@spec decode(String.t()) :: {:ok, map()} | {:error, decode_error()}

Decodes a Base64 PAYMENT-REQUIRED value to a map.

Returns {:error, :payload_too_large} when the encoded value exceeds 8 KB. Returns {:error, :invalid_base64} when the value cannot be Base64-decoded. Returns {:error, :invalid_json} when JSON cannot be decoded to a map.

Examples

iex> {:ok, encoded} = X402.PaymentRequired.encode(%{"x402Version" => 2, "accepts" => []})
iex> X402.PaymentRequired.decode(encoded)
{:ok, %{"accepts" => [], "x402Version" => 2}}

iex> X402.PaymentRequired.decode("%%%")
{:error, :invalid_base64}

@spec encode(map()) :: {:ok, String.t()} | {:error, encode_error()}

Encodes a payment requirement payload to a Base64 header value.

Examples

iex> payload = %{"x402Version" => 2, "resource" => %{"url" => "https://example.com/data"}, "accepts" => [], "extensions" => %{}}
iex> {:ok, value} = X402.PaymentRequired.encode(payload)
iex> {:ok, decoded} = X402.PaymentRequired.decode(value)
iex> decoded["x402Version"]
2

iex> X402.PaymentRequired.encode(nil)
{:error, :invalid_payload}

@spec header_name() :: String.t()

Returns the canonical x402 header name.

Examples

iex> X402.PaymentRequired.header_name()
"PAYMENT-REQUIRED"