A library to turn an unreliable remote source of Ethereum blocks into a reliable stream of blocks. Handles block and log removals on chain reorganization and block and log backfills on skipped blocks.
Requirements for supported Ethereum node
Blockstream requires support for EIP-234 in the configured Ethereum node. EIP-234 was merged Jul 28, 2018 and implemented in Geth and Parity shortly after. Versions that provide the needed functionality:
- Parity: v2.1.0+
- geth: v1.8.13+
Usage
Full Example
// blockRetention is how many blocks of history to keep in memory. it defaults to 100 if not supplied;;;;;;;blockAndLogStreamer.reconcileNewBlockgetLatestBlock;// you will get a callback for the block and any logs that match the filter heretriggerBlockMining;triggerBlockMining;triggerBlockMining;blockAndLogStreamer.reconcileNewBlockgetLatestBlock;// you will get a callback for all blocks and logs that match the filter that have been added to the chain since the previous call to reconcileNewBlocktriggerChainReorg;blockAndLogStreamer.reconcileNewBlockgetLatestBlock;// you will get a callback for block/log removals that occurred due to the chain re-org, followed by block/log additionsblockAndLogStreamer.unsubscribeFromOnBlockAddedonBlockAddedSubscriptionToken;blockAndLogStreamer.unsubscribeFromOnBlockRemovedonBlockRemovedSubscriptionToken;blockAndLogStreamer.unsubscribeFromOnLogAddedonLogAddedSubscriptionToken;blockAndLogStreamer.unsubscribeFromOnLogRemovedonLogRemovedSubscriptionToken;blockAndLogStreamer.removeLogFilterlogFilterToken;console.logblockAndLogStreamer.getLatestReconciledBlock;
Signatures
Note: if you have a TypeScript aware editor this will all be available in the tooltip
- Filter/FilterOptions - More details at Parity JSON-RPC Wiki
- Block - More details at Parity JSON-RPC Wiki
- Log - More details at Parity JSON-RPC Wiki
Development
Build
docker build -t blockstream .
or
npm run build
Test
docker run blockstream
or
npm run test