/** Fill in the fee on behalf of the client.
This is called when the client does not explicitly specify the fee.
The client may also put a ceiling on the amount of the fee. This ceiling
is expressed as a multiplier based on the current ledger's fee schedule.
JSON fields
"Fee" The fee paid by the transaction. Omitted when the client
wants the fee filled in.
"fee_mult_max" A multiplier applied to the current ledger's transaction
fee that caps the maximum the fee server should auto fill.
If this optional field is not specified, then a default
multiplier is used.
@param tx The JSON corresponding to the transaction to fill in
@param ledger A ledger for retrieving the current fee schedule
@param result A JSON object for injecting error results, if any
@param admin `true` if this is called by an administrative endpoint.
*/
static void autofill_fee (Json::Value& request,
Ledger::pointer ledger, Json::Value& result, bool admin)
{
Json::Value& tx (request["tx_json"]);
if (tx.isMember ("Fee"))
return;
int mult = DEFAULT_AUTO_FILL_FEE_MULTIPLIER;
if (request.isMember ("fee_mult_max"))
{
if (request["fee_mult_max"].isNumeric ())
{
mult = request["fee_mult_max"].asInt();
}
else
{
RPC::inject_error (rpcHIGH_FEE, RPC::expected_field_message (
"fee_mult_max", "a number"), result);
return;
}
}
std::uint64_t const feeDefault = getConfig().FEE_DEFAULT;
// Administrative endpoints are exempt from local fees
std::uint64_t const fee = ledger->scaleFeeLoad (feeDefault, admin);
std::uint64_t const limit = mult * feeDefault;
if (fee > limit)
{
std::stringstream ss;
ss <<
"Fee of " << fee <<
" exceeds the requested tx limit of " << limit;
RPC::inject_error (rpcHIGH_FEE, ss.str(), result);
return;
}
tx ["Fee"] = static_cast<int>(fee);
}
