Layr8.Attachment (layr8 v0.2.5)

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A DIDComm v2 attachment.

Attachments carry payloads that travel alongside a message but are not part of the message body — signed credentials, large binaries, file references, etc.

Fields

  • id — unique attachment identifier (within the containing message)
  • description — human-readable description
  • filename — suggested filename for downloaded content
  • media_type — IANA media type of the content (e.g. application/jwt)
  • format — protocol-specific format identifier (e.g. application/vc+jwt)
  • lastmod_time — last modification time as a Unix timestamp (integer)
  • byte_count — size of the attached content in bytes
  • data — map carrying the payload; see DIDComm v2 spec §5

data map

The data map may contain one or more of:

  • "base64" — base64url-encoded bytes (no padding)
  • "json" — inline JSON value
  • "jws" — a JSON-serialized JWS (object, not a compact string)
  • "hash" — base64url-encoded SHA-256 of the referenced content
  • "links" — list of URLs pointing to the content

For signed credentials sent as compact JWT strings, use data.base64:

Base.url_encode64(compact_jwt, padding: false)

placed under the "base64" key.

Wire format

%{
  "id" => "...",
  "format" => "...",
  "media_type" => "...",
  "data" => %{"base64" => "..."}
}

Optional fields are omitted when empty/nil.

Summary

Types

data_map()
t()

Functions

marshal(att)

Serializes an Attachment into a DIDComm v2 JSON envelope map.

parse(map)

Parses a DIDComm v2 attachment map into an Attachment struct.

Types

data_map()

@type data_map() :: %{optional(String.t()) => term()}

t()

@type t() :: %Layr8.Attachment{
  byte_count: non_neg_integer() | nil,
  data: data_map(),
  description: String.t(),
  filename: String.t(),
  format: String.t(),
  id: String.t(),
  lastmod_time: non_neg_integer() | nil,
  media_type: String.t()
}

Functions

marshal(att)

@spec marshal(t()) :: map()

Serializes an Attachment into a DIDComm v2 JSON envelope map.

Optional string fields are omitted when empty; optional numeric fields are omitted when nil. data is always included (defaults to %{}).

parse(map)

@spec parse(map()) :: t()

Parses a DIDComm v2 attachment map into an Attachment struct.

Missing fields default to empty strings / nil / %{}.