot be found, or the cookie fails to authenticate or decrypt, None is returned.

Note: This method does not observe changes made via additions and removals to the cookie jar. To observe those changes, use CookieJar::get_pending().

Example

use rocket::http::CookieJar;

#[get("/")]
fn handler(jar: &CookieJar<'_>) {
    let cookie = jar.get_private("name");
}

pub fn get_pending(&self, name: &str) -> Option<Cookie<'static>>

Returns a reference to the original or pending Cookie inside this container with the name name, irrespective of whether the cookie was private or not. If no such cookie exists, returns None.

In general, due to performance overhead, calling this method should be avoided if it is known that a cookie called name is not pending. Instead, prefer to use CookieJar::get() or CookieJar::get_private().

Example

use rocket::http::CookieJar;

#[get("/")]
fn handler(jar: &CookieJar<'_>) {
    let pending_cookie = jar.get_pending("name");
}

pub fn add<C: Into<Cookie<'static>>>(&self, cookie: C)

Adds cookie to this collection.

Unless a value is set for the given property, the following defaults are set on cookie before being added to self:

• path: "/"
• SameSite: Strict

Furthermore, if TLS is enabled, the Secure cookie flag is set.

Example

use rocket::http::{Cookie, SameSite, CookieJar};

#[get("/")]
fn handler(jar: &CookieJar<'_>) {
    jar.add(("first", "value"));

    let cookie = Cookie::build(("other", "value_two"))
        .path("/")
        .secure(true)
        .same_site(SameSite::Lax);

    jar.add(cookie);
}

pub fn add_private<C: Into<Cookie<'static>>>(&self, cookie: C)

Available on crate feature secrets only.

Adds cookie to the collection. The cookie’s value is encrypted with authenticated encryption assuring confidentiality, integrity, and authenticity. The cookie can later be retrieved using get_private and removed using remove_private.

Unless a value is set for the given property, the following defaults are set on cookie before being added to self:

• path: "/"
• SameSite: Strict
• HttpOnly: true
• Expires: 1 week from now

Furthermore, if TLS is enabled, the Secure cookie flag is set. These defaults ensure maximum usability and security. For additional security, you may wish to set the secure flag.

Example

use rocket::http::CookieJar;

#[get("/")]
fn handler(jar: &CookieJar<'_>) {
    jar.add_private(("name", "value"));
}

pub fn remove<C: Into<Cookie<'static>>>(&self, cookie: C)

Removes cookie from this collection and generates a “removal” cookie to send to the client on response. A “removal” cookie is a cookie that has the same name as the original cookie but has an empty value, a max-age of 0, and an expiration date far in the past.

For successful removal, cookie must contain the same path and domain as the cookie that was originally set. The cookie will fail to be deleted if any other path and domain are provided. For convenience, a path of "/" is automatically set when one is not specified. The full list of defaults when corresponding values aren’t specified is:

• path: "/"
• SameSite: Lax

Note: a default setting of Lax for SameSite carries no security implications: the removal cookie has expired, so it is never transferred to any origin.

Example

use rocket::http::{Cookie, CookieJar};

#[get("/")]
fn handler(jar: &CookieJar<'_>) {
    // `path` and `SameSite` are set to defaults (`/` and `Lax`)
    jar.remove("name");

    // Use a custom-built cookie to set a custom path.
    jar.remove(Cookie::build("name").path("/login"));

    // Use a custom-built cookie to set a custom path and domain.
    jar.remove(Cookie::build("id").path("/guide").domain("rocket.rs"));
}

pub fn remove_private<C: Into<Cookie<'static>>>(&self, cookie: C)

Available on crate feature secrets only.

Removes the private cookie from the collection.

For successful removal, cookie must contain the same path and domain as the cookie that was originally set. The cookie will fail to be deleted if any other path and domain are provided. For convenience, a path of "/" is automatically set when one is not specified. The full list of defaults when corresponding values aren’t specified is:

• path: "/"
• SameSite: Lax

Note: a default setting of Lax for SameSite carries no security implications: the removal cookie has expired, so it is never transferred to any origin.

Example

use rocket::http::{CookieJar, Cookie};

#[get("/")]
fn handler(jar: &CookieJar<'_>) {
    // `path` and `SameSite` are set to defaults (`/` and `Lax`)
    jar.remove_private("name");

    // Use a custom-built cookie to set a custom path.
    jar.remove_private(Cookie::build("name").path("/login"));

    // Use a custom-built cookie to set a custom path and domain.
    let cookie = Cookie::build("id").path("/guide").domain("rocket.rs");
    jar.remove_private(cookie);
}

pub fn iter(&self) -> impl Iterator<Item = &Cookie<'static>>

Returns an iterator over all of the original cookies present in this collection.

Note: This method does not observe changes made via additions and removals to the cookie jar.

Example

use rocket::http::CookieJar;

#[get("/")]
fn handler(jar: &CookieJar<'_>) {
    for c in jar.iter() {
        println!("Name: {:?}, Value: {:?}", c.name(), c.value());
    }
}

Trait Implementations

impl<'a> Clone for CookieJar<'a>

fn clone(&self) -> Self

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for CookieJar<'_>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'r> FromRequest<'r> for &'r CookieJar<'r>

type Error = Infallible

The associated error to be returned if derivation fails.

fn from_request<'life0, 'async_trait>( request: &'r Request<'life0> ) -> Pin<Box<dyn Future<Output = Outcome<Self, Infallible>> + Send + 'async_trait>>

where Self: 'async_trait, 'r: 'async_trait, 'life0: 'async_trait,

Derives an instance of Self from the incoming request metadata.