Repository: actix/actix-web
File: actix-http/src/cookie/secure/private.rs (Rust)

Code before:
            key: key_array,
        }
    }

    /// Given a sealed value `str` and a key name `name`, where the nonce is
    /// prepended to the original value and then both are Base64 encoded,
    /// verifies and decrypts the sealed value and returns it. If there's a
    /// problem, returns an `Err` with a string describing the issue.
    fn unseal(&self, name: &str, value: &str) -> Result<String, &'static str> {
        let mut data = base64::decode(value).map_err(|_| "bad base64 value")?;
        if data.len() <= NONCE_LEN {
            return Err("length of decoded data is <= NONCE_LEN");
        }

        let ad = Aad::from(name.as_bytes());
        let key = OpeningKey::new(ALGO, &self.key).expect("opening key");
        let (nonce, sealed) = data.split_at_mut(NONCE_LEN);
        let nonce =
            Nonce::try_assume_unique_for_key(nonce).expect("invalid length of `nonce`");
        let unsealed = open_in_place(&key, nonce, ad, 0, sealed)
            .map_err(|_| "invalid key/nonce/value: bad seal")?;

        if let Ok(unsealed_utf8) = str::from_utf8(unsealed) {
            Ok(unsealed_utf8.to_string())
        } else {
            error!("Private cookie does not have utf8 content!
It is likely the secret key used to encrypt them has been leaked.
Please change it as soon as possible.");
            Err("bad unsealed utf8")
        }
    }

    /// Returns a reference to the `Cookie` inside this jar with the name `name`
    /// and authenticates and decrypts the cookie's value, returning a `Cookie`
    /// with the decrypted value. If the cookie cannot be found, or the cookie
    /// fails to authenticate or decrypt, `None` is returned.
    ///
    /// # Example
    ///
    /// ```rust
    /// use actix_http::cookie::{CookieJar, Cookie, Key};
    ///
    /// let key = Key::generate();
    /// let mut jar = CookieJar::new();
    /// let mut private_jar = jar.private(&key);
    /// assert!(private_jar.get("name").is_none());
    ///
    /// private_jar.add(Cookie::new("name", "value"));
    /// assert_eq!(private_jar.get("name").unwrap().value(), "value");
    /// ```
    pub fn get(&self, name: &str) -> Option<Cookie<'static>> {

Review comment (suggestion):
Looks good, but I think it should be a `warn` macro rather than error.
It doesn't per se would indicate immediate error, but more or less a warning as original issue asks

Code after:
            key: key_array,
        }
    }

    /// Given a sealed value `str` and a key name `name`, where the nonce is
    /// prepended to the original value and then both are Base64 encoded,
    /// verifies and decrypts the sealed value and returns it. If there's a
    /// problem, returns an `Err` with a string describing the issue.
    fn unseal(&self, name: &str, value: &str) -> Result<String, &'static str> {
        let mut data = base64::decode(value).map_err(|_| "bad base64 value")?;
        if data.len() <= NONCE_LEN {
            return Err("length of decoded data is <= NONCE_LEN");
        }

        let ad = Aad::from(name.as_bytes());
        let key = OpeningKey::new(ALGO, &self.key).expect("opening key");
        let (nonce, sealed) = data.split_at_mut(NONCE_LEN);
        let nonce =
            Nonce::try_assume_unique_for_key(nonce).expect("invalid length of `nonce`");
        let unsealed = open_in_place(&key, nonce, ad, 0, sealed)
            .map_err(|_| "invalid key/nonce/value: bad seal")?;

        if let Ok(unsealed_utf8) = str::from_utf8(unsealed) {
            Ok(unsealed_utf8.to_string())
        } else {
            warn!("Private cookie does not have utf8 content!
It is likely the secret key used to encrypt them has been leaked.
Please change it as soon as possible.");
            Err("bad unsealed utf8")
        }
    }

    /// Returns a reference to the `Cookie` inside this jar with the name `name`
    /// and authenticates and decrypts the cookie's value, returning a `Cookie`
    /// with the decrypted value. If the cookie cannot be found, or the cookie
    /// fails to authenticate or decrypt, `None` is returned.
    ///
    /// # Example
    ///
    /// ```rust
    /// use actix_http::cookie::{CookieJar, Cookie, Key};
    ///
    /// let key = Key::generate();
    /// let mut jar = CookieJar::new();
    /// let mut private_jar = jar.private(&key);
    /// assert!(private_jar.get("name").is_none());
    ///
    /// private_jar.add(Cookie::new("name", "value"));
    /// assert_eq!(private_jar.get("name").unwrap().value(), "value");
    /// ```
    pub fn get(&self, name: &str) -> Option<Cookie<'static>> {