SIP-0004: Update Host Price Table RPC

Update Host Price Table RPC

Description

When the renter and the host form a session, the host will build his pricing table. This price table contains a list of RPCs the host offers alongside with their price. This SIP will introduce a new RPC call on the host to request an updated price table.

Motivation

When the host communicates his price table, he will also set a block height at which the prices expire and are no longer valid. Due to this TTL, the renter will have to make sure that if he wants to transact with the host, he has updated pricing information. This price table update has to be in the form of a request to the host, seeing as the RPC to trigger the update is in and of itself an RPC that requires payment. This is inevitable as otherwise the host would be susceptible to DoS attacks.

Note that the renter will usually update this price table relatively frequent. He does not want to wait just up until the expiry block height as the host will not except any RPCs as long as the price table has not been updated. The renter will not want to encounter the host denying all RPC requests mid-download because of outdated pricing.