Cannot set expire in private cookie Rocket-Rust - cookies

Question

I'm trying to setting expire in private Cookie in Rust (Rocket Framework version 0.5.0-rc.1) using rocket::http::Cookie.
In rocket add_private doc I read:
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
I don't understand how to set the Expires property.
I tried to create a new cookie and setting expire using .set_expires() (as in doc example), but it gives me the error: "the trait From<OffsetDateTime> is not implemented for std::option::Option<time::offset_date_time::OffsetDateTime>". The code that return the error is something like (values here only for test purpose):
use rocket::http::{Cookie, CookieJar};
use cookie::time::{Duration, OffsetDateTime};
fn handler(jar: &CookieJar<'_>) {
let mut cookie = Cookie::new("name", "value");
let mut now = OffsetDateTime::now_utc();
now += Duration::days(1);
cookie.set_expires(now);
jar.add_private(cookie);
}
I wonder if I have to use cookie crate instead of rocket::http to create the cookie, but in that case I cannot use CookieJar in the response handler because it expected a rocket::http::Cookie and not a cookie::Cookie.
Is there any other way to set an expire or a max age in private cookie using Rocket http module?

Answer 1

I encountered this same problem and I think I've figured it out:
Rocket uses both the cookie and time packages internally
The example code in the Rocket docs for rocket::http::Cookie actually comes from the cookie package and therefor confusingly uses use cookies::Cookie; instead of use rocket::http::Cookie.
Key thing: The docs at https://api.rocket.rs/v0.5-rc/ appear to be newer that the code that's in crates.io, and use different versions of the cookie and time crates.
So you need to use the same version or cookie or time that Rocket is using. If you're using rocket 0.5.0-rc.1 from crates.io then you need cookie 0.15 or time 0.2.11.
I was able to get my code working with these lines in my Cargo.toml:
rocket = { version = "0.5.0-rc.1", features = ["secrets", "json"] }
time = "0.2.11"
Your example code would then become:
use rocket::http::{Cookie, CookieJar};
use time::{Duration, OffsetDateTime};
fn handler(jar: &CookieJar<'_>) {
let mut cookie = Cookie::new("name", "value");
let mut now = OffsetDateTime::now_utc();
now += Duration::days(1);
cookie.set_expires(now);
jar.add_private(cookie);
}
Alternatively, I think if you use version 0.15 of cookie (you might be using 0.16.0-rc.1) then your code should work as you have it. I think it's cleaner to import Duration and OffsetTime directly from the time package though.
It looks like the latest version of Rocket in Github exposes time as rocket::time so we should be able to switch to that when final 0.5 release comes out.