
Security News
Deno 2.4 Brings Back deno bundle, Improves Dependency Management and Observability
Deno 2.4 brings back bundling, improves dependency updates and telemetry, and makes the runtime more practical for real-world JavaScript projects.
ethereumjs-blockstream
Advanced tools
A library to turn an unreliable remote source of Ethereum blocks into a reliable stream of blocks with removals on re-orgs and backfills on skips.
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.
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:
// blockRetention is how many blocks of history to keep in memory. it defaults to 100 if not supplied
const configuration = { blockRetention: 100 };
async function getBlockByHash(hash: string): Promise<Block|null> {
const response = await fetch("http://localhost:8545", {
method: "POST",
headers: new Headers({"Content-Type": "application/json"}),
body: { jsonrpc: "2.0", id: 1, method: "eth_getBlockByHash", params: [hash, false] }
});
return await response.json();
}
async function getLogs(filterOptions: FilterOptions): Promise<Log[]> {
const response = await fetch("http://localhost:8545", {
method: "POST",
headers: new Headers({"Content-Type": "application/json"}),
body: { jsonrpc: "2.0", id: 1, method: "eth_getLogs", params: [filterOptions] }
});
return await response.json();
}
async function getLatestBlock(): Promise<Block> {
const response = await fetch("http://localhost:8545", {
method: "POST",
headers: new Headers({"Content-Type": "application/json"}),
body: { jsonrpc: "2.0", id: 1, method: "eth_getBlockByNumber", params: ["latest", false] }
});
return await response.json();
}
const blockAndLogStreamer = new BlockAndLogStreamer(getBlockByHash, getLogs, configuration);
const onBlockAddedSubscriptionToken = blockAndLogStreamer.subscribeToOnBlockAdded(block => console.log(block));
const onLogAddedSubscriptionToken = blockAndLogStreamer.subscribeToOnLogAdded(log => console.log(log));
const onBlockRemovedSubscriptionToken = blockAndLogStreamer.subscribeToOnBlockRemoved(block => console.log(block));
const onLogRemovedSubscriptionToken = blockAndLogStreamer.subscribeToOnLogRemoved(log => console.log(log));
const logFilterToken = blockAndLogStreamer.addLogFilter({address: "0xdeadbeefdeadbeefdeadbeefdeadbeefdeadbeef", topics: ["0xbadf00dbadf00dbadf00dbadf00dbadf00dbadf00dbadf00dbadf00dbaadf00d"]});
blockAndLogStreamer.reconcileNewBlock(getLatestBlock());
// you will get a callback for the block and any logs that match the filter here
triggerBlockMining();
triggerBlockMining();
triggerBlockMining();
blockAndLogStreamer.reconcileNewBlock(getLatestBlock());
// 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 reconcileNewBlock
triggerChainReorg();
blockAndLogStreamer.reconcileNewBlock(getLatestBlock());
// you will get a callback for block/log removals that occurred due to the chain re-org, followed by block/log additions
blockAndLogStreamer.unsubscribeFromOnBlockAdded(onBlockAddedSubscriptionToken);
blockAndLogStreamer.unsubscribeFromOnBlockRemoved(onBlockRemovedSubscriptionToken);
blockAndLogStreamer.unsubscribeFromOnLogAdded(onLogAddedSubscriptionToken);
blockAndLogStreamer.unsubscribeFromOnLogRemoved(onLogRemovedSubscriptionToken);
blockAndLogStreamer.removeLogFilter(logFilterToken);
console.log(blockAndLogStreamer.getLatestReconciledBlock());
Note: if you have a TypeScript aware editor this will all be available in the tooltip
docker build -t blockstream .
or
npm run build
docker run blockstream
or
npm run test
FAQs
A library to turn an unreliable remote source of Ethereum blocks into a reliable stream of blocks with removals on re-orgs and backfills on skips.
The npm package ethereumjs-blockstream receives a total of 1,209 weekly downloads. As such, ethereumjs-blockstream popularity was classified as popular.
We found that ethereumjs-blockstream demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 7 open source maintainers collaborating on the project.
Did you know?
Socket for GitHub automatically highlights issues in each pull request and monitors the health of all your open source dependencies. Discover the contents of your packages and block harmful activity before you install or update your dependencies.
Security News
Deno 2.4 brings back bundling, improves dependency updates and telemetry, and makes the runtime more practical for real-world JavaScript projects.
Security News
CVEForecast.org uses machine learning to project a record-breaking surge in vulnerability disclosures in 2025.
Security News
Browserslist-rs now uses static data to reduce binary size by over 1MB, improving memory use and performance for Rust-based frontend tools.