Crate der_derive

Custom derive support for the der crate.

This crate contains custom derive macros intended to be used in the following way:

• Decodable and Encodable: for representing ASN.1 CHOICE as a Rust enum
• Message: for representing ASN.1 SEQUENCE as a Rust struct

Note that this crate shouldn't be used directly, but instead accessed by using the derive feature of the der crate.

#[asn1(type = "...")] attribute

This attribute can be used to specify the ASN.1 type for a particular enum variant or struct field.

It's presently mandatory for all struct fields, even when using one of the ASN.1 types defined by this crate.

For structs, placing this attribute on a field makes it possible to decode/encode types which don't directly implement the Decode/Encode traits but do impl From and TryInto and From for one of the ASN.1 types listed below (use the ASN.1 type keywords as the type):

• BIT STRING: performs an intermediate conversion to der::BitString
• GeneralizedTime: performs an intermediate conversion to der::GeneralizedTime
• OCTET STRING: performs an intermediate conversion to der::OctetString
• PrintableString: performs an intermediate conversion to der::PrintableString
• UTCTime: performs an intermediate conversion to der::UtcTime
• UTF8String: performs an intermediate conversion to der::Utf8String

Example:

// NOTE: requires the `derive` feature of `der`
use der::{Decodable, Encodable};

/// `Time` as defined in RFC 5280
#[derive(Decodable, Encodable)]
pub enum Time {
    #[asn1(type = "UTCTime")]
    UtcTime(UtcTime),

    #[asn1(type = "GeneralizedTime")]
    GeneralTime(GeneralizedTime),
}

Note: please open a GitHub Issue if you would like to request support for additional ASN.1 types.

Derive Macros

Decodable	Derive the Decodable trait on an enum.
Encodable	Derive the Encodable trait on an enum.
Message	Derive the Message trait on a struct.