Function sign_request 

pub fn sign_request(
    method: &str,
    url: &str,
    body: Option<&[u8]>,
    key_id: &str,
    key: &SigningKey<'_>,
    now: i64,
) -> Result<SignedHeaders, Error>

Sign an outgoing request.

Covers @method and @target-uri, plus content-digest when there is a body — the components Mastodon covers, so that a Mastodon peer verifies what it expects to. The algorithm follows from the key.

Arguments

• method – HTTP method; canonicalised to uppercase for @method
• url – full request URL, which becomes @target-uri
• body – request body, or None for a bodyless request
• key_id – keyid parameter, the URI identifying the key
• key – the private key to sign with
• now – the time, in seconds since the Unix epoch, which becomes created

Errors

Returns an error if the key cannot be parsed or the signature cannot be made.