rosetta-sia

This is an implementation of the Rosetta blockchain standard. Both the Data API and Construction API are supported.

The Data API consists of four services:

• The Block service provides block data, queryable by height or ID. Sia blocks must be converted to Rosetta blocks, which requires looking up the value of the SiacoinInputs in each transaction. Currently, the Sia Rosetta implementation does not handle Siafunds at all (although it will properly account for siacoins created from a SiafundClaimOutput). Support for Siafunds may be added in a later release.
• The Account service provides the current balance of any account. (In the Sia implementation, an "account" is an address/UnlockHash.) It also reports the UTXOs controlled by the account, which are called "Coins" in the Rosetta API. Importantly, "controlled" does not mean "spendable" -- timelocked UTXOs, such as miner rewards, are reported immediately, rather than at their maturity height.
• The Mempool service provides a view into the transaction pool, with Sia transactions converted to their Rosetta equivalents.
• The Network service reports various metadata, such as active peers, current block, and supported operation types.

The Construction API consists of a single service -- the Construction service -- which is by far the most complex. This service allows a client to construct transactions using the UTXO they control. The client submits a set of "intended operations" to the API, which turns them into an opaque, unsigned, Sia-encoded transaction, along with a set of payloads to sign. The client signs the payloads, and uses another Construction endpoint to add the signatures to the unsigned transaction. The resulting signed transaction can then be broadcast. The Construction API is intended to be run in an offline environment, so various metadata must be piped through the process. In Sia's case, this currently consists of the public key for each SiacoinInput.

The rosetta-sia implementation consists of a single type, RosettaService, which implements the interfaces for all of the above services. It subscribes to updates from Sia's modules.ConsensusSet so that it can store service-related data in its database. Most significantly, it stores the value of all UTXOs, and associates each address seen in the blockchain with the UTXOs it controls (as of the most recent block). It also stores the timelocked outputs created by miner payouts and file contracts. RosettaService does not store the blocks themselves; they are fetched (by ID) from modules.ConsensusSet, then converted to the Rosetta format, and finally augmented with the timelocked outputs.