Accrue.Webhook.CachingBodyReader (accrue v0.3.1)

Custom body reader for Plug.Parsers that tees the raw body into conn.assigns[:raw_body] for webhook signature verification.

Only used inside the :accrue_webhook_raw_body pipeline (D2-20) -- never globally. This ensures that non-webhook routes are unaffected by raw-body capture (WH-01).

Usage

pipeline :accrue_webhook_raw_body do
  plug Plug.Parsers,
    parsers: [:json],
    pass: ["*/*"],
    json_decoder: Jason,
    body_reader: {Accrue.Webhook.CachingBodyReader, :read_body, []},
    length: 1_000_000
end

Implementation

Chunks are prepended (O(1) cons) during streaming reads and reversed at flatten time in the consuming plug. This avoids quadratic binary concatenation when the body arrives in multiple chunks.

Summary

Functions

read_body(conn, opts)

Reads the request body and tees it into conn.assigns[:raw_body].

Functions

read_body(conn, opts)

@spec read_body(
  Plug.Conn.t(),
  keyword()
) ::
  {:ok, binary(), Plug.Conn.t()}
  | {:more, binary(), Plug.Conn.t()}
  | {:error, term()}

Reads the request body and tees it into conn.assigns[:raw_body].

Returns {:ok, body, conn}, {:more, body, conn}, or {:error, reason} matching the Plug.Conn.read_body/2 contract expected by Plug.Parsers.